Messages in this thread |  | | Date | Mon, 07 Apr 2008 21:43:06 +0900 | From | Tejun Heo <> | Subject | Re: [RFC PATCH] sysfs: refill attribute buffer when reading from offset 0 |
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Hello,
Andrew Morton wrote: >> The application for this change is to allow a userspace >> RAID metadata handler to check the state of an array without causing any >> memory allocations. Thus not causing writeback to a raid array that might >> be blocked waiting for userspace to take action. > > Although that sounds like a rather, umm, optimistic application. I guess > if everything's mlocked you might get lucky. > >> Cc: NeilBrown <neilb@suse.de> >> Cc: Tejun Heo <htejun@gmail.com> >> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Tejun Heo <htejun@gmail.com>
> Has this been tested with pread()? That should work - doing an lseek+read > is plain dopey. > > Can we now remove need_read_fill? Not if we want to support > open+lseek+read, I guess - this initial read might not be at offset > zero.
Heh.. needs_read_fill is set after read and poll regardless of file pos and I bet there are applications depending on it. :-(
-- tejun
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