From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH 3/7] block: ensure bios return from blk_get_request are properly initialized To: Christoph Hellwig References: <1465831278-23653-1-git-send-email-hch@lst.de> <1465831278-23653-4-git-send-email-hch@lst.de> Cc: mst@redhat.com, ooo@electrozaur.com, bhalevy@primarydata.com, nab@linux-iscsi.org, linux-block@vger.kernel.org From: Jens Axboe Message-ID: <575F6942.5060406@kernel.dk> Date: Mon, 13 Jun 2016 20:17:38 -0600 MIME-Version: 1.0 In-Reply-To: <1465831278-23653-4-git-send-email-hch@lst.de> Content-Type: text/plain; charset=windows-1252; format=flowed List-ID: On 06/13/2016 09:21 AM, Christoph Hellwig wrote: > blk_get_request is used for BLOCK_PC and similar pass through requests. > Currently we always need to call blk_rq_set_block_pc or an opencoded > version of it to allow appending bios using the request mapping helpers > later on, which is a somewhat awkward API. Instead move the > initialization part of blk_rq_set_block_pc into blk_get_request, so that > we always have a safe to use request. blk_rq_set_block_pc now goes away > in favor of just setting cmd_type to REQ_TYPE_BLOCK_PC, or nothing in case > it was overriden with a different type a little later (or earlier in case > of the SCSI OSD code..) It may be awkward, but we have those to avoid doing things like this: + rq->__data_len = 0; + rq->__sector = (sector_t) -1; + rq->bio = rq->biotail = NULL; + memset(rq->__cmd, 0, sizeof(rq->__cmd)); for every request we allocate, when we don't use ->cmd at all. Honest, I'd rather have struct request *blk_get_pc_request(); and similar helpers around this, so we don't have to do extra initialization when we don't need it. -- Jens Axboe