[dpdk-dev] [PATCH v7 1/2] eal: add uevent monitor for hot plug

Guo, Jia jia.guo at intel.com
Mon Jan 8 06:26:37 CET 2018


thanks , matan


On 1/3/2018 1:02 AM, Matan Azrad wrote:
> Hi Jeff
>
> Maybe I'm touching in previous discussions but please see some comments\questions.
>
> From: Jeff Guo:
>> This patch aim to add a general uevent mechanism in eal device layer,
>> to enable all linux kernel object hot plug monitoring, so user could use these
>> APIs to monitor and read out the device status info that sent from the kernel
>> side, then corresponding to handle it, such as detach or attach the
>> device, and even benefit to use it to do smoothly fail safe work.
>>
>> 1) About uevent monitoring:
>> a: add one epolling to poll the netlink socket, to monitor the uevent of
>>     the device, add device_state in struct of rte_device, to identify the
>>     device state machine.
>> b: add enum of rte_eal_dev_event_type and struct of rte_eal_uevent.
>> c: add below API in rte eal device common layer.
>>     rte_eal_dev_monitor_enable
>>     rte_dev_callback_register
>>     rte_dev_callback_unregister
>>     _rte_dev_callback_process
>>     rte_dev_monitor_start
>>     rte_dev_monitor_stop
>>
>> 2) About failure handler, use pci uio for example,
>>     add pci_remap_device in bus layer and below function to process it:
>>     rte_pci_remap_device
>>     pci_uio_remap_resource
>>     pci_map_private_resource
>>     add rte_pci_dev_bind_driver to bind pci device with explicit driver.
>>
>> Signed-off-by: Jeff Guo <jia.guo at intel.com>
>> ---
>> v7->v6:
>> a.modify vdev part according to the vdev rework
>> b.re-define and split the func into common and bus specific code
>> c.fix some incorrect issue.
>> b.fix the system hung after send packcet issue.
>> ---
>>   drivers/bus/pci/bsd/pci.c                          |  30 ++
>>   drivers/bus/pci/linux/pci.c                        |  87 +++++
>>   drivers/bus/pci/linux/pci_init.h                   |   1 +
>>   drivers/bus/pci/pci_common.c                       |  43 +++
>>   drivers/bus/pci/pci_common_uio.c                   |  28 ++
>>   drivers/bus/pci/private.h                          |  12 +
>>   drivers/bus/pci/rte_bus_pci.h                      |  25 ++
>>   drivers/bus/vdev/vdev.c                            |  36 +++
>>   lib/librte_eal/bsdapp/eal/eal_dev.c                |  64 ++++
>>   .../bsdapp/eal/include/exec-env/rte_dev.h          | 106 ++++++
>>   lib/librte_eal/common/eal_common_bus.c             |  30 ++
>>   lib/librte_eal/common/eal_common_dev.c             | 169 ++++++++++
>>   lib/librte_eal/common/include/rte_bus.h            |  69 ++++
>>   lib/librte_eal/common/include/rte_dev.h            |  89 ++++++
>>   lib/librte_eal/linuxapp/eal/Makefile               |   3 +-
>>   lib/librte_eal/linuxapp/eal/eal_alarm.c            |   5 +
>>   lib/librte_eal/linuxapp/eal/eal_dev.c              | 356
>> +++++++++++++++++++++
>>   .../linuxapp/eal/include/exec-env/rte_dev.h        | 106 ++++++
>>   lib/librte_eal/linuxapp/igb_uio/igb_uio.c          |   6 +
>>   lib/librte_pci/rte_pci.c                           |  20 ++
>>   lib/librte_pci/rte_pci.h                           |  17 +
>>   21 files changed, 1301 insertions(+), 1 deletion(-)
>>   create mode 100644 lib/librte_eal/bsdapp/eal/eal_dev.c
>>   create mode 100644 lib/librte_eal/bsdapp/eal/include/exec-env/rte_dev.h
>>   create mode 100644 lib/librte_eal/linuxapp/eal/eal_dev.c
>>   create mode 100644 lib/librte_eal/linuxapp/eal/include/exec-env/rte_dev.h
>>
>> diff --git a/drivers/bus/pci/bsd/pci.c b/drivers/bus/pci/bsd/pci.c
>> index b8e2178..d58dbf6 100644
>> --- a/drivers/bus/pci/bsd/pci.c
>> +++ b/drivers/bus/pci/bsd/pci.c
>> @@ -126,6 +126,29 @@ rte_pci_unmap_device(struct rte_pci_device *dev)
>>   	}
>>   }
>>
>> +/* re-map pci device */
>> +int
>> +rte_pci_remap_device(struct rte_pci_device *dev)
>> +{
>> +	int ret;
>> +
>> +	if (dev == NULL)
>> +		return -EINVAL;
>> +
>> +	switch (dev->kdrv) {
>> +	case RTE_KDRV_NIC_UIO:
>> +		ret = pci_uio_remap_resource(dev);
>> +		break;
>> +	default:
>> +		RTE_LOG(DEBUG, EAL,
>> +			"  Not managed by a supported kernel driver,
>> skipped\n");
>> +		ret = 1;
>> +		break;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>>   void
>>   pci_uio_free_resource(struct rte_pci_device *dev,
>>   		struct mapped_pci_resource *uio_res)
>> @@ -678,3 +701,10 @@ rte_pci_ioport_unmap(struct rte_pci_ioport *p)
>>
>>   	return ret;
>>   }
>> +
>> +int
>> +rte_pci_dev_bind_driver(const char *dev_name, const char *drv_type)
>> +{
>> +	return -1;
>> +}
>> +
>> diff --git a/drivers/bus/pci/linux/pci.c b/drivers/bus/pci/linux/pci.c
>> index 5da6728..792fd2c 100644
>> --- a/drivers/bus/pci/linux/pci.c
>> +++ b/drivers/bus/pci/linux/pci.c
>> @@ -145,6 +145,38 @@ rte_pci_unmap_device(struct rte_pci_device *dev)
>>   	}
>>   }
>>
>> +/* Map pci device */
>> +int
>> +rte_pci_remap_device(struct rte_pci_device *dev)
>> +{
>> +	int ret = -1;
>> +
>> +	if (dev == NULL)
>> +		return -EINVAL;
>> +
>> +	switch (dev->kdrv) {
>> +	case RTE_KDRV_VFIO:
>> +#ifdef VFIO_PRESENT
>> +		/* no thing to do */
>> +#endif
>> +		break;
>> +	case RTE_KDRV_IGB_UIO:
>> +	case RTE_KDRV_UIO_GENERIC:
>> +		if (rte_eal_using_phys_addrs()) {
>> +			/* map resources for devices that use uio */
>> +			ret = pci_uio_remap_resource(dev);
>> +		}
>> +		break;
>> +	default:
>> +		RTE_LOG(DEBUG, EAL,
>> +			"  Not managed by a supported kernel driver,
>> skipped\n");
>> +		ret = 1;
>> +		break;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>>   void *
>>   pci_find_max_end_va(void)
>>   {
>> @@ -386,6 +418,8 @@ pci_scan_one(const char *dirname, const struct
>> rte_pci_addr *addr)
>>   		rte_pci_add_device(dev);
>>   	}
>>
>> +	dev->device.state = DEVICE_PARSED;
>> +	TAILQ_INIT(&(dev->device.uev_cbs));
>>   	return 0;
>>   }
>>
>> @@ -854,3 +888,56 @@ rte_pci_ioport_unmap(struct rte_pci_ioport *p)
>>
>>   	return ret;
>>   }
>> +
>> +int
>> +rte_pci_dev_bind_driver(const char *dev_name, const char *drv_type)
>> +{
>> +	char drv_bind_path[1024];
>> +	char drv_override_path[1024]; /* contains the /dev/uioX */
>> +	int drv_override_fd;
>> +	int drv_bind_fd;
>> +
>> +	RTE_SET_USED(drv_type);
>> +
>> +	snprintf(drv_override_path, sizeof(drv_override_path),
>> +		"/sys/bus/pci/devices/%s/driver_override", dev_name);
>> +
>> +	/* specify the driver for a device by writing to driver_override */
>> +	drv_override_fd = open(drv_override_path, O_WRONLY);
>> +	if (drv_override_fd < 0) {
>> +		RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
>> +			drv_override_path, strerror(errno));
>> +		goto err;
>> +	}
>> +
>> +	if (write(drv_override_fd, drv_type, sizeof(drv_type)) < 0) {
>> +		RTE_LOG(ERR, EAL,
>> +			"Error: bind failed - Cannot write "
>> +			"driver %s to device %s\n", drv_type, dev_name);
>> +		goto err;
>> +	}
>> +
>> +	close(drv_override_fd);
>> +
>> +	snprintf(drv_bind_path, sizeof(drv_bind_path),
>> +		"/sys/bus/pci/drivers/%s/bind", drv_type);
>> +
>> +	/* do the bind by writing device to the specific driver  */
>> +	drv_bind_fd = open(drv_bind_path, O_WRONLY | O_APPEND);
>> +	if (drv_bind_fd < 0) {
>> +		RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
>> +			drv_bind_path, strerror(errno));
>> +		goto err;
>> +	}
>> +
>> +	if (write(drv_bind_fd, dev_name, sizeof(dev_name)) < 0)
>> +		goto err;
>> +
>> +	close(drv_bind_fd);
>> +	return 0;
>> +err:
>> +	close(drv_override_fd);
>> +	close(drv_bind_fd);
>> +	return -1;
>> +}
>> +
>> diff --git a/drivers/bus/pci/linux/pci_init.h b/drivers/bus/pci/linux/pci_init.h
>> index f342c47..5838402 100644
>> --- a/drivers/bus/pci/linux/pci_init.h
>> +++ b/drivers/bus/pci/linux/pci_init.h
>> @@ -58,6 +58,7 @@ int pci_uio_alloc_resource(struct rte_pci_device *dev,
>>   		struct mapped_pci_resource **uio_res);
>>   void pci_uio_free_resource(struct rte_pci_device *dev,
>>   		struct mapped_pci_resource *uio_res);
>> +int pci_uio_remap_resource(struct rte_pci_device *dev);
>>   int pci_uio_map_resource_by_index(struct rte_pci_device *dev, int
>> res_idx,
>>   		struct mapped_pci_resource *uio_res, int map_idx);
>>
>> diff --git a/drivers/bus/pci/pci_common.c b/drivers/bus/pci/pci_common.c
>> index 104fdf9..5417b32 100644
>> --- a/drivers/bus/pci/pci_common.c
>> +++ b/drivers/bus/pci/pci_common.c
>> @@ -282,6 +282,7 @@ pci_probe_all_drivers(struct rte_pci_device *dev)
>>   		if (rc > 0)
>>   			/* positive value means driver doesn't support it */
>>   			continue;
>> +		dev->device.state = DEVICE_PROBED;
>>   		return 0;
>>   	}
>>   	return 1;
>> @@ -481,6 +482,7 @@ rte_pci_insert_device(struct rte_pci_device
>> *exist_pci_dev,
>>   void
>>   rte_pci_remove_device(struct rte_pci_device *pci_dev)
>>   {
>> +	RTE_LOG(DEBUG, EAL, " rte_pci_remove_device for device list\n");
>>   	TAILQ_REMOVE(&rte_pci_bus.device_list, pci_dev, next);
>>   }
>>
>> @@ -502,6 +504,44 @@ pci_find_device(const struct rte_device *start,
>> rte_dev_cmp_t cmp,
>>   	return NULL;
>>   }
>>
>> +static struct rte_device *
>> +pci_find_device_by_name(const struct rte_device *start,
>> +		rte_dev_cmp_name_t cmp_name,
>> +		const void *data)
>> +{
>> +	struct rte_pci_device *dev;
>> +
>> +	FOREACH_DEVICE_ON_PCIBUS(dev) {
>> +		if (start && &dev->device == start) {
>> +			start = NULL; /* starting point found */
>> +			continue;
>> +		}
>> +		if (cmp_name(dev->device.name, data) == 0)
>> +			return &dev->device;
>> +	}
>> +
>> +	return NULL;
>> +}
>> +
>> +static int
>> +pci_remap_device(struct rte_device *dev)
>> +{
>> +	struct rte_pci_device *pdev;
>> +	int ret;
>> +
>> +	if (dev == NULL)
>> +		return -EINVAL;
>> +
>> +	pdev = RTE_DEV_TO_PCI(dev);
>> +
>> +	/* remap resources for devices that use igb_uio */
>> +	ret = rte_pci_remap_device(pdev);
>> +	if (ret != 0)
>> +		RTE_LOG(ERR, EAL, "failed to remap device %s",
>> +			dev->name);
>> +	return ret;
>> +}
>> +
>>   static int
>>   pci_plug(struct rte_device *dev)
>>   {
>> @@ -528,10 +568,13 @@ struct rte_pci_bus rte_pci_bus = {
>>   		.scan = rte_pci_scan,
>>   		.probe = rte_pci_probe,
>>   		.find_device = pci_find_device,
>> +		.find_device_by_name = pci_find_device_by_name,
>>   		.plug = pci_plug,
>>   		.unplug = pci_unplug,
>>   		.parse = pci_parse,
>>   		.get_iommu_class = rte_pci_get_iommu_class,
>> +		.remap_device = pci_remap_device,
>> +		.bind_driver = rte_pci_dev_bind_driver,
>>   	},
>>   	.device_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.device_list),
>>   	.driver_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.driver_list),
>> diff --git a/drivers/bus/pci/pci_common_uio.c
>> b/drivers/bus/pci/pci_common_uio.c
>> index 0671131..8cb4009 100644
>> --- a/drivers/bus/pci/pci_common_uio.c
>> +++ b/drivers/bus/pci/pci_common_uio.c
>> @@ -176,6 +176,34 @@ pci_uio_unmap(struct mapped_pci_resource
>> *uio_res)
>>   	}
>>   }
>>
>> +/* remap the PCI resource of a PCI device in private virtual memory */
>> +int
>> +pci_uio_remap_resource(struct rte_pci_device *dev)
>> +{
>> +	int i;
>> +	uint64_t phaddr;
>> +	void *map_address;
>> +
>> +	/* Map all BARs */
>> +	for (i = 0; i != PCI_MAX_RESOURCE; i++) {
>> +		/* skip empty BAR */
>> +		phaddr = dev->mem_resource[i].phys_addr;
>> +		if (phaddr == 0)
>> +			continue;
>> +		map_address = pci_map_private_resource(
>> +				dev->mem_resource[i].addr, 0,
>> +				(size_t)dev->mem_resource[i].len);
>> +		if (map_address == MAP_FAILED)
>> +			goto error;
>> +		memset(map_address, 0xFF, (size_t)dev-
>>> mem_resource[i].len);
>> +		dev->mem_resource[i].addr = map_address;
>> +	}
>> +
>> +	return 0;
>> +error:
>> +	return -1;
>> +}
>> +
>>   static struct mapped_pci_resource *
>>   pci_uio_find_resource(struct rte_pci_device *dev)
>>   {
>> diff --git a/drivers/bus/pci/private.h b/drivers/bus/pci/private.h
>> index 2283f09..10baa1a 100644
>> --- a/drivers/bus/pci/private.h
>> +++ b/drivers/bus/pci/private.h
>> @@ -202,6 +202,18 @@ void pci_uio_free_resource(struct rte_pci_device
>> *dev,
>>   		struct mapped_pci_resource *uio_res);
>>
>>   /**
>> + * remap the pci uio resource..
>> + *
>> + * @param dev
>> + *   Point to the struct rte pci device.
>> + * @return
>> + *   - On success, zero.
>> + *   - On failure, a negative value.
>> + */
>> +int
>> +pci_uio_remap_resource(struct rte_pci_device *dev);
>> +
>> +/**
>>    * Map device memory to uio resource
>>    *
>>    * This function is private to EAL.
>> diff --git a/drivers/bus/pci/rte_bus_pci.h b/drivers/bus/pci/rte_bus_pci.h
>> index d4a2996..1662f3b 100644
>> --- a/drivers/bus/pci/rte_bus_pci.h
>> +++ b/drivers/bus/pci/rte_bus_pci.h
>> @@ -52,6 +52,8 @@ extern "C" {
>>   #include <sys/queue.h>
>>   #include <stdint.h>
>>   #include <inttypes.h>
>> +#include <unistd.h>
>> +#include <fcntl.h>
>>
>>   #include <rte_debug.h>
>>   #include <rte_interrupts.h>
>> @@ -197,6 +199,15 @@ int rte_pci_map_device(struct rte_pci_device *dev);
>>   void rte_pci_unmap_device(struct rte_pci_device *dev);
>>
>>   /**
>> + * Remap this device
>> + *
>> + * @param dev
>> + *   A pointer to a rte_pci_device structure describing the device
>> + *   to use
>> + */
>> +int rte_pci_remap_device(struct rte_pci_device *dev);
>> +
>> +/**
>>    * Dump the content of the PCI bus.
>>    *
>>    * @param f
>> @@ -333,6 +344,20 @@ void rte_pci_ioport_read(struct rte_pci_ioport *p,
>>   void rte_pci_ioport_write(struct rte_pci_ioport *p,
>>   		const void *data, size_t len, off_t offset);
>>
>> +/**
>> + * It can be used to bind a device to a specific type of driver.
>> + *
>> + * @param dev_name
>> + *  The device name.
>> + * @param drv_type
>> + *  The specific driver's type.
>> + *
>> + * @return
>> + *  - On success, zero.
>> + *  - On failure, a negative value.
>> + */
>> +int rte_pci_dev_bind_driver(const char *dev_name, const char *drv_type);
>> +
>>   #ifdef __cplusplus
>>   }
>>   #endif
>> diff --git a/drivers/bus/vdev/vdev.c b/drivers/bus/vdev/vdev.c
>> index fd7736d..773f6e0 100644
>> --- a/drivers/bus/vdev/vdev.c
>> +++ b/drivers/bus/vdev/vdev.c
>> @@ -323,6 +323,39 @@ vdev_find_device(const struct rte_device *start,
>> rte_dev_cmp_t cmp,
>>   	return NULL;
>>   }
>>
>> +static struct rte_device *
>> +vdev_find_device_by_name(const struct rte_device *start,
>> +		rte_dev_cmp_name_t cmp_name,
>> +		const void *data)
>> +{
>> +	struct rte_vdev_device *dev;
>> +
>> +	TAILQ_FOREACH(dev, &vdev_device_list, next) {
>> +		if (start && &dev->device == start) {
>> +			start = NULL;
>> +			continue;
>> +		}
>> +		if (cmp_name(dev->device.name, data) == 0)
>> +			return &dev->device;
>> +	}
>> +	return NULL;
>> +}
>> +
>> +static int
>> +vdev_remap_device(struct rte_device *dev)
>> +{
>> +	RTE_SET_USED(dev);
>> +	return 0;
>> +}
>> +
>> +static int
>> +vdev_bind_driver(const char *dev_name, const char *drv_type)
>> +{
>> +	RTE_SET_USED(dev_name);
>> +	RTE_SET_USED(drv_type);
>> +	return 0;
>> +}
>> +
>>   static int
>>   vdev_plug(struct rte_device *dev)
>>   {
>> @@ -339,9 +372,12 @@ static struct rte_bus rte_vdev_bus = {
>>   	.scan = vdev_scan,
>>   	.probe = vdev_probe,
>>   	.find_device = vdev_find_device,
>> +	.find_device_by_name = vdev_find_device_by_name,
>>   	.plug = vdev_plug,
>>   	.unplug = vdev_unplug,
>>   	.parse = vdev_parse,
>> +	.remap_device = vdev_remap_device,
>> +	.bind_driver = vdev_bind_driver,
>>   };
>>
>>   RTE_REGISTER_BUS(vdev, rte_vdev_bus);
>> diff --git a/lib/librte_eal/bsdapp/eal/eal_dev.c
>> b/lib/librte_eal/bsdapp/eal/eal_dev.c
>> new file mode 100644
>> index 0000000..6ea9a74
>> --- /dev/null
>> +++ b/lib/librte_eal/bsdapp/eal/eal_dev.c
>> @@ -0,0 +1,64 @@
>> +/*-
>> + *   Copyright(c) 2010-2017 Intel Corporation.
>> + *   All rights reserved.
>> + *
>> + *   Redistribution and use in source and binary forms, with or without
>> + *   modification, are permitted provided that the following conditions
>> + *   are met:
>> + *
>> + *     * Redistributions of source code must retain the above copyright
>> + *       notice, this list of conditions and the following disclaimer.
>> + *     * Redistributions in binary form must reproduce the above copyright
>> + *       notice, this list of conditions and the following disclaimer in
>> + *       the documentation and/or other materials provided with the
>> + *       distribution.
>> + *     * Neither the name of Intel Corporation nor the names of its
>> + *       contributors may be used to endorse or promote products derived
>> + *       from this software without specific prior written permission.
>> + *
>> + *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
>> CONTRIBUTORS
>> + *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
>> NOT
>> + *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
>> FITNESS FOR
>> + *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
>> COPYRIGHT
>> + *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
>> INCIDENTAL,
>> + *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
>> NOT
>> + *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
>> OF USE,
>> + *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
>> AND ON ANY
>> + *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
>> TORT
>> + *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
>> THE USE
>> + *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
>> DAMAGE.
>> + */
>> +
>> +#include <stdio.h>
>> +#include <string.h>
>> +#include <inttypes.h>
>> +#include <sys/queue.h>
>> +#include <sys/signalfd.h>
>> +#include <sys/ioctl.h>
>> +#include <sys/socket.h>
>> +#include <linux/netlink.h>
>> +#include <sys/epoll.h>
>> +#include <unistd.h>
>> +#include <signal.h>
>> +#include <stdbool.h>
>> +
>> +#include <rte_malloc.h>
>> +#include <rte_bus.h>
>> +#include <rte_dev.h>
>> +#include <rte_devargs.h>
>> +#include <rte_debug.h>
>> +#include <rte_log.h>
>> +
>> +#include "eal_thread.h"
>> +
>> +int
>> +rte_dev_monitor_start(void)
>> +{
>> +	return -1;
>> +}
>> +
>> +int
>> +rte_dev_monitor_stop(void)
>> +{
>> +	return -1;
>> +}
>> diff --git a/lib/librte_eal/bsdapp/eal/include/exec-env/rte_dev.h
>> b/lib/librte_eal/bsdapp/eal/include/exec-env/rte_dev.h
>> new file mode 100644
>> index 0000000..6a6feb5
>> --- /dev/null
>> +++ b/lib/librte_eal/bsdapp/eal/include/exec-env/rte_dev.h
>> @@ -0,0 +1,106 @@
>> +/*-
>> + *   BSD LICENSE
>> + *
>> + *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
>> + *   All rights reserved.
>> + *
>> + *   Redistribution and use in source and binary forms, with or without
>> + *   modification, are permitted provided that the following conditions
>> + *   are met:
>> + *
>> + *     * Redistributions of source code must retain the above copyright
>> + *       notice, this list of conditions and the following disclaimer.
>> + *     * Redistributions in binary form must reproduce the above copyright
>> + *       notice, this list of conditions and the following disclaimer in
>> + *       the documentation and/or other materials provided with the
>> + *       distribution.
>> + *     * Neither the name of Intel Corporation nor the names of its
>> + *       contributors may be used to endorse or promote products derived
>> + *       from this software without specific prior written permission.
>> + *
>> + *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
>> CONTRIBUTORS
>> + *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
>> NOT
>> + *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
>> FITNESS FOR
>> + *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
>> COPYRIGHT
>> + *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
>> INCIDENTAL,
>> + *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
>> NOT
>> + *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
>> OF USE,
>> + *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
>> AND ON ANY
>> + *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
>> TORT
>> + *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
>> THE USE
>> + *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
>> DAMAGE.
>> + */
>> +
>> +#ifndef _RTE_DEV_H_
>> +#error "don't include this file directly, please include generic <rte_dev.h>"
>> +#endif
>> +
>> +#ifndef _RTE_LINUXAPP_DEV_H_
>> +#define _RTE_LINUXAPP_DEV_H_
>> +
>> +#include <stdio.h>
>> +
>> +#include <rte_dev.h>
>> +
>> +#define RTE_EAL_UEV_MSG_LEN 4096
>> +#define RTE_EAL_UEV_MSG_ELEM_LEN 128
>> +
>> +enum uev_subsystem {
>> +	UEV_SUBSYSTEM_UIO,
>> +	UEV_SUBSYSTEM_VFIO,
>> +	UEV_SUBSYSTEM_PCI,
>> +	UEV_SUBSYSTEM_MAX
>> +};
>> +
>> +enum uev_monitor_netlink_group {
>> +	UEV_MONITOR_KERNEL,
>> +	UEV_MONITOR_UDEV,
>> +};
>> +
>> +/**
>> + * The device event type.
>> + */
>> +enum rte_eal_dev_event_type {
>> +	RTE_EAL_DEV_EVENT_UNKNOWN,	/**< unknown event type */
>> +	RTE_EAL_DEV_EVENT_ADD,		/**< device adding event */
>> +	RTE_EAL_DEV_EVENT_REMOVE,
>> +					/**< device removing event */
>> +	RTE_EAL_DEV_EVENT_CHANGE,
>> +					/**< device status change event */
>> +	RTE_EAL_DEV_EVENT_MOVE,		/**< device sys path move
>> event */
>> +	RTE_EAL_DEV_EVENT_ONLINE,	/**< device online event */
>> +	RTE_EAL_DEV_EVENT_OFFLINE,	/**< device offline event */
>> +	RTE_EAL_DEV_EVENT_MAX		/**< max value of this enum
>> */
>> +};
>> +
>> +struct rte_eal_uevent {
>> +	enum rte_eal_dev_event_type type;	/**< device event type */
>> +	int subsystem;				/**< subsystem id */
>> +	char *devname;				/**< device name */
>> +	enum uev_monitor_netlink_group group;	/**< device netlink
>> group */
>> +};
>> +
>> +/**
>> + * Start the device uevent monitoring.
>> + *
>> + * @param none
>> + * @return
>> + *   - On success, zero.
>> + *   - On failure, a negative value.
>> + */
>> +int
>> +rte_dev_monitor_start(void);
>> +
>> +/**
>> + * Stop the device uevent monitoring .
>> + *
>> + * @param none
>> + * @return
>> + *   - On success, zero.
>> + *   - On failure, a negative value.
>> + */
>> +
>> +int
>> +rte_dev_monitor_stop(void);
>> +
>> +#endif /* _RTE_LINUXAPP_DEV_H_ */
>> diff --git a/lib/librte_eal/common/eal_common_bus.c
>> b/lib/librte_eal/common/eal_common_bus.c
>> index 3e022d5..b7219c9 100644
>> --- a/lib/librte_eal/common/eal_common_bus.c
>> +++ b/lib/librte_eal/common/eal_common_bus.c
>> @@ -51,8 +51,11 @@ rte_bus_register(struct rte_bus *bus)
>>   	RTE_VERIFY(bus->scan);
>>   	RTE_VERIFY(bus->probe);
>>   	RTE_VERIFY(bus->find_device);
>> +	RTE_VERIFY(bus->find_device_by_name);
>>   	/* Buses supporting driver plug also require unplug. */
>>   	RTE_VERIFY(!bus->plug || bus->unplug);
>> +	RTE_VERIFY(bus->remap_device);
>> +	RTE_VERIFY(bus->bind_driver);
>>
>>   	TAILQ_INSERT_TAIL(&rte_bus_list, bus, next);
>>   	RTE_LOG(DEBUG, EAL, "Registered [%s] bus.\n", bus->name);
>> @@ -170,6 +173,14 @@ cmp_rte_device(const struct rte_device *dev1,
>> const void *_dev2)
>>   }
>>
>>   static int
>> +cmp_rte_device_name(const char *dev_name1, const void *_dev_name2)
>> +{
>> +	const char *dev_name2 = _dev_name2;
>> +
>> +	return strcmp(dev_name1, dev_name2);
>> +}
>> +
>> +static int
>>   bus_find_device(const struct rte_bus *bus, const void *_dev)
>>   {
>>   	struct rte_device *dev;
>> @@ -178,6 +189,25 @@ bus_find_device(const struct rte_bus *bus, const
>> void *_dev)
>>   	return dev == NULL;
>>   }
>>
>> +static struct rte_device *
>> +bus_find_device_by_name(const struct rte_bus *bus, const void
>> *_dev_name)
>> +{
>> +	struct rte_device *dev;
>> +
>> +	dev = bus->find_device_by_name(NULL, cmp_rte_device_name,
>> _dev_name);
>> +	return dev;
>> +}
>> +
>> +struct rte_device *
>> +
>> +rte_bus_find_device(const struct rte_bus *bus, const void *_dev_name)
>> +{
>> +	struct rte_device *dev;
>> +
>> +	dev = bus_find_device_by_name(bus, _dev_name);
>> +	return dev;
>> +}
>> +
>>   struct rte_bus *
>>   rte_bus_find_by_device(const struct rte_device *dev)
>>   {
>> diff --git a/lib/librte_eal/common/eal_common_dev.c
>> b/lib/librte_eal/common/eal_common_dev.c
>> index dda8f58..47909e8 100644
>> --- a/lib/librte_eal/common/eal_common_dev.c
>> +++ b/lib/librte_eal/common/eal_common_dev.c
>> @@ -42,9 +42,31 @@
>>   #include <rte_devargs.h>
>>   #include <rte_debug.h>
>>   #include <rte_log.h>
>> +#include <rte_spinlock.h>
>> +#include <rte_malloc.h>
>>
>>   #include "eal_private.h"
>>
>> +/* spinlock for device callbacks */
>> +static rte_spinlock_t rte_dev_cb_lock = RTE_SPINLOCK_INITIALIZER;
>> +
>> +/**
>> + * The user application callback description.
>> + *
>> + * It contains callback address to be registered by user application,
>> + * the pointer to the parameters for callback, and the event type.
>> + */
>> +struct rte_eal_dev_callback {
>> +	TAILQ_ENTRY(rte_eal_dev_callback) next; /**< Callbacks list */
>> +	rte_eal_dev_cb_fn cb_fn;                /**< Callback address */
>> +	void *cb_arg;                           /**< Parameter for callback */
>> +	void *ret_param;                        /**< Return parameter */
>> +	enum rte_eal_dev_event_type event;      /**< device event type */
>> +	uint32_t active;                        /**< Callback is executing */
>> +};
>> +
>> +static struct rte_eal_dev_callback *dev_add_cb;
>> +
>>   static int cmp_detached_dev_name(const struct rte_device *dev,
>>   	const void *_name)
>>   {
>> @@ -234,3 +256,150 @@ int rte_eal_hotplug_remove(const char *busname,
>> const char *devname)
>>   	rte_eal_devargs_remove(busname, devname);
>>   	return ret;
>>   }
>> +
>> +int
>> +rte_eal_dev_monitor_enable(void)
>> +{
>> +	int ret;
>> +
>> +	ret = rte_dev_monitor_start();
>> +	if (ret)
>> +		RTE_LOG(ERR, EAL, "Can not init device monitor\n");
>> +	return ret;
>> +}
>> +
>> +int
>> +rte_dev_callback_register(struct rte_device *device,
>> +			enum rte_eal_dev_event_type event,
>> +			rte_eal_dev_cb_fn cb_fn, void *cb_arg)
>> +{
>> +	struct rte_eal_dev_callback *user_cb;
>> +
>> +	if (!cb_fn)
>> +		return -EINVAL;
>> +
> What's about checking the device pointer is not NULL ?
sure.
>
>> +	rte_spinlock_lock(&rte_dev_cb_lock);
>> +
>> +	if (TAILQ_EMPTY(&(device->uev_cbs)))
>> +		TAILQ_INIT(&(device->uev_cbs));
>> +
>> +	if (event == RTE_EAL_DEV_EVENT_ADD) {
>> +		user_cb = NULL;
>> +	} else {
>> +		TAILQ_FOREACH(user_cb, &(device->uev_cbs), next) {
>> +			if (user_cb->cb_fn == cb_fn &&
>> +				user_cb->cb_arg == cb_arg &&
>> +				user_cb->event == event) {
>> +				break;
>> +			}
>> +		}
>> +	}
>> +
>> +	/* create a new callback. */
>> +	if (user_cb == NULL) {
>> +		/* allocate a new interrupt callback entity */
>> +		user_cb = rte_zmalloc("eal device event",
>> +					sizeof(*user_cb), 0);
>> +		if (user_cb == NULL) {
>> +			RTE_LOG(ERR, EAL, "Can not allocate memory\n");
> Missing rte_spinlock_unlock.
got it.
>
>> +			return -ENOMEM;
>> +		}
>> +		user_cb->cb_fn = cb_fn;
>> +		user_cb->cb_arg = cb_arg;
>> +		user_cb->event = event;
>> +		if (event == RTE_EAL_DEV_EVENT_ADD)
>> +			dev_add_cb = user_cb;
> Only one dpdk entity can register to ADD callback?
>
> I suggest to add option to register all devices maybe by using dummy device which will include all the "ALL_DEVICES"  callbacks per event.
> All means past, present and future devices, by this way 1 callback can be called for all the devices and more than one dpdk entity could register to  an ADD\NEW event.
> What's about NEW instead of ADD?
>
> I also suggest to add the device pointer as a parameter to the callback(which will be managed by EAL).
if you talk about dev_add_cb, the add means device add not cb add, if 
you talk about dev event type, the ADD type is consistent with the type 
form kernel side, anyway could be find a better. but for 1 callback for 
all device, it is make sense , i will think about that.
>> +		else
>> +			TAILQ_INSERT_TAIL(&(device->uev_cbs), user_cb,
>> next);
>> +	}
>> +
>> +	rte_spinlock_unlock(&rte_dev_cb_lock);
>> +	return 0;
>> +}
>> +
>> +int
>> +rte_dev_callback_unregister(struct rte_device *device,
>> +			enum rte_eal_dev_event_type event,
>> +			rte_eal_dev_cb_fn cb_fn, void *cb_arg)
>> +{
>> +	int ret;
>> +	struct rte_eal_dev_callback *cb, *next;
>> +
>> +	if (!cb_fn)
>> +		return -EINVAL;
>> +
>> +	rte_spinlock_lock(&rte_dev_cb_lock);
>> +
>> +	ret = 0;
>> +	if (event == RTE_EAL_DEV_EVENT_ADD) {
>> +		rte_free(dev_add_cb);
>> +		dev_add_cb = NULL;
>> +	} else {
> Device NULL checking?
yes.
>> +		for (cb = TAILQ_FIRST(&(device->uev_cbs)); cb != NULL;
>> +		      cb = next) {
>> +
>> +			next = TAILQ_NEXT(cb, next);
>> +
>> +			if (cb->cb_fn != cb_fn || cb->event != event ||
>> +					(cb->cb_arg != (void *)-1 &&
>> +					cb->cb_arg != cb_arg))
>> +				continue;
>> +
>> +			/*
>> +			 * if this callback is not executing right now,
>> +			 * then remove it.
>> +			 */
>> +			if (cb->active == 0) {
>> +				TAILQ_REMOVE(&(device->uev_cbs), cb,
>> next);
>> +				rte_free(cb);
>> +			} else {
>> +				ret = -EAGAIN;
>> +			}
>> +		}
>> +	}
>> +	rte_spinlock_unlock(&rte_dev_cb_lock);
>> +	return ret;
>> +}
>> +
>> +int
>> +_rte_dev_callback_process(struct rte_device *device,
>> +			enum rte_eal_dev_event_type event,
>> +			void *cb_arg, void *ret_param)
>> +{
>> +	struct rte_eal_dev_callback dev_cb;
>> +	struct rte_eal_dev_callback *cb_lst;
>> +	int rc = 0;
>> +
>> +	rte_spinlock_lock(&rte_dev_cb_lock);
>> +	if (event == RTE_EAL_DEV_EVENT_ADD) {
>> +		if (cb_arg != NULL)
>> +			dev_add_cb->cb_arg = cb_arg;
>> +
>> +		if (ret_param != NULL)
>> +			dev_add_cb->ret_param = ret_param;
>> +
>> +		rte_spinlock_unlock(&rte_dev_cb_lock);
> Can't someone free it when it running?
> I suggest to  keep the lock locked.
> Callbacks are not allowed to use this mechanism to prevent deadlock.
seems it would bring some deadlock here, let's check it more.
>> +		rc = dev_add_cb->cb_fn(dev_add_cb->event,
>> +				dev_add_cb->cb_arg, dev_add_cb-
>>> ret_param);
>> +		rte_spinlock_lock(&rte_dev_cb_lock);
>> +	} else {
>> +		TAILQ_FOREACH(cb_lst, &(device->uev_cbs), next) {
>> +			if (cb_lst->cb_fn == NULL || cb_lst->event != event)
>> +				continue;
>> +			dev_cb = *cb_lst;
>> +			cb_lst->active = 1;
>> +			if (cb_arg != NULL)
>> +				dev_cb.cb_arg = cb_arg;
>> +			if (ret_param != NULL)
>> +				dev_cb.ret_param = ret_param;
>> +
>> +			rte_spinlock_unlock(&rte_dev_cb_lock);
> The current active flag doesn't do it  thread safe here, I suggest to keep the lock locked.
> Scenario:
> 	1. Thread A see active = 0 in unregister function.
> 	2. Context switch.
> 	3. Thread B start the callback.
> 	4. Context switch.
> 	5. Thread A free it.
> 	6. Context switch.
> 	7. Seg fault in Thread B.
the same as above.
>> +			rc = dev_cb.cb_fn(dev_cb.event,
>> +					dev_cb.cb_arg, dev_cb.ret_param);
>> +			rte_spinlock_lock(&rte_dev_cb_lock);
>> +			cb_lst->active = 0;
>> +		}
>> +	}
>> +	rte_spinlock_unlock(&rte_dev_cb_lock);
>> +	return rc;
>> +}
>> diff --git a/lib/librte_eal/common/include/rte_bus.h
>> b/lib/librte_eal/common/include/rte_bus.h
>> index 6fb0834..6c4ae31 100644
>> --- a/lib/librte_eal/common/include/rte_bus.h
>> +++ b/lib/librte_eal/common/include/rte_bus.h
>> @@ -122,6 +122,34 @@ typedef struct rte_device *
>>   			 const void *data);
>>
>>   /**
>> + * Device iterator to find a device on a bus.
>> + *
>> + * This function returns an rte_device if one of those held by the bus
>> + * matches the data passed as parameter.
>> + *
>> + * If the comparison function returns zero this function should stop iterating
>> + * over any more devices. To continue a search the device of a previous
>> search
>> + * can be passed via the start parameter.
>> + *
>> + * @param cmp
>> + *	the device name comparison function.
>> + *
>> + * @param data
>> + *	Data to compare each device against.
>> + *
>> + * @param start
>> + *	starting point for the iteration
>> + *
>> + * @return
>> + *	The first device matching the data, NULL if none exists.
>> + */
>> +typedef struct rte_device *
>> +(*rte_bus_find_device_by_name_t)(const struct rte_device *start,
>> +			 rte_dev_cmp_name_t cmp,
>> +			 const void *data);
>> +
>> +
>> +/**
>>    * Implementation specific probe function which is responsible for linking
>>    * devices on that bus with applicable drivers.
>>    *
>> @@ -168,6 +196,37 @@ typedef int (*rte_bus_unplug_t)(struct rte_device
>> *dev);
>>   typedef int (*rte_bus_parse_t)(const char *name, void *addr);
>>
>>   /**
>> + * Implementation specific remap function which is responsible for
>> remmaping
>> + * devices on that bus from original share memory resource to a private
>> memory
>> + * resource for the sake of device has been removal.
>> + *
>> + * @param dev
>> + *	Device pointer that was returned by a previous call to find_device.
>> + *
>> + * @return
>> + *	0 on success.
>> + *	!0 on error.
>> + */
>> +typedef int (*rte_bus_remap_device_t)(struct rte_device *dev);
>> +
>> +/**
>> + * Implementation specific bind driver function which is responsible for bind
>> + * a explicit type of driver with a devices on that bus.
>> + *
>> + * @param dev_name
>> + *	device textual description.
>> + *
>> + * @param drv_type
>> + *	driver type textual description.
>> + *
>> + * @return
>> + *	0 on success.
>> + *	!0 on error.
>> + */
>> +typedef int (*rte_bus_bind_driver_t)(const char *dev_name,
>> +				const char *drv_type);
>> +
>> +/**
>>    * Bus scan policies
>>    */
>>   enum rte_bus_scan_mode {
>> @@ -206,9 +265,13 @@ struct rte_bus {
>>   	rte_bus_scan_t scan;         /**< Scan for devices attached to bus */
>>   	rte_bus_probe_t probe;       /**< Probe devices on bus */
>>   	rte_bus_find_device_t find_device; /**< Find a device on the bus */
>> +	rte_bus_find_device_by_name_t find_device_by_name;
>> +				     /**< Find a device on the bus */
>>   	rte_bus_plug_t plug;         /**< Probe single device for drivers */
>>   	rte_bus_unplug_t unplug;     /**< Remove single device from driver
>> */
>>   	rte_bus_parse_t parse;       /**< Parse a device name */
>> +	rte_bus_remap_device_t remap_device;       /**< remap a device */
>> +	rte_bus_bind_driver_t bind_driver; /**< bind a driver for bus device
>> */
>>   	struct rte_bus_conf conf;    /**< Bus configuration */
>>   	rte_bus_get_iommu_class_t get_iommu_class; /**< Get iommu
>> class */
>>   };
>> @@ -306,6 +369,12 @@ struct rte_bus *rte_bus_find(const struct rte_bus
>> *start, rte_bus_cmp_t cmp,
>>   struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev);
>>
>>   /**
>> + * Find the registered bus for a particular device.
>> + */
>> +struct rte_device *rte_bus_find_device(const struct rte_bus *bus,
>> +				const void *dev_name);
>> +
>> +/**
>>    * Find the registered bus for a given name.
>>    */
>>   struct rte_bus *rte_bus_find_by_name(const char *busname);
>> diff --git a/lib/librte_eal/common/include/rte_dev.h
>> b/lib/librte_eal/common/include/rte_dev.h
>> index 9342e0c..19971d0 100644
>> --- a/lib/librte_eal/common/include/rte_dev.h
>> +++ b/lib/librte_eal/common/include/rte_dev.h
>> @@ -51,6 +51,15 @@ extern "C" {
>>
>>   #include <rte_log.h>
>>
>> +#include <exec-env/rte_dev.h>
>> +
>> +typedef int (*rte_eal_dev_cb_fn)(enum rte_eal_dev_event_type event,
>> +					void *cb_arg, void *ret_param);
>> +
>> +struct rte_eal_dev_callback;
>> +/** @internal Structure to keep track of registered callbacks */
>> +TAILQ_HEAD(rte_eal_dev_cb_list, rte_eal_dev_callback);
>> +
>>   __attribute__((format(printf, 2, 0)))
>>   static inline void
>>   rte_pmd_debug_trace(const char *func_name, const char *fmt, ...)
>> @@ -157,6 +166,13 @@ struct rte_driver {
>>    */
>>   #define RTE_DEV_NAME_MAX_LEN 64
>>
>> +enum device_state {
>> +	DEVICE_UNDEFINED,
>> +	DEVICE_FAULT,
>> +	DEVICE_PARSED,
>> +	DEVICE_PROBED,
>> +};
>> +
>>   /**
>>    * A structure describing a generic device.
>>    */
>> @@ -166,6 +182,9 @@ struct rte_device {
>>   	const struct rte_driver *driver;/**< Associated driver */
>>   	int numa_node;                /**< NUMA node connection */
>>   	struct rte_devargs *devargs;  /**< Device user arguments */
>> +	enum device_state state;  /**< Device state */
>> +	/** User application callbacks for device event */
>> +	struct rte_eal_dev_cb_list uev_cbs;
>>   };
>>
>>   /**
>> @@ -248,6 +267,8 @@ int rte_eal_hotplug_remove(const char *busname,
>> const char *devname);
>>    */
>>   typedef int (*rte_dev_cmp_t)(const struct rte_device *dev, const void
>> *data);
>>
>> +typedef int (*rte_dev_cmp_name_t)(const char *dev_name, const void
>> *data);
>> +
>>   #define RTE_PMD_EXPORT_NAME_ARRAY(n, idx) n##idx[]
>>
>>   #define RTE_PMD_EXPORT_NAME(name, idx) \
>> @@ -293,4 +314,72 @@ __attribute__((used)) = str
>>   }
>>   #endif
>>
>> +/**
>> + * It enable the device event monitoring for a specific event.
>> + *
>> + * @param none
>> + * @return
>> + *   - On success, zero.
>> + *   - On failure, a negative value.
>> + */
>> +int
>> +rte_eal_dev_monitor_enable(void);
>> +/**
>> + * It registers the callback for the specific event. Multiple
>> + * callbacks cal be registered at the same time.
>> + * @param event
>> + *  The device event type.
>> + * @param cb_fn
>> + *  callback address.
>> + * @param cb_arg
>> + *  address of parameter for callback.
>> + *
>> + * @return
>> + *  - On success, zero.
>> + *  - On failure, a negative value.
>> + */
>> +int rte_dev_callback_register(struct rte_device *device,
>> +			enum rte_eal_dev_event_type event,
>> +			rte_eal_dev_cb_fn cb_fn, void *cb_arg);
>> +
>> +/**
>> + * It unregisters the callback according to the specified event.
>> + *
>> + * @param event
>> + *  The event type which corresponding to the callback.
>> + * @param cb_fn
>> + *  callback address.
>> + *  address of parameter for callback, (void *)-1 means to remove all
>> + *  registered which has the same callback address.
>> + *
>> + * @return
>> + *  - On success, return the number of callback entities removed.
>> + *  - On failure, a negative value.
>> + */
>> +int rte_dev_callback_unregister(struct rte_device *device,
>> +			enum rte_eal_dev_event_type event,
>> +			rte_eal_dev_cb_fn cb_fn, void *cb_arg);
>> +
>> +/**
>> + * @internal Executes all the user application registered callbacks for
>> + * the specific device. It is for DPDK internal user only. User
>> + * application should not call it directly.
>> + *
>> + * @param event
>> + *  The device event type.
>> + * @param cb_arg
>> + *  callback parameter.
>> + * @param ret_param
>> + *  To pass data back to user application.
>> + *  This allows the user application to decide if a particular function
>> + *  is permitted or not.
>> + *
>> + * @return
>> + *  - On success, return zero.
>> + *  - On failure, a negative value.
>> + */
>> +int
>> +_rte_dev_callback_process(struct rte_device *device,
>> +			enum rte_eal_dev_event_type event,
>> +			void *cb_arg, void *ret_param);
>>   #endif /* _RTE_DEV_H_ */
>> diff --git a/lib/librte_eal/linuxapp/eal/Makefile
>> b/lib/librte_eal/linuxapp/eal/Makefile
>> index 5a7b8b2..05a2437 100644
>> --- a/lib/librte_eal/linuxapp/eal/Makefile
>> +++ b/lib/librte_eal/linuxapp/eal/Makefile
>> @@ -67,6 +67,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) +=
>> eal_lcore.c
>>   SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_timer.c
>>   SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_interrupts.c
>>   SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_alarm.c
>> +SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_dev.c
>>
>>   # from common dir
>>   SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_lcore.c
>> @@ -120,7 +121,7 @@ ifeq ($(CONFIG_RTE_TOOLCHAIN_GCC),y)
>>   CFLAGS_eal_thread.o += -Wno-return-type
>>   endif
>>
>> -INC := rte_kni_common.h
>> +INC := rte_kni_common.h rte_dev.h
>>
>>   SYMLINK-$(CONFIG_RTE_EXEC_ENV_LINUXAPP)-include/exec-env := \
>>   	$(addprefix include/exec-env/,$(INC))
>> diff --git a/lib/librte_eal/linuxapp/eal/eal_alarm.c
>> b/lib/librte_eal/linuxapp/eal/eal_alarm.c
>> index 8e4a775..29e73a7 100644
>> --- a/lib/librte_eal/linuxapp/eal/eal_alarm.c
>> +++ b/lib/librte_eal/linuxapp/eal/eal_alarm.c
>> @@ -209,6 +209,7 @@ rte_eal_alarm_cancel(rte_eal_alarm_callback cb_fn,
>> void *cb_arg)
>>   	int count = 0;
>>   	int err = 0;
>>   	int executing;
>> +	int ret;
>>
>>   	if (!cb_fn) {
>>   		rte_errno = EINVAL;
>> @@ -259,6 +260,10 @@ rte_eal_alarm_cancel(rte_eal_alarm_callback cb_fn,
>> void *cb_arg)
>>   			}
>>   			ap_prev = ap;
>>   		}
>> +
>> +		ret |= rte_intr_callback_unregister(&intr_handle,
>> +				eal_alarm_callback, NULL);
>> +
>>   		rte_spinlock_unlock(&alarm_list_lk);
>>   	} while (executing != 0);
>>
>> diff --git a/lib/librte_eal/linuxapp/eal/eal_dev.c
>> b/lib/librte_eal/linuxapp/eal/eal_dev.c
>> new file mode 100644
>> index 0000000..49fd0dc
>> --- /dev/null
>> +++ b/lib/librte_eal/linuxapp/eal/eal_dev.c
>> @@ -0,0 +1,356 @@
>> +/*-
>> + *   Copyright(c) 2010-2017 Intel Corporation.
>> + *   All rights reserved.
>> + *
>> + *   Redistribution and use in source and binary forms, with or without
>> + *   modification, are permitted provided that the following conditions
>> + *   are met:
>> + *
>> + *     * Redistributions of source code must retain the above copyright
>> + *       notice, this list of conditions and the following disclaimer.
>> + *     * Redistributions in binary form must reproduce the above copyright
>> + *       notice, this list of conditions and the following disclaimer in
>> + *       the documentation and/or other materials provided with the
>> + *       distribution.
>> + *     * Neither the name of Intel Corporation nor the names of its
>> + *       contributors may be used to endorse or promote products derived
>> + *       from this software without specific prior written permission.
>> + *
>> + *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
>> CONTRIBUTORS
>> + *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
>> NOT
>> + *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
>> FITNESS FOR
>> + *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
>> COPYRIGHT
>> + *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
>> INCIDENTAL,
>> + *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
>> NOT
>> + *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
>> OF USE,
>> + *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
>> AND ON ANY
>> + *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
>> TORT
>> + *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
>> THE USE
>> + *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
>> DAMAGE.
>> + */
>> +
>> +#include <stdio.h>
>> +#include <string.h>
>> +#include <inttypes.h>
>> +#include <sys/queue.h>
>> +#include <sys/signalfd.h>
>> +#include <sys/ioctl.h>
>> +#include <sys/socket.h>
>> +#include <linux/netlink.h>
>> +#include <sys/epoll.h>
>> +#include <unistd.h>
>> +#include <signal.h>
>> +#include <stdbool.h>
>> +
>> +#include <rte_malloc.h>
>> +#include <rte_bus.h>
>> +#include <rte_dev.h>
>> +#include <rte_devargs.h>
>> +#include <rte_debug.h>
>> +#include <rte_log.h>
>> +
>> +#include "eal_thread.h"
>> +
>> +/* uev monitoring thread */
>> +static pthread_t uev_monitor_thread;
>> +
>> +bool udev_exit = true;
>> +
>> +bool no_request_thread = true;
>> +
>> +static void sig_handler(int signum)
>> +{
>> +	if (signum == SIGINT || signum == SIGTERM)
>> +		rte_dev_monitor_stop();
>> +}
>> +
>> +static int
>> +dev_monitor_fd_new(void)
>> +{
>> +
>> +	int uevent_fd;
>> +
>> +	uevent_fd = socket(PF_NETLINK, SOCK_RAW | SOCK_CLOEXEC |
>> +			SOCK_NONBLOCK,
>> +			NETLINK_KOBJECT_UEVENT);
>> +	if (uevent_fd < 0) {
>> +		RTE_LOG(ERR, EAL, "create uevent fd failed\n");
>> +		return -1;
>> +	}
>> +	return uevent_fd;
>> +}
>> +
>> +static int
>> +dev_monitor_enable(int netlink_fd)
>> +{
>> +	struct sockaddr_nl addr;
>> +	int ret;
>> +	int size = 64 * 1024;
>> +	int nonblock = 1;
>> +
>> +	memset(&addr, 0, sizeof(addr));
>> +	addr.nl_family = AF_NETLINK;
>> +	addr.nl_pid = 0;
>> +	addr.nl_groups = 0xffffffff;
>> +
>> +	if (bind(netlink_fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
>> +		RTE_LOG(ERR, EAL, "bind failed\n");
>> +		goto err;
>> +	}
>> +
>> +	setsockopt(netlink_fd, SOL_SOCKET, SO_PASSCRED, &size,
>> sizeof(size));
>> +
>> +	ret = ioctl(netlink_fd, FIONBIO, &nonblock);
>> +	if (ret != 0) {
>> +		RTE_LOG(ERR, EAL, "ioctl(FIONBIO) failed\n");
>> +		goto err;
>> +	}
>> +	return 0;
>> +err:
>> +	close(netlink_fd);
>> +	return -1;
>> +}
>> +
>> +static void
>> +dev_uev_parse(const char *buf, struct rte_eal_uevent *event)
>> +{
>> +	char action[RTE_EAL_UEV_MSG_ELEM_LEN];
>> +	char subsystem[RTE_EAL_UEV_MSG_ELEM_LEN];
>> +	char dev_path[RTE_EAL_UEV_MSG_ELEM_LEN];
>> +	char pci_slot_name[RTE_EAL_UEV_MSG_ELEM_LEN];
>> +	int i = 0;
>> +
>> +	memset(action, 0, RTE_EAL_UEV_MSG_ELEM_LEN);
>> +	memset(subsystem, 0, RTE_EAL_UEV_MSG_ELEM_LEN);
>> +	memset(dev_path, 0, RTE_EAL_UEV_MSG_ELEM_LEN);
>> +	memset(pci_slot_name, 0, RTE_EAL_UEV_MSG_ELEM_LEN);
>> +
>> +	while (i < RTE_EAL_UEV_MSG_LEN) {
>> +		for (; i < RTE_EAL_UEV_MSG_LEN; i++) {
>> +			if (*buf)
>> +				break;
>> +			buf++;
>> +		}
>> +		if (!strncmp(buf, "libudev", 7)) {
>> +			buf += 7;
>> +			i += 7;
>> +			event->group = UEV_MONITOR_UDEV;
>> +		}
>> +		if (!strncmp(buf, "ACTION=", 7)) {
>> +			buf += 7;
>> +			i += 7;
>> +			snprintf(action, sizeof(action), "%s", buf);
>> +		} else if (!strncmp(buf, "DEVPATH=", 8)) {
>> +			buf += 8;
>> +			i += 8;
>> +			snprintf(dev_path, sizeof(dev_path), "%s", buf);
>> +		} else if (!strncmp(buf, "SUBSYSTEM=", 10)) {
>> +			buf += 10;
>> +			i += 10;
>> +			snprintf(subsystem, sizeof(subsystem), "%s", buf);
>> +		} else if (!strncmp(buf, "PCI_SLOT_NAME=", 14)) {
>> +			buf += 14;
>> +			i += 14;
>> +			snprintf(pci_slot_name, sizeof(subsystem), "%s",
>> buf);
>> +			event->devname = pci_slot_name;
>> +		}
>> +		for (; i < RTE_EAL_UEV_MSG_LEN; i++) {
>> +			if (*buf == '\0')
>> +				break;
>> +			buf++;
>> +		}
>> +	}
>> +
>> +	if (!strncmp(subsystem, "pci", 3))
>> +		event->subsystem = UEV_SUBSYSTEM_PCI;
>> +	if (!strncmp(action, "add", 3))
>> +		event->type = RTE_EAL_DEV_EVENT_ADD;
>> +	if (!strncmp(action, "remove", 6))
>> +		event->type = RTE_EAL_DEV_EVENT_REMOVE;
>> +	event->devname = pci_slot_name;
>> +}
>> +
>> +static int
>> +dev_uev_receive(int fd, struct rte_eal_uevent *uevent)
>> +{
>> +	int ret;
>> +	char buf[RTE_EAL_UEV_MSG_LEN];
>> +
>> +	memset(uevent, 0, sizeof(struct rte_eal_uevent));
>> +	memset(buf, 0, RTE_EAL_UEV_MSG_LEN);
>> +
>> +	ret = recv(fd, buf, RTE_EAL_UEV_MSG_LEN - 1, MSG_DONTWAIT);
>> +	if (ret < 0) {
>> +		RTE_LOG(ERR, EAL,
>> +		"Socket read error(%d): %s\n",
>> +		errno, strerror(errno));
>> +		return -1;
>> +	} else if (ret == 0)
>> +		/* connection closed */
>> +		return -1;
>> +
>> +	dev_uev_parse(buf, uevent);
>> +
>> +	return 0;
>> +}
>> +
>> +static int
>> +dev_uev_process(struct epoll_event *events, int nfds)
>> +{
>> +	struct rte_bus *bus;
>> +	struct rte_device *dev;
>> +	struct rte_eal_uevent uevent;
>> +	int ret;
>> +	int i;
>> +
>> +	for (i = 0; i < nfds; i++) {
>> +		/**
>> +		 * check device uevent from kernel side, no need to check
>> +		 * uevent from udev.
>> +		 */
>> +		if ((dev_uev_receive(events[i].data.fd, &uevent)) ||
>> +			(uevent.group == UEV_MONITOR_UDEV))
>> +			return 0;
>> +
>> +		/* default handle all pci devcie when is being hot plug */
>> +		if (uevent.subsystem == UEV_SUBSYSTEM_PCI) {
>> +			bus = rte_bus_find_by_name("pci");
>> +			dev = rte_bus_find_device(bus, uevent.devname);
>> +			if (uevent.type == RTE_EAL_DEV_EVENT_REMOVE) {
>> +
>> +				if ((!dev) || dev->state ==
>> DEVICE_UNDEFINED)
>> +					return 0;
>> +				dev->state = DEVICE_FAULT;
>> +
>> +				/**
>> +				 * remap the resource to be fake
>> +				 * before user's removal processing
>> +				 */
>> +				ret = bus->remap_device(dev);
>> +				if (!ret)
>> +
>> 	return(_rte_dev_callback_process(dev,
>> +					  RTE_EAL_DEV_EVENT_REMOVE,
>> +					  NULL, NULL));
> What is the reason to keep this device in EAL device list after the removal?
> I suggest to remove it (driver remove, bus remove and EAL remove) after the callbacks running.
> By this way EAL can initiate all device removals.
agree, device should be remove from the eal device list after the removal.
>> +			} else if (uevent.type == RTE_EAL_DEV_EVENT_ADD)
>> {
>> +				if (dev == NULL) {
>> +					/**
>> +					 * bind the driver to the device
>> +					 * before user's add processing
>> +					 */
>> +					bus->bind_driver(
>> +						uevent.devname,
>> +						"igb_uio");
>> +
> Similar comments here:
> EAL can initiate all device probe operations by adding the device and probing it here before the callback running.
> Then, also the device pointer can be passed to the callbacks.
pass a device pointer could be bring some more change, let's think about 
more.
>> 	return(_rte_dev_callback_process(NULL,
>> +					  RTE_EAL_DEV_EVENT_ADD,
>> +					  uevent.devname, NULL));
>> +				}
>> +			}
>> +		}
>> +	}
>> +	return 0;
>> +}
>> +
>> +/**
>> + * It builds/rebuilds up the epoll file descriptor with all the
>> + * file descriptors being waited on. Then handles the interrupts.
>> + *
>> + * @param arg
>> + *  pointer. (unused)
>> + *
>> + * @return
>> + *  never return;
>> + */
>> +static __attribute__((noreturn)) void *
>> +dev_uev_monitoring(__rte_unused void *arg)
>> +{
>> +	struct sigaction act;
>> +	sigset_t mask;
>> +	int netlink_fd;
>> +	struct epoll_event ep_kernel;
>> +	int fd_ep;
>> +
>> +	udev_exit = false;
>> +
>> +	/* set signal handlers */
>> +	memset(&act, 0x00, sizeof(struct sigaction));
>> +	act.sa_handler = sig_handler;
>> +	sigemptyset(&act.sa_mask);
>> +	act.sa_flags = SA_RESTART;
>> +	sigaction(SIGINT, &act, NULL);
>> +	sigaction(SIGTERM, &act, NULL);
>> +	sigemptyset(&mask);
>> +	sigaddset(&mask, SIGINT);
>> +	sigaddset(&mask, SIGTERM);
>> +	sigprocmask(SIG_UNBLOCK, &mask, NULL);
>> +
>> +	fd_ep = epoll_create1(EPOLL_CLOEXEC);
>> +	if (fd_ep < 0) {
>> +		RTE_LOG(ERR, EAL, "error creating epoll fd: %m\n");
>> +		goto out;
>> +	}
>> +
>> +	netlink_fd = dev_monitor_fd_new();
>> +
>> +	if (dev_monitor_enable(netlink_fd) < 0) {
>> +		RTE_LOG(ERR, EAL, "error subscribing to kernel events\n");
>> +		goto out;
>> +	}
>> +
>> +	memset(&ep_kernel, 0, sizeof(struct epoll_event));
>> +	ep_kernel.events = EPOLLIN | EPOLLPRI | EPOLLRDHUP | EPOLLHUP;
>> +	ep_kernel.data.fd = netlink_fd;
>> +	if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, netlink_fd,
>> +		&ep_kernel) < 0) {
>> +		RTE_LOG(ERR, EAL, "error addding fd to epoll: %m\n");
>> +		goto out;
>> +	}
>> +
>> +	while (!udev_exit) {
>> +		int fdcount;
>> +		struct epoll_event ev[1];
>> +
>> +		fdcount = epoll_wait(fd_ep, ev, 1, -1);
>> +		if (fdcount < 0) {
>> +			if (errno != EINTR)
>> +				RTE_LOG(ERR, EAL, "error receiving uevent "
>> +					"message: %m\n");
>> +				continue;
>> +			}
>> +
>> +		/* epoll_wait has at least one fd ready to read */
>> +		if (dev_uev_process(ev, fdcount) < 0) {
>> +			if (errno != EINTR)
>> +				RTE_LOG(ERR, EAL, "error processing uevent
>> "
>> +					"message: %m\n");
>> +		}
>> +	}
>> +out:
>> +	if (fd_ep >= 0)
>> +		close(fd_ep);
>> +	if (netlink_fd >= 0)
>> +		close(netlink_fd);
>> +	rte_panic("uev monitoring fail\n");
>> +}
>> +
>> +int
>> +rte_dev_monitor_start(void)
>> +{
> Maybe add option to run it also by new EAL command line parameter?
good idea.
>> +	int ret;
>> +
>> +	if (!no_request_thread)
>> +		return 0;
>> +	no_request_thread = false;
>> +
>> +	/* create the host thread to wait/handle the uevent from kernel */
>> +	ret = pthread_create(&uev_monitor_thread, NULL,
>> +		dev_uev_monitoring, NULL);
> What is the reason to open new thread for hotplug?
> Why not to use the current dpdk host thread by the alarm mechanism?
appropriate if you could talk about what you mean the disadvantage of 
new thread here and the advantage of alarm mechanism at the case?
>> +	return ret;
>> +}
>> +
>> +int
>> +rte_dev_monitor_stop(void)
>> +{
>> +	udev_exit = true;
>> +	no_request_thread = true;
>> +	return 0;
>> +}
>> diff --git a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_dev.h
>> b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_dev.h
>> new file mode 100644
>> index 0000000..6a6feb5
>> --- /dev/null
>> +++ b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_dev.h
>> @@ -0,0 +1,106 @@
>> +/*-
>> + *   BSD LICENSE
>> + *
>> + *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
>> + *   All rights reserved.
>> + *
>> + *   Redistribution and use in source and binary forms, with or without
>> + *   modification, are permitted provided that the following conditions
>> + *   are met:
>> + *
>> + *     * Redistributions of source code must retain the above copyright
>> + *       notice, this list of conditions and the following disclaimer.
>> + *     * Redistributions in binary form must reproduce the above copyright
>> + *       notice, this list of conditions and the following disclaimer in
>> + *       the documentation and/or other materials provided with the
>> + *       distribution.
>> + *     * Neither the name of Intel Corporation nor the names of its
>> + *       contributors may be used to endorse or promote products derived
>> + *       from this software without specific prior written permission.
>> + *
>> + *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
>> CONTRIBUTORS
>> + *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT
>> NOT
>> + *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
>> FITNESS FOR
>> + *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
>> COPYRIGHT
>> + *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
>> INCIDENTAL,
>> + *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
>> NOT
>> + *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
>> OF USE,
>> + *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
>> AND ON ANY
>> + *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
>> TORT
>> + *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
>> THE USE
>> + *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
>> DAMAGE.
>> + */
>> +
>> +#ifndef _RTE_DEV_H_
>> +#error "don't include this file directly, please include generic <rte_dev.h>"
>> +#endif
>> +
>> +#ifndef _RTE_LINUXAPP_DEV_H_
>> +#define _RTE_LINUXAPP_DEV_H_
>> +
>> +#include <stdio.h>
>> +
>> +#include <rte_dev.h>
>> +
>> +#define RTE_EAL_UEV_MSG_LEN 4096
>> +#define RTE_EAL_UEV_MSG_ELEM_LEN 128
>> +
>> +enum uev_subsystem {
>> +	UEV_SUBSYSTEM_UIO,
>> +	UEV_SUBSYSTEM_VFIO,
>> +	UEV_SUBSYSTEM_PCI,
>> +	UEV_SUBSYSTEM_MAX
>> +};
>> +
>> +enum uev_monitor_netlink_group {
>> +	UEV_MONITOR_KERNEL,
>> +	UEV_MONITOR_UDEV,
>> +};
>> +
>> +/**
>> + * The device event type.
>> + */
>> +enum rte_eal_dev_event_type {
>> +	RTE_EAL_DEV_EVENT_UNKNOWN,	/**< unknown event type */
>> +	RTE_EAL_DEV_EVENT_ADD,		/**< device adding event */
>> +	RTE_EAL_DEV_EVENT_REMOVE,
>> +					/**< device removing event */
>> +	RTE_EAL_DEV_EVENT_CHANGE,
>> +					/**< device status change event */
>> +	RTE_EAL_DEV_EVENT_MOVE,		/**< device sys path move
>> event */
>> +	RTE_EAL_DEV_EVENT_ONLINE,	/**< device online event */
>> +	RTE_EAL_DEV_EVENT_OFFLINE,	/**< device offline event */
>> +	RTE_EAL_DEV_EVENT_MAX		/**< max value of this enum
>> */
>> +};
>> +
>> +struct rte_eal_uevent {
>> +	enum rte_eal_dev_event_type type;	/**< device event type */
>> +	int subsystem;				/**< subsystem id */
>> +	char *devname;				/**< device name */
>> +	enum uev_monitor_netlink_group group;	/**< device netlink
>> group */
>> +};
>> +
>> +/**
>> + * Start the device uevent monitoring.
>> + *
>> + * @param none
>> + * @return
>> + *   - On success, zero.
>> + *   - On failure, a negative value.
>> + */
>> +int
>> +rte_dev_monitor_start(void);
>> +
>> +/**
>> + * Stop the device uevent monitoring .
>> + *
>> + * @param none
>> + * @return
>> + *   - On success, zero.
>> + *   - On failure, a negative value.
>> + */
>> +
>> +int
>> +rte_dev_monitor_stop(void);
>> +
>> +#endif /* _RTE_LINUXAPP_DEV_H_ */
>> diff --git a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
>> b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
>> index a3a98c1..d0e07b4 100644
>> --- a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
>> +++ b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
>> @@ -354,6 +354,12 @@ igbuio_pci_release(struct uio_info *info, struct
>> inode *inode)
>>   	struct rte_uio_pci_dev *udev = info->priv;
>>   	struct pci_dev *dev = udev->pdev;
>>
>> +	/* check if device have been remove before release */
>> +	if ((&dev->dev.kobj)->state_remove_uevent_sent == 1) {
>> +		pr_info("The device have been removed\n");
>> +		return -1;
>> +	}
>> +
>>   	/* disable interrupts */
>>   	igbuio_pci_disable_interrupts(udev);
>>
>> diff --git a/lib/librte_pci/rte_pci.c b/lib/librte_pci/rte_pci.c
>> index 0160fc1..feb5fd7 100644
>> --- a/lib/librte_pci/rte_pci.c
>> +++ b/lib/librte_pci/rte_pci.c
>> @@ -172,6 +172,26 @@ rte_pci_addr_parse(const char *str, struct
>> rte_pci_addr *addr)
>>   	return -1;
>>   }
>>
>> +/* map a private resource from an address*/
>> +void *
>> +pci_map_private_resource(void *requested_addr, off_t offset, size_t size)
>> +{
>> +	void *mapaddr;
>> +
>> +	mapaddr = mmap(requested_addr, size,
>> +			   PROT_READ | PROT_WRITE,
>> +			   MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED,
>> -1, 0);
>> +	if (mapaddr == MAP_FAILED) {
>> +		RTE_LOG(ERR, EAL, "%s(): cannot mmap(%p, 0x%lx, 0x%lx): "
>> +			"%s (%p)\n",
>> +			__func__, requested_addr,
>> +			(unsigned long)size, (unsigned long)offset,
>> +			strerror(errno), mapaddr);
>> +	} else
>> +		RTE_LOG(DEBUG, EAL, "  PCI memory mapped at %p\n",
>> mapaddr);
>> +
>> +	return mapaddr;
>> +}
>>
>>   /* map a particular resource from a file */
>>   void *
>> diff --git a/lib/librte_pci/rte_pci.h b/lib/librte_pci/rte_pci.h
>> index 4f2cd18..f6091a6 100644
>> --- a/lib/librte_pci/rte_pci.h
>> +++ b/lib/librte_pci/rte_pci.h
>> @@ -227,6 +227,23 @@ int rte_pci_addr_cmp(const struct rte_pci_addr
>> *addr,
>>   int rte_pci_addr_parse(const char *str, struct rte_pci_addr *addr);
>>
>>   /**
>> + * @internal
>> + * Map to a particular private resource.
>> + *
>> + * @param requested_addr
>> + *      The starting address for the new mapping range.
>> + * @param offset
>> + *      The offset for the mapping range.
>> + * @param size
>> + *      The size for the mapping range.
>> + * @return
>> + *   - On success, the function returns a pointer to the mapped area.
>> + *   - On error, the value MAP_FAILED is returned.
>> + */
>> +void *pci_map_private_resource(void *requested_addr, off_t offset,
>> +		size_t size);
>> +
>> +/**
>>    * Map a particular resource from a file.
>>    *
>>    * @param requested_addr
>> --
>> 2.7.4



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