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

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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: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2013-01-09 13:26:26 -07:00 committed by Greg Kroah-Hartman
parent 718c4d68d9
commit 6bd7645731
1 changed files with 51 additions and 44 deletions
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95
drivers/staging/comedi/comedi_buf.c
View File

@ -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)
{
@ -74,55 +122,14 @@ int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
/* deallocate old buffer */
__comedi_buf_free(dev, s, async->n_buf_pages);
/* allocate new buffer */
/* 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;
}