From b983f7e92348d7e7d091db1b78b7915e9dd3d63a Mon Sep 17 00:00:00 2001
From: Pavel Shilovsky <pshilov@microsoft.com>
Date: Wed, 19 Dec 2018 22:49:09 +0000
Subject: [PATCH] CIFS: Fix adjustment of credits for MTU requests
Git-commit: b983f7e92348d7e7d091db1b78b7915e9dd3d63a
Patch-mainline: v5.0-rc2
References: bsc#1051510, bsc#1144333

Currently for MTU requests we allocate maximum possible credits
in advance and then adjust them according to the request size.
While we were adjusting the number of credits belonging to the
server, we were skipping adjustment of credits belonging to the
request. This patch fixes it by setting request credits to
CreditCharge field value of SMB2 packet header.

Also ask 1 credit more for async read and write operations to
increase parallelism and match the behavior of other operations.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Acked-by: Paulo Alcantara <palcantara@suse.de>
---
 fs/cifs/smb2pdu.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index e57f6aa1d638..b9d7891edaa1 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -3278,12 +3278,14 @@ smb2_async_readv(struct cifs_readdata *rdata)
 	if (rdata->credits) {
 		shdr->CreditCharge = cpu_to_le16(DIV_ROUND_UP(rdata->bytes,
 						SMB2_MAX_BUFFER_SIZE));
-		shdr->CreditRequest = shdr->CreditCharge;
+		shdr->CreditRequest =
+			cpu_to_le16(le16_to_cpu(shdr->CreditCharge) + 1);
 		spin_lock(&server->req_lock);
 		server->credits += rdata->credits -
 						le16_to_cpu(shdr->CreditCharge);
 		spin_unlock(&server->req_lock);
 		wake_up(&server->request_q);
+		rdata->credits = le16_to_cpu(shdr->CreditCharge);
 		flags |= CIFS_HAS_CREDITS;
 	}
 
@@ -3555,12 +3557,14 @@ smb2_async_writev(struct cifs_writedata *wdata,
 	if (wdata->credits) {
 		shdr->CreditCharge = cpu_to_le16(DIV_ROUND_UP(wdata->bytes,
 						    SMB2_MAX_BUFFER_SIZE));
-		shdr->CreditRequest = shdr->CreditCharge;
+		shdr->CreditRequest =
+			cpu_to_le16(le16_to_cpu(shdr->CreditCharge) + 1);
 		spin_lock(&server->req_lock);
 		server->credits += wdata->credits -
 						le16_to_cpu(shdr->CreditCharge);
 		spin_unlock(&server->req_lock);
 		wake_up(&server->request_q);
+		wdata->credits = le16_to_cpu(shdr->CreditCharge);
 		flags |= CIFS_HAS_CREDITS;
 	}
 
-- 
2.16.4