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    SubjectRe: [RFC -tip 0/4] x86: reduce fixup of uaccess
    H. Peter Anvin wrote:
    > Hiroshi Shimamoto wrote:
    >> This is my second try to reduce fixup code size for exceptions of uaccess.
    >> This patch series reduces fixup code for exceptions of uaccess in signal.
    >> I gave up to make direct jump to end of function when an exception occurs.
    >> However, I thought fixup code could be reduced. The concept is that to add
    >> uaccess_err in thread_info and set it to -EFAULT on exception, finally check
    >> this value on the last of function.
    >> Is this good to reduce code size?
    > Hello Hiroshi,

    Hello Peter,

    > The patches look technically really nice. I have a couple of stylistic
    > comments, though, which I'd like yours and others' comments on.

    Thanks for comments.

    > This introduces a new blocking construct, and it's not immediately
    > obvious in the source code. I think introducing a technically redundant

    Yeah, I think it's not friendly about readability now.

    > set of braces and dropping the parens from the try construct and the
    > redundant pointer might look better:
    > get_user_try {
    > /* do stuff */
    > } get_user_catch(err);

    OK, I'll update like that.

    > This makes it, in my opinion, much clearer that it is a new bracing
    > construct, and it also eliminates the need to form a pointer to "err"

    I'm not sure which is better plain "err" or pointer to "err".

    > (even though the compiler doesn't actually do so, it looks like it does
    > to the programmer.)
    > Also, I don't think we need double underscores for the wrapping
    > construct, since the get_user/__get_user (check/nocheck) etc.
    > distinction doesn't directly apply there.

    OK. Will drop underscores.

    I'll repost update patches.


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