CIFS: Respect negotiated MaxMpxCount

Some servers sets this value less than 50 that was hardcoded and
we lost the connection if when we exceed this limit. Fix this by
respecting this value - not sending more than the server allows.

Cc: stable@kernel.org
Reviewed-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <stevef@smf-gateway.(none)>

1 files changed, 7 insertions, 2 deletions

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 8b7794c31591..cd66b76e3282 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -458,7 +458,10 @@ CIFSSMBNegotiate(unsigned int xid, struct cifs_ses *ses)
                         goto neg_err_exit;
                 }
                 server->sec_mode = (__u8)le16_to_cpu(rsp->SecurityMode);
-                server->maxReq = le16_to_cpu(rsp->MaxMpxCount);
+                server->maxReq = min_t(unsigned int,
+                                       le16_to_cpu(rsp->MaxMpxCount),
+                                       cifs_max_pending);
+                server->oplocks = server->maxReq > 1 ? enable_oplocks : false;
                 server->maxBuf = le16_to_cpu(rsp->MaxBufSize);
                 server->max_vcs = le16_to_cpu(rsp->MaxNumberVcs);
                 /* even though we do not use raw we might as well set this
@@ -564,7 +567,9 @@ CIFSSMBNegotiate(unsigned int xid, struct cifs_ses *ses)
 
         /* one byte, so no need to convert this or EncryptionKeyLen from
            little endian */
-        server->maxReq = le16_to_cpu(pSMBr->MaxMpxCount);
+        server->maxReq = min_t(unsigned int, le16_to_cpu(pSMBr->MaxMpxCount),
+                               cifs_max_pending);
+        server->oplocks = server->maxReq > 1 ? enable_oplocks : false;
         /* probably no need to store and check maxvcs */
         server->maxBuf = le32_to_cpu(pSMBr->MaxBufferSize);
         server->max_rw = le32_to_cpu(pSMBr->MaxRawSize);