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| author | Steven Price <steven.price@arm.com> | 2020-04-07 06:08:43 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-07 20:43:41 +0300 |
| commit | 3f3673d7d324d872d9d8ddb73b3e5e47fbf12e0d (patch) | |
| tree | a47842c1923bef662142c16fdf2446af46f3bd10 | |
| parent | e4a9bc58969abc695a6ebb06d801a99c1bafc001 (diff) | |
| download | linux-3f3673d7d324d872d9d8ddb73b3e5e47fbf12e0d.tar.xz | |
include/linux/swapops.h: correct guards for non_swap_entry()
If CONFIG_DEVICE_PRIVATE is defined, but neither CONFIG_MEMORY_FAILURE nor
CONFIG_MIGRATION, then non_swap_entry() will return 0, meaning that the
condition (non_swap_entry(entry) && is_device_private_entry(entry)) in
zap_pte_range() will never be true even if the entry is a device private
one.
Equally any other code depending on non_swap_entry() will not function as
expected.
I originally spotted this just by looking at the code, I haven't actually
observed any problems.
Looking a bit more closely it appears that actually this situation
(currently at least) cannot occur:
DEVICE_PRIVATE depends on ZONE_DEVICE
ZONE_DEVICE depends on MEMORY_HOTREMOVE
MEMORY_HOTREMOVE depends on MIGRATION
Fixes: 5042db43cc26 ("mm/ZONE_DEVICE: new type of ZONE_DEVICE for unaddressable memory")
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Link: http://lkml.kernel.org/r/20200305130550.22693-1-steven.price@arm.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/swapops.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/swapops.h b/include/linux/swapops.h index 9a6f06de183b..d9b7c9132c2f 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -350,7 +350,8 @@ static inline void num_poisoned_pages_inc(void) } #endif -#if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) +#if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION) || \ + defined(CONFIG_DEVICE_PRIVATE) static inline int non_swap_entry(swp_entry_t entry) { return swp_type(entry) >= MAX_SWAPFILES; |