Messages in this thread |  | | | Date | Tue, 14 Apr 2009 21:48:25 +0200 | | From | Andrea Arcangeli <> | | Subject | Re: [RFC][PATCH v3 2/6] mm, directio: fix fork vs direct-io race (read(2) side IOW gup(write) side) |
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On Tue, Apr 14, 2009 at 02:10:08PM -0400, Jeff Moyer wrote: > Really? I don't actually see that in the code, have I missed it?
Checking the spinlock version, when any writer is waiting, the sem->wait_list won't empty and down_read will wait too. The wakeup is FIFO with __rwsem_do_wake is doing a wake-one if first one in queue is a down_write. So it looks ok to me. asm version should have an equivalent logic.
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