From: Omar Sandoval <osandov-nWWhXC5lh1RBDgjK7y7TUQ@public.gmane.org>
To: Al Viro <viro-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
Cc: Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
Trond Myklebust
<trond.myklebust-7I+n7zu2hftEKMMhf/gKZA@public.gmane.org>,
Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Mel Gorman <mgorman-l3A5Bk7waGM@public.gmane.org>
Subject: Re: [PATCH v2 4/5] swapfile: use ->read_iter and ->write_iter
Date: Sun, 21 Dec 2014 23:32:34 -0800 [thread overview]
Message-ID: <20141222073234.GA14207@mew> (raw)
In-Reply-To: <20141220061337.GB22149-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
On Sat, Dec 20, 2014 at 06:13:37AM +0000, Al Viro wrote:
> On Fri, Dec 19, 2014 at 07:18:28PM -0800, Omar Sandoval wrote:
>
> > + ret = swap_file->f_op->read_iter(&kiocb, &to);
> > + if (ret == PAGE_SIZE) {
> > + SetPageUptodate(page);
> > count_vm_event(PSWPIN);
> > + ret = 0;
> > + } else {
> > + ClearPageUptodate(page);
> > + SetPageError(page);
> > + }
> > + unlock_page(page);
>
> Umm... What's to guarantee that ->read_iter() won't try lock_page() on what
> turns out to be equal to page?
Ergh. I don't see why ->read_iter would be screwing around in the swap
cache or with the pages in the iterator, anything in particular you can
see happening?
--
Omar
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next prev parent reply other threads:[~2014-12-22 7:32 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-20 3:18 [PATCH v2 0/5] clean up and generalize swap-over-NFS Omar Sandoval
2014-12-20 3:18 ` [PATCH v2 1/5] iov_iter: add ITER_BVEC helpers Omar Sandoval
2014-12-20 3:18 ` [PATCH v2 2/5] direct-io: don't dirty ITER_BVEC pages on read Omar Sandoval
2014-12-20 6:01 ` Al Viro
2014-12-22 7:12 ` Omar Sandoval
2014-12-20 3:18 ` [PATCH v2 3/5] nfs: don't dirty ITER_BVEC pages read through direct I/O Omar Sandoval
2015-01-05 14:41 ` Anna Schumaker
[not found] ` <54AAA27C.6040906-ZwjVKphTwtPQT0dZR+AlfA@public.gmane.org>
2015-01-08 9:25 ` Omar Sandoval
2014-12-20 3:18 ` [PATCH v2 4/5] swapfile: use ->read_iter and ->write_iter Omar Sandoval
2014-12-20 6:13 ` Al Viro
[not found] ` <20141220061337.GB22149-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2014-12-22 7:32 ` Omar Sandoval [this message]
2014-12-20 3:18 ` [PATCH v2 5/5] vfs: update swap_{,de}activate documentation Omar Sandoval
[not found] ` <cover.1419044605.git.osandov-nWWhXC5lh1RBDgjK7y7TUQ@public.gmane.org>
2015-01-14 3:18 ` [PATCH v2 0/5] clean up and generalize swap-over-NFS Omar Sandoval
2015-01-21 19:14 ` Omar Sandoval
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