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

2010-05-05 Thread Mauro Carvalho Chehab 
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;


-- 

Cheers,
Mauro
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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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[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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