Messages in this thread |  | | Date | Mon, 2 Oct 2017 19:33:29 -0400 (EDT) | From | Nicolas Pitre <> | Subject | Re: [PATCH v4 4/5] cramfs: add mmap support |
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On Tue, 3 Oct 2017, Richard Weinberger wrote:
> On Mon, Oct 2, 2017 at 12:29 AM, Nicolas Pitre <nicolas.pitre@linaro.org> wrote: > > On Sun, 1 Oct 2017, Christoph Hellwig wrote: > > > >> up_read(&mm->mmap_sem) in the fault path is a still a complete > >> no-go, > >> > >> NAK > > > > Care to elaborate? > > > > What about mm/filemap.c:__lock_page_or_retry() then? > > As soon you up_read() in the page fault path other tasks will race > with you before > you're able to grab the write lock.
But I _know_ that.
Could you highlight an area in my code where this is not accounted for?
Nicolas
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