[dpdk-stable] patch 'net/enic: allocate stats DMA buffer upfront during probe' has been queued to stable release 18.02.2

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 18.02.2

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 05/02/18. So please
shout if anyone has objections.

Thanks.

Luca Boccassi

---
>From bff48febbdbeaa0875cde88868937a67e743ba73 Mon Sep 17 00:00:00 2001
From: Hyong Youb Kim <hyonkim at cisco.com>
Date: Wed, 7 Mar 2018 18:46:58 -0800
Subject: [PATCH] net/enic: allocate stats DMA buffer upfront during probe

[ upstream commit 8d782f3f89e1dcd0c8af1c3c93501d7a06159d66 ]

The driver provides a DMA buffer to the firmware when it requests port
stats. The NIC then fills that buffer with latest stats. Currently,
the driver allocates the DMA buffer the first time it requests stats
and saves it for later use. This can lead to crashes when
primary/secondary processes are involved. For example, the following
sequence crashes the secondary process.

1. Start a primary app that does not call rte_eth_stats_get()
2. dpdk-procinfo -- --stats

dpdk-procinfo crashes while trying to allocate the stats DMA buffer
because the alloc function pointer (vdev.alloc_consistent) is valid
only in the primary process, not in the secondary process.

Overwriting the alloc function pointer in the secondary process is not
an option, as it will simply make the pointer invalid in the primary
process. Instead, allocate the DMA buffer during probe so that only
the primary process does both allocate and free. This allows the
secondary process to dump stats as well.

Fixes: 9913fbb91df0 ("enic/base: common code")

Signed-off-by: Hyong Youb Kim <hyonkim at cisco.com>
Reviewed-by: John Daley <johndale at cisco.com>
---
 drivers/net/enic/base/vnic_dev.c | 24 ++++++++++++++----------
 drivers/net/enic/base/vnic_dev.h |  1 +
 drivers/net/enic/enic_main.c     |  9 +++++++++
 3 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/drivers/net/enic/base/vnic_dev.c b/drivers/net/enic/base/vnic_dev.c
index 05b595eb8..1f8d222fc 100644
--- a/drivers/net/enic/base/vnic_dev.c
+++ b/drivers/net/enic/base/vnic_dev.c
@@ -587,17 +587,9 @@ int vnic_dev_stats_dump(struct vnic_dev *vdev, struct vnic_stats **stats)
 {
 	u64 a0, a1;
 	int wait = 1000;
-	static u32 instance;
-	char name[NAME_MAX];
 
-	if (!vdev->stats) {
-		snprintf((char *)name, sizeof(name),
-			"vnic_stats-%u", instance++);
-		vdev->stats = vdev->alloc_consistent(vdev->priv,
-			sizeof(struct vnic_stats), &vdev->stats_pa, (u8 *)name);
-		if (!vdev->stats)
-			return -ENOMEM;
-	}
+	if (!vdev->stats)
+		return -ENOMEM;
 
 	*stats = vdev->stats;
 	a0 = vdev->stats_pa;
@@ -922,6 +914,18 @@ u32 vnic_dev_get_intr_coal_timer_max(struct vnic_dev *vdev)
 	return vdev->intr_coal_timer_info.max_usec;
 }
 
+int vnic_dev_alloc_stats_mem(struct vnic_dev *vdev)
+{
+	char name[NAME_MAX];
+	static u32 instance;
+
+	snprintf((char *)name, sizeof(name), "vnic_stats-%u", instance++);
+	vdev->stats = vdev->alloc_consistent(vdev->priv,
+					     sizeof(struct vnic_stats),
+					     &vdev->stats_pa, (u8 *)name);
+	return vdev->stats == NULL ? -ENOMEM : 0;
+}
+
 void vnic_dev_unregister(struct vnic_dev *vdev)
 {
 	if (vdev) {
diff --git a/drivers/net/enic/base/vnic_dev.h b/drivers/net/enic/base/vnic_dev.h
index 8c0992063..7e5736b4d 100644
--- a/drivers/net/enic/base/vnic_dev.h
+++ b/drivers/net/enic/base/vnic_dev.h
@@ -165,6 +165,7 @@ struct vnic_dev *vnic_dev_register(struct vnic_dev *vdev,
 	void *priv, struct rte_pci_device *pdev, struct vnic_dev_bar *bar,
 	unsigned int num_bars);
 struct rte_pci_device *vnic_dev_get_pdev(struct vnic_dev *vdev);
+int vnic_dev_alloc_stats_mem(struct vnic_dev *vdev);
 int vnic_dev_cmd_init(struct vnic_dev *vdev, int fallback);
 int vnic_dev_get_size(void);
 int vnic_dev_int13(struct vnic_dev *vdev, u64 arg, u32 op);
diff --git a/drivers/net/enic/enic_main.c b/drivers/net/enic/enic_main.c
index ec9d343fd..caccdafff 100644
--- a/drivers/net/enic/enic_main.c
+++ b/drivers/net/enic/enic_main.c
@@ -1351,6 +1351,15 @@ int enic_probe(struct enic *enic)
 		enic_alloc_consistent,
 		enic_free_consistent);
 
+	/*
+	 * Allocate the consistent memory for stats upfront so both primary and
+	 * secondary processes can dump stats.
+	 */
+	err = vnic_dev_alloc_stats_mem(enic->vdev);
+	if (err) {
+		dev_err(enic, "Failed to allocate cmd memory, aborting\n");
+		goto err_out_unregister;
+	}
 	/* Issue device open to get device in known state */
 	err = enic_dev_open(enic);
 	if (err) {
-- 
2.14.2