lkml.org 
[lkml]   [2021]   [Jun]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2] dma-mapping: use vmalloc_to_page for vmalloc addresses
Date
This commit is dedicated to fix incorrect conversion from
cpu_addr to page address in cases when we get virtual
address which allocated in the vmalloc range.
As the result, virt_to_page() cannot convert this address
properly and return incorrect page address.

Need to detect such cases and obtains the page address using
vmalloc_to_page() instead.

Signed-off-by: Roman Skakun <roman_skakun@epam.com>
Reviewed-by: Andrii Anisov <andrii_anisov@epam.com>
---
Hey!
Thanks for suggestions, Christoph!
I updated the patch according to your advice.
But, I'm so surprised because nobody catches this problem
in the common code before. It looks a bit strange as for me.


kernel/dma/ops_helpers.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/kernel/dma/ops_helpers.c b/kernel/dma/ops_helpers.c
index 910ae69cae77..782728d8a393 100644
--- a/kernel/dma/ops_helpers.c
+++ b/kernel/dma/ops_helpers.c
@@ -5,6 +5,14 @@
*/
#include <linux/dma-map-ops.h>

+static struct page *cpu_addr_to_page(void *cpu_addr)
+{
+ if (is_vmalloc_addr(cpu_addr))
+ return vmalloc_to_page(cpu_addr);
+ else
+ return virt_to_page(cpu_addr);
+}
+
/*
* Create scatter-list for the already allocated DMA buffer.
*/
@@ -12,7 +20,7 @@ int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs)
{
- struct page *page = virt_to_page(cpu_addr);
+ struct page *page = cpu_addr_to_page(cpu_addr);
int ret;

ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
@@ -43,7 +51,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
return -ENXIO;

return remap_pfn_range(vma, vma->vm_start,
- page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff,
+ page_to_pfn(cpu_addr_to_page(cpu_addr)) + vma->vm_pgoff,
user_count << PAGE_SHIFT, vma->vm_page_prot);
#else
return -ENXIO;
--
2.25.1
\
 
 \ /
  Last update: 2021-06-22 15:35    [W:0.091 / U:0.392 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site