Re: [PATCH 2/2] V4L/DVB: buf-dma-sg.c: support non-pageable user-allocated memory

2010-05-20 Thread Arnout Vandecappelle 

On Thursday 06 May 2010 06:06:21, Mauro Carvalho Chehab wrote:
 Hi Arnout,
 
 Arnout Vandecappelle wrote:
  videobuf_dma_init_user_locked() uses get_user_pages() to get the
  virtual-to-physical address mapping for user-allocated memory.
  However, the user-allocated memory may be non-pageable because it
  is an I/O range or similar.  get_user_pages() fails with -EFAULT
  in that case.
  
  If the user-allocated memory is physically contiguous, the approach
  of V4L2_MEMORY_OVERLAY can be used.  If it is not, -EFAULT is still
  returned.
  ---
  
   drivers/media/video/videobuf-dma-sg.c |   18 ++
   1 files changed, 18 insertions(+), 0 deletions(-)
 
 Your patch looked sane to my eyes. I just noticed one warning at the
 dprintk, when compiled with 32 bits address space, and a few coding
 style issues. I needed to rebase it also, due to some changes at
 videobuf.
 
 However, you missed your SOB. Could you please send it? I'm enclosing
 the version with my changes for you to sign.
 
 ---
 
 V4L/DVB: buf-dma-sg.c: support non-pageable user-allocated memory
 Date: Wed, 17 Mar 2010 22:53:05 -
 From: Arnout Vandecappelle arn...@mind.be
 
 videobuf_dma_init_user_locked() uses get_user_pages() to get the
 virtual-to-physical address mapping for user-allocated memory.
 However, the user-allocated memory may be non-pageable because it
 is an I/O range or similar.  get_user_pages() fails with -EFAULT
 in that case.
 
 If the user-allocated memory is physically contiguous, the approach
 of V4L2_MEMORY_OVERLAY can be used.  If it is not, -EFAULT is still
 returned.
 
 [mche...@redhat.com: Fixed CodingStyle and warning at dprintk on i386]
 
 ---
 drivers/media/video/videobuf-dma-sg.c |   18 ++
  drivers/media/video/videobuf-dma-sg.c |   20 
  1 file changed, 20 insertions(+)
 
 --- work.orig/drivers/media/video/videobuf-dma-sg.c
 +++ work/drivers/media/video/videobuf-dma-sg.c
 @@ -145,6 +145,7 @@ static int videobuf_dma_init_user_locked
  {
   unsigned long first, last;
   int err, rw = 0;
 + struct vm_area_struct *vma;
 
   dma-direction = direction;
   switch (dma-direction) {
 @@ -162,6 +163,25 @@ static int videobuf_dma_init_user_locked
   last  = ((data+size-1)  PAGE_MASK)  PAGE_SHIFT;
   dma-offset   = data  ~PAGE_MASK;
   dma-nr_pages = last-first+1;
 +
 + /* In case the buffer is user-allocated and is actually an IO buffer
 for +some other hardware, we cannot map pages for it.  It in fact
 behaves +the same as an overlay. */
 + vma = find_vma(current-mm, data);
 + if (vma  (vma-vm_flags  VM_IO)) {
 + /* Only a single contiguous buffer is supported. */
 + if (vma-vm_end  data + size) {
 + dprintk(1, init user: non-contiguous IO buffer.\n);
 + /* same error that get_user_pages() would give */
 + return -EFAULT;
 + }
 + dma-bus_addr = (vma-vm_pgoff  PAGE_SHIFT) +
 + (data - vma-vm_start);
 + dprintk(1, init user IO [0x%lx+0x%lx = %d pages at 0x%llx]\n,
 + data, size, dma-nr_pages, (long long)dma-bus_addr);
 + return 0;
 + }
 +
   dma-pages = kmalloc(dma-nr_pages * sizeof(struct page *),
 GFP_KERNEL); if (NULL == dma-pages)
   return -ENOMEM;

Signed-off-by: Arnout Vandecappelle arn...@mind.be

-- 
Arnout Vandecappelle   arnout at mind be
Senior Embedded Software Architect +32-16-286540
Essensium/Mind http://www.mind.be
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Re: [PATCH 1/2] V4L/DVB: buf-dma-sg.c: don't assume nr_pages == sglen

2010-03-30 Thread Arnout Vandecappelle 

On Wednesday 24 March 2010 06:43:22, Sakari Ailus wrote:
 Hi Arnout,
 
 Thanks for the patch.
 
 Arnout Vandecappelle wrote:
[snip]
  -   dma_sync_sg_for_cpu(q-dev, dma-sglist, dma-nr_pages, 
  dma-direction); 
  +   dma_sync_sg_for_cpu(q-dev, dma-sglist, dma-sglen, dma-direction);
 
 I think the same problem still exists --- dma-sglen is not initialised
 anywhere, is it?

 Yes it is.
 In videobuf_dma_map (where dma-sglist is set), there are two conditions:

if (dma-bus_addr) {
dma-sglist = kmalloc(sizeof(struct scatterlist), GFP_KERNEL);
if (NULL != dma-sglist) {
dma-sglen  = 1;
...
}
}
...
if (!dma-bus_addr) {
dma-sglen = dma_map_sg(q-dev, dma-sglist,
dma-nr_pages, dma-direction);
...
}


 Regards,
 Arnout
-- 
Arnout Vandecappelle   arnout at mind be
Senior Embedded Software Architect +32-16-286540
Essensium/Mind http://www.mind.be
G.Geenslaan 9, 3001 Leuven, BelgiumBE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
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Re: [PATCH 1/2] V4L/DVB: buf-dma-sg.c: don't assume nr_pages == sglen

2010-03-17 Thread Arnout Vandecappelle 

On Wednesday 17 March 2010 21:57:18, Sakari Ailus wrote:
 Arnout Vandecappelle wrote:
  diff --git a/drivers/media/video/videobuf-dma-sg.c
  b/drivers/media/video/videobuf-dma-sg.c index da1790e..3b6f1b8 100644
  --- a/drivers/media/video/videobuf-dma-sg.c
  +++ b/drivers/media/video/videobuf-dma-sg.c
  @@ -244,7 +244,7 @@ int videobuf_dma_map(struct videobuf_queue* q,
  struct videobuf_dmabuf *dma)
  
  }
  if (!dma-bus_addr) {
  
  dma-sglen = dma_map_sg(q-dev, dma-sglist,
  
  -   dma-nr_pages, dma-direction);
  +   dma-sglen, dma-direction);
  
  if (0 == dma-sglen) {
  
  printk(KERN_WARNING
  
 %s: videobuf_map_sg failed\n,__func__);
 
 Where is dma-sglen actually set?
 
 videobuf_dma_map() is used in __videobuf_iolock
 (drivers/media/video/videobuf-dma-sg.c) but neither
 videobuf_dma_init_kernel() nor videobuf_dma_init_user() seem to set it.
 This apparently leaves the value uninitialised.
 
 I definitely think it should be assigned somewhere. :-)

 It's assigned there exactly - nr_pages shouldn't have been replaced there.

 Updated patches follow.

 Regards,
 Arnout

-- 
Arnout Vandecappelle   arnout at mind be
Senior Embedded Software Architect +32-16-286540
Essensium/Mind http://www.mind.be
G.Geenslaan 9, 3001 Leuven, BelgiumBE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
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[PATCH v3] Support for zerocopy to DMA buffers

2010-03-17 Thread Arnout Vandecappelle 
 Hoi,

 [Please CC me, I'm not subscribed.]

 I'm implementing zerocopy transfer from a v4l2 camera to the DSP on an 
OMAP3 (based on earlier work by Stefan Kost [1][2]).  Therefore I'm using 
V4L2_MEMORY_USERPTR to pass in the memory area allocated by TI's DMAI 
driver.  However, this has flags VM_IO | VM_PFNMAP.  This means that it is 
not possible to do get_user_pages() on it - it's an area that is not 
pageable and possibly even doesn't pass the MMU.

 In order to support this kind of zerocopy construct, I propose to add 
checks for VM_IO | VM_PFNMAP and only get pages from areas that don't have 
these flags set.

 I also fixed another issue: it was assumed that dma-sglen == dma-nr_pages,
which is not true for the USERPTR memory.  Thanks to Sakari Ailus for
pointing out a bug I introduced there.

 Regards,
 Arnout

[1] https://bugzilla.gnome.org/show_bug.cgi?id=583890
[2] http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/6209

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[PATCH 1/2] V4L/DVB: buf-dma-sg.c: don't assume nr_pages == sglen

2010-03-17 Thread Arnout Vandecappelle 
videobuf_pages_to_sg() and videobuf_vmalloc_to_sg() happen to create
a scatterlist element for every page.  However, this is not true for
bus addresses, so other functions shouldn't rely on the length of the
scatter list being equal to nr_pages.
---
 drivers/media/video/videobuf-dma-sg.c |4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/video/videobuf-dma-sg.c 
b/drivers/media/video/videobuf-dma-sg.c
index da1790e..18aaf54 100644
--- a/drivers/media/video/videobuf-dma-sg.c
+++ b/drivers/media/video/videobuf-dma-sg.c
@@ -262,7 +262,7 @@ int videobuf_dma_sync(struct videobuf_queue *q, struct 
videobuf_dmabuf *dma)
MAGIC_CHECK(dma-magic, MAGIC_DMABUF);
BUG_ON(!dma-sglen);
 
-   dma_sync_sg_for_cpu(q-dev, dma-sglist, dma-nr_pages, dma-direction);
+   dma_sync_sg_for_cpu(q-dev, dma-sglist, dma-sglen, dma-direction);
return 0;
 }
 
@@ -272,7 +272,7 @@ int videobuf_dma_unmap(struct videobuf_queue* q,struct 
videobuf_dmabuf *dma)
if (!dma-sglen)
return 0;
 
-   dma_unmap_sg(q-dev, dma-sglist, dma-nr_pages, dma-direction);
+   dma_unmap_sg(q-dev, dma-sglist, dma-sglen, dma-direction);
 
kfree(dma-sglist);
dma-sglist = NULL;
-- 
1.6.3.3

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[PATCH 2/2] V4L/DVB: buf-dma-sg.c: support non-pageable user-allocated memory

2010-03-17 Thread Arnout Vandecappelle 
videobuf_dma_init_user_locked() uses get_user_pages() to get the
virtual-to-physical address mapping for user-allocated memory.
However, the user-allocated memory may be non-pageable because it
is an I/O range or similar.  get_user_pages() fails with -EFAULT
in that case.

If the user-allocated memory is physically contiguous, the approach
of V4L2_MEMORY_OVERLAY can be used.  If it is not, -EFAULT is still
returned.
---
 drivers/media/video/videobuf-dma-sg.c |   18 ++
 1 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/drivers/media/video/videobuf-dma-sg.c 
b/drivers/media/video/videobuf-dma-sg.c
index 18aaf54..bd2d95d 100644
--- a/drivers/media/video/videobuf-dma-sg.c
+++ b/drivers/media/video/videobuf-dma-sg.c
@@ -136,6 +136,7 @@ static int videobuf_dma_init_user_locked(struct 
videobuf_dmabuf *dma,
 {
unsigned long first,last;
int err, rw = 0;
+   struct vm_area_struct *vma;
 
dma-direction = direction;
switch (dma-direction) {
@@ -153,6 +154,23 @@ static int videobuf_dma_init_user_locked(struct 
videobuf_dmabuf *dma,
last  = ((data+size-1)  PAGE_MASK)  PAGE_SHIFT;
dma-offset   = data  ~PAGE_MASK;
dma-nr_pages = last-first+1;
+
+   /* In case the buffer is user-allocated and is actually an IO buffer for
+  some other hardware, we cannot map pages for it.  It in fact behaves
+  the same as an overlay. */
+   vma = find_vma (current-mm, data);
+   if (vma  (vma-vm_flags  VM_IO)) {
+   /* Only a single contiguous buffer is supported. */
+   if (vma-vm_end  data + size) {
+   dprintk(1, init user: non-contiguous IO buffer.\n);
+   return -EFAULT; /* same error that get_user_pages() 
would give */
+   }
+   dma-bus_addr = (vma-vm_pgoff  PAGE_SHIFT) + (data - 
vma-vm_start);
+   dprintk(1,init user IO [0x%lx+0x%lx = %d pages at 0x%x]\n,
+   data, size, dma-nr_pages, dma-bus_addr);
+   return 0;
+   }
+
dma-pages = kmalloc(dma-nr_pages * sizeof(struct page*),
 GFP_KERNEL);
if (NULL == dma-pages)
-- 
1.6.3.3

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[PATCHv2] Support for zerocopy to DSP on OMAP3

2010-03-04 Thread Arnout Vandecappelle 
 Here is an updated patch, properly split up and with commit messages.

 I've tested it on my OMAP3 board an it works.  I don't have anything else
to test it with.

 Regards,
 Arnout

 [PATCH 1/2] V4L/DVB: buf-dma-sg.c: don't assume nr_pages == sglen
 [PATCH 2/2] V4L/DVB: buf-dma-sg.c: support non-pageable user-allocated memory
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[PATCH 1/2] V4L/DVB: buf-dma-sg.c: don't assume nr_pages == sglen

2010-03-04 Thread Arnout Vandecappelle 
videobuf_pages_to_sg() and videobuf_vmalloc_to_sg() happen to create
a scatterlist element for every page.  However, this is not true for
bus addresses, so other functions shouldn't rely on the length of the
scatter list being equal to nr_pages.
---
 drivers/media/video/videobuf-dma-sg.c |6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/media/video/videobuf-dma-sg.c 
b/drivers/media/video/videobuf-dma-sg.c
index da1790e..3b6f1b8 100644
--- a/drivers/media/video/videobuf-dma-sg.c
+++ b/drivers/media/video/videobuf-dma-sg.c
@@ -244,7 +244,7 @@ int videobuf_dma_map(struct videobuf_queue* q, struct 
videobuf_dmabuf *dma)
}
if (!dma-bus_addr) {
dma-sglen = dma_map_sg(q-dev, dma-sglist,
-   dma-nr_pages, dma-direction);
+   dma-sglen, dma-direction);
if (0 == dma-sglen) {
printk(KERN_WARNING
   %s: videobuf_map_sg failed\n,__func__);
@@ -262,7 +262,7 @@ int videobuf_dma_sync(struct videobuf_queue *q, struct 
videobuf_dmabuf *dma)
MAGIC_CHECK(dma-magic, MAGIC_DMABUF);
BUG_ON(!dma-sglen);
 
-   dma_sync_sg_for_cpu(q-dev, dma-sglist, dma-nr_pages, dma-direction);
+   dma_sync_sg_for_cpu(q-dev, dma-sglist, dma-sglen, dma-direction);
return 0;
 }
 
@@ -272,7 +272,7 @@ int videobuf_dma_unmap(struct videobuf_queue* q,struct 
videobuf_dmabuf *dma)
if (!dma-sglen)
return 0;
 
-   dma_unmap_sg(q-dev, dma-sglist, dma-nr_pages, dma-direction);
+   dma_unmap_sg(q-dev, dma-sglist, dma-sglen, dma-direction);
 
kfree(dma-sglist);
dma-sglist = NULL;
-- 
1.6.3.3

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[PATCH 2/2] V4L/DVB: buf-dma-sg.c: support non-pageable user-allocated memory

2010-03-04 Thread Arnout Vandecappelle 
videobuf_dma_init_user_locked() uses get_user_pages() to get the
virtual-to-physical address mapping for user-allocated memory.
However, the user-allocated memory may be non-pageable because it
is an I/O range or similar.  get_user_pages() fails with -EFAULT
in that case.

If the user-allocated memory is physically contiguous, the approach
of V4L2_MEMORY_OVERLAY can be used.  If it is not, -EFAULT is still
returned.
---
 drivers/media/video/videobuf-dma-sg.c |   18 ++
 1 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/drivers/media/video/videobuf-dma-sg.c 
b/drivers/media/video/videobuf-dma-sg.c
index 3b6f1b8..7884207 100644
--- a/drivers/media/video/videobuf-dma-sg.c
+++ b/drivers/media/video/videobuf-dma-sg.c
@@ -136,6 +136,7 @@ static int videobuf_dma_init_user_locked(struct 
videobuf_dmabuf *dma,
 {
unsigned long first,last;
int err, rw = 0;
+   struct vm_area_struct *vma;
 
dma-direction = direction;
switch (dma-direction) {
@@ -153,6 +154,23 @@ static int videobuf_dma_init_user_locked(struct 
videobuf_dmabuf *dma,
last  = ((data+size-1)  PAGE_MASK)  PAGE_SHIFT;
dma-offset   = data  ~PAGE_MASK;
dma-nr_pages = last-first+1;
+
+   /* In case the buffer is user-allocated and is actually an IO buffer for
+  some other hardware, we cannot map pages for it.  It in fact behaves
+  the same as an overlay. */
+   vma = find_vma (current-mm, data);
+   if (vma  (vma-vm_flags  VM_IO)) {
+   /* Only a single contiguous buffer is supported. */
+   if (vma-vm_end  data + size) {
+   dprintk(1, init user: non-contiguous IO buffer.\n);
+   return -EFAULT; /* same error that get_user_pages() 
would give */
+   }
+   dma-bus_addr = (vma-vm_pgoff  PAGE_SHIFT) + (data - 
vma-vm_start);
+   dprintk(1,init user IO [0x%lx+0x%lx = %d pages at 0x%x]\n,
+   data, size, dma-nr_pages, dma-bus_addr);
+   return 0;
+   }
+
dma-pages = kmalloc(dma-nr_pages * sizeof(struct page*),
 GFP_KERNEL);
if (NULL == dma-pages)
-- 
1.6.3.3

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Support for zerocopy to DSP on OMAP3

2010-03-03 Thread Arnout Vandecappelle 
 Hoi,

 [Please CC me, I'm not subscribed.]

 I'm implementing zerocopy transfer from a v4l2 camera to the DSP on an 
OMAP3 (based on earlier work by Stefan Kost [1][2]).  Therefore I'm using 
V4L2_MEMORY_USERPTR to pass in the memory area allocated by TI's DMAI 
driver.  However, this has flags VM_IO | VM_PFNMAP.  This means that it is 
not possible to do get_user_pages() on it - it's an area that is not 
pageable and possibly even doesn't pass the MMU.

 In order to support this kind of zerocopy construct, I propose to add 
checks for VM_IO | VM_PFNMAP and only get pages from areas that don't have 
these flags set.

 If I get positive feedback on this, I'll supply a patch.


[1] https://bugzilla.gnome.org/show_bug.cgi?id=583890
[2] http://thread.gmane.org/gmane.linux.drivers.video-input-
infrastructure/6209

-- 
Arnout Vandecappelle   arnout at mind be
Senior Embedded Software Architect +32-16-286540
Essensium/Mind http://www.mind.be
G.Geenslaan 9, 3001 Leuven, BelgiumBE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  31BB CF53 8660 6F88 345D  54CC A836 5879 20D7 CF43
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[PATCH RFCv1] Support for zerocopy to DSP on OMAP3

2010-03-03 Thread Arnout Vandecappelle 
 Here's a first attempt at allowing IO memory for USERPTR buffers.

 It also fixes another issue: it was assumed that 
dma-sglen == dma-nr_pages.  I'll split that up in a separate patch in the 
final version.

 Regards,
 Arnout

On Wednesday 03 March 2010 15:12:44, Arnout Vandecappelle wrote:
  Hoi,
 
  [Please CC me, I'm not subscribed.]
 
  I'm implementing zerocopy transfer from a v4l2 camera to the DSP on an
 OMAP3 (based on earlier work by Stefan Kost [1][2]).  Therefore I'm using
 V4L2_MEMORY_USERPTR to pass in the memory area allocated by TI's DMAI
 driver.  However, this has flags VM_IO | VM_PFNMAP.  This means that it
 is not possible to do get_user_pages() on it - it's an area that is not
 pageable and possibly even doesn't pass the MMU.
 
  In order to support this kind of zerocopy construct, I propose to add
 checks for VM_IO | VM_PFNMAP and only get pages from areas that don't
 have these flags set.
 
  If I get positive feedback on this, I'll supply a patch.
 
 
 [1] https://bugzilla.gnome.org/show_bug.cgi?id=583890
 [2] http://thread.gmane.org/gmane.linux.drivers.video-input-
 infrastructure/6209

-- 
Arnout Vandecappelle   arnout at mind be
Senior Embedded Software Architect +32-16-286540
Essensium/Mind http://www.mind.be
G.Geenslaan 9, 3001 Leuven, BelgiumBE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  31BB CF53 8660 6F88 345D  54CC A836 5879 20D7 CF43
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