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Commit 6bd76457 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
Browse files

staging: comedi: comedi_buf: factor out new buffer allocation code 



The function comedi_buf_alloc() first frees any allocated buffer then,
optionally, allocates a new buffer.

Factor out the new buffer allocation code to a new function. This
allows reducing the indent level and makes the code a bit cleaner.

Also, cleanup to factored out code to make it a bit more concise.
Use a local variable for the current comedi_buf_page being allocated.
This cleans up the ugly line breaks used to keep the lines < 80 chars.

Move the #ifdef'ery for the page protection determination out of the
vmap() call.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 718c4d68

drivers/staging/comedi/comedi_buf.c

+52 −45
Original line number Diff line number Diff line
@@ -22,6 +22,12 @@ 
#include "comedidev.h"

#include "comedi_internal.h"



#ifdef PAGE_KERNEL_NOCACHE

#define COMEDI_PAGE_PROTECTION		PAGE_KERNEL_NOCACHE

#else

#define COMEDI_PAGE_PROTECTION		PAGE_KERNEL

#endif



static void __comedi_buf_free(struct comedi_device *dev,

			      struct comedi_subdevice *s,

			      unsigned n_pages)
@@ -59,6 +65,48 @@ static void __comedi_buf_free(struct comedi_device *dev, 
	async->n_buf_pages = 0;

}



static void __comedi_buf_alloc(struct comedi_device *dev,

			       struct comedi_subdevice *s,

			       unsigned n_pages)

{

	struct comedi_async *async = s->async;

	struct page **pages = NULL;

	struct comedi_buf_page *buf;

	unsigned i;



	async->buf_page_list = vzalloc(sizeof(*buf) * n_pages);

	if (async->buf_page_list)

		pages = vmalloc(sizeof(struct page *) * n_pages);



	if (!pages)

		return;



	for (i = 0; i < n_pages; i++) {

		buf = &async->buf_page_list[i];

		if (s->async_dma_dir != DMA_NONE)

			buf->virt_addr = dma_alloc_coherent(dev->hw_dev,

							    PAGE_SIZE,

							    &buf->dma_addr,

							    GFP_KERNEL |

							    __GFP_COMP);

		else

			buf->virt_addr = (void *)get_zeroed_page(GFP_KERNEL);

		if (!buf->virt_addr)

			break;



		set_bit(PG_reserved, &(virt_to_page(buf->virt_addr)->flags));



		pages[i] = virt_to_page(buf->virt_addr);

	}



	/* vmap the prealloc_buf if all the pages were allocated */

	if (i == n_pages)

		async->prealloc_buf = vmap(pages, n_pages, VM_MAP,

					   COMEDI_PAGE_PROTECTION);



	vfree(pages);

}



int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,

		     unsigned long new_size)

{
@@ -76,53 +124,12 @@ int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s, 


	/* allocate new buffer */

	if (new_size) {

		unsigned i = 0;

		unsigned n_pages = new_size >> PAGE_SHIFT;

		struct page **pages = NULL;



		async->buf_page_list =

		    vzalloc(sizeof(struct comedi_buf_page) * n_pages);

		if (async->buf_page_list)

			pages = vmalloc(sizeof(struct page *) * n_pages);



		if (pages) {

			for (i = 0; i < n_pages; i++) {

				if (s->async_dma_dir != DMA_NONE) {

					async->buf_page_list[i].virt_addr =

					    dma_alloc_coherent(dev->hw_dev,

							       PAGE_SIZE,

							       &async->

							       buf_page_list

							       [i].dma_addr,

							       GFP_KERNEL |

							       __GFP_COMP);

				} else {

					async->buf_page_list[i].virt_addr =

					    (void *)

					    get_zeroed_page(GFP_KERNEL);

				}

				if (async->buf_page_list[i].virt_addr == NULL)

					break;



				set_bit(PG_reserved,

					&(virt_to_page(async->buf_page_list[i].

							virt_addr)->flags));

				pages[i] = virt_to_page(async->buf_page_list[i].

								virt_addr);

			}

		}

		if (i == n_pages) {

			async->prealloc_buf =

#ifdef PAGE_KERNEL_NOCACHE

			    vmap(pages, n_pages, VM_MAP, PAGE_KERNEL_NOCACHE);

#else

			    vmap(pages, n_pages, VM_MAP, PAGE_KERNEL);

#endif

		}

		vfree(pages);

		__comedi_buf_alloc(dev, s, n_pages);



		if (!async->prealloc_buf) {

			/* Some allocation failed above */

			/* allocation failed */

			__comedi_buf_free(dev, s, n_pages);

			return -ENOMEM;

		}