From 9e9f561269dff35e6f84ed21776ec37fd6360b03 Mon Sep 17 00:00:00 2001 From: Myeonghun Pak Date: Mon, 27 Jul 2026 23:03:22 +0900 Subject: [PATCH] mmc: sdhci: unmap the bounce buffer before device release 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@vger.kernel.org Co-developed-by: Ijae Kim Signed-off-by: Ijae Kim Signed-off-by: Myeonghun Pak Reviewed-by: Linus Walleij Signed-off-by: Ulf Hansson --- drivers/mmc/host/sdhci.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index e3bf901b10aa..efb4c7742fe2 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -4187,6 +4187,14 @@ void __sdhci_read_caps(struct sdhci_host *host, const u16 *ver, } EXPORT_SYMBOL_GPL(__sdhci_read_caps); +static void sdhci_unmap_bounce_buffer(void *data) +{ + struct sdhci_host *host = data; + + dma_unmap_single(mmc_dev(host->mmc), host->bounce_addr, + host->bounce_buffer_size, DMA_BIDIRECTIONAL); +} + static void sdhci_allocate_bounce_buffer(struct sdhci_host *host) { struct mmc_host *mmc = host->mmc; @@ -4247,6 +4255,14 @@ static void sdhci_allocate_bounce_buffer(struct sdhci_host *host) } host->bounce_buffer_size = bounce_size; + ret = devm_add_action_or_reset(mmc_dev(mmc), + sdhci_unmap_bounce_buffer, host); + if (ret) { + devm_kfree(mmc_dev(mmc), host->bounce_buffer); + host->bounce_buffer = NULL; + host->bounce_buffer_size = 0; + return; + } out: /* Lie about this since we're bouncing */