From: Andrew Morton <akpm@linux-foundation.org>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: jens.axboe@oracle.com, Max Kellermann <max@duempel.org>,
torvalds@linux-foundation.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [patch 2/3] splice: implement default splice_read method
Date: Tue, 12 May 2009 22:35:00 -0700 [thread overview]
Message-ID: <20090512223500.d7ef4648.akpm@linux-foundation.org> (raw)
In-Reply-To: <20090507133748.161689790@szeredi.hu>
On Thu, 07 May 2009 15:37:36 +0200 Miklos Szeredi <miklos@szeredi.hu> wrote:
> + for (i = 0; i < spd.nr_pages; i++) {
> + kunmap(pages[i]);
It is deadlockable if any thread of control holds more than a single
kmap at a time.
Because there are a finite number of kmaps available, and if one is
unavailable, kmap() waits for one to become free. If the number of
waiting threads equals the number of available slots, nobody makes any
progress.
next prev parent reply other threads:[~2009-05-13 5:38 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-07 13:37 [patch 0/3] make splice more generic Miklos Szeredi
2009-05-07 13:37 ` [patch 1/3] splice: implement pipe to pipe splicing Miklos Szeredi
2009-05-07 13:37 ` [patch 2/3] splice: implement default splice_read method Miklos Szeredi
2009-05-13 5:35 ` Andrew Morton [this message]
2009-05-13 6:37 ` Jens Axboe
2009-05-13 9:01 ` Miklos Szeredi
2009-05-14 17:29 ` Jens Axboe
2009-05-14 17:54 ` Miklos Szeredi
2009-05-14 18:00 ` Jens Axboe
2009-05-18 12:36 ` Miklos Szeredi
2009-05-19 9:38 ` Jens Axboe
2009-05-07 13:37 ` [patch 3/3] splice: implement default splice_write method Miklos Szeredi
2009-05-07 15:55 ` [patch 0/3] make splice more generic Linus Torvalds
2009-05-11 15:17 ` Miklos Szeredi
2009-05-09 11:36 ` Max Kellermann
2009-05-11 12:12 ` Jens Axboe
2009-05-11 15:22 ` Miklos Szeredi
2009-05-14 20:27 ` Jamie Lokier
2009-05-15 7:32 ` Jens Axboe
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