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Subject[PATCH 5.4 202/434] RDMA/core: Set DMA parameters correctly
Date
From: Bart Van Assche <bvanassche@acm.org>

[ Upstream commit c9121262d57b8a3be4f08073546436ba0128ca6a ]

The dma_set_max_seg_size() call in setup_dma_device() does not have any
effect since device->dev.dma_parms is NULL. Fix this by initializing
device->dev.dma_parms first.

Link: https://lore.kernel.org/r/20191025225830.257535-5-bvanassche@acm.org
Fixes: d10bcf947a3e ("RDMA/umem: Combine contiguous PAGE_SIZE regions in SGEs")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/core/device.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c
index 50a92442c4f7..e6327d8f5b79 100644
--- a/drivers/infiniband/core/device.c
+++ b/drivers/infiniband/core/device.c
@@ -1199,9 +1199,21 @@ static void setup_dma_device(struct ib_device *device)
WARN_ON_ONCE(!parent);
device->dma_device = parent;
}
- /* Setup default max segment size for all IB devices */
- dma_set_max_seg_size(device->dma_device, SZ_2G);

+ if (!device->dev.dma_parms) {
+ if (parent) {
+ /*
+ * The caller did not provide DMA parameters, so
+ * 'parent' probably represents a PCI device. The PCI
+ * core sets the maximum segment size to 64
+ * KB. Increase this parameter to 2 GB.
+ */
+ device->dev.dma_parms = parent->dma_parms;
+ dma_set_max_seg_size(device->dma_device, SZ_2G);
+ } else {
+ WARN_ON_ONCE(true);
+ }
+ }
}

/*
--
2.20.1


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