It was brought to our attention that some MMC host drivers are referencing sg_virt(sg) directly on scatterlist entries, which will not perform buffer bouncing for CONFIG_HIGHMEM pages that reside in highmem. See the following mail from Christoph and the discussion: https://lore.kernel.org/linux-mmc/20240122073423.GA25859@xxxxxx/ This means that bugs with highmem pages can go unnoticed until an actual highmem page is finally used and not bounced, resulting in things like unpredictable file corruption. Attempt to fix this by amending all host controllers calling sg_virt() for PIO to instead do proper traversal of the scatterlists using sg_miter helpers that will kmap() the pages properly, possibly bouncing it from highmem if need be. All patches are compile-tested except the m68k one, sdhci-esdhc-mcf. Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> --- Changes in v2: - Bite the bullet and just patch all drivers to use sg_miter - Link to v1: https://lore.kernel.org/r/20240125-mmc-proper-kmap-v1-0-ba953c1ac3f9@xxxxxxxxxx --- Linus Walleij (9): mmc: davinci_mmc: Use sg_miter for PIO mmc: moxart-mmc: Factor out moxart_use_dma() helper mmc: moxart-mmc: Fix accounting in DMA transfer mmc: moxart-mmc: Use sg_miter for PIO mmc: mvsdio: Use sg_miter for PIO mmc: mxcmmc: Use sg_miter for PIO mmc: omap: Use sg_miter for PIO mmc: sdhci-esdhc-mcf: Use sg_miter for swapping mmc: sh_mmcif: Use sg_miter for PIO drivers/mmc/host/davinci_mmc.c | 61 ++++++++++------------ drivers/mmc/host/moxart-mmc.c | 90 ++++++++++++++++---------------- drivers/mmc/host/mvsdio.c | 71 +++++++++++++++++++------- drivers/mmc/host/mxcmmc.c | 53 +++++++++++-------- drivers/mmc/host/omap.c | 53 +++++++++---------- drivers/mmc/host/sdhci-esdhc-mcf.c | 12 +++-- drivers/mmc/host/sh_mmcif.c | 102 +++++++++++++++++++++++-------------- 7 files changed, 251 insertions(+), 191 deletions(-) --- base-commit: 6613476e225e090cc9aad49be7fa504e290dd33d change-id: 20240125-mmc-proper-kmap-f2d4cf5d1756 Best regards, -- Linus Walleij <linus.walleij@xxxxxxxxxx>
