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authorSouptick Joarder <jrdr.linux@gmail.com>2020-06-07 21:40:55 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-08 11:05:56 -0700
commitdadbb612f6e50bbf9101c2f5d82690ce9ea4d66b (patch)
tree6395c50985da61e0b2b25ccf73947f51b81918bf /mm
parente77132e75845470065768e2205727e6be52cb7f4 (diff)
downloadlwn-dadbb612f6e50bbf9101c2f5d82690ce9ea4d66b.tar.gz
lwn-dadbb612f6e50bbf9101c2f5d82690ce9ea4d66b.zip
mm/gup.c: convert to use get_user_{page|pages}_fast_only()
API __get_user_pages_fast() renamed to get_user_pages_fast_only() to align with pin_user_pages_fast_only(). As part of this we will get rid of write parameter. Instead caller will pass FOLL_WRITE to get_user_pages_fast_only(). This will not change any existing functionality of the API. All the callers are changed to pass FOLL_WRITE. Also introduce get_user_page_fast_only(), and use it in a few places that hard-code nr_pages to 1. Updated the documentation of the API. Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Paul Mackerras <paulus@ozlabs.org> [arch/powerpc/kvm] Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Michal Suchanek <msuchanek@suse.de> Link: http://lkml.kernel.org/r/1590396812-31277-1-git-send-email-jrdr.linux@gmail.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/gup.c29
1 files changed, 16 insertions, 13 deletions
diff --git a/mm/gup.c b/mm/gup.c
index e19ff770eb4c..9d1bf3ec8e39 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2294,7 +2294,7 @@ pte_unmap:
* to be special.
*
* For a futex to be placed on a THP tail page, get_futex_key requires a
- * __get_user_pages_fast implementation that can pin pages. Thus it's still
+ * get_user_pages_fast_only implementation that can pin pages. Thus it's still
* useful to have gup_huge_pmd even if we can't operate on ptes.
*/
static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
@@ -2699,7 +2699,7 @@ static inline void gup_pgd_range(unsigned long addr, unsigned long end,
#ifndef gup_fast_permitted
/*
- * Check if it's allowed to use __get_user_pages_fast() for the range, or
+ * Check if it's allowed to use get_user_pages_fast_only() for the range, or
* we need to fall back to the slow version:
*/
static bool gup_fast_permitted(unsigned long start, unsigned long end)
@@ -2811,8 +2811,14 @@ static int internal_get_user_pages_fast(unsigned long start, int nr_pages,
return ret;
}
-
-/*
+/**
+ * get_user_pages_fast_only() - pin user pages in memory
+ * @start: starting user address
+ * @nr_pages: number of pages from start to pin
+ * @gup_flags: flags modifying pin behaviour
+ * @pages: array that receives pointers to the pages pinned.
+ * Should be at least nr_pages long.
+ *
* 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
@@ -2825,8 +2831,8 @@ static int internal_get_user_pages_fast(unsigned long start, int nr_pages,
* access can get ambiguous page results. If you call this function without
* 'write' set, you'd better be sure that you're ok with that ambiguity.
*/
-int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
- struct page **pages)
+int get_user_pages_fast_only(unsigned long start, int nr_pages,
+ unsigned int gup_flags, struct page **pages)
{
int nr_pinned;
/*
@@ -2836,10 +2842,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
* FOLL_FAST_ONLY is required in order to match the API description of
* this routine: no fall back to regular ("slow") GUP.
*/
- unsigned int gup_flags = FOLL_GET | FOLL_FAST_ONLY;
-
- if (write)
- gup_flags |= FOLL_WRITE;
+ gup_flags |= FOLL_GET | FOLL_FAST_ONLY;
nr_pinned = internal_get_user_pages_fast(start, nr_pages, gup_flags,
pages);
@@ -2855,7 +2858,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
return nr_pinned;
}
-EXPORT_SYMBOL_GPL(__get_user_pages_fast);
+EXPORT_SYMBOL_GPL(get_user_pages_fast_only);
/**
* get_user_pages_fast() - pin user pages in memory
@@ -2926,8 +2929,8 @@ int pin_user_pages_fast(unsigned long start, int nr_pages,
EXPORT_SYMBOL_GPL(pin_user_pages_fast);
/*
- * This is the FOLL_PIN equivalent of __get_user_pages_fast(). Behavior is the
- * same, except that this one sets FOLL_PIN instead of FOLL_GET.
+ * This is the FOLL_PIN equivalent of get_user_pages_fast_only(). Behavior
+ * is the same, except that this one sets FOLL_PIN instead of FOLL_GET.
*
* The API rules are the same, too: no negative values may be returned.
*/