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@redhat.com
--- 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;