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Message-ID: <5b20f3cda7cd841555c2626f98d23aa25a039828.1696174961.git.lstoakes@gmail.com>
Date: Sun, 1 Oct 2023 17:00:03 +0100
From: Lorenzo Stoakes <lstoakes@...il.com>
To: linux-mm@...ck.org, linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Mark Rutland <mark.rutland@....com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Ian Rogers <irogers@...gle.com>,
Adrian Hunter <adrian.hunter@...el.com>,
Oleg Nesterov <oleg@...hat.com>,
Richard Cochran <richardcochran@...il.com>,
Jason Gunthorpe <jgg@...dia.com>,
John Hubbard <jhubbard@...dia.com>,
Arnd Bergmann <arnd@...db.de>,
Lorenzo Stoakes <lstoakes@...il.com>
Subject: [PATCH 2/4] 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, we were not explicitly checking to see if the user passed in
FOLL_TOUCH somehow, this patch fixes that.
Signed-off-by: Lorenzo Stoakes <lstoakes@...il.com>
---
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 449891ad7fdb..499016c6b01d 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1018,6 +1018,9 @@ 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
--
2.42.0
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