From: Long Li <longli@xxxxxxxxxxxxx>
On write I/O finish, deregister the memory region if this was for a RDMA read. The call to smbd_deregister_mr will do local invalidation and possibly wait, if remote invalidate is not used.
Signed-off-by: Long Li <longli@xxxxxxxxxxxxx>
---
fs/cifs/smb2pdu.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 5581afd..5551053 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2666,6 +2666,18 @@ smb2_writev_callback(struct mid_q_entry *mid)
break;
}
+ /*
+ * If this wdata has a memory registered, the MR can be freed
+ * The number of MRs available is limited, it's important to recover
+ * used MR as soon as I/O is finished. Hold MR longer in the later
+ * I/O process can possibly result in I/O deadlock due to lack of MR
+ * to send request on I/O retry
+ */
+ if (wdata->mr) {
+ smbd_deregister_mr(wdata->mr);
+ wdata->mr = NULL;
+ }
+
if (wdata->result)
cifs_stats_fail_inc(tcon, SMB2_WRITE_HE);
--
2.7.4
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