[PATCH 4.17 015/324] smb3: increase initial number of credits requested to allow write

Greg Kroah-Hartman
2018-08-23T08:40:47Z

From: Steve French <stfrench@microsoft.com>

[ Upstream commit d409014e4feeab486fb36b350abfc4c94de8be37 ]

Compared to other clients the Linux smb3 client ramps up
credits very slowly, taking more than 128 operations before a
maximum size write could be sent (since the number of credits
requested is only 2 per small operation, causing the credit
limit to grow very slowly).

This lack of credits initially would impact large i/o performance,
when large i/o is tried early before enough credits are built up.

Signed-off-by: Steve French <stfrench@gmail.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/cifs/smb2pdu.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -923,8 +923,9 @@ SMB2_sess_alloc_buffer(struct SMB2_sess_
req->PreviousSessionId = sess_data->previous_session;

req->Flags = 0; /* MBZ */
- /* to enable echos and oplocks */
- req->sync_hdr.CreditRequest = cpu_to_le16(3);
+
+ /* enough to enable echos and oplocks and one max size write */
+ req->sync_hdr.CreditRequest = cpu_to_le16(130);

/* only one of SMB2 signing flags may be set in SMB2 request */
if (server->sign)