diff options
Diffstat (limited to 'drivers/infiniband/core')
| -rw-r--r-- | drivers/infiniband/core/rw.c | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/drivers/infiniband/core/rw.c b/drivers/infiniband/core/rw.c index 5337393d4dfe..4fad732f9b3c 100644 --- a/drivers/infiniband/core/rw.c +++ b/drivers/infiniband/core/rw.c @@ -20,14 +20,17 @@ module_param_named(force_mr, rdma_rw_force_mr, bool, 0); MODULE_PARM_DESC(force_mr, "Force usage of MRs for RDMA READ/WRITE operations"); /* - * Check if the device might use memory registration. This is currently only - * true for iWarp devices. In the future we can hopefully fine tune this based - * on HCA driver input. + * Report whether memory registration should be used. Memory registration must + * be used for iWarp devices because of iWARP-specific limitations. Memory + * registration is also enabled if registering memory might yield better + * performance than using multiple SGE entries, see rdma_rw_io_needs_mr() */ static inline bool rdma_rw_can_use_mr(struct ib_device *dev, u8 port_num) { if (rdma_protocol_iwarp(dev, port_num)) return true; + if (dev->attrs.max_sgl_rd) + return true; if (unlikely(rdma_rw_force_mr)) return true; return false; @@ -35,17 +38,19 @@ static inline bool rdma_rw_can_use_mr(struct ib_device *dev, u8 port_num) /* * Check if the device will use memory registration for this RW operation. - * We currently always use memory registrations for iWarp RDMA READs, and - * have a debug option to force usage of MRs. - * - * XXX: In the future we can hopefully fine tune this based on HCA driver - * input. + * For RDMA READs we must use MRs on iWarp and can optionally use them as an + * optimization otherwise. Additionally we have a debug option to force usage + * of MRs to help testing this code path. */ static inline bool rdma_rw_io_needs_mr(struct ib_device *dev, u8 port_num, enum dma_data_direction dir, int dma_nents) { - if (rdma_protocol_iwarp(dev, port_num) && dir == DMA_FROM_DEVICE) - return true; + if (dir == DMA_FROM_DEVICE) { + if (rdma_protocol_iwarp(dev, port_num)) + return true; + if (dev->attrs.max_sgl_rd && dma_nents > dev->attrs.max_sgl_rd) + return true; + } if (unlikely(rdma_rw_force_mr)) return true; return false; |