Re: [PATCH v2] dma/pool: respect __GFP_NOWARN in dma_alloc_from_pool()
From: Robin Murphy
Date: Mon Jan 12 2026 - 09:13:23 EST
On 2026-01-12 10:47 am, Sai Sree Kartheek Adivi wrote:
Currently, dma_alloc_from_pool() unconditionally warns and dumps a stack
trace when an allocation fails.
This prevents callers from using the __GFP_NOWARN flag to suppress error
messages, breaking the expectation that this flag will silence
allocation failure logs.
This is not an "allocation failure" in that sense, though. It's not like the caller has opportunistically requested a large allocation, and is happy to try again with a smaller size - if someone has asked for an allocation in atomic context that can only be satisfied from an atomic pool, and there is no atomic pool at all, that points at something being more fundamentally wrong with the system, in a manner that the caller probably isn't expecting.
Under what circumstances are you seeing the warning without things being totally broken anyway?
Thanks,
Robin.
Align dma_pool behaviour with other core allocators by checking for
__GFP_NOWARN before issuing the warning.
Fixes: 9420139f516d ("dma-pool: fix coherent pool allocations for IOMMU mappings")
Signed-off-by: Sai Sree Kartheek Adivi <s-adivi@xxxxxx>
---
kernel/dma/pool.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index 26392badc36b..f63e027b8a27 100644
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -276,7 +276,7 @@ struct page *dma_alloc_from_pool(struct device *dev, size_t size,
return page;
}
- WARN(1, "Failed to get suitable pool for %s\n", dev_name(dev));
+ WARN(!(gfp & __GFP_NOWARN), "Failed to get suitable pool for %s\n", dev_name(dev));
return NULL;
}