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[media] media: vb2: Convert vb2_dc_get_userptr() to use frame vector
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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.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
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>
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Jan Kara authored and Mauro Carvalho Chehab committed Aug 16, 2015
1 parent 5a9e4de commit fb639eb
Showing 1 changed file with 34 additions and 178 deletions.
212 changes: 34 additions & 178 deletions drivers/media/v4l2-core/videobuf2-dma-contig.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
};
Expand All @@ -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;
Expand Down Expand Up @@ -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);
Expand All @@ -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);
}

Expand Down Expand Up @@ -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();
Expand All @@ -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.
Expand All @@ -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;

Expand All @@ -704,25 +572,13 @@ static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
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);
Expand Down

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