ipmi: Don't flush messages in sender() in run-to-completion mode

When flushing queued messages in run-to-completion mode,
smi_event_handler() is recursively called.

flush_messages()
 smi_event_handler()
  handle_transaction_done()
   deliver_recv_msg()
    ipmi_smi_msg_received()
     smi_recv_tasklet()
      sender()
       flush_messages()
        smi_event_handler()
         ...

The depth of the recursive call depends on the number of queued
messages, so it can cause a stack overflow if many messages have
been queued.

To solve this problem, this patch removes flush_messages()
from sender()@ipmi_si_intf.c.  Instead, add flush_messages() to
caller side of sender() if needed.  Additionally, to implement this,
add new handler flush_messages to struct ipmi_smi_handlers.

Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>

Fixed up a comment and some spacing issues.

Signed-off-by: Corey Minyard <cminyard@mvista.com>

3 files changed, 13 insertions, 5 deletions

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index 5e31c339062e..6e191ff910e6 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -4295,6 +4295,9 @@ static void ipmi_panic_request_and_wait(ipmi_smi_t           intf,
                             0, 1); /* Don't retry, and don't wait. */
         if (rv)
                 atomic_sub(2, &panic_done_count);
+        else if (intf->handlers->flush_messages)
+                intf->handlers->flush_messages(intf->send_info);
+
         while (atomic_read(&panic_done_count) != 0)
                 ipmi_poll(intf);
 }
diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index 5bd6d5b974cd..2f4cf6e78f72 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -924,8 +924,9 @@ static void check_start_timer_thread(struct smi_info *smi_info)
         }
 }
 
-static void flush_messages(struct smi_info *smi_info)
+static void flush_messages(void *send_info)
 {
+        struct smi_info *smi_info = send_info;
         enum si_sm_result result;
 
         /*
@@ -949,12 +950,10 @@ static void sender(void                *send_info,
 
         if (smi_info->run_to_completion) {
                 /*
-                 * If we are running to completion, start it and run
-                 * transactions until everything is clear.
+                 * If we are running to completion, start it.  Upper
+                 * layer will call flush_messages to clear it out.
                  */
                 smi_info->waiting_msg = msg;
-
-                flush_messages(smi_info);
                 return;
         }
 
@@ -1260,6 +1259,7 @@ static const struct ipmi_smi_handlers handlers = {
         .set_need_watch         = set_need_watch,
         .set_maintenance_mode   = set_maintenance_mode,
         .set_run_to_completion  = set_run_to_completion,
+        .flush_messages         = flush_messages,
         .poll                   = poll,
 };
 
diff --git a/include/linux/ipmi_smi.h b/include/linux/ipmi_smi.h
index 41de0cf34c49..f8cea14485dd 100644
--- a/include/linux/ipmi_smi.h
+++ b/include/linux/ipmi_smi.h
@@ -115,6 +115,11 @@ struct ipmi_smi_handlers {
            implement it. */
         void (*set_need_watch)(void *send_info, bool enable);
 
+        /*
+         * Called when flushing all pending messages.
+         */
+        void (*flush_messages)(void *send_info);
+
         /* Called when the interface should go into "run to
            completion" mode.  If this call sets the value to true, the
            interface should make sure that all messages are flushed