Re: [PATCH] mmc: sdhci: unmap the bounce buffer before device release

[Linus Walleij]

On Mon, Jul 27, 2026 at 4:11 PM Myeonghun Pak <mhun512@xxxxxxxxx> wrote:

> sdhci_allocate_bounce_buffer() allocates its buffer with devm_kmalloc()
> but maps it with dma_map_single(). The buffer is therefore released by
> devres without the streaming DMA mapping being unmapped.
>
> Register a managed action after dma_map_single() succeeds so the mapping
> is removed before devres releases the buffer. The action is registered
> only for buffers allocated and mapped by the SDHCI core, leaving buffers
> provided by host drivers under their existing ownership.
>
> Fixes: bd9b902798ab ("mmc: sdhci: Implement an SDHCI-specific bounce buffer")
> Cc: stable@xxxxxxxxxxxxxxx
> Co-developed-by: Ijae Kim <ae878000@xxxxxxxxx>
> Signed-off-by: Ijae Kim <ae878000@xxxxxxxxx>
> Signed-off-by: Myeonghun Pak <mhun512@xxxxxxxxx>

LGTM:
Reviewed-by: Linus Walleij <linusw@xxxxxxxxxx>

Yours,
Linus Walleij