[PATCH]videobuf_dma_sg: a new implementation for mmap

[PATCH]videobuf_dma_sg: a new implementation for mmap

[Figo.zhang]

a mmap issue for videobuf-dma-sg: it will alloc a new page for mmaping
when it encounter page fault at video_vm_ops->fault().

a new implementation for mmap, it translate the vmalloc to page at
video_vm_ops->fault().

Signed-off-by: Figo.zhang <figo1802@gmail.com>
---
drivers/media/video/videobuf-dma-sg.c |   38
++++++++++++++++++++++++++++----
 1 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/drivers/media/video/videobuf-dma-sg.c
b/drivers/media/video/videobuf-dma-sg.c
index 8359e6b..c9a8817 100644
--- a/drivers/media/video/videobuf-dma-sg.c
+++ b/drivers/media/video/videobuf-dma-sg.c
@@ -397,16 +397,44 @@ static void videobuf_vm_close(struct
vm_area_struct *vma)
  */
 static int videobuf_vm_fault(struct vm_area_struct *vma, struct
vm_fault *vmf)
 {
-	struct page *page;
+	struct page *page = NULL;
+	struct videobuf_mapping *map = vma->vm_private_data;
+	struct videobuf_queue *q = map->q;
+	struct videobuf_dma_sg_memory *mem = NULL;
+
+	unsigned long offset;
+	unsigned long page_nr;
+	int first;
 
 	dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
 		(unsigned long)vmf->virtual_address,
 		vma->vm_start, vma->vm_end);
 
-	page = alloc_page(GFP_USER | __GFP_DMA32);
-	if (!page)
-		return VM_FAULT_OOM;
-	clear_user_highpage(page, (unsigned long)vmf->virtual_address);
+	mutex_lock(&q->vb_lock);
+
+	offset = (unsigned long)vmf->virtual_address - vma->vm_start;
+	page_nr = offset >> PAGE_SHIFT;
+
+	for (first = 0; first < VIDEO_MAX_FRAME; first++) {
+			if (NULL == q->bufs[first])
+				continue;
+
+			MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
+
+			if (q->bufs[first]->map == map)
+				break;
+	}
+
+	mem = q->bufs[first]->priv;
+	if (!mem)
+		return VM_FAULT_SIGBUS;
+	if (mem->dma.vmalloc)
+		page = vmalloc_to_page(mem->dma.vmalloc+
+				(offset & (~PAGE_MASK)));
+	if (mem->dma.pages)
+		page = mem->dma.pages[page_nr];
+	mutex_unlock(&q->vb_lock);
+
 	vmf->page = page;
 
 	return 0;

Re: [PATCH]videobuf_dma_sg: a new implementation for mmap

[Laurent Pinchart]

Hi,

On Tuesday 27 July 2010 14:21:40 Figo.zhang wrote:
> a mmap issue for videobuf-dma-sg: it will alloc a new page for mmaping
> when it encounter page fault at video_vm_ops->fault().
> 
> a new implementation for mmap, it translate the vmalloc to page at
> video_vm_ops->fault().

How is that supposed to work ? mem->dma.vmalloc is NULL in the vm_fault 
handler for V4L2_MEMORY_MMAP buffers. Have you tested the code at all ?

> Signed-off-by: Figo.zhang <figo1802@gmail.com>
> ---
> drivers/media/video/videobuf-dma-sg.c |   38
> ++++++++++++++++++++++++++++----
>  1 files changed, 33 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/media/video/videobuf-dma-sg.c
> b/drivers/media/video/videobuf-dma-sg.c
> index 8359e6b..c9a8817 100644
> --- a/drivers/media/video/videobuf-dma-sg.c
> +++ b/drivers/media/video/videobuf-dma-sg.c
> @@ -397,16 +397,44 @@ static void videobuf_vm_close(struct
> vm_area_struct *vma)
>   */
>  static int videobuf_vm_fault(struct vm_area_struct *vma, struct
> vm_fault *vmf)
>  {
> -	struct page *page;
> +	struct page *page = NULL;
> +	struct videobuf_mapping *map = vma->vm_private_data;
> +	struct videobuf_queue *q = map->q;
> +	struct videobuf_dma_sg_memory *mem = NULL;
> +
> +	unsigned long offset;
> +	unsigned long page_nr;
> +	int first;
> 
>  	dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
>  		(unsigned long)vmf->virtual_address,
>  		vma->vm_start, vma->vm_end);
> 
> -	page = alloc_page(GFP_USER | __GFP_DMA32);
> -	if (!page)
> -		return VM_FAULT_OOM;
> -	clear_user_highpage(page, (unsigned long)vmf->virtual_address);
> +	mutex_lock(&q->vb_lock);
> +
> +	offset = (unsigned long)vmf->virtual_address - vma->vm_start;
> +	page_nr = offset >> PAGE_SHIFT;
> +
> +	for (first = 0; first < VIDEO_MAX_FRAME; first++) {
> +			if (NULL == q->bufs[first])
> +				continue;
> +
> +			MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
> +
> +			if (q->bufs[first]->map == map)
> +				break;
> +	}
> +
> +	mem = q->bufs[first]->priv;
> +	if (!mem)
> +		return VM_FAULT_SIGBUS;
> +	if (mem->dma.vmalloc)
> +		page = vmalloc_to_page(mem->dma.vmalloc+
> +				(offset & (~PAGE_MASK)));
> +	if (mem->dma.pages)
> +		page = mem->dma.pages[page_nr];
> +	mutex_unlock(&q->vb_lock);
> +
>  	vmf->page = page;
> 
>  	return 0;

-- 
Regards,

Laurent Pinchart

[PATCH v2]videobuf_dma_sg: a new implementation for mmap

[Figo.zhang]

a mmap issue for videobuf-dma-sg: it will alloc a new page for mmaping
when it encounter page fault at video_vm_ops->fault().

a new implementation for mmap, it translate the vmalloc to page at
video_vm_ops->fault().

in v2, if mem->dma.vmalloc is NULL at video_vm_ops->fault(), it will
alloc memory by vmalloc_32().

Signed-off-by: Figo.zhang <figo1802@gmail.com>
---
 drivers/media/video/videobuf-dma-sg.c |   51
+++++++++++++++++++++++++++------
 1 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/drivers/media/video/videobuf-dma-sg.c
b/drivers/media/video/videobuf-dma-sg.c
index 8359e6b..767483d 100644
--- a/drivers/media/video/videobuf-dma-sg.c
+++ b/drivers/media/video/videobuf-dma-sg.c
@@ -201,10 +201,11 @@ int videobuf_dma_init_kernel(struct
videobuf_dmabuf *dma, int direction,
 	dprintk(1, "init kernel [%d pages]\n", nr_pages);
 
 	dma->direction = direction;
-	dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT);
-	if (NULL == dma->vmalloc) {
-		dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
-		return -ENOMEM;
+	if (!dma->vmalloc)
+		dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT);
+		if (NULL == dma->vmalloc) {
+			dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
+			return -ENOMEM;
 	}
 
 	dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n",
@@ -397,16 +398,48 @@ static void videobuf_vm_close(struct
vm_area_struct *vma)
  */
 static int videobuf_vm_fault(struct vm_area_struct *vma, struct
vm_fault *vmf)
 {
-	struct page *page;
+	struct page *page = NULL;
+	struct videobuf_mapping *map = vma->vm_private_data;
+	struct videobuf_queue *q = map->q;
+	struct videobuf_dma_sg_memory *mem = NULL;
+
+	unsigned long offset;
+	unsigned long page_nr;
+	int first;
 
 	dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
 		(unsigned long)vmf->virtual_address,
 		vma->vm_start, vma->vm_end);
 
-	page = alloc_page(GFP_USER | __GFP_DMA32);
-	if (!page)
-		return VM_FAULT_OOM;
-	clear_user_highpage(page, (unsigned long)vmf->virtual_address);
+	mutex_lock(&q->vb_lock);
+
+	offset = (unsigned long)vmf->virtual_address - vma->vm_start;
+	page_nr = offset >> PAGE_SHIFT;
+
+	for (first = 0; first < VIDEO_MAX_FRAME; first++) {
+			if (NULL == q->bufs[first])
+				continue;
+
+			MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
+
+			if (q->bufs[first]->map == map)
+				break;
+	}
+
+	mem = q->bufs[first]->priv;
+	if (!mem)
+		return VM_FAULT_SIGBUS;
+	if (!mem->dma.vmalloc) {
+		mem->dma.vmalloc = vmalloc_32(PAGE_ALIGN(q->bufs[first]->size));
+		if (NULL == mem->dma.vmalloc) {
+			dprintk(1, "%s: vmalloc_32() failed\n", __func__);
+			return VM_FAULT_OOM;
+		}
+	} else
+		page = vmalloc_to_page(mem->dma.vmalloc+
+				(offset & (~PAGE_MASK)));
+	mutex_unlock(&q->vb_lock);
+
 	vmf->page = page;
 
 	return 0;

[PATCH v2]videobuf_dma_sg: a new implementation for mmap

[Figo.zhang]

a mmap issue for videobuf-dma-sg: it will alloc a new page for mmaping
when it encounter page fault at video_vm_ops->fault().

a new implementation for mmap, it translate the vmalloc to page at
video_vm_ops->fault().

in v2, if mem->dma.vmalloc is NULL at video_vm_ops->fault(), it will
alloc memory by vmalloc_32().

Signed-off-by: Figo.zhang <figo1802@gmail.com>
---
drivers/media/video/videobuf-dma-sg.c |   51
+++++++++++++++++++++++++++------
 1 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/drivers/media/video/videobuf-dma-sg.c
b/drivers/media/video/videobuf-dma-sg.c
index 8359e6b..767483d 100644
--- a/drivers/media/video/videobuf-dma-sg.c
+++ b/drivers/media/video/videobuf-dma-sg.c
@@ -201,10 +201,11 @@ int videobuf_dma_init_kernel(struct
videobuf_dmabuf *dma, int direction,
 	dprintk(1, "init kernel [%d pages]\n", nr_pages);
 
 	dma->direction = direction;
-	dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT);
-	if (NULL == dma->vmalloc) {
-		dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
-		return -ENOMEM;
+	if (!dma->vmalloc)
+		dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT);
+		if (NULL == dma->vmalloc) {
+			dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
+			return -ENOMEM;
 	}
 
 	dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n",
@@ -397,16 +398,48 @@ static void videobuf_vm_close(struct
vm_area_struct *vma)
  */
 static int videobuf_vm_fault(struct vm_area_struct *vma, struct
vm_fault *vmf)
 {
-	struct page *page;
+	struct page *page = NULL;
+	struct videobuf_mapping *map = vma->vm_private_data;
+	struct videobuf_queue *q = map->q;
+	struct videobuf_dma_sg_memory *mem = NULL;
+
+	unsigned long offset;
+	unsigned long page_nr;
+	int first;
 
 	dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
 		(unsigned long)vmf->virtual_address,
 		vma->vm_start, vma->vm_end);
 
-	page = alloc_page(GFP_USER | __GFP_DMA32);
-	if (!page)
-		return VM_FAULT_OOM;
-	clear_user_highpage(page, (unsigned long)vmf->virtual_address);
+	mutex_lock(&q->vb_lock);
+
+	offset = (unsigned long)vmf->virtual_address - vma->vm_start;
+	page_nr = offset >> PAGE_SHIFT;
+
+	for (first = 0; first < VIDEO_MAX_FRAME; first++) {
+			if (NULL == q->bufs[first])
+				continue;
+
+			MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
+
+			if (q->bufs[first]->map == map)
+				break;
+	}
+
+	mem = q->bufs[first]->priv;
+	if (!mem)
+		return VM_FAULT_SIGBUS;
+	if (!mem->dma.vmalloc) {
+		mem->dma.vmalloc = vmalloc_32(PAGE_ALIGN(q->bufs[first]->size));
+		if (NULL == mem->dma.vmalloc) {
+			dprintk(1, "%s: vmalloc_32() failed\n", __func__);
+			return VM_FAULT_OOM;
+		}
+	} else
+		page = vmalloc_to_page(mem->dma.vmalloc+
+				(offset & (~PAGE_MASK)));
+	mutex_unlock(&q->vb_lock);
+
 	vmf->page = page;
 
 	return 0;

Re: [PATCH v2]videobuf_dma_sg: a new implementation for mmap

[Figo.zhang]

hi Laurent,
would you like to test this patch?

btw, why i send the patch , patchwork websit display a part of my patch?
https://patchwork.kernel.org/patch/114760/

Best,
Figo.zhang

On Wed, 2010-07-28 at 21:08 +0800, Figo.zhang wrote:
> a mmap issue for videobuf-dma-sg: it will alloc a new page for mmaping
> when it encounter page fault at video_vm_ops->fault().
> 
> a new implementation for mmap, it translate the vmalloc to page at
> video_vm_ops->fault().
> 
> in v2, if mem->dma.vmalloc is NULL at video_vm_ops->fault(), it will
> alloc memory by vmalloc_32().
> 
> Signed-off-by: Figo.zhang <figo1802@gmail.com>
> ---
> drivers/media/video/videobuf-dma-sg.c |   51
> +++++++++++++++++++++++++++------
>  1 files changed, 42 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/media/video/videobuf-dma-sg.c
> b/drivers/media/video/videobuf-dma-sg.c
> index 8359e6b..767483d 100644
> --- a/drivers/media/video/videobuf-dma-sg.c
> +++ b/drivers/media/video/videobuf-dma-sg.c
> @@ -201,10 +201,11 @@ int videobuf_dma_init_kernel(struct
> videobuf_dmabuf *dma, int direction,
>  	dprintk(1, "init kernel [%d pages]\n", nr_pages);
>  
>  	dma->direction = direction;
> -	dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT);
> -	if (NULL == dma->vmalloc) {
> -		dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
> -		return -ENOMEM;
> +	if (!dma->vmalloc)
> +		dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT);
> +		if (NULL == dma->vmalloc) {
> +			dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
> +			return -ENOMEM;
>  	}
>  
>  	dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n",
> @@ -397,16 +398,48 @@ static void videobuf_vm_close(struct
> vm_area_struct *vma)
>   */
>  static int videobuf_vm_fault(struct vm_area_struct *vma, struct
> vm_fault *vmf)
>  {
> -	struct page *page;
> +	struct page *page = NULL;
> +	struct videobuf_mapping *map = vma->vm_private_data;
> +	struct videobuf_queue *q = map->q;
> +	struct videobuf_dma_sg_memory *mem = NULL;
> +
> +	unsigned long offset;
> +	unsigned long page_nr;
> +	int first;
>  
>  	dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
>  		(unsigned long)vmf->virtual_address,
>  		vma->vm_start, vma->vm_end);
>  
> -	page = alloc_page(GFP_USER | __GFP_DMA32);
> -	if (!page)
> -		return VM_FAULT_OOM;
> -	clear_user_highpage(page, (unsigned long)vmf->virtual_address);
> +	mutex_lock(&q->vb_lock);
> +
> +	offset = (unsigned long)vmf->virtual_address - vma->vm_start;
> +	page_nr = offset >> PAGE_SHIFT;
> +
> +	for (first = 0; first < VIDEO_MAX_FRAME; first++) {
> +			if (NULL == q->bufs[first])
> +				continue;
> +
> +			MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
> +
> +			if (q->bufs[first]->map == map)
> +				break;
> +	}
> +
> +	mem = q->bufs[first]->priv;
> +	if (!mem)
> +		return VM_FAULT_SIGBUS;
> +	if (!mem->dma.vmalloc) {
> +		mem->dma.vmalloc = vmalloc_32(PAGE_ALIGN(q->bufs[first]->size));
> +		if (NULL == mem->dma.vmalloc) {
> +			dprintk(1, "%s: vmalloc_32() failed\n", __func__);
> +			return VM_FAULT_OOM;
> +		}
> +	} else
> +		page = vmalloc_to_page(mem->dma.vmalloc+
> +				(offset & (~PAGE_MASK)));
> +	mutex_unlock(&q->vb_lock);
> +
>  	vmf->page = page;
>  
>  	return 0;
> 

Re: [PATCH v2]videobuf_dma_sg: a new implementation for mmap

[Mauro Carvalho Chehab]

Em 29-07-2010 10:38, Figo.zhang escreveu:

> btw, why i send the patch , patchwork websit display a part of my patch?
> https://patchwork.kernel.org/patch/114760/

Because your emailer broke long lines, mangling part of your patch. The way
you sent, it will fail to apply.

Please, re-send it, being sure that your emailer won't break long lines.

Cheers,
Mauro.

Re: [PATCH v2]videobuf_dma_sg: a new implementation for mmap

[Laurent Pinchart]

Hi,
On Wednesday 28 July 2010 15:08:24 Figo.zhang wrote:
> a mmap issue for videobuf-dma-sg: it will alloc a new page for mmaping
> when it encounter page fault at video_vm_ops->fault().
> 
> a new implementation for mmap, it translate the vmalloc to page at
> video_vm_ops->fault().
> 
> in v2, if mem->dma.vmalloc is NULL at video_vm_ops->fault(), it will
> alloc memory by vmalloc_32().


Can you please elaborate on what you're trying to do ? What problem is this 
patch supposed to fix ?

> Signed-off-by: Figo.zhang <figo1802@gmail.com>
> ---
> drivers/media/video/videobuf-dma-sg.c |   51
> +++++++++++++++++++++++++++------
>  1 files changed, 42 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/media/video/videobuf-dma-sg.c
> b/drivers/media/video/videobuf-dma-sg.c
> index 8359e6b..767483d 100644
> --- a/drivers/media/video/videobuf-dma-sg.c
> +++ b/drivers/media/video/videobuf-dma-sg.c
> @@ -201,10 +201,11 @@ int videobuf_dma_init_kernel(struct
> videobuf_dmabuf *dma, int direction,
>  	dprintk(1, "init kernel [%d pages]\n", nr_pages);
> 
>  	dma->direction = direction;
> -	dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT);
> -	if (NULL == dma->vmalloc) {
> -		dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
> -		return -ENOMEM;
> +	if (!dma->vmalloc)
> +		dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT);
> +		if (NULL == dma->vmalloc) {
> +			dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
> +			return -ENOMEM;
>  	}
> 
>  	dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n",
> @@ -397,16 +398,48 @@ static void videobuf_vm_close(struct
> vm_area_struct *vma)
>   */
>  static int videobuf_vm_fault(struct vm_area_struct *vma, struct
> vm_fault *vmf)
>  {
> -	struct page *page;
> +	struct page *page = NULL;
> +	struct videobuf_mapping *map = vma->vm_private_data;
> +	struct videobuf_queue *q = map->q;
> +	struct videobuf_dma_sg_memory *mem = NULL;
> +
> +	unsigned long offset;
> +	unsigned long page_nr;
> +	int first;
> 
>  	dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
>  		(unsigned long)vmf->virtual_address,
>  		vma->vm_start, vma->vm_end);
> 
> -	page = alloc_page(GFP_USER | __GFP_DMA32);
> -	if (!page)
> -		return VM_FAULT_OOM;
> -	clear_user_highpage(page, (unsigned long)vmf->virtual_address);
> +	mutex_lock(&q->vb_lock);
> +
> +	offset = (unsigned long)vmf->virtual_address - vma->vm_start;
> +	page_nr = offset >> PAGE_SHIFT;
> +
> +	for (first = 0; first < VIDEO_MAX_FRAME; first++) {
> +			if (NULL == q->bufs[first])
> +				continue;
> +
> +			MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
> +
> +			if (q->bufs[first]->map == map)
> +				break;
> +	}
> +
> +	mem = q->bufs[first]->priv;
> +	if (!mem)
> +		return VM_FAULT_SIGBUS;
> +	if (!mem->dma.vmalloc) {
> +		mem->dma.vmalloc = vmalloc_32(PAGE_ALIGN(q->bufs[first]->size));
> +		if (NULL == mem->dma.vmalloc) {
> +			dprintk(1, "%s: vmalloc_32() failed\n", __func__);
> +			return VM_FAULT_OOM;
> +		}
> +	} else
> +		page = vmalloc_to_page(mem->dma.vmalloc+
> +				(offset & (~PAGE_MASK)));
> +	mutex_unlock(&q->vb_lock);
> +
>  	vmf->page = page;
> 
>  	return 0;

-- 
Regards,

Laurent Pinchart