On Mon, Dec 07, 2020 at 06:07:39PM +0000, Pavel Begunkov wrote:
> On 01/12/2020 12:06, Ming Lei wrote:
> > Pavel reported that iov_iter_npages is a bit heavy in case of bvec
> > iter.
> >
> > Turns out it isn't necessary to iterate every page in the bvec iter,
> > and we call iov_iter_npages() just for figuring out how many bio
> > vecs need to be allocated. And we can simply map each vector in bvec iter
> > to bio's vec, so just return iter->nr_segs from bio_iov_iter_nvecs() for
> > bvec iter.
> >
> > Also rename local variable 'nr_pages' as 'nr_vecs' which exactly matches its
> > real usage.
> >
> > This patch is based on Mathew's post:
>
> Tried this, the system didn't boot + discovered a filesystem blowned after
> booting with a stable kernel. That's on top of 4498a8536c816 ("block: use
> an xarray for disk->part_tbl"), which works fine. Ideas?
I guess it is caused by Christoph's "store a pointer to the block_device in struct bio (again)"
which has been reverted in for-5.11/block.
I'd suggest to run your test against the latest for-5.11/block one more time.
thanks,
Ming
