[PATCH v4 6/7] mtd: nand: omap2: Fix high memory dma prefetch transfer
From: Franklin S Cooper Jr <hidden>
Date: 2016-03-10 23:57:02
Also in:
linux-omap, lkml
Subsystem:
memory technology devices (mtd), nand flash subsystem, the rest · Maintainers:
Miquel Raynal, Richard Weinberger, Vignesh Raghavendra, Linus Torvalds
Based on DMA documentation and testing using high memory buffer when doing dma transfers can lead to various issues including kernel panics. To workaround this simply use cpu copy. The amount of high memory buffers used are very uncommon so no noticeable performance hit should be seen. Signed-off-by: Franklin S Cooper Jr <redacted> --- drivers/mtd/nand/omap2.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-)
diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index 0863a83..22b0112 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c@@ -467,17 +467,8 @@ static inline int omap_nand_dma_transfer(struct mtd_info *mtd, void *addr, int ret; u32 val; - if (addr >= high_memory) { - struct page *p1; - - if (((size_t)addr & PAGE_MASK) != - ((size_t)(addr + len - 1) & PAGE_MASK)) - goto out_copy; - p1 = vmalloc_to_page(addr); - if (!p1) - goto out_copy; - addr = page_address(p1) + ((size_t)addr & ~PAGE_MASK); - } + if (addr >= high_memory) + goto out_copy; sg_init_one(&sg, addr, len); n = dma_map_sg(info->dma->device->dev, &sg, 1, dir);
@@ -534,6 +525,7 @@ out_copy: else is_write == 0 ? omap_read_buf8(mtd, (u_char *) addr, len) : omap_write_buf8(mtd, (u_char *) addr, len); + return 0; }
--
2.7.0