[LU-17039] Cleanup solution for broken Mellanox ib_dma_map_sg()

• Type: Improvement
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.16.0
• Severity: 3
• Assignee: Shaun Tancheff
• Reporter: Shaun Tancheff

Description

Currently the solution to open code the inline function: ib_dma_map_sg() can be simplified by #undef CONFIG_INFINIBAND_VIRT_DMA in the case where a broken ib_dma_map_sg() is discovered.

CONFIG_INFINIBAND_VIRT_DMA is a kernel configuration option that in some cases
conflicts with the configuration of the externally provided OFED stack.

The #undef CONFIG_INFINIBAND_VIRT_DMA should be restricted to broken implementations [MOFED/OPA] and only when building against the external stack.

An in-kernel broken ib_dma_map_sg suggests that the kernel is badly misconfigured and not a Lustre specific problem.