From: John Linville <linville@redhat.com>
Date: Fri, 28 May 2010 17:08:34 -0400
Subject: [net] wireless: convert reg_regdb_search_lock to mutex
Message-id: <20100528170834.GC30834@redhat.com>
Patchwork-id: 25897
O-Subject: [RHEL5 PATCH] wireless: convert reg_regdb_search_lock to mutex
Bugzilla: 597334
RH-Acked-by: Stanislaw Gruszka <sgruszka@redhat.com>
RH-Acked-by: Jiri Olsa <jolsa@redhat.com>
RH-Acked-by: Ivan Vecera <ivecera@redhat.com>
RH-Acked-by: Jiri Pirko <jpirko@redhat.com>

BZ597334

Backport of the following upstream commit...

commit 368d06f5b0eefcbf37d677d3b65381310a251f03
Author: John W. Linville <linville@tuxdriver.com>
Date:   Tue Mar 16 15:40:59 2010 -0400

    wireless: convert reg_regdb_search_lock to mutex

    Stanse discovered that kmalloc is being called with GFP_KERNEL while
    holding this spinlock.  The spinlock can be a mutex instead, which also
    enables the removal of the unlock/lock around the lock/unlock of
    cfg80211_mutex and the call to set_regdom.

    Reported-by: Jiri Slaby <jirislaby@gmail.com>
    Cc: stable@kernel.org
    Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index cdca8b7..e24e9de 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -367,7 +367,7 @@ struct reg_regdb_search_request {
 };
 
 static LIST_HEAD(reg_regdb_search_list);
-static DEFINE_SPINLOCK(reg_regdb_search_lock);
+static DEFINE_MUTEX(reg_regdb_search_mutex);
 
 static void reg_regdb_search(void *unused)
 {
@@ -375,7 +375,7 @@ static void reg_regdb_search(void *unused)
 	const struct ieee80211_regdomain *curdom, *regdom;
 	int i, r;
 
-	spin_lock(&reg_regdb_search_lock);
+	mutex_lock(&reg_regdb_search_mutex);
 	while (!list_empty(&reg_regdb_search_list)) {
 		request = list_first_entry(&reg_regdb_search_list,
 					   struct reg_regdb_search_request,
@@ -389,18 +389,16 @@ static void reg_regdb_search(void *unused)
 				r = reg_copy_regd(&regdom, curdom);
 				if (r)
 					break;
-				spin_unlock(&reg_regdb_search_lock);
 				mutex_lock(&cfg80211_mutex);
 				set_regdom(regdom);
 				mutex_unlock(&cfg80211_mutex);
-				spin_lock(&reg_regdb_search_lock);
 				break;
 			}
 		}
 
 		kfree(request);
 	}
-	spin_unlock(&reg_regdb_search_lock);
+	mutex_unlock(&reg_regdb_search_mutex);
 }
 
 static DECLARE_WORK(reg_regdb_work, reg_regdb_search, NULL);
@@ -418,9 +416,9 @@ static void reg_regdb_query(const char *alpha2)
 
 	memcpy(request->alpha2, alpha2, 2);
 
-	spin_lock(&reg_regdb_search_lock);
+	mutex_lock(&reg_regdb_search_mutex);
 	list_add_tail(&request->list, &reg_regdb_search_list);
-	spin_unlock(&reg_regdb_search_lock);
+	mutex_unlock(&reg_regdb_search_mutex);
 
 	schedule_work(&reg_regdb_work);
 }