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![]() On architectures where long is more then 32 bits, modifying a 32-bit field with set_bit (and other atomic bit operations) may cause bytes following the field to by modified. Because the endianness of the bits within a field is the native endianness of the CPU[1], on big-endian machines, bit number zero is in the last byte of the field. Therefore, `set_bit(0, ptr)' on a 64-bit big-endian machine is roughly equivalent to `((char *)ptr)[7] |= 1', and since w1 driver uses a 32-bit field for holding the flags, this causes bytes beyond the field to be modified. [1] From Documentation/atomic_ops.txt: Native atomic bit operations are defined to operate on objects aligned to the size of an "unsigned long" C data type, and are least of that size. The endianness of the bits within each "unsigned long" are the native endianness of the cpu. Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Cc: Evgeniy Polyakov <zbr@ioremap.net> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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.. | ||
masters | ||
slaves | ||
Kconfig | ||
Makefile | ||
w1.c | ||
w1.h | ||
w1_family.c | ||
w1_family.h | ||
w1_int.c | ||
w1_int.h | ||
w1_io.c | ||
w1_log.h | ||
w1_netlink.c | ||
w1_netlink.h |