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authorLorenzo Stoakes <lstoakes@gmail.com>2023-10-03 00:14:52 +0100
committerAndrew Morton <akpm@linux-foundation.org>2023-10-18 14:34:15 -0700
commit0f20bba1688bdf3b32df0162511a67d4eda15790 (patch)
tree0a9399071a697d39100cf8b0869dc8d1a1c84641
parentc43cfa42541c04a3a94312e39ab81c41ba431277 (diff)
mm/gup: explicitly define and check internal GUP flags, disallow FOLL_TOUCH
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@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--mm/gup.c5
-rw-r--r--mm/internal.h3
2 files changed, 5 insertions, 3 deletions
diff --git a/mm/gup.c b/mm/gup.c
index 2f8a2d89fde1..b21b33d1787e 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2227,12 +2227,11 @@ static bool is_valid_gup_args(struct page **pages, int *locked,
/*
* 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;
diff --git a/mm/internal.h b/mm/internal.h
index 5a5c923725d3..2b79da9deb64 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1017,6 +1017,9 @@ 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