lkml.org 
[lkml]   [2020]   [Dec]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v1 0/6] no-copy bvec
On Tue, Dec 15, 2020 at 11:14:20AM +0000, Pavel Begunkov wrote:
> On 15/12/2020 01:41, Ming Lei wrote:
> > On Tue, Dec 15, 2020 at 12:20:19AM +0000, Pavel Begunkov wrote:
> >> Instead of creating a full copy of iter->bvec into bio in direct I/O,
> >> the patchset makes use of the one provided. It changes semantics and
> >> obliges users of asynchronous kiocb to track bvec lifetime, and [1/6]
> >> converts the only place that doesn't.
> >
> > Just think of one corner case: iov_iter(BVEC) may pass bvec table with zero
> > length bvec, which may not be supported by block layer or driver, so
> > this patchset has to address this case first.
>
> The easiest for me would be to fallback to copy if there are zero bvecs,
> e.g. finding such during iov_iter_alignment(), but do we know from where
> zero bvecs can came? As it's internals we may want to forbid them if
> there is not too much hassle.

You may find clue from the following link:

https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg2262077.html


Thanks,
Ming

\
 
 \ /
  Last update: 2020-12-15 13:08    [W:0.083 / U:23.088 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site