[PATCH 1/4] omap: mailbox: convert rwlocks to spinlock
Hiroshi DOYU
Hiroshi.DOYU at nokia.com
Mon May 10 05:16:50 EDT 2010
From: Ohad Ben-Cohen <ohad at wizery.com>
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 at wizery.com>
Signed-off-by: Kanigeri Hari <h-kanigeri2 at ti.com>
Signed-off-by: Hiroshi DOYU <Hiroshi.DOYU at nokia.com>
---
arch/arm/plat-omap/mailbox.c | 30 +++++++++++++++---------------
1 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/arch/arm/plat-omap/mailbox.c b/arch/arm/plat-omap/mailbox.c
index 08a2df7..af3a6ac 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 int mbox_configured;
@@ -249,16 +249,16 @@ static int omap_mbox_startup(struct omap_mbox *mbox)
struct omap_mbox_queue *mq;
if (likely(mbox->ops->startup)) {
- write_lock(&mboxes_lock);
+ spin_lock(&mboxes_lock);
if (!mbox_configured)
ret = mbox->ops->startup(mbox);
if (unlikely(ret)) {
- write_unlock(&mboxes_lock);
+ spin_unlock(&mboxes_lock);
return ret;
}
mbox_configured++;
- write_unlock(&mboxes_lock);
+ spin_unlock(&mboxes_lock);
}
ret = request_irq(mbox->irq, mbox_interrupt, IRQF_SHARED,
@@ -304,12 +304,12 @@ static void omap_mbox_fini(struct omap_mbox *mbox)
free_irq(mbox->irq, mbox);
if (unlikely(mbox->ops->shutdown)) {
- write_lock(&mboxes_lock);
+ spin_lock(&mboxes_lock);
if (mbox_configured > 0)
mbox_configured--;
if (!mbox_configured)
mbox->ops->shutdown(mbox);
- write_unlock(&mboxes_lock);
+ spin_unlock(&mboxes_lock);
}
}
@@ -330,14 +330,14 @@ 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)
@@ -363,15 +363,15 @@ 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;
@@ -384,18 +384,18 @@ 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;
}
--
1.7.1.rc1
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