cifs: avoid use of global locks for high contention data

During analysis of multichannel perf, it was seen that
the global locks cifs_tcp_ses_lock and GlobalMid_Lock, which
were shared between various data structures were causing a
lot of contention points.

With this change, we're breaking down the use of these locks
by introducing new locks at more granular levels. i.e.
server->srv_lock, ses->ses_lock and tcon->tc_lock to protect
the unprotected fields of server, session and tcon structs;
and server->mid_lock to protect mid related lists and entries
at server level.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 14 insertions, 14 deletions

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 9ed21752f2df..04a4c304d004 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -74,13 +74,13 @@ cifs_mark_open_files_invalid(struct cifs_tcon *tcon)
 	struct list_head *tmp1;
 
 	/* only send once per connect */
-	spin_lock(&cifs_tcp_ses_lock);
+	spin_lock(&tcon->ses->ses_lock);
 	if ((tcon->ses->ses_status != SES_GOOD) || (tcon->status != TID_NEED_RECON)) {
-		spin_unlock(&cifs_tcp_ses_lock);
+		spin_unlock(&tcon->ses->ses_lock);
 		return;
 	}
 	tcon->status = TID_IN_FILES_INVALIDATE;
-	spin_unlock(&cifs_tcp_ses_lock);
+	spin_unlock(&tcon->ses->ses_lock);
 
 	/* list all files open on tree connection and mark them invalid */
 	spin_lock(&tcon->open_file_lock);
@@ -98,10 +98,10 @@ cifs_mark_open_files_invalid(struct cifs_tcon *tcon)
 	memset(tcon->crfid.fid, 0, sizeof(struct cifs_fid));
 	mutex_unlock(&tcon->crfid.fid_mutex);
 
-	spin_lock(&cifs_tcp_ses_lock);
+	spin_lock(&tcon->tc_lock);
 	if (tcon->status == TID_IN_FILES_INVALIDATE)
 		tcon->status = TID_NEED_TCON;
-	spin_unlock(&cifs_tcp_ses_lock);
+	spin_unlock(&tcon->tc_lock);
 
 	/*
 	 * BB Add call to invalidate_inodes(sb) for all superblocks mounted
@@ -134,18 +134,18 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
 	 * only tree disconnect, open, and write, (and ulogoff which does not
 	 * have tcon) are allowed as we start force umount
 	 */
-	spin_lock(&cifs_tcp_ses_lock);
+	spin_lock(&tcon->tc_lock);
 	if (tcon->status == TID_EXITING) {
 		if (smb_command != SMB_COM_WRITE_ANDX &&
 		    smb_command != SMB_COM_OPEN_ANDX &&
 		    smb_command != SMB_COM_TREE_DISCONNECT) {
-			spin_unlock(&cifs_tcp_ses_lock);
+			spin_unlock(&tcon->tc_lock);
 			cifs_dbg(FYI, "can not send cmd %d while umounting\n",
 				 smb_command);
 			return -ENODEV;
 		}
 	}
-	spin_unlock(&cifs_tcp_ses_lock);
+	spin_unlock(&tcon->tc_lock);
 
 	retries = server->nr_targets;
 
@@ -165,12 +165,12 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
 		}
 
 		/* are we still trying to reconnect? */
-		spin_lock(&cifs_tcp_ses_lock);
+		spin_lock(&server->srv_lock);
 		if (server->tcpStatus != CifsNeedReconnect) {
-			spin_unlock(&cifs_tcp_ses_lock);
+			spin_unlock(&server->srv_lock);
 			break;
 		}
-		spin_unlock(&cifs_tcp_ses_lock);
+		spin_unlock(&server->srv_lock);
 
 		if (retries && --retries)
 			continue;
@@ -201,13 +201,13 @@ cifs_reconnect_tcon(struct cifs_tcon *tcon, int smb_command)
 	 * and the server never sends an answer the socket will be closed
 	 * and tcpStatus set to reconnect.
 	 */
-	spin_lock(&cifs_tcp_ses_lock);
+	spin_lock(&server->srv_lock);
 	if (server->tcpStatus == CifsNeedReconnect) {
-		spin_unlock(&cifs_tcp_ses_lock);
+		spin_unlock(&server->srv_lock);
 		rc = -EHOSTDOWN;
 		goto out;
 	}
-	spin_unlock(&cifs_tcp_ses_lock);
+	spin_unlock(&server->srv_lock);
 
 	/*
 	 * need to prevent multiple threads trying to simultaneously