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authorShyam Prasad N <sprasad@microsoft.com>2022-07-27 22:49:56 +0300
committerSteve French <stfrench@microsoft.com>2022-08-01 09:34:45 +0300
commitd7d7a66aacd6fd8ca57baf08a7bac5421282f6f8 (patch)
tree2565cb830065b2c06cefd085866c3de926d688b5 /fs/cifs/smb2ops.c
parent1bfa25ee30dfebe32a3b40c1a954052becbd7b8d (diff)
downloadlinux-d7d7a66aacd6fd8ca57baf08a7bac5421282f6f8.tar.xz
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>
Diffstat (limited to 'fs/cifs/smb2ops.c')
-rw-r--r--fs/cifs/smb2ops.c47
1 files changed, 26 insertions, 21 deletions
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 5bed8b584086..82dd2e973753 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -126,13 +126,13 @@ smb2_add_credits(struct TCP_Server_Info *server,
optype, scredits, add);
}
- spin_lock(&cifs_tcp_ses_lock);
+ spin_lock(&server->srv_lock);
if (server->tcpStatus == CifsNeedReconnect
|| server->tcpStatus == CifsExiting) {
- spin_unlock(&cifs_tcp_ses_lock);
+ spin_unlock(&server->srv_lock);
return;
}
- spin_unlock(&cifs_tcp_ses_lock);
+ spin_unlock(&server->srv_lock);
switch (rc) {
case -1:
@@ -218,12 +218,12 @@ smb2_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size,
spin_lock(&server->req_lock);
} else {
spin_unlock(&server->req_lock);
- spin_lock(&cifs_tcp_ses_lock);
+ spin_lock(&server->srv_lock);
if (server->tcpStatus == CifsExiting) {
- spin_unlock(&cifs_tcp_ses_lock);
+ spin_unlock(&server->srv_lock);
return -ENOENT;
}
- spin_unlock(&cifs_tcp_ses_lock);
+ spin_unlock(&server->srv_lock);
spin_lock(&server->req_lock);
scredits = server->credits;
@@ -319,19 +319,19 @@ smb2_get_next_mid(struct TCP_Server_Info *server)
{
__u64 mid;
/* for SMB2 we need the current value */
- spin_lock(&GlobalMid_Lock);
+ spin_lock(&server->mid_lock);
mid = server->CurrentMid++;
- spin_unlock(&GlobalMid_Lock);
+ spin_unlock(&server->mid_lock);
return mid;
}
static void
smb2_revert_current_mid(struct TCP_Server_Info *server, const unsigned int val)
{
- spin_lock(&GlobalMid_Lock);
+ spin_lock(&server->mid_lock);
if (server->CurrentMid >= val)
server->CurrentMid -= val;
- spin_unlock(&GlobalMid_Lock);
+ spin_unlock(&server->mid_lock);
}
static struct mid_q_entry *
@@ -346,7 +346,7 @@ __smb2_find_mid(struct TCP_Server_Info *server, char *buf, bool dequeue)
return NULL;
}
- spin_lock(&GlobalMid_Lock);
+ spin_lock(&server->mid_lock);
list_for_each_entry(mid, &server->pending_mid_q, qhead) {
if ((mid->mid == wire_mid) &&
(mid->mid_state == MID_REQUEST_SUBMITTED) &&
@@ -356,11 +356,11 @@ __smb2_find_mid(struct TCP_Server_Info *server, char *buf, bool dequeue)
list_del_init(&mid->qhead);
mid->mid_flags |= MID_DELETED;
}
- spin_unlock(&GlobalMid_Lock);
+ spin_unlock(&server->mid_lock);
return mid;
}
}
- spin_unlock(&GlobalMid_Lock);
+ spin_unlock(&server->mid_lock);
return NULL;
}
@@ -403,9 +403,9 @@ smb2_negotiate(const unsigned int xid,
{
int rc;
- spin_lock(&GlobalMid_Lock);
+ spin_lock(&server->mid_lock);
server->CurrentMid = 0;
- spin_unlock(&GlobalMid_Lock);
+ spin_unlock(&server->mid_lock);
rc = SMB2_negotiate(xid, ses, server);
/* BB we probably don't need to retry with modern servers */
if (rc == -EAGAIN)
@@ -2585,7 +2585,9 @@ smb2_is_network_name_deleted(char *buf, struct TCP_Server_Info *server)
list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
if (tcon->tid == le32_to_cpu(shdr->Id.SyncId.TreeId)) {
+ spin_lock(&tcon->tc_lock);
tcon->need_reconnect = true;
+ spin_unlock(&tcon->tc_lock);
spin_unlock(&cifs_tcp_ses_lock);
pr_warn_once("Server share %s deleted.\n",
tcon->treeName);
@@ -4561,9 +4563,11 @@ smb2_get_enc_key(struct TCP_Server_Info *server, __u64 ses_id, int enc, u8 *key)
list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
if (ses->Suid == ses_id) {
+ spin_lock(&ses->ses_lock);
ses_enc_key = enc ? ses->smb3encryptionkey :
ses->smb3decryptionkey;
memcpy(key, ses_enc_key, SMB3_ENC_DEC_KEY_SIZE);
+ spin_unlock(&ses->ses_lock);
spin_unlock(&cifs_tcp_ses_lock);
return 0;
}
@@ -5078,20 +5082,21 @@ static void smb2_decrypt_offload(struct work_struct *work)
mid->callback(mid);
} else {
- spin_lock(&cifs_tcp_ses_lock);
- spin_lock(&GlobalMid_Lock);
+ spin_lock(&dw->server->srv_lock);
if (dw->server->tcpStatus == CifsNeedReconnect) {
+ spin_lock(&dw->server->mid_lock);
mid->mid_state = MID_RETRY_NEEDED;
- spin_unlock(&GlobalMid_Lock);
- spin_unlock(&cifs_tcp_ses_lock);
+ spin_unlock(&dw->server->mid_lock);
+ spin_unlock(&dw->server->srv_lock);
mid->callback(mid);
} else {
+ spin_lock(&dw->server->mid_lock);
mid->mid_state = MID_REQUEST_SUBMITTED;
mid->mid_flags &= ~(MID_DELETED);
list_add_tail(&mid->qhead,
&dw->server->pending_mid_q);
- spin_unlock(&GlobalMid_Lock);
- spin_unlock(&cifs_tcp_ses_lock);
+ spin_unlock(&dw->server->mid_lock);
+ spin_unlock(&dw->server->srv_lock);
}
}
cifs_mid_q_entry_release(mid);