From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: [PATCH 1/2] scsi: add a max_segment_size limitation to struct Scsi_Host Date: Mon, 11 Apr 2016 15:47:25 -0700 Message-ID: <1460414846-29540-2-git-send-email-hch@lst.de> References: <1460414846-29540-1-git-send-email-hch@lst.de> Return-path: In-Reply-To: <1460414846-29540-1-git-send-email-hch-jcswGhMUV9g@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-scsi@vger.kernel.org RDMA drivers need segments that aren't larger than a single HCA page for memory registrations to work properly, so wire up this limitation in the host. While we could just call blk_queue_max_segment_size from ->slave_configure, that would override the global limit based on the DMA device, so let's do it the traditional way by adding a field to the Scsi_Host structure. Signed-off-by: Christoph Hellwig --- drivers/scsi/scsi_lib.c | 3 ++- include/scsi/scsi_host.h | 1 + 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 8106515..04c660d 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -2120,7 +2120,8 @@ static void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q) blk_queue_segment_boundary(q, shost->dma_boundary); dma_set_seg_boundary(dev, shost->dma_boundary); - blk_queue_max_segment_size(q, dma_get_max_seg_size(dev)); + blk_queue_max_segment_size(q, + min(shost->max_segment_size, dma_get_max_seg_size(dev))); if (!shost->use_clustering) q->limits.cluster = 0; diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index fcfa3d7..f11d3fe 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -621,6 +621,7 @@ struct Scsi_Host { short unsigned int sg_tablesize; short unsigned int sg_prot_tablesize; unsigned int max_sectors; + unsigned int max_segment_size; unsigned long dma_boundary; /* * In scsi-mq mode, the number of hardware queues supported by the LLD. -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html