[PATCH] powerpc: fix __get_user_pages_fast() irq handling
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2013-11-14 04:01:58
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
From: Heiko Carstens <redacted> __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 <redacted> --- (Was originally sent to lkml only, sending to linuxppc-dev so patchwork gets it) arch/powerpc/mm/gup.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/mm/gup.c b/arch/powerpc/mm/gup.c
index 6936547..c5f734e 100644
--- a/arch/powerpc/mm/gup.c
+++ b/arch/powerpc/mm/gup.c@@ -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; }
--
1.8.3.4