The patch titled
include/linux/types.h: aligned_64: improve the code comment
has been added to the -mm tree. Its filename is
include-linux-typesh-aligned_64-improve-the-code-comment.patch
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Subject: include/linux/types.h: aligned_64: improve the code comment
From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Enhance the comment describing the reasons for using aligned_u64. Via
Andreas and Andi.
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: Eric Paris <eparis@xxxxxxxxxx>
Cc: Jan Engelhardt <jengelh@xxxxxxxxxx>
Cc: Andreas Gruenbacher <agruen@xxxxxxx>
Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/types.h | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff -puN include/linux/types.h~include-linux-typesh-aligned_64-improve-the-code-comment include/linux/types.h
--- a/include/linux/types.h~include-linux-typesh-aligned_64-improve-the-code-comment
+++ a/include/linux/types.h
@@ -121,7 +121,15 @@ typedef __u64 u_int64_t;
typedef __s64 int64_t;
#endif
-/* this is a special 64bit data type that is 8-byte aligned */
+/*
+ * aligned_u64 should be used in defining kernel<->userspace ABIs to avoid
+ * common 32/64-bit compat problems.
+ * 64-bit values align to 4-byte boundaries on x86_32 (and possibly other
+ * architectures) and to 8-byte boundaries on 64-bit architetures. The new
+ * aligned_64 type enforces 8-byte alignment so that structs containing
+ * aligned_64 values have the same alignment on 32-bit and 64-bit architectures.
+ * No conversions are necessary between 32-bit user-space and a 64-bit kernel.
+ */
#define aligned_u64 __u64 __attribute__((aligned(8)))
#define aligned_be64 __be64 __attribute__((aligned(8)))
#define aligned_le64 __le64 __attribute__((aligned(8)))
_
Patches currently in -mm which might be from akpm@xxxxxxxxxxxxxxxxxxxx are
include-linux-typesh-aligned_64-improve-the-code-comment.patch
linux-next.patch
next-remove-localversion.patch
fs-inodec-work-around-bug.patch
arch-x86-kernel-entry_64s-fix-build-with-gas-2161.patch
arch-x86-kernel-entry_32s-i386-too.patch
i-need-old-gcc.patch
arch-alpha-kernel-systblss-remove-debug-check.patch
mm-vmap-area-cache.patch
arch-mips-include-asm-fcntlh-needs-typesh.patch
gcc-46-btrfs-clean-up-unused-variables-bugs.patch
drivers-gpu-drm-radeon-atomc-fix-warning.patch
drivers-media-video-cx23885-cx23885-corec-fix-cx23885_dev_checkrevision.patch
fs-notify-fanotify-fanotify_userc-fix-warnings.patch
leds-route-kbd-leds-through-the-generic-leds-layer.patch
leds-add-led-trigger-for-input-subsystem-led-events-checkpatch-fixes.patch
backlight-add-low-threshold-to-pwm-backlight.patch
serial8250-ratelimit-too-much-work-error-fix.patch
serial8250-ratelimit-too-much-work-error-fix-fix.patch
sched-make-sched_param-argument-static-variables-in-some-sched_setscheduler-caller.patch
drivers-message-fusion-mptsasc-fix-warning.patch
drivers-block-aoe-aoeblkc-ratelimit-a-warning-printk.patch
vfs-allow-mnt_want_write-to-sleep-fix.patch
mm.patch
oom-kill-all-threads-sharing-oom-killed-tasks-mm-fix.patch
oom-kill-all-threads-sharing-oom-killed-tasks-mm-fix-fix.patch
oom-rewrite-error-handling-for-oom_adj-and-oom_score_adj-tunables.patch
oom-fix-locking-for-oom_adj-and-oom_score_adj.patch
mm-only-build-per-node-scan_unevictable-functions-when-numa-is-enabled-cleanup.patch
memory-hotplug-unify-is_removable-and-offline-detection-code-checkpatch-fixes.patch
mm-stack-based-kmap_atomic-checkpatch-fixes.patch
mm-stack-based-kmap_atomic-fix.patch
mm-retry-page-fault-when-blocking-on-disk-transfer.patch
mm-retry-page-fault-when-blocking-on-disk-transfer-update-fix.patch
rmap-make-anon_vma_free-static-fix.patch
vmstat-include-compactionh-when-config_compaction-fix.patch
fs-fs-writebackc-restore-lost-comment.patch
mm-memory_hotplugc-make-scan_lru_pages-static.patch
frv-duplicate-output_buffer-of-e03-checkpatch-fixes.patch
hpet-factor-timer-allocate-from-open.patch
hpet-factor-timer-allocate-from-open-fix.patch
kernelh-add-minmax3-macros-fix.patch
include-linux-kernelh-add-__must_check-to-strict_strto.patch
printk-declare-printk_ratelimit_state-in-ratelimith-fix.patch
vsprintfc-use-default-pointer-field-size-for-null-strings-fix.patch
scripts-get_maintainerpl-add-git-blame-rolestats-authored-lines-information.patch
idr-fix-idr_pre_get-locking-description-fix.patch
checkpatch-returning-errno-typically-should-be-negative.patch
select-rename-estimate_accuracy-to-select_estimate_accuracy.patch
vcs-add-poll-fasync-support-fix-fix.patch
rtc-rtc-s3c-fix-access-unit-from-byte-to-word-on-rtccon-checkpatch-fixes.patch
cgroup_freezer-update_freezer_state-does-incorrect-state-transitions-checkpatch-fixes.patch
memcg-cpu-hotplug-aware-quick-acount_move-detection-checkpatch-fixes.patch
core_pattern-fix-long-parameters-was-truncated-by-core_pattern-handler-update.patch
core_pattern-fix-long-parameters-was-truncated-by-core_pattern-handler-update-2.patch
core_pattern-fix-long-parameters-was-truncated-by-core_pattern-handler-update-2-checkpatch-fixes.patch
drivers-char-hvc_consolec-remove-unneeded-__set_current_statetask_running.patch
delay-accounting-re-implement-c-for-getdelaysc-to-report-information-on-a-target-command-checkpatch-fixes.patch
fuse-use-release_pages.patch
pps-add-async-pps-event-handler-fix.patch
memstick-add-driver-for-ricoh-r5c592-card-reader-fix.patch
kernel-resourcec-handle-reinsertion-of-an-already-inserted-resource.patch
ramoops-use-the-platform-data-structure-instead-of-module-params-fix.patch
journal_add_journal_head-debug.patch
slab-leaks3-default-y.patch
put_bh-debug.patch
getblk-handle-2tb-devices.patch
memblock-add-input-size-checking-to-memblock_find_region.patch
memblock-add-input-size-checking-to-memblock_find_region-fix.patch
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