[PATCH 4.2 126/134] IB/mlx5: avoid destroying a NULL mr in reg_user_mr error flow

From: Greg Kroah-Hartman
Date: Sat Sep 26 2015 - 17:59:54 EST

4.2-stable review patch. If anyone has any objections, please let me know.


From: Haggai Eran <haggaie@xxxxxxxxxxxx>

commit 11d748045c6dadb279d1acdb6d2ea8f3f2ede85b upstream.

The mlx5_ib_reg_user_mr() function will attempt to call clean_mr() in
its error flow even though there is never a case where the error flow
occurs with a valid MR pointer to destroy.

Remove the clean_mr() call and the incorrect comment above it.

Fixes: b4cfe447d47b ("IB/mlx5: Implement on demand paging by adding
support for MMU notifiers")
Cc: Eli Cohen <eli@xxxxxxxxxxxx>
Signed-off-by: Haggai Eran <haggaie@xxxxxxxxxxxx>
Reviewed-by: Sagi Grimberg <sagig@xxxxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/infiniband/hw/mlx5/mr.c | 12 ------------
1 file changed, 12 deletions(-)

--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -1118,19 +1118,7 @@ struct ib_mr *mlx5_ib_reg_user_mr(struct
return &mr->ibmr;

- /*
- * Destroy the umem *before* destroying the MR, to ensure we
- * will not have any in-flight notifiers when destroying the
- * MR.
- *
- * As the MR is completely invalid to begin with, and this
- * error path is only taken if we can't push the mr entry into
- * the pagefault tree, this is safe.
- */
- /* Kill the MR, and return an error code. */
- clean_mr(mr);
return ERR_PTR(err);

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