[Patch v2 18/19] CIFS: SMBD: Deregister memory when finishing SMB READ

Long Li
2017-08-20T19:04:42Z

From: Long Li <longli@microsoft.com>

When SMB READ is finished, deregister the memory regions if RDMA write is used for this SMB READ. smbd_deregister_mr may need to do local invalidation and sleep, if server remote invalidation is not used.

Signed-off-by: Long Li <longli@microsoft.com>
---
fs/cifs/smb2pdu.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 1f08c75..43a7b60 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -2504,6 +2504,16 @@ smb2_readv_callback(struct mid_q_entry *mid)
rdata->result = -EIO;
}

+ /*
+ * If this rdata has a memmory registered, the MR can be freed
+ * MR needs to be freed as soon as I/O finishes to prevent deadlock
+ * because they have limited number and are used for future I/Os
+ */
+ if (rdata->mr) {
+ smbd_deregister_mr(rdata->mr);
+ rdata->mr = NULL;
+ }
+
if (rdata->result)
cifs_stats_fail_inc(tcon, SMB2_READ_HE);

--
2.7.4