From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 30 Jan 2018 11:42:13 +0800 From: Ming Lei To: Bart Van Assche Cc: "linux-block@vger.kernel.org" , "hch@infradead.org" , "snitzer@redhat.com" , "martin.petersen@oracle.com" , "axboe@kernel.dk" , "linux-scsi@vger.kernel.org" , "jejb@linux.vnet.ibm.com" , "loberman@redhat.com" , "dm-devel@redhat.com" Subject: Re: [PATCH V3] blk-mq: introduce BLK_STS_DEV_RESOURCE Message-ID: <20180130034212.GG17176@ming.t460p> References: <1516726653.3339.20.camel@wdc.com> <20180124033109.GA15945@ming.t460p> <20180127190920.GA24759@redhat.com> <1517091161.3055.7.camel@wdc.com> <20180127234151.GA21710@ming.t460p> <1517244510.2687.10.camel@wdc.com> <20180130010701.GC17176@ming.t460p> <1517274681.2687.68.camel@wdc.com> <20180130033118.GF17176@ming.t460p> <1517283456.12842.2.camel@wdc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1517283456.12842.2.camel@wdc.com> List-ID: On Tue, Jan 30, 2018 at 03:37:38AM +0000, Bart Van Assche wrote: > On Tue, 2018-01-30 at 11:31 +0800, Ming Lei wrote: > > Please take a look at drivers, when BLK_STS_RESOURCE is returned, who > > will call blk_mq_delay_run_hw_queue() for drivers? > > As you know the SCSI and dm drivers in kernel v4.15 already call that function > whenever necessary. We have concluded that it is generic issue which need generic solution[1]. [1] https://marc.info/?l=linux-kernel&m=151638176727612&w=2 [ming@ming linux]$ git grep -n BLK_STS_RESOURCE ./drivers/ | wc -l 43 Almost every driver need this kind of change if BLK_STS_RESOURCE is returned from IO path. And the failure can be caused by kmalloc(GFP_ATOMIC), DMA Mapping, or what ever. Thanks, Ming