From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tilman Schmidt Subject: Re: [PATCH 2.6.31-rc4] gigaset: really fix chars_in_buffer Date: Sun, 02 Aug 2009 01:37:12 +0200 Message-ID: <4A74D1A8.4000701@imap.cc> References: <20090801-patch-01.tilman@imap.cc> <20090801171141.7a463347@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig0972C9705275DF9E42A0D0EC" Cc: davem@davemloft.net, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Alan Cox , Hansjoerg Lipp To: Alan Cox Return-path: Received: from out1.smtp.messagingengine.com ([66.111.4.25]:43667 "EHLO out1.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751150AbZHAXiK (ORCPT ); Sat, 1 Aug 2009 19:38:10 -0400 In-Reply-To: <20090801171141.7a463347@lxorguk.ukuu.org.uk> Sender: netdev-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig0972C9705275DF9E42A0D0EC Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi Alan, thanks a lot for getting in contact with me, and for your explanation of the rationale behind your patch. On Sat, 1 Aug 2009 17:11:41 +0100, Alan Cox wrote: > Is that correct. If you take a signal so the mutex_lock_interruptible > takes the error path we'll exit any waits for characters to be flushed > from buffers and lose the bytes in some cases ? You are right. I'll have to change it to use non-interruptible mutex_lock. I'll prepare a new patch. > Thats why I didn't > convert it - I didn't understand why it was using _interruptible at all= ? No specific reason. just the general rule to prefer sleeping interuptibly whenever possible, because unkillable processes are so annoying. Seeing that chars_in_buffer was declared as returning int, I assumed (wrongly as it now turns out) that it would be allowed to return the customary negative values for errors, so that it could use the _interruptible variant. When I saw your patch I read into it that zero would be the appropriate return value for all error cases, including a signal while waiting for the mutex. I guess there was a bit of wishful thinking in that. Well, thanks again for your help. I'll follow up with a revised patch. Regards, Tilman --=20 Tilman Schmidt E-Mail: tilman@imap.cc Bonn, Germany Diese Nachricht besteht zu 100% aus wiederverwerteten Bits. Unge=F6ffnet mindestens haltbar bis: (siehe R=FCckseite) --------------enig0972C9705275DF9E42A0D0EC Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4-svn0 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFKdNHdQ3+did9BuFsRAnmKAJ9FTAsQp9Gtvj+AFvkPzmwzzSUwLwCeJcO8 orp7s4kMpu4UBA5o0AzANVM= =O3qV -----END PGP SIGNATURE----- --------------enig0972C9705275DF9E42A0D0EC--