Messages in this thread | | | Date | Fri, 13 Sep 2002 17:26:39 +0900 (JST) | Subject | Re: [patch] readv/writev rework | From | Hirokazu Takahashi <> |
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Hello,
I appreciate for your kind answer. I understand clearly. Ok, this means new filemap_copy_from_user_iovec() also have to use regular kmap when page fault has happened. I'll fix it soon.
> > I updated the writev patch which may be easy to understand. > > How about it? > > Looks nice. And yes, you hung onto the atomic kmap across multiple > iov segments ;) That will save a tlb invalidate per segment.
Yes.
> > But I have one question, Could let me know if you have any idea, > > why does filemap_copy_from_user() try to call kamp()+__copy_from_user() > > again after the first trial get fault. > > > > Is there any meanings? > > We're not allowed to schedule away inside atomic_kmap - must remain > in the same task, on the same CPU etc. So the pagefault handler > will return immediately if we take a pagefault while copying to/from > userspace while holding an atomic kmap.
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