[PATCH AUTOSEL 5.1 109/141] nvme-pci: limit max_hw_sectors based on the DMA max mapping size

Sasha Levin
2019-07-19T04:28:20Z

From: Christoph Hellwig <hch@lst.de>

[ Upstream commit 7637de311bd2124b298a072852448b940d8a34b9 ]

When running a NVMe device that is attached to a addressing
challenged PCIe root port that requires bounce buffering, our
request sizes can easily overflow the swiotlb bounce buffer
size. Limit the maximum I/O size to the limit exposed by
the DMA mapping subsystem.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Atish Patra <Atish.Patra@wdc.com>
Tested-by: Atish Patra <Atish.Patra@wdc.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/host/pci.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index b97ba5ea0e61..5112983a59fb 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2538,7 +2538,8 @@ static void nvme_reset_work(struct work_struct *work)
* Limit the max command size to prevent iod->sg allocations going
* over a single page.
*/
- dev->ctrl.max_hw_sectors = NVME_MAX_KB_SZ << 1;
+ dev->ctrl.max_hw_sectors = min_t(u32,
+ NVME_MAX_KB_SZ << 1, dma_max_mapping_size(dev->dev) >> 9);
dev->ctrl.max_segments = NVME_MAX_SEGS;
mutex_unlock(&dev->shutdown_lock);

--
2.20.1