From 49db746d39887287d8dc4ff76d760320388e9eeb Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Tue, 3 Oct 2023 00:14:52 +0100 Subject: [PATCH] mm/gup: explicitly define and check internal GUP flags, disallow FOLL_TOUCH [ Upstream commit 0f20bba1688bdf3b32df0162511a67d4eda15790 ] 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 Reviewed-by: Arnd Bergmann Reviewed-by: David Hildenbrand Reviewed-by: Jason Gunthorpe Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Catalin Marinas Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: John Hubbard Cc: Mark Rutland Cc: Namhyung Kim Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Richard Cochran Cc: Will Deacon Signed-off-by: Andrew Morton Stable-dep-of: 631426ba1d45 ("mm/madvise: make MADV_POPULATE_(READ|WRITE) handle VM_FAULT_RETRY properly") Signed-off-by: Sasha Levin --- mm/gup.c | 5 ++--- mm/internal.h | 3 +++ 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 30cf724ddbce..50cf76d30a88 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -964,6 +964,9 @@ 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