From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: [PATCH 1/5] Block: Discard may need to allocate pages Date: Fri, 17 Apr 2009 17:23:42 -0400 Message-ID: <49E8F35E.2060103@rtr.ca> References: <1238683047-13588-1-git-send-email-willy@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from rtr.ca ([76.10.145.34]:60166 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752501AbZDQVXq (ORCPT ); Fri, 17 Apr 2009 17:23:46 -0400 In-Reply-To: <1238683047-13588-1-git-send-email-willy@linux.intel.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Matthew Wilcox Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, jgarzik@redhat.com, Matthew Wilcox Matthew Wilcox wrote: > From: Matthew Wilcox > > SCSI and ATA both need to send data to the device. In order to do this, > the BIO must be allocated with room for a page to be added, and the bio > needs to be passed to the discard prep function. We also need to free > the page attached to the BIO before we free it. > > init_request_from_bio() is not currently called from a context which > forbids sleeping, and to make sure it stays that way (so we don't have > to use GFP_ATOMIC), add a might_sleep() to it. > > Signed-off-by: Matthew Wilcox ... > @@ -1118,7 +1120,7 @@ void init_request_from_bio(struct request *req, struct bio *bio) > req->cmd_flags |= REQ_DISCARD; > if (bio_barrier(bio)) > req->cmd_flags |= REQ_SOFTBARRIER; > - req->q->prepare_discard_fn(req->q, req); > + req->q->prepare_discard_fn(req->q, req, bio); > } else if (unlikely(bio_barrier(bio))) > req->cmd_flags |= (REQ_HARDBARRIER | REQ_NOMERGE); > .. Matthew, note that prepare_discardfn() may fail, and return an error result. The above code does not check for this or handle it very well. Cheers