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Commit d0811078 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin Committed by Linus Torvalds
Browse files

mm/gup.c: document return value 

__get_user_pages_fast handles errors differently from
get_user_pages_fast: the former always returns the number of pages
pinned, the later might return a negative error code.

Link: http://lkml.kernel.org/r/1522962072-182137-6-git-send-email-mst@redhat.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thorsten Leemhuis <regressions@leemhuis.info>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c61611f7

arch/mips/mm/gup.c

+2 −0
Original line number Diff line number Diff line
@@ -178,6 +178,8 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end, 
/*

 * Like get_user_pages_fast() except its IRQ-safe in that it won't fall

 * back to the regular GUP.

 * Note a difference with get_user_pages_fast: this always returns the

 * number of pages pinned, 0 if no pages were pinned.

 */

int __get_user_pages_fast(unsigned long start, int nr_pages, int write,

			  struct page **pages)

arch/s390/mm/gup.c

+2 −0
Original line number Diff line number Diff line
@@ -220,6 +220,8 @@ static inline int gup_p4d_range(pgd_t *pgdp, pgd_t pgd, unsigned long addr, 
/*

 * Like get_user_pages_fast() except its IRQ-safe in that it won't fall

 * back to the regular GUP.

 * Note a difference with get_user_pages_fast: this always returns the

 * number of pages pinned, 0 if no pages were pinned.

 */

int __get_user_pages_fast(unsigned long start, int nr_pages, int write,

			  struct page **pages)

arch/sh/mm/gup.c

+2 −0
Original line number Diff line number Diff line
@@ -160,6 +160,8 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end, 
/*

 * Like get_user_pages_fast() except its IRQ-safe in that it won't fall

 * back to the regular GUP.

 * Note a difference with get_user_pages_fast: this always returns the

 * number of pages pinned, 0 if no pages were pinned.

 */

int __get_user_pages_fast(unsigned long start, int nr_pages, int write,

			  struct page **pages)

arch/sparc/mm/gup.c

+4 −0
Original line number Diff line number Diff line
@@ -193,6 +193,10 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end, 
	return 1;

}



/*

 * Note a difference with get_user_pages_fast: this always returns the

 * number of pages pinned, 0 if no pages were pinned.

 */

int __get_user_pages_fast(unsigned long start, int nr_pages, int write,

			  struct page **pages)

{

mm/gup.c

+3 −1
Original line number Diff line number Diff line
@@ -1740,7 +1740,9 @@ bool gup_fast_permitted(unsigned long start, int nr_pages, int write) 


/*

 * Like get_user_pages_fast() except it's IRQ-safe in that it won't fall back to

 * the regular GUP. It will only return non-negative values.

 * the regular GUP.

 * Note a difference with get_user_pages_fast: this always returns the

 * number of pages pinned, 0 if no pages were pinned.

 */

int __get_user_pages_fast(unsigned long start, int nr_pages, int write,

			  struct page **pages)