[dpdk-stable] patch 'net/mlx5: fix r/w lock usage in DMA unmap' has been queued to stable release 20.11.3

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 20.11.3

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 07/14/21. 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.

Queued patches are on a temporary branch at:
https://github.com/bluca/dpdk-stable

This queued commit can be viewed at:
https://github.com/bluca/dpdk-stable/commit/653b095f492f5219ae7f00e904bf23b397a2adb7

Thanks.

Luca Boccassi

---
>From 653b095f492f5219ae7f00e904bf23b397a2adb7 Mon Sep 17 00:00:00 2001
From: Feifei Wang <feifei.wang2 at arm.com>
Date: Thu, 27 May 2021 17:48:06 +0800
Subject: [PATCH] net/mlx5: fix r/w lock usage in DMA unmap

[ upstream commit 1c196da274b82e6f1642bde7b1c407a2066caee1 ]

For mlx5 DMA unmap, write lock should be used for rebuilding memory
region cache table rather than read lock.

Fixes: 989e999d9305 ("net/mlx5: support PCI device DMA map and unmap")

Signed-off-by: Feifei Wang <feifei.wang2 at arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang at arm.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo at nvidia.com>
---
 drivers/net/mlx5/mlx5_mr.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/mlx5/mlx5_mr.c b/drivers/net/mlx5/mlx5_mr.c
index 2cce3b9fe8..1dd14ddfe5 100644
--- a/drivers/net/mlx5/mlx5_mr.c
+++ b/drivers/net/mlx5/mlx5_mr.c
@@ -302,10 +302,10 @@ mlx5_dma_unmap(struct rte_pci_device *pdev, void *addr,
 	}
 	priv = dev->data->dev_private;
 	sh = priv->sh;
-	rte_rwlock_read_lock(&sh->share_cache.rwlock);
+	rte_rwlock_write_lock(&sh->share_cache.rwlock);
 	mr = mlx5_mr_lookup_list(&sh->share_cache, &entry, (uintptr_t)addr);
 	if (!mr) {
-		rte_rwlock_read_unlock(&sh->share_cache.rwlock);
+		rte_rwlock_write_unlock(&sh->share_cache.rwlock);
 		DRV_LOG(WARNING, "address 0x%" PRIxPTR " wasn't registered "
 				 "to PCI device %p", (uintptr_t)addr,
 				 (void *)pdev);
@@ -330,7 +330,7 @@ mlx5_dma_unmap(struct rte_pci_device *pdev, void *addr,
 	DEBUG("broadcasting local cache flush, gen=%d",
 	      sh->share_cache.dev_gen);
 	rte_smp_wmb();
-	rte_rwlock_read_unlock(&sh->share_cache.rwlock);
+	rte_rwlock_write_unlock(&sh->share_cache.rwlock);
 	return 0;
 }
 
-- 
2.30.2

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2021-07-12 13:41:41.529022936 +0100
+++ 0096-net-mlx5-fix-r-w-lock-usage-in-DMA-unmap.patch	2021-07-12 13:41:36.794128943 +0100
@@ -1 +1 @@
-From 1c196da274b82e6f1642bde7b1c407a2066caee1 Mon Sep 17 00:00:00 2001
+From 653b095f492f5219ae7f00e904bf23b397a2adb7 Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit 1c196da274b82e6f1642bde7b1c407a2066caee1 ]
+
@@ -10 +11,0 @@
-Cc: stable at dpdk.org
@@ -20 +21 @@
-index 0b6cfc8cb9..89c43fc9e9 100644
+index 2cce3b9fe8..1dd14ddfe5 100644
@@ -23 +24 @@
-@@ -304,10 +304,10 @@ mlx5_dma_unmap(struct rte_pci_device *pdev, void *addr,
+@@ -302,10 +302,10 @@ mlx5_dma_unmap(struct rte_pci_device *pdev, void *addr,
@@ -36,3 +37,2 @@
-@@ -327,7 +327,7 @@ mlx5_dma_unmap(struct rte_pci_device *pdev, void *addr,
- 	++sh->share_cache.dev_gen;
- 	DRV_LOG(DEBUG, "broadcasting local cache flush, gen=%d",
+@@ -330,7 +330,7 @@ mlx5_dma_unmap(struct rte_pci_device *pdev, void *addr,
+ 	DEBUG("broadcasting local cache flush, gen=%d",
@@ -39,0 +40 @@
+ 	rte_smp_wmb();