From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Sebastian Ott <sebott@linux.ibm.com>,
Sagi Grimberg <sagi@grimberg.me>,
Max Gurtovoy <maxg@mellanox.com>,
Bart Van Assche <bvanassche@acm.org>,
Ulf Hansson <ulf.hansson@linaro.org>,
Alan Stern <stern@rowland.harvard.edu>,
Oliver Neukum <oneukum@suse.com>,
linux-block@vger.kernel.org, linux-rdma@vger.kernel.org,
linux-mmc@vger.kernel.org, linux-nvme@lists.infradead.org,
linux-scsi@vger.kernel.org, megaraidlinux.pdl@broadcom.com,
MPT-FusionLinux.pdl@broadcom.com, linux-hyperv@vger.kernel.org,
linux-usb@vger.kernel.org, usb-storage@lists.one-eyed-alien.net,
linux-kernel@vger.kernel.org
Subject: properly communicate queue limits to the DMA layer
Date: Wed, 5 Jun 2019 21:08:23 +0200 [thread overview]
Message-ID: <20190605190836.32354-1-hch@lst.de> (raw)
Hi Jens,
we've always had a bit of a problem communicating the block layer
queue limits to the DMA layer, which needs to respect them when
an IOMMU that could merge segments is used. Unfortunately most
drivers don't get this right. Oddly enough we've been mostly
getting away with it, although lately dma-debug has been catching
a few of those issues.
The segment merging fix for devices with PRP-like structures seems
to have escalated this a bit. The first patch fixes the actual
report from Sebastian, while the rest fix every drivers that appears
to have the problem based on a code audit looking for drivers using
blk_queue_max_segment_size, blk_queue_segment_boundary or
blk_queue_virt_boundary and calling dma_map_sg eventually. Note
that for SCSI drivers I've taken the blk_queue_virt_boundary setting
to the SCSI core, similar to how we did it for the other two settings
a while ago. This also deals with the fact that the DMA layer
settings are on a per-device granularity, so the per-device settings
in a few SCSI drivers can't actually work in an IOMMU environment.
It would be nice to eventually pass these limits as arguments to
dma_map_sg, but that is a far too big series for the 5.2 merge
window.
next reply other threads:[~2019-06-05 19:10 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-05 19:08 Christoph Hellwig [this message]
2019-06-05 19:08 ` [PATCH 01/13] nvme-pci: don't limit DMA segement size Christoph Hellwig
2019-06-05 19:08 ` [PATCH 02/13] rsxx: don't call dma_set_max_seg_size Christoph Hellwig
2019-06-05 19:08 ` [PATCH 03/13] mtip32xx: also set max_segment_size in the device Christoph Hellwig
2019-06-05 19:08 ` [PATCH 04/13] mmc: " Christoph Hellwig
2019-06-05 19:08 ` [PATCH 05/13] scsi: add a host / host template field for the virt boundary Christoph Hellwig
2019-06-05 19:08 ` [PATCH 06/13] ufshcd: set max_segment_size in the scsi host template Christoph Hellwig
2019-06-05 19:08 ` [PATCH 07/13] storvsc: set virt_boundary_mask " Christoph Hellwig
2019-06-05 19:08 ` [PATCH 08/13] IB/iser: set virt_boundary_mask in the scsi host Christoph Hellwig
2019-06-05 20:22 ` Jason Gunthorpe
2019-06-05 23:35 ` Sagi Grimberg
2019-06-06 6:24 ` Christoph Hellwig
2019-06-06 12:59 ` Jason Gunthorpe
2019-06-06 14:19 ` Christoph Hellwig
2019-06-05 19:08 ` [PATCH 09/13] IB/srp: " Christoph Hellwig
2019-06-05 19:08 ` [PATCH 10/13] megaraid_sas: " Christoph Hellwig
2019-06-06 6:02 ` Hannes Reinecke
2019-06-06 6:41 ` Christoph Hellwig
2019-06-06 15:37 ` Kashyap Desai
2019-06-08 8:14 ` Christoph Hellwig
2019-06-13 19:58 ` Kashyap Desai
2019-06-17 8:44 ` Christoph Hellwig
2019-06-17 9:10 ` Kashyap Desai
2019-06-13 8:44 ` Christoph Hellwig
2019-06-13 20:04 ` Kashyap Desai
2019-06-05 19:08 ` [PATCH 11/13] mpt3sas: " Christoph Hellwig
2019-06-05 19:08 ` [PATCH 12/13] usb-storage: " Christoph Hellwig
2019-06-05 19:08 ` [PATCH 13/13] uas: " Christoph Hellwig
2019-06-05 19:17 ` properly communicate queue limits to the DMA layer Jens Axboe
2019-06-05 19:24 ` Christoph Hellwig
2019-06-07 5:52 ` Jens Axboe
2019-06-07 17:30 ` Martin K. Petersen
2019-06-08 8:10 ` Jens Axboe
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