@@ -79,11 +79,11 @@ void cifs_dump_mids(struct TCP_Server_Info *server)
spin_lock(&GlobalMid_Lock);
list_for_each(tmp, &server->pending_mid_q) {
mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
- cERROR(1, "State: %d Cmd: %d Pid: %d Tsk: %p Mid %d",
+ cERROR(1, "State: %d Cmd: %d Pid: %d Cbdata: %p Mid %d",
mid_entry->midState,
(int)mid_entry->command,
mid_entry->pid,
- mid_entry->tsk,
+ mid_entry->callback_data,
mid_entry->mid);
#ifdef CONFIG_CIFS_STATS2
cERROR(1, "IsLarge: %d buf: %p time rcv: %ld now: %ld",
@@ -218,11 +218,11 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
mid_entry = list_entry(tmp3, struct mid_q_entry,
qhead);
seq_printf(m, "\tState: %d com: %d pid:"
- " %d tsk: %p mid %d\n",
+ " %d cbdata: %p mid %d\n",
mid_entry->midState,
(int)mid_entry->command,
mid_entry->pid,
- mid_entry->tsk,
+ mid_entry->callback_data,
mid_entry->mid);
}
spin_unlock(&GlobalMid_Lock);
@@ -508,6 +508,18 @@ static inline void cifs_stats_bytes_read(struct cifsTconInfo *tcon,
#endif
+struct mid_q_entry;
+
+/*
+ * This is the prototype for the mid callback function. When creating one,
+ * take special care to avoid deadlocks. Things to bear in mind:
+ *
+ * - it will be called by cifsd
+ * - the GlobalMid_Lock will be held
+ * - the mid will be removed from the pending_mid_q list
+ */
+typedef void (mid_callback_t)(struct mid_q_entry *mid);
+
/* one of these for every pending CIFS request to the server */
struct mid_q_entry {
struct list_head qhead; /* mids waiting on reply from this server */
@@ -519,7 +531,8 @@ struct mid_q_entry {
unsigned long when_sent; /* time when smb send finished */
unsigned long when_received; /* when demux complete (taken off wire) */
#endif
- struct task_struct *tsk; /* task waiting for response */
+ mid_callback_t *callback; /* call completion callback */
+ void *callback_data; /* general purpose pointer for callback */
struct smb_hdr *resp_buf; /* response buffer */
int midState; /* wish this were enum but can not pass to wait_event */
__u8 command; /* smb command code */
@@ -152,6 +152,7 @@ cifs_reconnect(struct TCP_Server_Info *server)
/* before reconnecting the tcp session, mark the smb session (uid)
and the tid bad so they are not used until reconnected */
+ cFYI(1, "%s: marking sessions and tcons for reconnect", __func__);
spin_lock(&cifs_tcp_ses_lock);
list_for_each(tmp, &server->smb_ses_list) {
ses = list_entry(tmp, struct cifsSesInfo, smb_ses_list);
@@ -163,7 +164,9 @@ cifs_reconnect(struct TCP_Server_Info *server)
}
}
spin_unlock(&cifs_tcp_ses_lock);
+
/* do not want to be sending data on a socket we are freeing */
+ cFYI(1, "%s: tearing down socket", __func__);
mutex_lock(&server->srv_mutex);
if (server->ssocket) {
cFYI(1, "State: 0x%x Flags: 0x%lx", server->ssocket->state,
@@ -180,22 +183,22 @@ cifs_reconnect(struct TCP_Server_Info *server)
kfree(server->session_key.response);
server->session_key.response = NULL;
server->session_key.len = 0;
+ mutex_unlock(&server->srv_mutex);
+ /*
+ * move in-progress mids to a private list so that we can walk it later
+ * without needing a lock. We'll mark them for retry after reconnect.
+ */
+ cFYI(1, "%s: issuing mid callbacks", __func__);
spin_lock(&GlobalMid_Lock);
- list_for_each(tmp, &server->pending_mid_q) {
- mid_entry = list_entry(tmp, struct
- mid_q_entry,
- qhead);
- if (mid_entry->midState == MID_REQUEST_SUBMITTED) {
- /* Mark other intransit requests as needing
- retry so we do not immediately mark the
- session bad again (ie after we reconnect
- below) as they timeout too */
+ list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
+ mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
+ if (mid_entry->midState == MID_REQUEST_SUBMITTED)
mid_entry->midState = MID_RETRY_NEEDED;
- }
+ list_del_init(&mid_entry->qhead);
+ mid_entry->callback(mid_entry);
}
spin_unlock(&GlobalMid_Lock);
- mutex_unlock(&server->srv_mutex);
while ((server->tcpStatus != CifsExiting) &&
(server->tcpStatus != CifsGood)) {
@@ -212,10 +215,9 @@ cifs_reconnect(struct TCP_Server_Info *server)
if (server->tcpStatus != CifsExiting)
server->tcpStatus = CifsGood;
spin_unlock(&GlobalMid_Lock);
- /* atomic_set(&server->inFlight,0);*/
- wake_up(&server->response_q);
}
}
+
return rc;
}
@@ -345,7 +347,7 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
struct msghdr smb_msg;
struct kvec iov;
struct socket *csocket = server->ssocket;
- struct list_head *tmp;
+ struct list_head *tmp, *tmp2;
struct task_struct *task_to_wake = NULL;
struct mid_q_entry *mid_entry;
char temp;
@@ -558,10 +560,9 @@ incomplete_rcv:
continue;
}
-
- task_to_wake = NULL;
+ mid_entry = NULL;
spin_lock(&GlobalMid_Lock);
- list_for_each(tmp, &server->pending_mid_q) {
+ list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
if ((mid_entry->mid == smb_buffer->Mid) &&
@@ -602,8 +603,9 @@ incomplete_rcv:
mid_entry->resp_buf = smb_buffer;
mid_entry->largeBuf = isLargeBuf;
multi_t2_fnd:
- task_to_wake = mid_entry->tsk;
mid_entry->midState = MID_RESPONSE_RECEIVED;
+ list_del_init(&mid_entry->qhead);
+ mid_entry->callback(mid_entry);
#ifdef CONFIG_CIFS_STATS2
mid_entry->when_received = jiffies;
#endif
@@ -613,9 +615,11 @@ multi_t2_fnd:
server->lstrp = jiffies;
break;
}
+ mid_entry = NULL;
}
spin_unlock(&GlobalMid_Lock);
- if (task_to_wake) {
+
+ if (mid_entry != NULL) {
/* Was previous buf put in mpx struct for multi-rsp? */
if (!isMultiRsp) {
/* smb buffer will be freed by user thread */
@@ -624,7 +628,6 @@ multi_t2_fnd:
else
smallbuf = NULL;
}
- wake_up_process(task_to_wake);
} else if (!is_valid_oplock_break(smb_buffer, server) &&
!isMultiRsp) {
cERROR(1, "No task to wake, unknown frame received! "
@@ -678,15 +681,12 @@ multi_t2_fnd:
if (!list_empty(&server->pending_mid_q)) {
spin_lock(&GlobalMid_Lock);
- list_for_each(tmp, &server->pending_mid_q) {
+ list_for_each_safe(tmp, tmp2, &server->pending_mid_q) {
mid_entry = list_entry(tmp, struct mid_q_entry, qhead);
- if (mid_entry->midState == MID_REQUEST_SUBMITTED) {
- cFYI(1, "Clearing Mid 0x%x - waking up ",
- mid_entry->mid);
- task_to_wake = mid_entry->tsk;
- if (task_to_wake)
- wake_up_process(task_to_wake);
- }
+ cFYI(1, "Clearing Mid 0x%x - issuing callback",
+ mid_entry->mid);
+ list_del_init(&mid_entry->qhead);
+ mid_entry->callback(mid_entry);
}
spin_unlock(&GlobalMid_Lock);
/* 1/8th of sec is more than enough time for them to exit */
@@ -36,6 +36,12 @@
extern mempool_t *cifs_mid_poolp;
+static void
+wake_up_task(struct mid_q_entry *mid)
+{
+ wake_up_process(mid->callback_data);
+}
+
static struct mid_q_entry *
AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server)
{
@@ -58,7 +64,13 @@ AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server)
/* do_gettimeofday(&temp->when_sent);*/ /* easier to use jiffies */
/* when mid allocated can be before when sent */
temp->when_alloc = jiffies;
- temp->tsk = current;
+
+ /*
+ * The default is for the mid to be synchronous, so the
+ * default callback just wakes up the current task.
+ */
+ temp->callback = wake_up_task;
+ temp->callback_data = current;
}
atomic_inc(&midCount);
@@ -367,6 +379,9 @@ sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
mid->mid, mid->midState);
spin_lock(&GlobalMid_Lock);
+ /* ensure that it's no longer on the pending_mid_q */
+ list_del_init(&mid->qhead);
+
switch (mid->midState) {
case MID_RESPONSE_RECEIVED:
spin_unlock(&GlobalMid_Lock);
@@ -389,7 +404,7 @@ sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
}
spin_unlock(&GlobalMid_Lock);
- delete_mid(mid);
+ DeleteMidQEntry(mid);
return rc;
}