linux-kernel - Re: [PATCH] sendfile removal

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Date:	Thu, 31 May 2007 21:09:19 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Jens Axboe <jens.axboe@...cle.com>
CC:	Eric Dumazet <dada1@...mosbay.com>, linux-kernel@...r.kernel.org,
	cotte@...ibm.com, hugh@...itas.com, neilb@...e.de,
	zanussi@...ibm.com, Linus Torvalds <torvalds@...l.org>,
	hch@...radead.org
Subject: Re: [PATCH] sendfile removal

Jens Axboe wrote:
>>   
>>> -	retval = in_file->f_op->sendfile(in_file, ppos, count, file_send_actor, out_file);
>>> +	fl = 0;
>>> +	if (in_file->f_flags & O_NONBLOCK)
>>> +		fl = SPLICE_F_NONBLOCK;
>>> +
>>> +	retval = do_splice_direct(in_file, ppos, out_file, count, fl);
>> I like this, but are you sure it wont break user land ?
>>
>> Some applications might react badly if sendfile() returns EAGAIN ?
> 
> Yeah, I didn't actually intend for that to sneak in. I'd think that
> userspace should handle it if they opened the file O_NONBLOCK (or used
> fcntl()), but it's a change in behaviour none the less and probably not
> a good idea.
> 

I would personally argue that sendfile() blocking on an O_NONBLOCK
desriptor, as opposed to returning EAGAIN, is a bug, and a fairly
serious such.

	-hpa
-
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