spin_lock_irqsave and spin_unlock_irqrestore is inteded to be called from
a context where it is unknown if interrupts are enabled or disabled (such
as interrupt handlers). From a process context, we should call
spin_lock_irq and spin_unlock_irq, that avoids the costly pushf and popf
instructions.
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
---
drivers/video/fbdev/udlfb.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
Index: linux-4.17-rc7/drivers/video/fbdev/udlfb.c
===================================================================
--- linux-4.17-rc7.orig/drivers/video/fbdev/udlfb.c 2018-06-03 13:17:46.000000000 +0200
+++ linux-4.17-rc7/drivers/video/fbdev/udlfb.c 2018-06-03 13:17:46.000000000 +0200
@@ -1855,18 +1855,17 @@ static void dlfb_free_urb_list(struct dl
struct list_head *node;
struct urb_node *unode;
struct urb *urb;
- unsigned long flags;
/* keep waiting and freeing, until we've got 'em all */
while (count--) {
down(&dlfb->urbs.limit_sem);
- spin_lock_irqsave(&dlfb->urbs.lock, flags);
+ spin_lock_irq(&dlfb->urbs.lock);
node = dlfb->urbs.list.next; /* have reserved one with sem */
list_del_init(node);
- spin_unlock_irqrestore(&dlfb->urbs.lock, flags);
+ spin_unlock_irq(&dlfb->urbs.lock);
unode = list_entry(node, struct urb_node, entry);
urb = unode->urb;
@@ -1944,7 +1943,6 @@ static struct urb *dlfb_get_urb(struct d
int ret;
struct list_head *entry;
struct urb_node *unode;
- unsigned long flags;
/* Wait for an in-flight buffer to complete and get re-queued */
ret = down_timeout(&dlfb->urbs.limit_sem, GET_URB_TIMEOUT);
@@ -1956,14 +1954,14 @@ static struct urb *dlfb_get_urb(struct d
return NULL;
}
- spin_lock_irqsave(&dlfb->urbs.lock, flags);
+ spin_lock_irq(&dlfb->urbs.lock);
BUG_ON(list_empty(&dlfb->urbs.list)); /* reserved one with limit_sem */
entry = dlfb->urbs.list.next;
list_del_init(entry);
dlfb->urbs.available--;
- spin_unlock_irqrestore(&dlfb->urbs.lock, flags);
+ spin_unlock_irq(&dlfb->urbs.lock);
unode = list_entry(entry, struct urb_node, entry);
return unode->urb;
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