[dpdk-stable] patch 'vfio: fix race condition with sysfs' has been queued to stable release 19.11.3

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 19.11.3

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 05/21/20. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Thanks.

Luca Boccassi

---
>From 5732151922c287abf7c21b92291d041ef1cc0cdb Mon Sep 17 00:00:00 2001
From: Michael Haeuptle <michael.haeuptle at hpe.com>
Date: Mon, 6 Apr 2020 22:23:23 +0000
Subject: [PATCH] vfio: fix race condition with sysfs

[ upstream commit b758423bc4fe412941a289f3181849669c02b904 ]

This fix treats a 0 return value from vfio_open_group_fd
in vfio_get_group_fd as the intended error condition instead
of putting an incorrect 0 file descriptor in the vfio_group table.

Sometimes, the creation of device files in sysfs is not
instantaneously causing vfio_open_groupfd to return 0.
This has been observed when hot removing/adding multiple
NVMe devices (>=4).

Fixes: 340b7bb8d583 ("vfio: extend data structure for multi container")

Signed-off-by: Michael Haeuptle <michael.haeuptle at hpe.com>
Acked-by: Darek Stojaczyk <dariusz.stojaczyk at intel.com>
Acked-by: Anatoly Burakov <anatoly.burakov at intel.com>
---
 lib/librte_eal/linux/eal/eal_vfio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/librte_eal/linux/eal/eal_vfio.c b/lib/librte_eal/linux/eal/eal_vfio.c
index 01b5ef3f42..b82a5018bf 100644
--- a/lib/librte_eal/linux/eal/eal_vfio.c
+++ b/lib/librte_eal/linux/eal/eal_vfio.c
@@ -379,7 +379,7 @@ vfio_get_group_fd(struct vfio_config *vfio_cfg,
 	}
 
 	vfio_group_fd = vfio_open_group_fd(iommu_group_num);
-	if (vfio_group_fd < 0) {
+	if (vfio_group_fd <= 0) {
 		RTE_LOG(ERR, EAL, "Failed to open group %d\n", iommu_group_num);
 		return -1;
 	}
-- 
2.20.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2020-05-19 13:56:21.770577448 +0100
+++ 0073-vfio-fix-race-condition-with-sysfs.patch	2020-05-19 13:56:18.299503260 +0100
@@ -1,8 +1,10 @@
-From b758423bc4fe412941a289f3181849669c02b904 Mon Sep 17 00:00:00 2001
+From 5732151922c287abf7c21b92291d041ef1cc0cdb Mon Sep 17 00:00:00 2001
 From: Michael Haeuptle <michael.haeuptle at hpe.com>
 Date: Mon, 6 Apr 2020 22:23:23 +0000
 Subject: [PATCH] vfio: fix race condition with sysfs
 
+[ upstream commit b758423bc4fe412941a289f3181849669c02b904 ]
+
 This fix treats a 0 return value from vfio_open_group_fd
 in vfio_get_group_fd as the intended error condition instead
 of putting an incorrect 0 file descriptor in the vfio_group table.
@@ -13,19 +15,18 @@
 NVMe devices (>=4).
 
 Fixes: 340b7bb8d583 ("vfio: extend data structure for multi container")
-Cc: stable at dpdk.org
 
 Signed-off-by: Michael Haeuptle <michael.haeuptle at hpe.com>
 Acked-by: Darek Stojaczyk <dariusz.stojaczyk at intel.com>
 Acked-by: Anatoly Burakov <anatoly.burakov at intel.com>
 ---
- lib/librte_eal/linux/eal_vfio.c | 2 +-
+ lib/librte_eal/linux/eal/eal_vfio.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
 
-diff --git a/lib/librte_eal/linux/eal_vfio.c b/lib/librte_eal/linux/eal_vfio.c
-index 4502aefed3..1979f6fdd8 100644
---- a/lib/librte_eal/linux/eal_vfio.c
-+++ b/lib/librte_eal/linux/eal_vfio.c
+diff --git a/lib/librte_eal/linux/eal/eal_vfio.c b/lib/librte_eal/linux/eal/eal_vfio.c
+index 01b5ef3f42..b82a5018bf 100644
+--- a/lib/librte_eal/linux/eal/eal_vfio.c
++++ b/lib/librte_eal/linux/eal/eal_vfio.c
 @@ -379,7 +379,7 @@ vfio_get_group_fd(struct vfio_config *vfio_cfg,
  	}