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mm/gup: make get_user_pages_fast_only() return the common return value 

There are only two callers, both can handle the common return code:

- get_user_page_fast_only() checks == 1

- gfn_to_page_many_atomic() already returns -1, and the only caller
  checks for negative return values

Remove the restriction against returning negative values.

Link: https://lkml.kernel.org/r/11-v2-987e91b59705+36b-gup_tidy_jgg@nvidia.com
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Jason Gunthorpe 2023-01-24 16:34:32 -04:00 committed by Andrew Morton
parent edad1bb1fb
commit 9198a9196e
1 changed files with 1 additions and 16 deletions
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17
mm/gup.c
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@ -3005,8 +3005,6 @@ static int internal_get_user_pages_fast(unsigned long start,
*
* Like get_user_pages_fast() except it's 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.
*
* If the architecture does not support this function, simply return with no
* pages pinned.
@ -3018,7 +3016,6 @@ static int internal_get_user_pages_fast(unsigned long start,
int get_user_pages_fast_only(unsigned long start, int nr_pages,
unsigned int gup_flags, struct page **pages)
{
int nr_pinned;
/*
* Internally (within mm/gup.c), gup fast variants must set FOLL_GET,
* because gup fast is always a "pin with a +1 page refcount" request.
@ -3030,19 +3027,7 @@ int get_user_pages_fast_only(unsigned long start, int nr_pages,
FOLL_GET | FOLL_FAST_ONLY))
return -EINVAL;
nr_pinned = internal_get_user_pages_fast(start, nr_pages, gup_flags,
pages);
/*
* As specified in the API description above, this routine is not
* allowed to return negative values. However, the common core
* routine internal_get_user_pages_fast() *can* return -errno.
* Therefore, correct for that here:
*/
if (nr_pinned < 0)
nr_pinned = 0;
return nr_pinned;
return internal_get_user_pages_fast(start, nr_pages, gup_flags, pages);
}
EXPORT_SYMBOL_GPL(get_user_pages_fast_only);