From f6588557023efa10463c1ca77010f0ee6c895a81 Mon Sep 17 00:00:00 2001 From: Michael Guralnik Date: Thu, 13 Mar 2025 16:29:49 +0200 Subject: [PATCH] RDMA/mlx5: Fix cache entry update on dereg error [ Upstream commit 24d693cf6c89d216a68634d44fa93e4400775d94 ] Fix double decrement of 'in_use' counter on push_mkey_locked() failure while deregistering an MR. If we fail to return an mkey to the cache in cache_ent_find_and_store() it'll update the 'in_use' counter. Its caller, revoke_mr(), also updates it, thus having double decrement. Wrong value of 'in_use' counter will be exposed through debugfs and can also cause wrong resizing of the cache when users try to set cache entry size using the 'size' debugfs. To address this issue, the 'in_use' counter is now decremented within mlx5_revoke_mr() also after a successful call to cache_ent_find_and_store() and not within cache_ent_find_and_store(). Other success or failure flows remains unchanged where it was also decremented. Fixes: 8c1185fef68c ("RDMA/mlx5: Change check for cacheable mkeys") Signed-off-by: Michael Guralnik Reviewed-by: Yishai Hadas Link: https://patch.msgid.link/97e979dff636f232ff4c83ce709c17c727da1fdb.1741875692.git.leon@kernel.org Signed-off-by: Leon Romanovsky Signed-off-by: Sasha Levin --- drivers/infiniband/hw/mlx5/mr.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c index 068eac3bdb50..830a15b66c12 100644 --- a/drivers/infiniband/hw/mlx5/mr.c +++ b/drivers/infiniband/hw/mlx5/mr.c @@ -1968,7 +1968,6 @@ static int cache_ent_find_and_store(struct mlx5_ib_dev *dev, if (mr->mmkey.cache_ent) { spin_lock_irq(&mr->mmkey.cache_ent->mkeys_queue.lock); - mr->mmkey.cache_ent->in_use--; goto end; } @@ -2036,6 +2035,7 @@ static int mlx5_revoke_mr(struct mlx5_ib_mr *mr) bool is_odp = is_odp_mr(mr); bool is_odp_dma_buf = is_dmabuf_mr(mr) && !to_ib_umem_dmabuf(mr->umem)->pinned; + bool from_cache = !!ent; int ret = 0; if (is_odp) @@ -2048,6 +2048,8 @@ static int mlx5_revoke_mr(struct mlx5_ib_mr *mr) ent = mr->mmkey.cache_ent; /* upon storing to a clean temp entry - schedule its cleanup */ spin_lock_irq(&ent->mkeys_queue.lock); + if (from_cache) + ent->in_use--; if (ent->is_tmp && !ent->tmp_cleanup_scheduled) { mod_delayed_work(ent->dev->cache.wq, &ent->dwork, msecs_to_jiffies(30 * 1000));