feat: add reg dma buf MR support

[dragonJACson]

No description provided.

[gemini-code-assist]

Code Review

This pull request introduces support for dma-buf-backed memory regions by adding reg_dmabuf_mr methods to both MemoryRegion and ProtectionDomain. It also includes updated documentation and a test case verifying failure when using an invalid file descriptor. Review feedback points out several unused imports and a significant contradiction in the documentation which claims runtime symbol resolution while the implementation uses a direct FFI call.

[codecov]

Codecov Report

❌ Patch coverage is 79.16667% with 5 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/ibverbs/memory_region.rs	58.33%	5 Missing ⚠️

Files with missing lines	Coverage Δ
src/ibverbs/mod.rs	0.00% <ø> (ø)
src/ibverbs/protection_domain.rs	91.42% <100.00%> (+4.47%)	⬆️
src/ibverbs/memory_region.rs	79.54% <58.33%> (-7.96%)	⬇️

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[Copilot]

Pull request overview

Adds support for registering dma-buf–backed RDMA memory regions (MRs) in the ibverbs wrapper, updating the sys dependency and extending integration tests to exercise the new API path.

Changes:

• Bump rdma-mummy-sys to 0.2.4 and wire in ibv_reg_dmabuf_mr bindings.
• Add ProtectionDomain::reg_dmabuf_mr and internal MemoryRegion::reg_dmabuf_mr implementation.
• Extend the MR/CQ integration test to call reg_dmabuf_mr (negative case with /dev/null).

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
tests/test_mr_and_cq.rs	Adds a negative test call for dma-buf MR registration using /dev/null.
src/ibverbs/protection_domain.rs	Exposes reg_dmabuf_mr API on ProtectionDomain with safety docs and example.
src/ibverbs/mod.rs	Updates AccessFlags docs to reference dma-buf MR registration manpage.
src/ibverbs/memory_region.rs	Implements MemoryRegion::reg_dmabuf_mr via ibv_reg_dmabuf_mr.
Cargo.toml	Updates rdma-mummy-sys dependency version.

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