mirror-linux/kernel/dma
Sai Sree Kartheek Adivi 56c430c7f0 dma/pool: distinguish between missing and exhausted atomic pools
Currently, dma_alloc_from_pool() unconditionally warns and dumps a stack
trace when an allocation fails, with the message "Failed to get suitable
pool".

This conflates two distinct failure modes:
1. Configuration error: No atomic pool is available for the requested
   DMA mask (a fundamental system setup issue)
2. Resource Exhaustion: A suitable pool exists but is currently full (a
   recoverable runtime state)

This lack of distinction prevents drivers from using __GFP_NOWARN to
suppress error messages during temporary pressure spikes, such as when
awaiting synchronous reclaim of descriptors.

Refactor the error handling to distinguish these cases:
- If no suitable pool is found, keep the unconditional WARN regarding
  the missing pool.
- If a pool was found but is exhausted, respect __GFP_NOWARN and update
  the warning message to explicitly state "DMA pool exhausted".

Fixes: 9420139f51 ("dma-pool: fix coherent pool allocations for IOMMU mappings")
Signed-off-by: Sai Sree Kartheek Adivi <s-adivi@ti.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260128133554.3056582-1-s-adivi@ti.com
2026-01-29 10:23:45 +01:00
..
Kconfig dma-debug: remove DMA_API_DEBUG_SG 2024-10-29 08:53:37 +01:00
Makefile dma-mapping: clearly mark DMA ops as an architecture feature 2024-09-04 07:08:51 +03:00
coherent.c dma-coherent: Warn if OF reserved memory is beyond current coherent DMA mask 2025-04-22 17:44:09 +02:00
contiguous.c of: reserved_mem: Allow reserved_mem framework detect "cma=" kernel param 2026-01-29 00:26:36 +01:00
debug.c dma-debug: don't report false positives with DMA_BOUNCE_UNALIGNED_KMALLOC 2025-10-15 13:24:33 -07:00
debug.h dma-mapping: export new dma_*map_phys() interface 2025-09-12 00:18:21 +02:00
direct.c VFIO updates for v6.19-rc1 2025-12-04 18:42:48 -08:00
direct.h dma-mapping: convert dma_direct_*map_page to be phys_addr_t based 2025-09-12 00:18:20 +02:00
dummy.c dma-mapping: convert dummy ops to physical address mapping 2025-10-29 10:27:29 +01:00
map_benchmark.c tools/dma: move dma_map_benchmark from selftests to tools/dma 2025-10-29 09:41:40 +01:00
mapping.c dma-mapping: remove unused map_page callback 2025-10-29 10:27:31 +01:00
ops_helpers.c dma-mapping: remove unused map_page callback 2025-10-29 10:27:31 +01:00
pool.c dma/pool: distinguish between missing and exhausted atomic pools 2026-01-29 10:23:45 +01:00
remap.c dma-remap: drop nth_page() in dma_common_contiguous_remap() 2025-09-21 14:22:06 -07:00
swiotlb.c mm: make INVALID_PHYS_ADDR a generic macro 2025-11-16 17:28:26 -08:00