[patch v3] doc: DMA-mapping.txt has undeclared variables [Bug 10397]

[patch v3] doc: DMA-mapping.txt has undeclared variables [Bug 10397]

[Matti Linnanvuori]

From: Matti Linnanvuori <mattilinnanvuori@yahoo.com>

Consistently use pdev as the variable of type struct pci_dev *.
Update DMA mapping documentation to use 'pdev' rather than 'dev' in 
example code that calls routines expecting 'struct pci_device *', since 'dev' 
might make readers think they're passing 'struct device *' parameters.
Bug 10397.

Signed-off-by: Matti Linnanvuori <mattilinnanvuori@yahoo.com>

---

--- linux-2.6/Documentation/DMA-mapping.txt    2008-03-23 09:01:06.304511500 +0200
+++ linux/Documentation/DMA-mapping.txt    2008-04-06 06:56:11.821314500 +0300
@@ -315,9 +315,9 @@
 
     dma_addr_t dma_handle;
 
-    cpu_addr = pci_alloc_consistent(dev, size, &dma_handle);
+    cpu_addr = pci_alloc_consistent(pdev, size, &dma_handle);
 
-where dev is a struct pci_dev *. You should pass NULL for PCI like buses
+where pdev is a struct pci_dev *. You should pass NULL for PCI like buses
 where devices don't have struct pci_dev (like ISA, EISA).  This may be
 called in interrupt context. 
 
@@ -354,9 +354,9 @@
 
 To unmap and free such a DMA region, you call:
 
-    pci_free_consistent(dev, size, cpu_addr, dma_handle);
+    pci_free_consistent(pdev, size, cpu_addr, dma_handle);
 
-where dev, size are the same as in the above call and cpu_addr and
+where pdev, size are the same as in the above call and cpu_addr and
 dma_handle are the values pci_alloc_consistent returned to you.
 This function may not be called in interrupt context.
 
@@ -371,9 +371,9 @@
 
     struct pci_pool *pool;
 
-    pool = pci_pool_create(name, dev, size, align, alloc);
+    pool = pci_pool_create(name, pdev, size, align, alloc);
 
-The "name" is for diagnostics (like a kmem_cache name); dev and size
+The "name" is for diagnostics (like a kmem_cache name); pdev and size
 are as above.  The device's hardware alignment requirement for this
 type of data is "align" (which is expressed in bytes, and must be a
 power of two).  If your device has no boundary crossing restrictions,
@@ -472,11 +472,11 @@
     void *addr = buffer->ptr;
     size_t size = buffer->len;
 
-    dma_handle = pci_map_single(dev, addr, size, direction);
+    dma_handle = pci_map_single(pdev, addr, size, direction);
 
 and to unmap it:
 
-    pci_unmap_single(dev, dma_handle, size, direction);
+    pci_unmap_single(pdev, dma_handle, size, direction);
 
 You should call pci_unmap_single when the DMA activity is finished, e.g.
 from the interrupt which told you that the DMA transfer is done.
@@ -493,17 +493,17 @@
     unsigned long offset = buffer->offset;
     size_t size = buffer->len;
 
-    dma_handle = pci_map_page(dev, page, offset, size, direction);
+    dma_handle = pci_map_page(pdev, page, offset, size, direction);
 
     ...
 
-    pci_unmap_page(dev, dma_handle, size, direction);
+    pci_unmap_page(pdev, dma_handle, size, direction);
 
 Here, "offset" means byte offset within the given page.
 
 With scatterlists, you map a region gathered from several regions by:
 
-    int i, count = pci_map_sg(dev, sglist, nents, direction);
+    int i, count = pci_map_sg(pdev, sglist, nents, direction);
     struct scatterlist *sg;
 
     for_each_sg(sglist, sg, count, i) {
@@ -527,7 +527,7 @@
 
 To unmap a scatterlist, just call:
 
-    pci_unmap_sg(dev, sglist, nents, direction);
+    pci_unmap_sg(pdev, sglist, nents, direction);
 
 Again, make sure DMA activity has already finished.
 
@@ -550,11 +550,11 @@
 So, firstly, just map it with pci_map_{single,sg}, and after each DMA
 transfer call either:
 
-    pci_dma_sync_single_for_cpu(dev, dma_handle, size, direction);
+    pci_dma_sync_single_for_cpu(pdev, dma_handle, size, direction);
 
 or:
 
-    pci_dma_sync_sg_for_cpu(dev, sglist, nents, direction);
+    pci_dma_sync_sg_for_cpu(pdev, sglist, nents, direction);
 
 as appropriate.
 
@@ -562,7 +562,7 @@
 finish accessing the data with the cpu, and then before actually
 giving the buffer to the hardware call either:
 
-    pci_dma_sync_single_for_device(dev, dma_handle, size, direction);
+    pci_dma_sync_single_for_device(pdev, dma_handle, size, direction);
 
 or:
 
@@ -739,7 +739,7 @@
 
     dma_addr_t dma_handle;
 
-    dma_handle = pci_map_single(dev, addr, size, direction);
+    dma_handle = pci_map_single(pdev, addr, size, direction);
     if (pci_dma_mapping_error(dma_handle)) {
         /*
          * reduce current DMA mapping usage,



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Re: [patch v3] doc: DMA-mapping.txt has undeclared variables [Bug 10397]

[Matthew Wilcox]

On Mon, Apr 28, 2008 at 05:58:49AM -0700, Matti Linnanvuori wrote:
> From: Matti Linnanvuori <mattilinnanvuori@yahoo.com>
> 
> Consistently use pdev as the variable of type struct pci_dev *.
> Update DMA mapping documentation to use 'pdev' rather than 'dev' in 
> example code that calls routines expecting 'struct pci_device *', since 'dev' 
> might make readers think they're passing 'struct device *' parameters.
> Bug 10397.
> 
> Signed-off-by: Matti Linnanvuori <mattilinnanvuori@yahoo.com>

Acked-by: Matthew Wilcox <willy@linux.intel.com>

> -    cpu_addr = pci_alloc_consistent(dev, size, &dma_handle);
> +    cpu_addr = pci_alloc_consistent(pdev, size, &dma_handle);
>  
> -where dev is a struct pci_dev *. You should pass NULL for PCI like buses
> +where pdev is a struct pci_dev *. You should pass NULL for PCI like buses
>  where devices don't have struct pci_dev (like ISA, EISA).  This may be
>  called in interrupt context. 

The second sentence is misleading (but it's unrelated to this patch).
If you don't have a pdev, you should be using dma_alloc_coherent()
instead (see DMA-API.txt).  Want to make another patch?  ;-)

-- 
Intel are signing my paycheques ... these opinions are still mine
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."

Re: [patch v3] doc: DMA-mapping.txt has undeclared variables [Bug 10397]

[Jesse Barnes]

On Monday, April 28, 2008 5:58 am Matti Linnanvuori wrote:
> From: Matti Linnanvuori <mattilinnanvuori@yahoo.com>
>
> Consistently use pdev as the variable of type struct pci_dev *.
> Update DMA mapping documentation to use 'pdev' rather than 'dev' in
> example code that calls routines expecting 'struct pci_device *', since
> 'dev' might make readers think they're passing 'struct device *'
> parameters. Bug 10397.
>
> Signed-off-by: Matti Linnanvuori <mattilinnanvuori@yahoo.com>

Looks like your mailer or cut & paste corrupted the whitespace in this patch.  
Care to send another as an attachment?

Thanks,
Jesse

Re: [patch v3] doc: DMA-mapping.txt has undeclared variables [Bug 10397]

[Grant Grundler]

On Mon, Apr 28, 2008 at 05:58:49AM -0700, Matti Linnanvuori wrote:
> From: Matti Linnanvuori <mattilinnanvuori@yahoo.com>
> 
> Consistently use pdev as the variable of type struct pci_dev *.
> Update DMA mapping documentation to use 'pdev' rather than 'dev' in 
> example code that calls routines expecting 'struct pci_device *', since 'dev' 
> might make readers think they're passing 'struct device *' parameters.
> Bug 10397.
> 
> Signed-off-by: Matti Linnanvuori <mattilinnanvuori@yahoo.com>

Acked-by: Grant Grundler <grundler@parisc-linux.org>

Thanks!
grant

> 
> ---
> 
> --- linux-2.6/Documentation/DMA-mapping.txt    2008-03-23 09:01:06.304511500 +0200
> +++ linux/Documentation/DMA-mapping.txt    2008-04-06 06:56:11.821314500 +0300
> @@ -315,9 +315,9 @@
>  
>      dma_addr_t dma_handle;
>  
> -    cpu_addr = pci_alloc_consistent(dev, size, &dma_handle);
> +    cpu_addr = pci_alloc_consistent(pdev, size, &dma_handle);
>  
> -where dev is a struct pci_dev *. You should pass NULL for PCI like buses
> +where pdev is a struct pci_dev *. You should pass NULL for PCI like buses
>  where devices don't have struct pci_dev (like ISA, EISA).  This may be
>  called in interrupt context. 
>  
> @@ -354,9 +354,9 @@
>  
>  To unmap and free such a DMA region, you call:
>  
> -    pci_free_consistent(dev, size, cpu_addr, dma_handle);
> +    pci_free_consistent(pdev, size, cpu_addr, dma_handle);
>  
> -where dev, size are the same as in the above call and cpu_addr and
> +where pdev, size are the same as in the above call and cpu_addr and
>  dma_handle are the values pci_alloc_consistent returned to you.
>  This function may not be called in interrupt context.
>  
> @@ -371,9 +371,9 @@
>  
>      struct pci_pool *pool;
>  
> -    pool = pci_pool_create(name, dev, size, align, alloc);
> +    pool = pci_pool_create(name, pdev, size, align, alloc);
>  
> -The "name" is for diagnostics (like a kmem_cache name); dev and size
> +The "name" is for diagnostics (like a kmem_cache name); pdev and size
>  are as above.  The device's hardware alignment requirement for this
>  type of data is "align" (which is expressed in bytes, and must be a
>  power of two).  If your device has no boundary crossing restrictions,
> @@ -472,11 +472,11 @@
>      void *addr = buffer->ptr;
>      size_t size = buffer->len;
>  
> -    dma_handle = pci_map_single(dev, addr, size, direction);
> +    dma_handle = pci_map_single(pdev, addr, size, direction);
>  
>  and to unmap it:
>  
> -    pci_unmap_single(dev, dma_handle, size, direction);
> +    pci_unmap_single(pdev, dma_handle, size, direction);
>  
>  You should call pci_unmap_single when the DMA activity is finished, e.g.
>  from the interrupt which told you that the DMA transfer is done.
> @@ -493,17 +493,17 @@
>      unsigned long offset = buffer->offset;
>      size_t size = buffer->len;
>  
> -    dma_handle = pci_map_page(dev, page, offset, size, direction);
> +    dma_handle = pci_map_page(pdev, page, offset, size, direction);
>  
>      ...
>  
> -    pci_unmap_page(dev, dma_handle, size, direction);
> +    pci_unmap_page(pdev, dma_handle, size, direction);
>  
>  Here, "offset" means byte offset within the given page.
>  
>  With scatterlists, you map a region gathered from several regions by:
>  
> -    int i, count = pci_map_sg(dev, sglist, nents, direction);
> +    int i, count = pci_map_sg(pdev, sglist, nents, direction);
>      struct scatterlist *sg;
>  
>      for_each_sg(sglist, sg, count, i) {
> @@ -527,7 +527,7 @@
>  
>  To unmap a scatterlist, just call:
>  
> -    pci_unmap_sg(dev, sglist, nents, direction);
> +    pci_unmap_sg(pdev, sglist, nents, direction);
>  
>  Again, make sure DMA activity has already finished.
>  
> @@ -550,11 +550,11 @@
>  So, firstly, just map it with pci_map_{single,sg}, and after each DMA
>  transfer call either:
>  
> -    pci_dma_sync_single_for_cpu(dev, dma_handle, size, direction);
> +    pci_dma_sync_single_for_cpu(pdev, dma_handle, size, direction);
>  
>  or:
>  
> -    pci_dma_sync_sg_for_cpu(dev, sglist, nents, direction);
> +    pci_dma_sync_sg_for_cpu(pdev, sglist, nents, direction);
>  
>  as appropriate.
>  
> @@ -562,7 +562,7 @@
>  finish accessing the data with the cpu, and then before actually
>  giving the buffer to the hardware call either:
>  
> -    pci_dma_sync_single_for_device(dev, dma_handle, size, direction);
> +    pci_dma_sync_single_for_device(pdev, dma_handle, size, direction);
>  
>  or:
>  
> @@ -739,7 +739,7 @@
>  
>      dma_addr_t dma_handle;
>  
> -    dma_handle = pci_map_single(dev, addr, size, direction);
> +    dma_handle = pci_map_single(pdev, addr, size, direction);
>      if (pci_dma_mapping_error(dma_handle)) {
>          /*
>           * reduce current DMA mapping usage,
> 
> 
> 
>       ____________________________________________________________________________________
> Be a better friend, newshound, and 
> know-it-all with Yahoo! Mobile.  Try it now.  http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ