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Subject[PATCH 01/13] nvme-pci: don't limit DMA segement size
Date
NVMe uses PRPs (or optionally unlimited SGLs) for data transfers and
has no specific limit for a single DMA segement. Limiting the size
will cause problems because the block layer assumes PRP-ish devices
using a virt boundary mask don't have a segment limit. And while this
is true, we also really need to tell the DMA mapping layer about it,
otherwise dma-debug will trip over it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Sebastian Ott <sebott@linux.ibm.com>
---
drivers/nvme/host/pci.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index f562154551ce..524d6bd6d095 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2513,6 +2513,12 @@ static void nvme_reset_work(struct work_struct *work)
*/
dev->ctrl.max_hw_sectors = NVME_MAX_KB_SZ << 1;
dev->ctrl.max_segments = NVME_MAX_SEGS;
+
+ /*
+ * Don't limit the IOMMU merged segment size.
+ */
+ dma_set_max_seg_size(dev->dev, 0xffffffff);
+
mutex_unlock(&dev->shutdown_lock);

/*
--
2.20.1
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