The patch titled
Subject: mm/gup: make get_user_pages_fast_only() return the common return value
has been added to the -mm mm-unstable branch. Its filename is
mm-gup-make-get_user_pages_fast_only-return-the-common-return-value.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-gup-make-get_user_pages_fast_only-return-the-common-return-value.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Jason Gunthorpe <jgg@xxxxxxxxxx>
Subject: mm/gup: make get_user_pages_fast_only() return the common return value
Date: Tue, 24 Jan 2023 16:34:32 -0400
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@xxxxxxxxxx
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Acked-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/mm/gup.c~mm-gup-make-get_user_pages_fast_only-return-the-common-return-value
+++ a/mm/gup.c
@@ -3005,8 +3005,6 @@ static int internal_get_user_pages_fast(
*
* 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(
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 lo
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);
_
Patches currently in -mm which might be from jgg@xxxxxxxxxx are
mm-gup-have-internal-functions-get-the-mmap_read_lock.patch
mm-gup-remove-obsolete-foll_longterm-comment.patch
mm-gup-dont-call-__gup_longterm_locked-if-foll_longterm-cannot-be-set.patch
mm-gup-move-try_grab_page-to-mm-internalh.patch
mm-gup-simplify-the-external-interface-functions-and-consolidate-invariants.patch
mm-gup-add-an-assertion-that-the-mmap-lock-is-locked.patch
mm-gup-remove-locked-being-null-from-faultin_vma_page_range.patch
mm-gup-add-foll_unlockable.patch
mm-gup-make-locked-never-null-in-the-internal-gup-functions.patch
mm-gup-remove-pin_user_pages_fast_only.patch
mm-gup-make-get_user_pages_fast_only-return-the-common-return-value.patch
mm-gup-move-gup_must_unshare-to-mm-internalh.patch
mm-gup-move-private-gup-foll_-flags-to-internalh.patch
