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[media] videobuf2-dma-sg: Support io userptr operations on io memory 

Memory exported via remap_pfn_range cannot be remapped via
get_user_pages.
Other videobuf2 methods (like the dma-contig) supports io memory.
This patch adds support for this kind of memory.
v2: Comments by Marek Szyprowski
-Use vb2_get_vma and vb2_put_vma

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
This commit is contained in:
Ricardo Ribalda 2013-11-26 09:58:44 -03:00 committed by Mauro Carvalho Chehab
parent 1380f5754c
commit 50ac952d22
1 changed files with 47 additions and 4 deletions
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51
drivers/media/v4l2-core/videobuf2-dma-sg.c
View File

@ -40,6 +40,7 @@ struct vb2_dma_sg_buf {
unsigned int num_pages;
atomic_t refcount;
struct vb2_vmarea_handler handler;
struct vm_area_struct *vma;
};
static void vb2_dma_sg_put(void *buf_priv);
@ -155,12 +156,18 @@ static void vb2_dma_sg_put(void *buf_priv)
}
}
static inline int vma_is_io(struct vm_area_struct *vma)
{
return !!(vma->vm_flags & (VM_IO | VM_PFNMAP));
}
static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
unsigned long size, int write)
{
struct vb2_dma_sg_buf *buf;
unsigned long first, last;
int num_pages_from_user;
struct vm_area_struct *vma;
buf = kzalloc(sizeof *buf, GFP_KERNEL);
if (!buf)
@ -180,7 +187,38 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
if (!buf->pages)
return NULL;
num_pages_from_user = get_user_pages(current, current->mm,
vma = find_vma(current->mm, vaddr);
if (!vma) {
dprintk(1, "no vma for address %lu\n", vaddr);
goto userptr_fail_find_vma;
}
if (vma->vm_end < vaddr + size) {
dprintk(1, "vma at %lu is too small for %lu bytes\n",
vaddr, size);
goto userptr_fail_find_vma;
}
buf->vma = vb2_get_vma(vma);
if (!buf->vma) {
dprintk(1, "failed to copy vma\n");
goto userptr_fail_find_vma;
}
if (vma_is_io(buf->vma)) {
for (num_pages_from_user = 0;
num_pages_from_user < buf->num_pages;
++num_pages_from_user, vaddr += PAGE_SIZE) {
unsigned long pfn;
if (follow_pfn(buf->vma, vaddr, &pfn)) {
dprintk(1, "no page for address %lu\n", vaddr);
break;
}
buf->pages[num_pages_from_user] = pfn_to_page(pfn);
}
} else
num_pages_from_user = get_user_pages(current, current->mm,
vaddr & PAGE_MASK,
buf->num_pages,
write,
@ -201,8 +239,11 @@ static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
userptr_fail_get_user_pages:
dprintk(1, "get_user_pages requested/got: %d/%d]\n",
buf->num_pages, num_pages_from_user);
while (--num_pages_from_user >= 0)
put_page(buf->pages[num_pages_from_user]);
if (!vma_is_io(buf->vma))
while (--num_pages_from_user >= 0)
put_page(buf->pages[num_pages_from_user]);
vb2_put_vma(buf->vma);
userptr_fail_find_vma:
kfree(buf->pages);
kfree(buf);
return NULL;
@ -225,9 +266,11 @@ static void vb2_dma_sg_put_userptr(void *buf_priv)
while (--i >= 0) {
if (buf->write)
set_page_dirty_lock(buf->pages[i]);
put_page(buf->pages[i]);
if (!vma_is_io(buf->vma))
put_page(buf->pages[i]);
}
kfree(buf->pages);
vb2_put_vma(buf->vma);
kfree(buf);
}