commit db662d478695a967b9d0a4c9893278e797b73f6c
author Johannes Berg <johannes.berg@intel.com> Thu Mar 15 13:26:44 2012 -0700
committer John W. Linville <linville@tuxdriver.com> Mon Apr 09 16:37:15 2012 -0400
tree 3a5cf5c45c1bf241eb5dbf354c5122d53c55a14a
parent 0c19744c344cf1bfda04f681ff4e1e46455577bd

iwlwifi: extend notification wait

Sometimes, for example when we ask the uCode
for calibration, we wait for the "complete"
response while we also need the results that
are sent in other, interim, notifications.

Currently we handle this by installing an RX
handler globally, but that isn't needed as
this is the only time we want to use these
notifications.

So in order to be able to simplify at least
future code that does the same, extend the
notification wait framework to allow you to
wait for multiple commands and decide based
on the command whether the wait finished.

While at it, also fix a race that can then
become relevant -- if the wait function has
returned true once it shouldn't be called
again, today this can happen due to races
between the triggering and the wakeup.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/iwlwifi/iwl-notif-wait.c

diff --git a/drivers/net/wireless/iwlwifi/iwl-notif-wait.c b/drivers/net/wireless/iwlwifi/iwl-notif-wait.c
index 88dc4a0..0066b89 100644
--- a/drivers/net/wireless/iwlwifi/iwl-notif-wait.c
+++ b/drivers/net/wireless/iwlwifi/iwl-notif-wait.c
@@ -75,21 +75,45 @@
 void iwl_notification_wait_notify(struct iwl_notif_wait_data *notif_wait,
 				  struct iwl_rx_packet *pkt)
 {
+	bool triggered = false;
+
 	if (!list_empty(&notif_wait->notif_waits)) {
 		struct iwl_notification_wait *w;
 
 		spin_lock(&notif_wait->notif_wait_lock);
 		list_for_each_entry(w, &notif_wait->notif_waits, list) {
-			if (w->cmd != pkt->hdr.cmd)
+			int i;
+			bool found = false;
+
+			/*
+			 * If it already finished (triggered) or has been
+			 * aborted then don't evaluate it again to avoid races,
+			 * Otherwise the function could be called again even
+			 * though it returned true before
+			 */
+			if (w->triggered || w->aborted)
 				continue;
-			w->triggered = true;
-			if (w->fn)
-				w->fn(notif_wait, pkt, w->fn_data);
+
+			for (i = 0; i < w->n_cmds; i++) {
+				if (w->cmds[i] == pkt->hdr.cmd) {
+					found = true;
+					break;
+				}
+			}
+			if (!found)
+				continue;
+
+			if (!w->fn || w->fn(notif_wait, pkt, w->fn_data)) {
+				w->triggered = true;
+				triggered = true;
+			}
 		}
 		spin_unlock(&notif_wait->notif_wait_lock);
 
-		wake_up_all(&notif_wait->notif_waitq);
 	}
+
+	if (triggered)
+		wake_up_all(&notif_wait->notif_waitq);
 }
 
 void iwl_abort_notification_waits(struct iwl_notif_wait_data *notif_wait)
@@ -109,14 +133,18 @@
 void
 iwl_init_notification_wait(struct iwl_notif_wait_data *notif_wait,
 			   struct iwl_notification_wait *wait_entry,
-			   u8 cmd,
-			   void (*fn)(struct iwl_notif_wait_data *notif_wait,
+			   const u8 *cmds, int n_cmds,
+			   bool (*fn)(struct iwl_notif_wait_data *notif_wait,
 				      struct iwl_rx_packet *pkt, void *data),
 			   void *fn_data)
 {
+	if (WARN_ON(n_cmds > MAX_NOTIF_CMDS))
+		n_cmds = MAX_NOTIF_CMDS;
+
 	wait_entry->fn = fn;
 	wait_entry->fn_data = fn_data;
-	wait_entry->cmd = cmd;
+	wait_entry->n_cmds = n_cmds;
+	memcpy(wait_entry->cmds, cmds, n_cmds);
 	wait_entry->triggered = false;
 	wait_entry->aborted = false;