Messages in this thread | | | Date | Wed, 9 Nov 2022 13:35:25 +0800 | Subject | Re: [Linux-cachefs] [PATCH v2 2/2] netfs: Fix dodgy maths | From | JeffleXu <> |
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On 11/5/22 12:38 AM, David Howells wrote: > Fix the dodgy maths in netfs_rreq_unlock_folios(). start_page could be > inside the folio, in which case the calculation of pgpos will be come up > with a negative number (though for the moment rreq->start is rounded down > earlier and folios would have to get merged whilst locked) > > Alter how this works to just frame the tracking in terms of absolute file > positions, rather than offsets from the start of the I/O request. This > simplifies the maths and makes it easier to follow. > > Fix the issue by using folio_pos() and folio_size() to calculate the end > position of the page. > > Fixes: 3d3c95046742 ("netfs: Provide readahead and readpage netfs helpers") > Reported-by: Matthew Wilcox <willy@infradead.org> > Signed-off-by: David Howells <dhowells@redhat.com> > cc: Jeff Layton <jlayton@kernel.org> > cc: linux-cachefs@redhat.com > cc: linux-fsdevel@vger.kernel.org > Link: https://lore.kernel.org/r/Y2SJw7w1IsIik3nb@casper.infradead.org/
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
-- Thanks, Jingbo
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