[v2] iser: explicitly set shost max_segment_size if non virtual boundary devices
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Message ID 20190607012914.2328-1-sagi@grimberg.me
State New
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  • [v2] iser: explicitly set shost max_segment_size if non virtual boundary devices
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Commit Message

Sagi Grimberg June 7, 2019, 1:29 a.m. UTC
if the rdma device supports sg gaps, we don't need to set a virtual
boundary but we then need to explicitly set the max_segment_size, otherwise
scsi takes BLK_MAX_SEGMENT_SIZE and sets it using dma_set_max_seg_size()
and this affects all the rdma device consumers.

Fix it by setting shost max_segment_size according to the device
capability if SG_GAPS are not supported.

Reported-by: Jason Gunthorpe <jgg@ziepe.ca>
Suggested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
---
Changes from v1:
- set max_segment_size only for non virtual boundary devices

 drivers/infiniband/ulp/iser/iscsi_iser.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Bart Van Assche June 7, 2019, 2 p.m. UTC | #1
On 6/6/19 6:29 PM, Sagi Grimberg wrote:
> if the rdma device supports sg gaps, we don't need to set a virtual
> boundary but we then need to explicitly set the max_segment_size, otherwise
> scsi takes BLK_MAX_SEGMENT_SIZE and sets it using dma_set_max_seg_size()
> and this affects all the rdma device consumers.
> 
> Fix it by setting shost max_segment_size according to the device
> capability if SG_GAPS are not supported.
> 
> Reported-by: Jason Gunthorpe <jgg@ziepe.ca>
> Suggested-by: Christoph Hellwig <hch@lst.de>
> Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
> ---
> Changes from v1:
> - set max_segment_size only for non virtual boundary devices
> 
>   drivers/infiniband/ulp/iser/iscsi_iser.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
> index 841b66397a57..a3a4b956bbb9 100644
> --- a/drivers/infiniband/ulp/iser/iscsi_iser.c
> +++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
> @@ -653,7 +653,9 @@ iscsi_iser_session_create(struct iscsi_endpoint *ep,
>   						   SHOST_DIX_GUARD_CRC);
>   		}
>   
> -		if (!(ib_dev->attrs.device_cap_flags & IB_DEVICE_SG_GAPS_REG))
> +		if (ib_dev->attrs.device_cap_flags & IB_DEVICE_SG_GAPS_REG)
> +			shost->max_segment_size = ib_dma_max_seg_size(ib_dev);
> +		else
>   			shost->virt_boundary_mask = ~MASK_4K;
>   
>   		if (iscsi_host_add(shost, ib_dev->dev.parent)) {

This is incomprehensible without a big comment that explains why 
max_segment_size is only set if the IB_DEVICE_SG_GAPS_REG feature is 
available.

Bart.

Patch
diff mbox series

diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
index 841b66397a57..a3a4b956bbb9 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.c
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
@@ -653,7 +653,9 @@  iscsi_iser_session_create(struct iscsi_endpoint *ep,
 						   SHOST_DIX_GUARD_CRC);
 		}
 
-		if (!(ib_dev->attrs.device_cap_flags & IB_DEVICE_SG_GAPS_REG))
+		if (ib_dev->attrs.device_cap_flags & IB_DEVICE_SG_GAPS_REG)
+			shost->max_segment_size = ib_dma_max_seg_size(ib_dev);
+		else
 			shost->virt_boundary_mask = ~MASK_4K;
 
 		if (iscsi_host_add(shost, ib_dev->dev.parent)) {