[PATCH v4 5/5] dma: swiotlb: Remove SWIOTLB_ANY

Catalin Marinas catalin.marinas at arm.com
Thu Sep 17 09:08:43 PDT 2026


On Mon, Sep 14, 2026 at 12:31:34PM +0530, Aneesh Kumar K.V (Arm) wrote:
> swiotlb pools are currently allocated below the architecture's low
> address limit by default. SWIOTLB_ANY overrides this and permits
> allocation anywhere in directly mapped memory.
> 
> SWIOTLB_INIT_ADDRESSING_LIMIT now explicitly identifies callers which
> need a pool that is reachable by devices with limited DMA addressing.
> Use it as the placement constraint and remove SWIOTLB_ANY.
> 
> This changes the default behavior for callers which do not set either
> flag. Previously, omitting SWIOTLB_ANY placed the default pool below the
> architecture's low address limit and also constrained dynamically
> allocated pools to the same range. After this change, omitting
> SWIOTLB_INIT_ADDRESSING_LIMIT permits both static and dynamic pools to
> use any directly mapped memory.
> 
> Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar at kernel.org>

Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>



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