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From:   Christoph Hellwig <hch@lst.de>
To:     "Martin K . Petersen" <martin.petersen@oracle.com>
Cc:     Sagi Grimberg <sagi@grimberg.me>, Max Gurtovoy <maxg@mellanox.com>,
        Bart Van Assche <bvanassche@acm.org>,
        linux-rdma@vger.kernel.org, linux-scsi@vger.kernel.org,
        megaraidlinux.pdl@broadcom.com, MPT-FusionLinux.pdl@broadcom.com,
        linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/8] scsi: take the DMA max mapping size into account
Date:   Mon, 17 Jun 2019 14:19:54 +0200
Message-Id: <20190617122000.22181-3-hch@lst.de>
In-Reply-To: <20190617122000.22181-1-hch@lst.de>
References: <20190617122000.22181-1-hch@lst.de>
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Sender: linux-kernel-owner@vger.kernel.org
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We need to limit the devices max_sectors to what the DMA mapping
implementation can support.  If not we risk running out of swiotlb
buffers easily.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/scsi_lib.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index d333bb6b1c59..f233bfd84cd7 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1768,6 +1768,8 @@ void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
 		blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
 	}
 
+	shost->max_sectors = min_t(unsigned int, shost->max_sectors,
+			dma_max_mapping_size(dev) << SECTOR_SHIFT);
 	blk_queue_max_hw_sectors(q, shost->max_sectors);
 	if (shost->unchecked_isa_dma)
 		blk_queue_bounce_limit(q, BLK_BOUNCE_ISA);
-- 
2.20.1