[dpdk-dev] [PATCH 4/7] eal: support different modules

[Stephen Hemminger]

On Mon, 03 Jun 2013 10:58:01 +0200
Damien Millescamps <damien.millescamps at 6wind.com> wrote:

> comments inlined.
> 
> On 05/30/2013 07:12 PM, Stephen Hemminger wrote:
> > An additional change is that failure to detect module should not be fatal,
> > but an error like other EAL setup problems, allowing the application
> > to recover.
> >
> > Signed-off-by: Stephen Hemminger <shemminger at vyatta.com>
> >
> > ---
> >  app/chkincs/test_pci.c                  |    3 ++-
> >  app/test/test_pci.c                     |    4 ++--
> >  lib/librte_eal/common/include/rte_pci.h |    5 ++---
> >  lib/librte_eal/linuxapp/eal/eal_pci.c   |    9 ++-------
> >  lib/librte_pmd_igb/e1000_ethdev.c       |    2 +-
> >  lib/librte_pmd_ixgbe/ixgbe_ethdev.c     |    4 ++--
> >  6 files changed, 11 insertions(+), 16 deletions(-)
> >
> > --- a/lib/librte_eal/common/include/rte_pci.h	2013-05-29 08:45:38.000000000 -0700
> > +++ b/lib/librte_eal/common/include/rte_pci.h	2013-05-29 09:02:50.000000000 -0700
> > @@ -151,12 +151,11 @@ struct rte_pci_driver {
> >  	pci_devinit_t *devinit;                 /**< Device init. function. */
> >  	struct rte_pci_id *id_table;            /**< ID table, NULL terminated. */
> >  	uint32_t drv_flags;                     /**< Flags contolling handling of device. */
> > +	const char *module_name;		/**< Associated kernel module */
> 
> You solution only permits for one module to be checked during
> initialization, while the former solution using flags could be easily
> extended to check for more than one module.
> However it is true that there is a problem with this module check since
> it is historically hard-coded for "igb_uio".
> 
> Some better solution could be to have a new flag that will check for a
> NULL terminated array of module_name.
> 
> >  };
> >  
> > -/** Device needs igb_uio kernel module */
> > -#define RTE_PCI_DRV_NEED_IGB_UIO 0x0001
> >  /** Device driver must be registered several times until failure */
> > -#define RTE_PCI_DRV_MULTIPLE 0x0002
> > +#define RTE_PCI_DRV_MULTIPLE 0x0001
> You are breaking a public API here, and I don't see any technical reason
> to do so. The RTE_PCI_DRV_NEED_IGB_UIO flag could be deprecated, but
> there is no way its value could be recycled into an already existing flag.
> 
> >  
> >  /**
> >   * Probe the PCI bus for registered drivers.
> > --- a/lib/librte_eal/linuxapp/eal/eal_pci.c	2013-03-28 08:50:50.000000000 -0700
> > +++ b/lib/librte_eal/linuxapp/eal/eal_pci.c	2013-05-29 09:04:00.000000000 -0700
> > @@ -76,7 +76,7 @@
> >   * This code is used to simulate a PCI probe by parsing information in
> >   * sysfs. Moreover, when a registered driver matches a device, the
> >   * kernel driver currently using it is unloaded and replaced by
> > - * igb_uio module, which is a very minimal userland driver for Intel
> > + * a module, which is a very minimal userland driver for Intel
> >   * network card, only providing access to PCI BAR to applications, and
> >   * enabling bus master.
> >   */
> > @@ -84,8 +84,6 @@
> >  
> >  #define PROC_MODULES "/proc/modules"
> >  
> > -#define IGB_UIO_NAME "igb_uio"
> > -
> >  #define UIO_NEWID "/sys/bus/pci/drivers/%s/new_id"
> >  #define UIO_BIND  "/sys/bus/pci/drivers/%s/bind"
> >  
> > @@ -700,12 +698,9 @@ int
> >  rte_eal_pci_probe_one_driver(struct rte_pci_driver *dr, struct rte_pci_device *dev)
> >  {
> >  	struct rte_pci_id *id_table;
> > -	const char *module_name = NULL;
> > +	const char *module_name = dr->module_name;
> >  	int uio_status = -1;
> >  
> > -	if (dr->drv_flags & RTE_PCI_DRV_NEED_IGB_UIO)
> > -		module_name = IGB_UIO_NAME;
> > -
> >  	uio_status = pci_uio_check_module(module_name);
> >  
> >  	for (id_table = dr->id_table ; id_table->vendor_id != 0; id_table++) {
> > --- a/lib/librte_pmd_ixgbe/ixgbe_ethdev.c	2013-05-29 08:45:38.000000000 -0700
> > +++ b/lib/librte_pmd_ixgbe/ixgbe_ethdev.c	2013-05-29 16:08:07.544000027 -0700
> > @@ -547,7 +547,7 @@ static struct eth_driver rte_ixgbe_pmd =
> >  	{
> >  		.name = "rte_ixgbe_pmd",
> >  		.id_table = pci_id_ixgbe_map,
> > -		.drv_flags = RTE_PCI_DRV_NEED_IGB_UIO,
> > +		.module_name = "igb_uio",
> >  	},
> >  	.eth_dev_init = eth_ixgbe_dev_init,
> >  	.dev_private_size = sizeof(struct ixgbe_adapter),
> > @@ -560,7 +560,7 @@ static struct eth_driver rte_ixgbevf_pmd
> >  	{
> >  		.name = "rte_ixgbevf_pmd",
> >  		.id_table = pci_id_ixgbevf_map,
> > -		.drv_flags = RTE_PCI_DRV_NEED_IGB_UIO,
> > +		.module_name = "igb_uio",
> >  	},
> >  	.eth_dev_init = eth_ixgbevf_dev_init,
> >  	.dev_private_size = sizeof(struct ixgbe_adapter),
> > --- a/app/test/test_pci.c	2013-03-28 08:50:50.000000000 -0700
> > +++ b/app/test/test_pci.c	2013-05-29 16:05:22.881670915 -0700
> > @@ -69,7 +69,7 @@ static int my_driver_init(struct rte_pci
> >  			  struct rte_pci_device *dev);
> >  
> >  /*
> > - * To test cases where RTE_PCI_DRV_NEED_IGB_UIO is set, and isn't set, two
> > + * To test cases where module_name is set, and isn't set, two
> >   * drivers are created (one with IGB devices, the other with IXGBE devices).
> >   */
> >  
> > @@ -101,7 +101,7 @@ struct rte_pci_driver my_driver = {
> >  	.name = "test_driver",
> >  	.devinit = my_driver_init,
> >  	.id_table = my_driver_id,
> > -	.drv_flags = RTE_PCI_DRV_NEED_IGB_UIO,
> > +	.module_name = "igb_uio",
> >  };
> >  
> >  struct rte_pci_driver my_driver2 = {
> > --- a/app/chkincs/test_pci.c	2013-03-28 08:50:50.210414181 -0700
> > +++ b/app/chkincs/test_pci.c	2013-05-29 16:07:43.880238599 -0700
> > @@ -64,7 +64,8 @@ struct rte_pci_driver my_driver = {
> >  	"test_driver",
> >  	my_driver_init,
> >  	my_driver_id,
> > -	RTE_PCI_DRV_NEED_IGB_UIO,
> > +	0,
> > +	"igb_uio",
> >  };
> >  
> >  static int
> > --- a/lib/librte_pmd_igb/e1000_ethdev.c	2013-05-29 08:45:38.888471864 -0700
> > +++ b/lib/librte_pmd_igb/e1000_ethdev.c	2013-05-29 16:04:50.410003570 -0700
> > @@ -336,7 +336,7 @@ static struct eth_driver rte_igb_pmd = {
> >  	{
> >  		.name = "rte_igb_pmd",
> >  		.id_table = pci_id_igb_map,
> > -		.drv_flags = RTE_PCI_DRV_NEED_IGB_UIO,
> > +		.module_name = "igb_uio",
> >  	},
> >  	.eth_dev_init = eth_igb_dev_init,
> >  	.dev_private_size = sizeof(struct e1000_adapter),
> >
> >
> 

It is one module per driver which works quite well.
The code identifies the module to load based on the PCI id.