[media] vb2: Push mmap_sem down to memops

Currently vb2 core acquires mmap_sem just around call to
__qbuf_userptr(). However since commit f035eb4e976ef5 (videobuf2: fix
lockdep warning) it isn't necessary to acquire it so early as we no
longer have to drop queue mutex before acquiring mmap_sem. So push
acquisition of mmap_sem down into .get_userptr and .put_userptr memops
so that the semaphore is acquired for a shorter time and it is clearer
what it is needed for.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index 66ada01c796ca934527321fe67406667c2927c9a..20cdbc0900ea5e0a9ecd4b4f416c3a1ded485a34 100644 (file)
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -1657,9 +1657,7 @@ static int __buf_prepare(struct vb2_buffer *vb, const struct v4l2_buffer *b)
                ret = __qbuf_mmap(vb, b);
                break;
        case V4L2_MEMORY_USERPTR:
-               down_read(&current->mm->mmap_sem);
                ret = __qbuf_userptr(vb, b);
-               up_read(&current->mm->mmap_sem);
                break;
        case V4L2_MEMORY_DMABUF:
                ret = __qbuf_dmabuf(vb, b);

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 644dec73d2203fdffa67a035231f6fe7450278d2..620c4aa78881844b16484c6cb157944e5c1d077d 100644 (file)
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -532,7 +532,9 @@ static void vb2_dc_put_userptr(void *buf_priv)
                sg_free_table(sgt);
                kfree(sgt);
        }
+       down_read(&current->mm->mmap_sem);
        vb2_put_vma(buf->vma);
+       up_read(&current->mm->mmap_sem);
        kfree(buf);
 }
 
@@ -616,6 +618,7 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
                goto fail_buf;
        }
 
+       down_read(&current->mm->mmap_sem);
        /* current->mm->mmap_sem is taken by videobuf2 core */
        vma = find_vma(current->mm, vaddr);
        if (!vma) {
@@ -642,6 +645,7 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
        if (ret) {
                unsigned long pfn;
                if (vb2_dc_get_user_pfn(start, n_pages, vma, &pfn) == 0) {
+                       up_read(&current->mm->mmap_sem);
                        buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, pfn);
                        buf->size = size;
                        kfree(pages);
@@ -651,6 +655,7 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
                pr_err("failed to get user pages\n");
                goto fail_vma;
        }
+       up_read(&current->mm->mmap_sem);
 
        sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
        if (!sgt) {
@@ -713,10 +718,12 @@ fail_get_user_pages:
                while (n_pages)
                        put_page(pages[--n_pages]);
 
+       down_read(&current->mm->mmap_sem);
 fail_vma:
        vb2_put_vma(buf->vma);
 
 fail_pages:
+       up_read(&current->mm->mmap_sem);
        kfree(pages); /* kfree is NULL-proof */
 
 fail_buf:

diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c
index 45c708e463b93e84721e0c3a65a7a3f52aa33f92..afd4b514affcaa6594f82bce2ad3dd0fdacdafa0 100644 (file)
--- a/drivers/media/v4l2-core/videobuf2-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c
@@ -263,6 +263,7 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
        if (!buf->pages)
                goto userptr_fail_alloc_pages;
 
+       down_read(&current->mm->mmap_sem);
        vma = find_vma(current->mm, vaddr);
        if (!vma) {
                dprintk(1, "no vma for address %lu\n", vaddr);
@@ -301,6 +302,7 @@ 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->num_pages)
                goto userptr_fail_get_user_pages;
@@ -328,8 +330,10 @@ userptr_fail_get_user_pages:
        if (!vma_is_io(buf->vma))
                while (--num_pages_from_user >= 0)
                        put_page(buf->pages[num_pages_from_user]);
+       down_read(&current->mm->mmap_sem);
        vb2_put_vma(buf->vma);
 userptr_fail_find_vma:
+       up_read(&current->mm->mmap_sem);
        kfree(buf->pages);
 userptr_fail_alloc_pages:
        kfree(buf);
@@ -362,7 +366,9 @@ static void vb2_dma_sg_put_userptr(void *buf_priv)
                        put_page(buf->pages[i]);
        }
        kfree(buf->pages);
+       down_read(&current->mm->mmap_sem);
        vb2_put_vma(buf->vma);
+       up_read(&current->mm->mmap_sem);
        kfree(buf);
 }
 

diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c b/drivers/media/v4l2-core/videobuf2-vmalloc.c
index 657ab302a5cf457549e151e603b3cc60e5f90be1..0ba40be21ebdfba6efec6fcbceeaf8ebb9ee9e76 100644 (file)
--- a/drivers/media/v4l2-core/videobuf2-vmalloc.c
+++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c
@@ -89,7 +89,7 @@ static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr,
        offset = vaddr & ~PAGE_MASK;
        buf->size = size;
 
-
+       down_read(&current->mm->mmap_sem);
        vma = find_vma(current->mm, vaddr);
        if (vma && (vma->vm_flags & VM_PFNMAP) && (vma->vm_pgoff)) {
                if (vb2_get_contig_userptr(vaddr, size, &vma, &physp))
@@ -121,6 +121,7 @@ static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr,
                if (!buf->vaddr)
                        goto fail_get_user_pages;
        }
+       up_read(&current->mm->mmap_sem);
 
        buf->vaddr += offset;
        return buf;
@@ -133,6 +134,7 @@ fail_get_user_pages:
        kfree(buf->pages);
 
 fail_pages_array_alloc:
+       up_read(&current->mm->mmap_sem);
        kfree(buf);
 
        return NULL;
@@ -144,6 +146,7 @@ static void vb2_vmalloc_put_userptr(void *buf_priv)
        unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
        unsigned int i;
 
+       down_read(&current->mm->mmap_sem);
        if (buf->pages) {
                if (vaddr)
                        vm_unmap_ram((void *)vaddr, buf->n_pages);
@@ -157,6 +160,7 @@ static void vb2_vmalloc_put_userptr(void *buf_priv)
                vb2_put_vma(buf->vma);
                iounmap((__force void __iomem *)buf->vaddr);
        }
+       up_read(&current->mm->mmap_sem);
        kfree(buf);
 }