ipmi: run to completion fixes

The "run_to_completion" mode was somewhat broken.  Locks need to be avoided in
run_to_completion mode, and it shouldn't be used by normal users, just
internally for panic situations.

This patch removes locks in run_to_completion mode and removes the user call
for setting the mode.  The only user was the poweroff code, but it was easily
converted to use the polling interface.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 16 insertions, 4 deletions

diff --git a/drivers/char/ipmi/ipmi_poweroff.c b/drivers/char/ipmi/ipmi_poweroff.c
index b86186de7f07..b065a53d1ca8 100644
--- a/drivers/char/ipmi/ipmi_poweroff.c
+++ b/drivers/char/ipmi/ipmi_poweroff.c
@@ -99,11 +99,14 @@ static unsigned char ipmi_version;
    allocate them, since we may be in a panic situation.  The whole
    thing is single-threaded, anyway, so multiple messages are not
    required. */
+static atomic_t dummy_count = ATOMIC_INIT(0);
 static void dummy_smi_free(struct ipmi_smi_msg *msg)
 {
+        atomic_dec(&dummy_count);
 }
 static void dummy_recv_free(struct ipmi_recv_msg *msg)
 {
+        atomic_dec(&dummy_count);
 }
 static struct ipmi_smi_msg halt_smi_msg =
 {
@@ -152,17 +155,28 @@ static int ipmi_request_wait_for_response(ipmi_user_t            user,
         return halt_recv_msg.msg.data[0];
 }
 
-/* We are in run-to-completion mode, no completion is desired. */
+/* Wait for message to complete, spinning. */
 static int ipmi_request_in_rc_mode(ipmi_user_t            user,
                                    struct ipmi_addr       *addr,
                                    struct kernel_ipmi_msg *send_msg)
 {
         int rv;
 
+        atomic_set(&dummy_count, 2);
         rv = ipmi_request_supply_msgs(user, addr, 0, send_msg, NULL,
                                       &halt_smi_msg, &halt_recv_msg, 0);
-        if (rv)
+        if (rv) {
+                atomic_set(&dummy_count, 0);
                 return rv;
+        }
+
+        /*
+         * Spin until our message is done.
+         */
+        while (atomic_read(&dummy_count) > 0) {
+                ipmi_poll_interface(user);
+                cpu_relax();
+        }
 
         return halt_recv_msg.msg.data[0];
 }
@@ -531,9 +545,7 @@ static void ipmi_poweroff_function (void)
                 return;
 
         /* Use run-to-completion mode, since interrupts may be off. */
-        ipmi_user_set_run_to_completion(ipmi_user, 1);
         specific_poweroff_func(ipmi_user);
-        ipmi_user_set_run_to_completion(ipmi_user, 0);
 }
 
 /* Wait for an IPMI interface to be installed, the first one installed