x86: Add 1/2/4/8 byte optimization to 64bit __copy_{from,to}_user_inatomic
The 64bit __copy_{from,to}_user_inatomic always called copy_from_user_generic, but skipped the special optimizations for 1/2/4/8 byte accesses. This especially hurts the futex call, which accesses the 4 byte futex user value with a complicated fast string operation in a function call, instead of a single movl. Use __copy_{from,to}_user for _inatomic instead to get the same optimizations. The only problem was the might_fault() in those functions. So move that to new wrapper and call __copy_{f,t}_user_nocheck() from *_inatomic directly. 32bit already did this correctly by duplicating the code. Signed-off-by: NAndi Kleen <ak@linux.intel.com> Link: http://lkml.kernel.org/r/1376687844-19857-2-git-send-email-andi@firstfloor.orgSigned-off-by: NH. Peter Anvin <hpa@linux.intel.com>
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