From: Long Li <longli@xxxxxxxxxxxxx>
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.
There are situations where the MID may not be created on I/O failure, under
which memory region is deregistered when read data context is released.
Signed-off-by: Long Li <longli@xxxxxxxxxxxxx>
---
fs/cifs/file.c | 5 +++++
fs/cifs/smb2pdu.c | 10 ++++++++++
2 files changed, 15 insertions(+)
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 41460a5..5a6df25 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2910,6 +2910,11 @@ cifs_readdata_release(struct kref *refcount)
struct cifs_readdata *rdata = container_of(refcount,
struct cifs_readdata, refcount);
+ if (rdata->mr) {
+ smbd_deregister_mr(rdata->mr);
+ rdata->mr = NULL;
+ }
+
if (rdata->cfile)
cifsFileInfo_put(rdata->cfile);
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
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