From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-cifs@vger.kernel.org, Richard Weinberger <richard@nod.at>,
ecryptfs@vger.kernel.org, linux-um@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org,
linux-mm@kvack.org, linux-mtd@lists.infradead.org,
linux-fsdevel@vger.kernel.org,
v9fs-developer@lists.sourceforge.net, ceph-devel@vger.kernel.org,
linux-afs@lists.infradead.org
Subject: Re: [PATCH v2 16/16] iomap: Make readpage synchronous
Date: Thu, 15 Oct 2020 17:43:33 +0100 [thread overview]
Message-ID: <20201015164333.GA20115@casper.infradead.org> (raw)
In-Reply-To: <20201015094203.GA21420@infradead.org>
On Thu, Oct 15, 2020 at 10:42:03AM +0100, Christoph Hellwig wrote:
> > +static void iomap_read_page_end_io(struct bio_vec *bvec,
> > + struct completion *done, bool error)
>
> I really don't like the parameters here. Part of the problem is
> that ctx is only assigned to bi_private conditionally, which can
> easily be fixed. The other part is the strange bool error when
> we can just pass on bi_stats. See the patch at the end of what
> I'd do intead.
I prefer assigning ctx conditionally to propagating the knowledge
that !rac means synchronous. I've gone with this:
static void iomap_read_page_end_io(struct bio_vec *bvec,
- struct completion *done, bool error)
+ struct iomap_readpage_ctx *ctx, blk_status_t status)
{
struct page *page = bvec->bv_page;
struct iomap_page *iop = to_iomap_page(page);
- if (!error)
+ if (status == BLK_STS_OK) {
iomap_set_range_uptodate(page, bvec->bv_offset, bvec->bv_len);
+ } else if (ctx && ctx->status == BLK_STS_OK) {
+ ctx->status = status;
+ }
if (!iop ||
atomic_sub_and_test(bvec->bv_len, &iop->read_bytes_pending)) {
- if (done)
- complete(done);
+ if (ctx)
+ complete(&ctx->done);
else
unlock_page(page);
}
> > } else {
> > WARN_ON_ONCE(ctx.cur_page_in_bio);
> > - unlock_page(page);
> > + complete(&ctx.done);
> > }
> >
> > + wait_for_completion(&ctx.done);
>
> I don't think we need the complete / wait_for_completion dance in
> this case.
>
> > + if (ret >= 0)
> > + ret = blk_status_to_errno(ctx.status);
> > + if (ret == 0)
> > + return AOP_UPDATED_PAGE;
> > + unlock_page(page);
> > + return ret;
>
> Nipick, but I'd rather have a goto out_unlock for both error case
> and have the AOP_UPDATED_PAGE for the normal path straight in line.
>
> Here is an untested patch with my suggestions:
I think we can go a little further here:
@@ -340,16 +335,12 @@ iomap_readpage(struct page *page, const struct iomap_ops *
ops)
if (ctx.bio) {
submit_bio(ctx.bio);
- WARN_ON_ONCE(!ctx.cur_page_in_bio);
- } else {
- WARN_ON_ONCE(ctx.cur_page_in_bio);
- complete(&ctx.done);
+ wait_for_completion(&ctx.done);
+ if (ret > 0)
+ ret = blk_status_to_errno(ctx.status);
}
- wait_for_completion(&ctx.done);
if (ret >= 0)
- ret = blk_status_to_errno(ctx.status);
- if (ret == 0)
return AOP_UPDATED_PAGE;
unlock_page(page);
return ret;
... there's no need to call blk_status_to_errno if we never submitted a bio.
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next prev parent reply other threads:[~2020-10-15 16:45 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-09 14:30 [PATCH v2 00/16] Allow readpage to return a locked page Matthew Wilcox (Oracle)
2020-10-09 14:30 ` [PATCH v2 01/16] mm: Add AOP_UPDATED_PAGE return value Matthew Wilcox (Oracle)
2020-10-15 9:06 ` Christoph Hellwig
2020-10-15 14:06 ` Matthew Wilcox
2020-10-09 14:30 ` [PATCH v2 02/16] mm: Inline wait_on_page_read into its one caller Matthew Wilcox (Oracle)
2020-10-15 9:08 ` Christoph Hellwig
2020-10-09 14:30 ` [PATCH v2 03/16] 9p: Tell the VFS that readpage was synchronous Matthew Wilcox (Oracle)
2020-10-09 14:30 ` [PATCH v2 04/16] afs: " Matthew Wilcox (Oracle)
2020-10-09 14:30 ` [PATCH v2 05/16] ceph: " Matthew Wilcox (Oracle)
2020-10-09 14:30 ` [PATCH v2 06/16] cifs: " Matthew Wilcox (Oracle)
2020-10-09 14:30 ` [PATCH v2 07/16] cramfs: " Matthew Wilcox (Oracle)
2020-10-09 14:30 ` [PATCH v2 08/16] ecryptfs: " Matthew Wilcox (Oracle)
2020-10-09 14:30 ` [PATCH v2 09/16] fuse: " Matthew Wilcox (Oracle)
2020-10-09 14:30 ` [PATCH v2 10/16] hostfs: " Matthew Wilcox (Oracle)
2020-10-09 14:30 ` [PATCH v2 11/16] jffs2: " Matthew Wilcox (Oracle)
2020-10-09 14:31 ` [PATCH v2 12/16] ubifs: " Matthew Wilcox (Oracle)
2020-10-09 14:31 ` [PATCH v2 13/16] udf: " Matthew Wilcox (Oracle)
2020-10-09 14:31 ` [PATCH v2 14/16] vboxsf: " Matthew Wilcox (Oracle)
2020-10-09 14:31 ` [PATCH v2 15/16] iomap: Inline iomap_iop_set_range_uptodate into its one caller Matthew Wilcox (Oracle)
2020-10-15 9:08 ` Christoph Hellwig
2020-10-09 14:31 ` [PATCH v2 16/16] iomap: Make readpage synchronous Matthew Wilcox (Oracle)
2020-10-15 9:42 ` Christoph Hellwig
2020-10-15 16:43 ` Matthew Wilcox [this message]
2020-10-15 17:58 ` Christoph Hellwig
2020-10-15 19:03 ` Matthew Wilcox
2020-10-16 6:35 ` Christoph Hellwig
2020-10-15 9:02 ` [PATCH v2 00/16] Allow readpage to return a locked page Christoph Hellwig
2020-10-15 11:49 ` Matthew Wilcox
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