On 12/21/2013 12:27 PM, Linus Torvalds wrote:
>
> HOWEVER. On x86, doing an efficient field-at-a-time copy also requires
> us to use put_user_try() and put_user_catch() in order to not have
> tons of clac/stac instructions for the extended permission testing.
> And the implementation of that was actually fairly non-optimal, so to
> actually get the code I wanted, I had to change how that all worked
> too, using "asm_volatile_goto()".
>
I guess I'm a bit puzzled... the current code should be just fine if
everything is present, and do we really care about the performance if we
actually have an error condition?
I'm a bit concerned about the put_user_fail: label having uniqueness
problem, which I know some versions of gcc at least get very noisy over.
I like the overall approach, however.
-hpa
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