[PATCH 7/9] media: vb2: Convert vb2_dc_get_userptr() to use frame vector

Jan Kara
2015-07-13T14:56:01Z

Convert vb2_dc_get_userptr() to use frame vector infrastructure. When we
are doing that there's no need to allocate page array and some code can
be simplified.

Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
drivers/media/v4l2-core/videobuf2-dma-contig.c | 212 ++++---------------------
1 file changed, 34 insertions(+), 178 deletions(-)

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index c548ce425701..2397ceb1dc6b 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -32,15 +32,13 @@ struct vb2_dc_buf {
dma_addr_t dma_addr;
enum dma_data_direction dma_dir;
struct sg_table *dma_sgt;
+ struct frame_vector *vec;

/* MMAP related */
struct vb2_vmarea_handler handler;
atomic_t refcount;
struct sg_table *sgt_base;

- /* USERPTR related */
- struct vm_area_struct *vma;
-
/* DMABUF related */
struct dma_buf_attachment *db_attach;
};
@@ -49,24 +47,6 @@ struct vb2_dc_buf {
/* scatterlist table functions */
/*********************************************/

-
-static void vb2_dc_sgt_foreach_page(struct sg_table *sgt,
- void (*cb)(struct page *pg))
-{
- struct scatterlist *s;
- unsigned int i;
-
- for_each_sg(sgt->sgl, s, sgt->orig_nents, i) {
- struct page *page = sg_page(s);
- unsigned int n_pages = PAGE_ALIGN(s->offset + s->length)
- >> PAGE_SHIFT;
- unsigned int j;
-
- for (j = 0; j < n_pages; ++j, ++page)
- cb(page);
- }
-}
-
static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
{
struct scatterlist *s;
@@ -429,92 +409,12 @@ static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, unsigned long flags)
/* callbacks for USERPTR buffers */
/*********************************************/

-static inline int vma_is_io(struct vm_area_struct *vma)
-{
- return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
-}
-
-static int vb2_dc_get_user_pfn(unsigned long start, int n_pages,
- struct vm_area_struct *vma, unsigned long *res)
-{
- unsigned long pfn, start_pfn, prev_pfn;
- unsigned int i;
- int ret;
-
- if (!vma_is_io(vma))
- return -EFAULT;
-
- ret = follow_pfn(vma, start, &pfn);
- if (ret)
- return ret;
-
- start_pfn = pfn;
- start += PAGE_SIZE;
-
- for (i = 1; i < n_pages; ++i, start += PAGE_SIZE) {
- prev_pfn = pfn;
- ret = follow_pfn(vma, start, &pfn);
-
- if (ret) {
- pr_err("no page for address %lu\n", start);
- return ret;
- }
- if (pfn != prev_pfn + 1)
- return -EINVAL;
- }
-
- *res = start_pfn;
- return 0;
-}
-
-static int vb2_dc_get_user_pages(unsigned long start, struct page **pages,
- int n_pages, struct vm_area_struct *vma,
- enum dma_data_direction dma_dir)
-{
- if (vma_is_io(vma)) {
- unsigned int i;
-
- for (i = 0; i < n_pages; ++i, start += PAGE_SIZE) {
- unsigned long pfn;
- int ret = follow_pfn(vma, start, &pfn);
-
- if (!pfn_valid(pfn))
- return -EINVAL;
-
- if (ret) {
- pr_err("no page for address %lu\n", start);
- return ret;
- }
- pages[i] = pfn_to_page(pfn);
- }
- } else {
- int n;
-
- n = get_user_pages(current, current->mm, start & PAGE_MASK,
- n_pages, dma_dir == DMA_FROM_DEVICE, 1, pages, NULL);
- /* negative error means that no page was pinned */
- n = max(n, 0);
- if (n != n_pages) {
- pr_err("got only %d of %d user pages\n", n, n_pages);
- while (n)
- put_page(pages[--n]);
- return -EFAULT;
- }
- }
-
- return 0;
-}
-
-static void vb2_dc_put_dirty_page(struct page *page)
-{
- set_page_dirty_lock(page);
- put_page(page);
-}
-
static void vb2_dc_put_userptr(void *buf_priv)
{
struct vb2_dc_buf *buf = buf_priv;
struct sg_table *sgt = buf->dma_sgt;
+ int i;
+ struct page **pages;

if (sgt) {
DEFINE_DMA_ATTRS(attrs);
@@ -526,13 +426,15 @@ static void vb2_dc_put_userptr(void *buf_priv)
*/
dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
buf->dma_dir, &attrs);
- if (!vma_is_io(buf->vma))
- vb2_dc_sgt_foreach_page(sgt, vb2_dc_put_dirty_page);
-
+ pages = frame_vector_pages(buf->vec);
+ /* sgt should exist only if vector contains pages... */
+ BUG_ON(IS_ERR(pages));
+ for (i = 0; i < frame_vector_count(buf->vec); i++)
+ set_page_dirty_lock(pages[i]);
sg_free_table(sgt);
kfree(sgt);
}
- vb2_put_vma(buf->vma);
+ vb2_destroy_framevec(buf->vec);
kfree(buf);
}

@@ -572,13 +474,10 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
{
struct vb2_dc_conf *conf = alloc_ctx;
struct vb2_dc_buf *buf;
- unsigned long start;
- unsigned long end;
+ struct frame_vector *vec;
unsigned long offset;
- struct page **pages;
- int n_pages;
+ int n_pages, i;
int ret = 0;
- struct vm_area_struct *vma;
struct sg_table *sgt;
unsigned long contig_size;
unsigned long dma_align = dma_get_cache_alignment();
@@ -604,75 +503,43 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
buf->dev = conf->dev;
buf->dma_dir = dma_dir;

- start = vaddr & PAGE_MASK;
offset = vaddr & ~PAGE_MASK;
- end = PAGE_ALIGN(vaddr + size);
- n_pages = (end - start) >> PAGE_SHIFT;
-
- pages = kmalloc(n_pages * sizeof(pages[0]), GFP_KERNEL);
- if (!pages) {
- ret = -ENOMEM;
- pr_err("failed to allocate pages table\n");
+ vec = vb2_create_framevec(vaddr, size, dma_dir == DMA_FROM_DEVICE);
+ if (IS_ERR(vec)) {
+ ret = PTR_ERR(vec);
goto fail_buf;
}
+ buf->vec = vec;
+ n_pages = frame_vector_count(vec);
+ ret = frame_vector_to_pages(vec);
+ if (ret < 0) {
+ unsigned long *nums = frame_vector_pfns(vec);

- down_read(&current->mm->mmap_sem);
- /* current->mm->mmap_sem is taken by videobuf2 core */
- vma = find_vma(current->mm, vaddr);
- if (!vma) {
- pr_err("no vma for address %lu\n", vaddr);
- ret = -EFAULT;
- goto fail_pages;
- }
-
- if (vma->vm_end < vaddr + size) {
- pr_err("vma at %lu is too small for %lu bytes\n", vaddr, size);
- ret = -EFAULT;
- goto fail_pages;
- }
-
- buf->vma = vb2_get_vma(vma);
- if (!buf->vma) {
- pr_err("failed to copy vma\n");
- ret = -ENOMEM;
- goto fail_pages;
- }
-
- /* extract page list from userspace mapping */
- ret = vb2_dc_get_user_pages(start, pages, n_pages, vma, dma_dir);
- 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);
- return buf;
- }
-
- pr_err("failed to get user pages\n");
- goto fail_vma;
+ /*
+ * Failed to convert to pages... Check the memory is physically
+ * contiguous and use direct mapping
+ */
+ for (i = 1; i < n_pages; i++)
+ if (nums[i-1] + 1 != nums[i])
+ goto fail_pfnvec;
+ buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, nums[0]);
+ goto out;
}
- up_read(&current->mm->mmap_sem);

sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
if (!sgt) {
pr_err("failed to allocate sg table\n");
ret = -ENOMEM;
- goto fail_get_user_pages;
+ goto fail_pfnvec;
}

- ret = sg_alloc_table_from_pages(sgt, pages, n_pages,
+ ret = sg_alloc_table_from_pages(sgt, frame_vector_pages(vec), n_pages,
offset, size, GFP_KERNEL);
if (ret) {
pr_err("failed to initialize sg table\n");
goto fail_sgt;
}

- /* pages are no longer needed */
- kfree(pages);
- pages = NULL;
-
/*
* No need to sync to the device, this will happen later when the
* prepare() memop is called.
@@ -694,8 +561,9 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
}

buf->dma_addr = sg_dma_address(sgt->sgl);
- buf->size = size;
buf->dma_sgt = sgt;
+out:
+ buf->size = size;

return buf;

@@ -704,25 +572,13 @@ fail_map_sg:
buf->dma_dir, &attrs);

fail_sgt_init:
- if (!vma_is_io(buf->vma))
- vb2_dc_sgt_foreach_page(sgt, put_page);
sg_free_table(sgt);

fail_sgt:
kfree(sgt);

-fail_get_user_pages:
- if (pages && !vma_is_io(buf->vma))
- 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_pfnvec:
+ vb2_destroy_framevec(vec);

fail_buf:
kfree(buf);
--
2.1.4