• Linus Torvalds's avatar
    Use the new batched user accesses in generic user string handling · 9fd4470f
    Linus Torvalds authored
    This converts the generic user string functions to use the batched user
    access functions.
    
    It makes a big difference on Skylake, which is the first x86
    microarchitecture to implement SMAP.  The STAC/CLAC instructions are not
    very fast, and doing them for each access inside the loop that copies
    strings from user space (which is what the pathname handling does for
    every pathname the kernel uses, for example) is very inefficient.
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    9fd4470f
strncpy_from_user.c 3 KB