From: Cooper Jr., Franklin <fcooper@ti.com>
Date: Fri, 15 Apr 2016 20:28:59 +0000 (-0500)
Subject: mtd: nand: omap2: Fix high memory dma prefetch transfer
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=8c6f0fc4d2d505b17fc67675f0797fe3fc6e6c26;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

mtd: nand: omap2: Fix high memory dma prefetch transfer

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.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
---

diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c
index d1496b1276df..08e158895635 100644
--- a/drivers/mtd/nand/omap2.c
+++ b/drivers/mtd/nand/omap2.c
@@ -473,17 +473,8 @@ 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 (!virt_addr_valid(addr))
+		goto out_copy;
 
 	sg_init_one(&sg, addr, len);
 	n = dma_map_sg(info->dma->device->dev, &sg, 1, dir);