cifs: reinstate sharing of SMB sessions sans races
We do this by abandoning the global list of SMB sessions and instead
moving to a per-server list. This entails adding a new list head to the
TCP_Server_Info struct. The refcounting for the cifsSesInfo is moved to
a non-atomic variable. We have to protect it by a lock anyway, so there's
no benefit to making it an atomic. The list and refcount are protected
by the global cifs_tcp_ses_lock.
The patch also adds a new routines to find and put SMB sessions and
that properly take and put references under the lock.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
index 40b5108..59841a6 100644
--- a/fs/cifs/cifs_debug.c
+++ b/fs/cifs/cifs_debug.c
@@ -107,9 +107,9 @@
#ifdef CONFIG_PROC_FS
static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
{
- struct list_head *tmp;
- struct list_head *tmp1;
+ struct list_head *tmp, *tmp2, *tmp3;
struct mid_q_entry *mid_entry;
+ struct TCP_Server_Info *server;
struct cifsSesInfo *ses;
struct cifsTconInfo *tcon;
int i;
@@ -122,43 +122,45 @@
seq_printf(m, "Servers:");
i = 0;
- read_lock(&GlobalSMBSeslock);
- list_for_each(tmp, &GlobalSMBSessionList) {
+ read_lock(&cifs_tcp_ses_lock);
+ list_for_each(tmp, &cifs_tcp_ses_list) {
+ server = list_entry(tmp, struct TCP_Server_Info,
+ tcp_ses_list);
i++;
- ses = list_entry(tmp, struct cifsSesInfo, cifsSessionList);
- if ((ses->serverDomain == NULL) || (ses->serverOS == NULL) ||
- (ses->serverNOS == NULL)) {
- seq_printf(m, "\nentry for %s not fully "
- "displayed\n\t", ses->serverName);
- } else {
- seq_printf(m,
+ list_for_each(tmp2, &server->smb_ses_list) {
+ ses = list_entry(tmp2, struct cifsSesInfo,
+ smb_ses_list);
+ if ((ses->serverDomain == NULL) ||
+ (ses->serverOS == NULL) ||
+ (ses->serverNOS == NULL)) {
+ seq_printf(m, "\nentry for %s not fully "
+ "displayed\n\t", ses->serverName);
+ } else {
+ seq_printf(m,
"\n%d) Name: %s Domain: %s Mounts: %d OS:"
" %s \n\tNOS: %s\tCapability: 0x%x\n\tSMB"
" session status: %d\t",
i, ses->serverName, ses->serverDomain,
- atomic_read(&ses->inUse),
- ses->serverOS, ses->serverNOS,
+ ses->ses_count, ses->serverOS, ses->serverNOS,
ses->capabilities, ses->status);
- }
- if (ses->server) {
+ }
seq_printf(m, "TCP status: %d\n\tLocal Users To "
- "Server: %d SecMode: 0x%x Req On Wire: %d",
- ses->server->tcpStatus,
- ses->server->srv_count,
- ses->server->secMode,
- atomic_read(&ses->server->inFlight));
+ "Server: %d SecMode: 0x%x Req On Wire: %d",
+ server->tcpStatus, server->srv_count,
+ server->secMode,
+ atomic_read(&server->inFlight));
#ifdef CONFIG_CIFS_STATS2
seq_printf(m, " In Send: %d In MaxReq Wait: %d",
- atomic_read(&ses->server->inSend),
- atomic_read(&ses->server->num_waiters));
+ atomic_read(&server->inSend),
+ atomic_read(&server->num_waiters));
#endif
seq_puts(m, "\nMIDs:\n");
spin_lock(&GlobalMid_Lock);
- list_for_each(tmp1, &ses->server->pending_mid_q) {
- mid_entry = list_entry(tmp1, struct
+ list_for_each(tmp3, &server->pending_mid_q) {
+ mid_entry = list_entry(tmp3, struct
mid_q_entry,
qhead);
seq_printf(m, "State: %d com: %d pid:"
@@ -171,9 +173,8 @@
}
spin_unlock(&GlobalMid_Lock);
}
-
}
- read_unlock(&GlobalSMBSeslock);
+ read_unlock(&cifs_tcp_ses_lock);
seq_putc(m, '\n');
seq_puts(m, "Shares:");