As Russell and Lars stated in the discussion [1], using devm_k*alloc() with DMA is not a good idea.
Let's use kmalloc (not kzalloc because no need for zero-out). Also, allocate the buffer as late as possible because it must be freed for any error that follows. [1] https://lkml.org/lkml/2017/3/8/693 Signed-off-by: Masahiro Yamada <yamada.masah...@socionext.com> Cc: Russell King <rmk+ker...@armlinux.org.uk> Cc: Lars-Peter Clausen <l...@metafoo.de> Acked-by: Robin Murphy <robin.mur...@arm.com> --- Changes in v3: None Changes in v2: - Newly added drivers/mtd/nand/denali.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-) diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c index 87e5f0f..d10702d 100644 --- a/drivers/mtd/nand/denali.c +++ b/drivers/mtd/nand/denali.c @@ -23,6 +23,7 @@ #include <linux/mutex.h> #include <linux/mtd/mtd.h> #include <linux/module.h> +#include <linux/slab.h> #include "denali.h" @@ -1388,13 +1389,6 @@ int denali_init(struct denali_nand_info *denali) if (ret) goto disable_irq; - denali->buf = devm_kzalloc(denali->dev, mtd->writesize + mtd->oobsize, - GFP_KERNEL); - if (!denali->buf) { - ret = -ENOMEM; - goto disable_irq; - } - if (ioread32(denali->flash_reg + FEATURES) & FEATURES__DMA) denali->dma_avail = 1; @@ -1514,17 +1508,30 @@ int denali_init(struct denali_nand_info *denali) if (ret) goto disable_irq; + /* + * This buffer is DMA-mapped by denali_{read,write}_page_raw. Do not + * use devm_kmalloc() because the memory allocated by devm_ does not + * guarantee DMA-safe alignment. + */ + denali->buf = kmalloc(mtd->writesize + mtd->oobsize, GFP_KERNEL); + if (!denali->buf) { + ret = -ENOMEM; + goto disable_irq; + } + ret = nand_scan_tail(mtd); if (ret) - goto disable_irq; + goto free_buf; ret = mtd_device_register(mtd, NULL, 0); if (ret) { dev_err(denali->dev, "Failed to register MTD: %d\n", ret); - goto disable_irq; + goto free_buf; } return 0; +free_buf: + kfree(denali->buf); disable_irq: denali_disable_irq(denali); @@ -1544,6 +1551,7 @@ void denali_remove(struct denali_nand_info *denali) int bufsize = mtd->writesize + mtd->oobsize; nand_release(mtd); + kfree(denali->buf); denali_disable_irq(denali); dma_unmap_single(denali->dev, denali->dma_addr, bufsize, DMA_BIDIRECTIONAL); -- 2.7.4
