Re: [PATCH net] octeontx2-af: Fix memory scaling limitation in SR-IOV mode

On Wed, Sep 16, 2026 at 07:51:11AM +0530, Ratheesh Kannoth wrote:

The original code used DMA_ATTR_FORCE_CONTIGUOUS, which could exhaust
the CMA pool when a large number of VFs were requested.

Fix this by switching to the DMA streaming API. This is equivalent on
Octeon platforms, which provide full I/O coherency via the SMMU.

Cc: Leon Romanovsky <leon@kernel.org>
Fixes: 73d33dbc0723 ("octeontx2-af: Use DMA_ATTR_FORCE_CONTIGUOUS attribute in DMA alloc")
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>

---
v9 -> v10: Updated commit message as suggested by Leon

v8 -> v9: Addressed Leon comment.
- Used kzalloc instead of kmalloc.

v7 -> v8: Addressed Leon comments.
- Replace __get_free_pages() and __GFP_COMP with kmalloc()
- Drop GFP_DMA32 retry loop and dma_capable()/phys_to_dma() mask probing
- Use dma_map_single()/dma_unmap_single() instead of dma_map_page_attrs()
  with DMA_ATTR_REQUIRE_COHERENT
- Remove defensive parameter checks and dma_max_mapping_size() from the
  allocator helper
- Move MAX_PAGE_ORDER validation to qmem_alloc()

v6 -> v7: Addressed Sashiko comments.
	https://lore.kernel.org/netdev/178863855246.219967.10510865726694393307@kernel.org/ (local)

v5 -> v6: Addressed review comments.
	https://lore.kernel.org/netdev/20260901015621.2708182-1-rkannoth@marvell.com/ (local)

v4 -> v5: Fixed compilation issues.
	https://lore.kernel.org/netdev/20260831024210.208447-1-rkannoth@marvell.com/ (local)

v3 -> v4: Fixed compilation issues.
	https://lore.kernel.org/netdev/apTpKcN_S1xIwRbZ@rkannoth-OptiPlex-7090/ (local)

v2 -> v3: Addressed sashiko comments.
	https://sashiko.dev/#/patchset/20260825045616.3723078-1-rkannoth%40marvell.com

v1 -> v2: Rewrote patch as per sashiko comment.
---
 .../ethernet/marvell/octeontx2/af/common.h    | 45 ++++++++++++++++---
 1 file changed, 39 insertions(+), 6 deletions(-)

Thanks,
Reviewed-by: Leon Romanovsky <leon@kernel.org>