The patch titled
Subject: mm/gup: explicitly define and check internal GUP flags, disallow FOLL_TOUCH
has been added to the -mm mm-unstable branch. Its filename is
mm-gup-explicitly-define-and-check-internal-gup-flags-disallow-foll_touch.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-gup-explicitly-define-and-check-internal-gup-flags-disallow-foll_touch.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: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Subject: mm/gup: explicitly define and check internal GUP flags, disallow FOLL_TOUCH
Date: Tue, 3 Oct 2023 00:14:52 +0100
Rather than open-coding a list of internal GUP flags in
is_valid_gup_args(), define which ones are internal.
In addition, explicitly check to see if the user passed in FOLL_TOUCH
somehow, as this appears to have been accidentally excluded.
Link: https://lkml.kernel.org/r/971e013dfe20915612ea8b704e801d7aef9a66b6.1696288092.git.lstoakes@xxxxxxxxx
Signed-off-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Reviewed-by: Arnd Bergmann <arnd@xxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Richard Cochran <richardcochran@xxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/gup.c | 5 ++---
mm/internal.h | 3 +++
2 files changed, 5 insertions(+), 3 deletions(-)
--- a/mm/gup.c~mm-gup-explicitly-define-and-check-internal-gup-flags-disallow-foll_touch
+++ a/mm/gup.c
@@ -2227,12 +2227,11 @@ static bool is_valid_gup_args(struct pag
/*
* These flags not allowed to be specified externally to the gup
* interfaces:
- * - FOLL_PIN/FOLL_TRIED/FOLL_FAST_ONLY are internal only
+ * - FOLL_TOUCH/FOLL_PIN/FOLL_TRIED/FOLL_FAST_ONLY are internal only
* - FOLL_REMOTE is internal only and used on follow_page()
* - FOLL_UNLOCKABLE is internal only and used if locked is !NULL
*/
- if (WARN_ON_ONCE(gup_flags & (FOLL_PIN | FOLL_TRIED | FOLL_UNLOCKABLE |
- FOLL_REMOTE | FOLL_FAST_ONLY)))
+ if (WARN_ON_ONCE(gup_flags & INTERNAL_GUP_FLAGS))
return false;
gup_flags |= to_set;
--- a/mm/internal.h~mm-gup-explicitly-define-and-check-internal-gup-flags-disallow-foll_touch
+++ a/mm/internal.h
@@ -1027,6 +1027,9 @@ enum {
FOLL_UNLOCKABLE = 1 << 21,
};
+#define INTERNAL_GUP_FLAGS (FOLL_TOUCH | FOLL_TRIED | FOLL_REMOTE | FOLL_PIN | \
+ FOLL_FAST_ONLY | FOLL_UNLOCKABLE)
+
/*
* Indicates for which pages that are write-protected in the page table,
* whether GUP has to trigger unsharing via FAULT_FLAG_UNSHARE such that the
_
Patches currently in -mm which might be from lstoakes@xxxxxxxxx are
mm-refactor-si_mem_available.patch
mm-filemap-clarify-filemap_fault-comments-for-not-uptodate-case.patch
mm-filemap-clarify-filemap_fault-comments-for-not-uptodate-case-fix.patch
mm-make-__access_remote_vm-static.patch
mm-gup-explicitly-define-and-check-internal-gup-flags-disallow-foll_touch.patch
mm-gup-make-failure-to-pin-an-error-if-foll_nowait-not-specified.patch
mm-gup-adapt-get_user_page_vma_remote-to-never-return-null.patch
