From: Matthew Wilcox <willy@infradead.org>
To: David Howells <dhowells@redhat.com>
Cc: George Law <glaw@redhat.com>, Jeff Layton <jlayton@kernel.org>,
linux-cachefs@redhat.com, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] netfs: Fix missing xas_retry() calls in xarray iteration
Date: Fri, 4 Nov 2022 03:40:51 +0000 [thread overview]
Message-ID: <Y2SJw7w1IsIik3nb@casper.infradead.org> (raw)
In-Reply-To: <166751120808.117671.15797010154703575921.stgit@warthog.procyon.org.uk>
On Thu, Nov 03, 2022 at 09:33:28PM +0000, David Howells wrote:
> +++ b/fs/netfs/buffered_read.c
> @@ -46,10 +46,15 @@ void netfs_rreq_unlock_folios(struct netfs_io_request *rreq)
>
> rcu_read_lock();
> xas_for_each(&xas, folio, last_page) {
> - unsigned int pgpos = (folio_index(folio) - start_page) * PAGE_SIZE;
> - unsigned int pgend = pgpos + folio_size(folio);
> + unsigned int pgpos, pgend;
"unsigned int" assumes that the number of bytes isn't going to exceed 32
bits. I tend to err on the side of safety here and use size_t.
> bool pg_failed = false;
>
> + if (xas_retry(&xas, folio))
> + continue;
> +
> + pgpos = (folio_index(folio) - start_page) * PAGE_SIZE;
> + pgend = pgpos + folio_size(folio);
What happens if start_page is somewhere inside folio? Seems to me
that pgend ends up overhanging into the next folio?
next prev parent reply other threads:[~2022-11-04 3:41 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-03 21:33 [PATCH] netfs: Fix missing xas_retry() calls in xarray iteration David Howells
2022-11-04 3:40 ` Matthew Wilcox [this message]
2022-11-04 15:34 ` David Howells
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