omap: mailbox: convert rwlocks to spinlock

rwlocks are slower and have potential starvation issues
therefore spinlocks are generally preferred.

see also: http://lwn.net/Articles/364583/

Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Kanigeri Hari <h-kanigeri2@ti.com>
Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU@nokia.com>

1 files changed, 10 insertions, 10 deletions

diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index c3402165488..fafe47bf2f5 100644
--- a/arch/arm/plat-omap/mailbox.c
+++ b/arch/arm/plat-omap/mailbox.c
@@ -31,7 +31,7 @@
 
 static struct workqueue_struct *mboxd;
 static struct omap_mbox *mboxes;
-static DEFINE_RWLOCK(mboxes_lock);
+static DEFINE_SPINLOCK(mboxes_lock);
 static bool rq_full;
 
 static int mbox_configured;
@@ -341,14 +341,14 @@ struct omap_mbox *omap_mbox_get(const char *name)
         struct omap_mbox *mbox;
         int ret;
 
-        read_lock(&mboxes_lock);
+        spin_lock(&mboxes_lock);
         mbox = *(find_mboxes(name));
         if (mbox == NULL) {
-                read_unlock(&mboxes_lock);
+                spin_unlock(&mboxes_lock);
                 return ERR_PTR(-ENOENT);
         }
 
-        read_unlock(&mboxes_lock);
+        spin_unlock(&mboxes_lock);
 
         ret = omap_mbox_startup(mbox);
         if (ret)
@@ -374,15 +374,15 @@ int omap_mbox_register(struct device *parent, struct omap_mbox *mbox)
         if (mbox->next)
                 return -EBUSY;
 
-        write_lock(&mboxes_lock);
+        spin_lock(&mboxes_lock);
         tmp = find_mboxes(mbox->name);
         if (*tmp) {
                 ret = -EBUSY;
-                write_unlock(&mboxes_lock);
+                spin_unlock(&mboxes_lock);
                 goto err_find;
         }
         *tmp = mbox;
-        write_unlock(&mboxes_lock);
+        spin_unlock(&mboxes_lock);
 
         return 0;
 
@@ -395,18 +395,18 @@ int omap_mbox_unregister(struct omap_mbox *mbox)
 {
         struct omap_mbox **tmp;
 
-        write_lock(&mboxes_lock);
+        spin_lock(&mboxes_lock);
         tmp = &mboxes;
         while (*tmp) {
                 if (mbox == *tmp) {
                         *tmp = mbox->next;
                         mbox->next = NULL;
-                        write_unlock(&mboxes_lock);
+                        spin_unlock(&mboxes_lock);
                         return 0;
                 }
                 tmp = &(*tmp)->next;
         }
-        write_unlock(&mboxes_lock);
+        spin_unlock(&mboxes_lock);
 
         return -EINVAL;
 }