[PATCH 5.2 362/413] RDMA/odp: Fix missed unlock in non-blocking invalidate_start

[Greg Kroah-Hartman]

From: Jason Gunthorpe <jgg@xxxxxxxxxxxx>

commit 7608bf40cf2480057ec0da31456cc428791c32ef upstream.

If invalidate_start returns with EAGAIN then the umem_rwsem needs to be
unlocked as no invalidate_end will be called.

Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: ca748c39ea3f ("RDMA/umem: Get rid of per_mm->notifier_count")
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Reviewed-by: Leon Romanovsky <leonro@xxxxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/infiniband/core/umem_odp.c |   14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

--- a/drivers/infiniband/core/umem_odp.c
+++ b/drivers/infiniband/core/umem_odp.c
@@ -151,6 +151,7 @@ static int ib_umem_notifier_invalidate_r
 {
 	struct ib_ucontext_per_mm *per_mm =
 		container_of(mn, struct ib_ucontext_per_mm, mn);
+	int rc;
 
 	if (mmu_notifier_range_blockable(range))
 		down_read(&per_mm->umem_rwsem);
@@ -167,11 +168,14 @@ static int ib_umem_notifier_invalidate_r
 		return 0;
 	}
 
-	return rbt_ib_umem_for_each_in_range(&per_mm->umem_tree, range->start,
-					     range->end,
-					     invalidate_range_start_trampoline,
-					     mmu_notifier_range_blockable(range),
-					     NULL);
+	rc = rbt_ib_umem_for_each_in_range(&per_mm->umem_tree, range->start,
+					   range->end,
+					   invalidate_range_start_trampoline,
+					   mmu_notifier_range_blockable(range),
+					   NULL);
+	if (rc)
+		up_read(&per_mm->umem_rwsem);
+	return rc;
 }
 
 static int invalidate_range_end_trampoline(struct ib_umem_odp *item, u64 start,