The patch titled unaligned: pack the struct, not the struct members has been added to the -mm tree. Its filename is unaligned-pack-the-struct-not-the-struct-members.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: unaligned: pack the struct, not the struct members From: Harvey Harrison <harvey.harrison@xxxxxxxxx> This is safe for the arches that currently use this as gcc says that defining a struct as packed is equivalent to putting packed on each struct member. The reason this is needed is that there are some arches that define structs to be aligned to something greater than a byte...so even if the first member of the struct is marked as packed, gcc will still treat it as having the default stuct alignment which will allow it to choose _builtin_memcpy... see the comments in the memmove-using arches. This also turned out to be the issue with ARM (needs confirmation) because _some_ ARM compilers have this alignment set to 4 bytes. If the struct _itself_ is marked as packed, the compiler cannot assume this default alignment and _must_ do the bytewise access in whatever way the arch does it. By making this change, the last 3 arches could move to the new asm-generic version and the bits in linux/unaligned/ can be removed. Signed-off-by: Harvey Harrison <harvey.harrison@xxxxxxxxx> Cc: <linux-arch@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/asm-generic/unaligned.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff -puN include/asm-generic/unaligned.h~unaligned-pack-the-struct-not-the-struct-members include/asm-generic/unaligned.h --- a/include/asm-generic/unaligned.h~unaligned-pack-the-struct-not-the-struct-members +++ a/include/asm-generic/unaligned.h @@ -68,9 +68,9 @@ static inline void put_unaligned_be64(u6 #else /* _UNALIGNED_ACCESS_OK */ -struct __una_u16 { u16 x __attribute__((packed)); }; -struct __una_u32 { u32 x __attribute__((packed)); }; -struct __una_u64 { u64 x __attribute__((packed)); }; +struct __una_u16 { u16 x; } __attribute__((packed)); +struct __una_u32 { u32 x; } __attribute__((packed)); +struct __una_u64 { u64 x; } __attribute__((packed)); static inline u16 __get_le16_noalign(const u8 *p) { _ Patches currently in -mm which might be from harvey.harrison@xxxxxxxxx are linux-next.patch arm-use-the-new-byteorder-headers.patch dvb-cinergyt2-annotate-struct-endiannes-remove-unused-variable-add-static.patch v4l-s2255drv-fix-firmware-test-on-big-endian.patch ia64-use-the-new-byteorder-headers.patch input-ads7846c-sparse-lock-annotation.patch m32r-use-the-new-byteorder-headers.patch blackfin-remove-__function__-in-new-serial-driver.patch blackfin-use-the-new-byteorder-headers.patch parisc-use-the-new-byteorder-headers.patch s390-use-the-new-byteorder-headers.patch scsi-replace-__inline-with-inline.patch scsi-use-the-common-hex_asc-array-rather-than-a-private-one.patch scsi-gdthc-use-unaligned-access-helpers.patch scsi-annotate-gdth_rdcap_data-gdth_rdcap16_data-endianness.patch frv-use-the-new-byteorder-headers.patch m68knommu-use-the-new-byteorder-headers.patch h8300-use-the-new-byteorder-headers.patch alpha-use-the-new-byteorder-headers.patch lib-fix-sparse-shadowed-variable-warning.patch lib-radix_treec-make-percpu-variable-static.patch lib-proportionsc-trivial-sparse-lock-annotation.patch ibmpex-add-endian-annotation-to-extract_data-helper.patch blackfin-remove-__function__-in-video-driver.patch fb-carminefb-trivial-annotation-packing-color-register.patch memstick-annotate-endianness-of-attribute-structs.patch unaligned-introduce-common-header.patch unaligned-convert-arches-where-unaligned-access-is-ok.patch unaligned-use-generic-implementation-on-packed-struct-arches.patch unaligned-remove-packed-struct-and-unaligned-access_ok-headers.patch unaligned-pack-the-struct-not-the-struct-members.patch unaligned-move-arm-m32r-h8300-to-the-asm-generic-version.patch unaligned-remove-last-bits-of-the-unaligned-access-helpers.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html