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

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Message-Id: <20180823074956.669164546@linuxfoundation.org>
Date:   Thu, 23 Aug 2018 09:51:21 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Steve French <stfrench@...il.com>,
        Ronnie Sahlberg <lsahlber@...hat.com>,
        Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 4.17 015/324] smb3: increase initial number of credits requested to allow write

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Steve French <stfrench@...rosoft.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@...il.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@...hat.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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)