Commit 548b6a1e authored by Miles Chen's avatar Miles Chen Committed by Linus Torvalds
Browse files

mm/gup.c: further document vma_permits_fault() 

Describe the caller's responsibilities when passing
FAULT_FLAG_ALLOW_RETRY.

Link: http://lkml.kernel.org/r/1586915606.5647.5.camel@mtkswgap22


Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e7920310

mm/gup.c

+2 −1
Original line number Diff line number Diff line
@@ -1176,7 +1176,8 @@ static bool vma_permits_fault(struct vm_area_struct *vma, 
 * @address:	user address

 * @fault_flags:flags to pass down to handle_mm_fault()

 * @unlocked:	did we unlock the mmap_sem while retrying, maybe NULL if caller

 *		does not allow retry

 *		does not allow retry. If NULL, the caller must guarantee

 *		that fault_flags does not contain FAULT_FLAG_ALLOW_RETRY.

 *

 * This is meant to be called in the specific scenario where for locking reasons

 * we try to access user memory in atomic context (within a pagefault_disable()