[media] media: vb2: fix potential deadlock in mmap vs. get_userptr handling

[can-eth-gw-linux.git] / drivers / media / video / videobuf2-dma-sg.c

diff --git a/drivers/media/video/videobuf2-dma-sg.c b/drivers/media/video/videobuf2-dma-sg.c
index 3bad8b105fea3260ffcb5fff745009b943885eec..25c3b360e1adf1cdfdce19f80c59f847d38f18b4 100644 (file)
--- a/drivers/media/video/videobuf2-dma-sg.c
+++ b/drivers/media/video/videobuf2-dma-sg.c
@@ -140,7 +140,6 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
        if (!buf->pages)
                goto userptr_fail_pages_array_alloc;
 
-       down_read(&current->mm->mmap_sem);
        num_pages_from_user = get_user_pages(current, current->mm,
                                             vaddr & PAGE_MASK,
                                             buf->sg_desc.num_pages,
@@ -148,7 +147,7 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
                                             1, /* force */
                                             buf->pages,
                                             NULL);
-       up_read(&current->mm->mmap_sem);
+
        if (num_pages_from_user != buf->sg_desc.num_pages)
                goto userptr_fail_get_user_pages;