Re: [PATCHSET 0/3] Add ability to save/restore iov_iter state

[Jens Axboe <axboe@kernel.dk>]

On 9/10/21 12:25 PM, Jens Axboe wrote:
> Hi,
> 
> Linus didn't particularly love the iov_iter->truncated addition and how
> it was used, and it was hard to disagree with that. Instead of relying
> on tracking ->truncated, add a few pieces of state so we can safely
> handle partial or errored read/write attempts (that we want to retry).
> 
> Then we can get rid of the iov_iter addition, and at the same time
> handle cases that weren't handled correctly before.
> 
> I've run this through vectored read/write with io_uring on the commonly
> problematic cases (dm and low depth SCSI device) which trigger these
> conditions often, and it seems to pass muster.
> 
> For a discussion on this topic, see the thread here:
> 
> https://lore.kernel.org/linux-fsdevel/CAHk-=wiacKV4Gh-MYjteU0LwNBSGpWrK-Ov25HdqB1ewinrFPg@mail.gmail.com/
> 
> You can find these patches here:
> 
> https://git.kernel.dk/cgit/linux-block/log/?h=iov_iter

Al, Linus, are you OK with this? I think we should get this in for 5.15.
I didn't resend the whole series, just a v2 of patch 1/3 to fix that bvec
vs iovec issue. Let me know if you want the while thing resent.

-- 
Jens Axboe