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powerpc: Fix __get_user_pages_fast() irq handling

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__get_user_pages_fast() may be called with interrupts disabled (see e.g.
get_futex_key() in kernel/futex.c) and therefore should use local_irq_save()
and local_irq_restore() instead of local_irq_disable()/enable().

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
CC: <stable@vger.kernel.org> [v3.12]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Heiko Carstens 2013-11-14 15:01:43 +11:00 committed by Benjamin Herrenschmidt
parent 0b5381a618
commit 95f715b08f
1 changed files with 3 additions and 2 deletions
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5
arch/powerpc/mm/gup.c
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@ -123,6 +123,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct mm_struct *mm = current->mm;
unsigned long addr, len, end;
unsigned long next;
unsigned long flags;
pgd_t *pgdp;
int nr = 0;
@ -156,7 +157,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
* So long as we atomically load page table pointers versus teardown,
* we can follow the address down to the the page and take a ref on it.
*/
local_irq_disable();
local_irq_save(flags);
pgdp = pgd_offset(mm, addr);
do {
@ -179,7 +180,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
break;
} while (pgdp++, addr = next, addr != end);
local_irq_enable();
local_irq_restore(flags);
return nr;
}