From: Linus Torvalds <torvalds@transmeta.com>
To: Hugh Dickins <hugh@veritas.com>
Cc: Christoph Hellwig <hch@lst.de>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] loop sendfile retval
Date: Mon, 11 Nov 2002 08:53:09 -0800 (PST) [thread overview]
Message-ID: <Pine.LNX.4.44.0211110846270.1805-100000@home.transmeta.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0211111626160.9968-100000@localhost.localdomain>
On Mon, 11 Nov 2002, Hugh Dickins wrote:
>
> Buffer I/O error on device loop: its use of sendfile is (trivially)
> broken - retval is usually count done, only an error when negative.
Hmm.. Sendfile can return other values than "count" (ie a partial read).
This return value change makes "do_lo_receive()" lose that information. As
such, the new do_lo_receive() is weaker than the old one.
If fixing the loop code to handle partial IO is too nasty, then I would
suggest doing maybe something like
if (ret > 0 && ret != bvec->bv_len)
ret = -EIO;
which at least makes a partial IO an error instead of making it a success
case (the code as-is seems to think that any non-negative return value
means that the IO was fully successful).
> Nearby spinlocking clearly bogus, delete instead of remarking on it.
I'll apply the patch, it looks better than what is there now, but it might
be worth fixing this _right_.
Linus
next prev parent reply other threads:[~2002-11-11 16:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-11-11 16:38 [PATCH] loop sendfile retval Hugh Dickins
2002-11-11 16:53 ` Linus Torvalds [this message]
2002-11-11 17:48 ` Hugh Dickins
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