From cb7e9eabb2b584884db0d11ae0376d31ac1cfdc1 Mon Sep 17 00:00:00 2001
From: Pavel Shilovsky <pshilovsky@samba.org>
Date: Thu, 5 Jun 2014 19:03:27 +0400
Subject: CIFS: Use multicredits for SMB 2.1/3 writes
If we negotiate SMB 2.1 and higher version of the protocol and
a server supports large write buffer size, we need to consume 1
credit per 65536 bytes. So, we need to know how many credits
we have and obtain the required number of them before constructing
a writedata structure in writepages and iovec write.
Reviewed-by: Shirish Pargaonkar <spargaonkar@suse.com>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
---
fs/cifs/smb2ops.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 53 insertions(+), 2 deletions(-)
(limited to 'fs/cifs/smb2ops.c')
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index e35ce5b3d88f..3427c1fa3806 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -112,6 +112,53 @@ smb2_get_credits(struct mid_q_entry *mid)
return le16_to_cpu(((struct smb2_hdr *)mid->resp_buf)->CreditRequest);
}
+static int
+smb2_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size,
+ unsigned int *num, unsigned int *credits)
+{
+ int rc = 0;
+ unsigned int scredits;
+
+ spin_lock(&server->req_lock);
+ while (1) {
+ if (server->credits <= 0) {
+ spin_unlock(&server->req_lock);
+ cifs_num_waiters_inc(server);
+ rc = wait_event_killable(server->request_q,
+ has_credits(server, &server->credits));
+ cifs_num_waiters_dec(server);
+ if (rc)
+ return rc;
+ spin_lock(&server->req_lock);
+ } else {
+ if (server->tcpStatus == CifsExiting) {
+ spin_unlock(&server->req_lock);
+ return -ENOENT;
+ }
+
+ scredits = server->credits;
+ /* can deadlock with reopen */
+ if (scredits == 1) {
+ *num = SMB2_MAX_BUFFER_SIZE;
+ *credits = 0;
+ break;
+ }
+
+ /* leave one credit for a possible reopen */
+ scredits--;
+ *num = min_t(unsigned int, size,
+ scredits * SMB2_MAX_BUFFER_SIZE);
+
+ *credits = DIV_ROUND_UP(*num, SMB2_MAX_BUFFER_SIZE);
+ server->credits -= *credits;
+ server->in_flight++;
+ break;
+ }
+ }
+ spin_unlock(&server->req_lock);
+ return rc;
+}
+
static __u64
smb2_get_next_mid(struct TCP_Server_Info *server)
{
@@ -182,8 +229,9 @@ smb2_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *volume_info)
/* start with specified wsize, or default */
wsize = volume_info->wsize ? volume_info->wsize : CIFS_DEFAULT_IOSIZE;
wsize = min_t(unsigned int, wsize, server->max_write);
- /* set it to the maximum buffer size value we can send with 1 credit */
- wsize = min_t(unsigned int, wsize, SMB2_MAX_BUFFER_SIZE);
+
+ if (!(server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU))
+ wsize = min_t(unsigned int, wsize, SMB2_MAX_BUFFER_SIZE);
return wsize;
}
@@ -1120,6 +1168,7 @@ struct smb_version_operations smb20_operations = {
.set_credits = smb2_set_credits,
.get_credits_field = smb2_get_credits_field,
.get_credits = smb2_get_credits,
+ .wait_mtu_credits = cifs_wait_mtu_credits,
.get_next_mid = smb2_get_next_mid,
.read_data_offset = smb2_read_data_offset,
.read_data_length = smb2_read_data_length,
@@ -1196,6 +1245,7 @@ struct smb_version_operations smb21_operations = {
.set_credits = smb2_set_credits,
.get_credits_field = smb2_get_credits_field,
.get_credits = smb2_get_credits,
+ .wait_mtu_credits = smb2_wait_mtu_credits,
.get_next_mid = smb2_get_next_mid,
.read_data_offset = smb2_read_data_offset,
.read_data_length = smb2_read_data_length,
@@ -1272,6 +1322,7 @@ struct smb_version_operations smb30_operations = {
.set_credits = smb2_set_credits,
.get_credits_field = smb2_get_credits_field,
.get_credits = smb2_get_credits,
+ .wait_mtu_credits = smb2_wait_mtu_credits,
.get_next_mid = smb2_get_next_mid,
.read_data_offset = smb2_read_data_offset,
.read_data_length = smb2_read_data_length,
--
cgit