Date:	Tue, 29 Apr 2008 18:37:38 -0600
From:	Grant Grundler <grundler@...isc-linux.org>
To:	Matti Linnanvuori <mattilinnanvuori@...oo.com>
Cc:	jbarnes@...tuousgeek.org, linux-kernel@...r.kernel.org,
	linux-pci@...ey.karlin.mff.cuni.cz, grundler@...isc-linux.org
Subject: Re: [patch v3] doc: DMA-mapping.txt has undeclared variables [Bug
	10397]

On Mon, Apr 28, 2008 at 05:58:49AM -0700, Matti Linnanvuori wrote:
> From: Matti Linnanvuori <mattilinnanvuori@...oo.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@...oo.com>

Acked-by: Grant Grundler <grundler@...isc-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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists