Patch "vdpa/mlx5: Fix possible failure in umem size calculation" has been added to the 5.13-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    vdpa/mlx5: Fix possible failure in umem size calculation

to the 5.13-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     vdpa-mlx5-fix-possible-failure-in-umem-size-calculat.patch
and it can be found in the queue-5.13 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 7a548f17965386cb7be176033f4994b2e9011b8f
Author: Eli Cohen <elic@xxxxxxxxxx>
Date:   Sun May 30 12:03:49 2021 +0300

    vdpa/mlx5: Fix possible failure in umem size calculation
    
    [ Upstream commit 71ab6a7cfbae27f86a3901daab10bfe13b3a1e3a ]
    
    umem size is a 32 bit unsigned value so assigning it to an int could
    cause false failures. Set the calculated value inside the function and
    modify function name to reflect the fact it updates the size.
    
    This bug was found during code review but never had real impact to this
    date.
    
    Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
    Signed-off-by: Eli Cohen <elic@xxxxxxxxxx>
    Link: https://lore.kernel.org/r/20210530090349.8360-1-elic@xxxxxxxxxx
    Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
    Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index e8865e6adf37..01eb6c100d2d 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -611,8 +611,8 @@ static void cq_destroy(struct mlx5_vdpa_net *ndev, u16 idx)
 	mlx5_db_free(ndev->mvdev.mdev, &vcq->db);
 }
 
-static int umem_size(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq, int num,
-		     struct mlx5_vdpa_umem **umemp)
+static void set_umem_size(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq, int num,
+			  struct mlx5_vdpa_umem **umemp)
 {
 	struct mlx5_core_dev *mdev = ndev->mvdev.mdev;
 	int p_a;
@@ -635,7 +635,7 @@ static int umem_size(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq
 		*umemp = &mvq->umem3;
 		break;
 	}
-	return p_a * mvq->num_ent + p_b;
+	(*umemp)->size = p_a * mvq->num_ent + p_b;
 }
 
 static void umem_frag_buf_free(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_umem *umem)
@@ -651,15 +651,10 @@ static int create_umem(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *m
 	void *in;
 	int err;
 	__be64 *pas;
-	int size;
 	struct mlx5_vdpa_umem *umem;
 
-	size = umem_size(ndev, mvq, num, &umem);
-	if (size < 0)
-		return size;
-
-	umem->size = size;
-	err = umem_frag_buf_alloc(ndev, umem, size);
+	set_umem_size(ndev, mvq, num, &umem);
+	err = umem_frag_buf_alloc(ndev, umem, umem->size);
 	if (err)
 		return err;