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staging: comedi: mite: tidy up mite_init_ring_descriptors() 

Use a local variable for the mite_dma_desc pointer to help clarify
this function.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2016-05-02 10:11:39 -07:00 committed by Greg Kroah-Hartman
parent b0af848ca3
commit 3303410d04
1 changed files with 10 additions and 12 deletions
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22
drivers/staging/comedi/drivers/mite.c
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@ -516,6 +516,7 @@ int mite_init_ring_descriptors(struct mite_ring *ring,
unsigned int nbytes)
{
struct comedi_async *async = s->async;
struct mite_dma_desc *desc = NULL;
unsigned int n_full_links = nbytes >> PAGE_SHIFT;
unsigned int remainder = nbytes % PAGE_SIZE;
int i;
@ -531,26 +532,23 @@ int mite_init_ring_descriptors(struct mite_ring *ring,
/* We set the descriptors for all full links. */
for (i = 0; i < n_full_links; ++i) {
ring->descs[i].count = cpu_to_le32(PAGE_SIZE);
ring->descs[i].addr =
cpu_to_le32(async->buf_map->page_list[i].dma_addr);
ring->descs[i].next =
cpu_to_le32(ring->dma_addr +
(i + 1) * sizeof(struct mite_dma_desc));
desc = &ring->descs[i];
desc->count = cpu_to_le32(PAGE_SIZE);
desc->addr = cpu_to_le32(async->buf_map->page_list[i].dma_addr);
desc->next = cpu_to_le32(ring->dma_addr +
(i + 1) * sizeof(*desc));
}
/* the last link is either a remainder or was a full link. */
if (remainder > 0) {
desc = &ring->descs[i];
/* set the lesser count for the remainder link */
ring->descs[i].count = cpu_to_le32(remainder);
ring->descs[i].addr =
cpu_to_le32(async->buf_map->page_list[i].dma_addr);
/* increment i so that assignment below refs last link */
++i;
desc->count = cpu_to_le32(remainder);
desc->addr = cpu_to_le32(async->buf_map->page_list[i].dma_addr);
}
/* Assign the last link->next to point back to the head of the list. */
ring->descs[i - 1].next = cpu_to_le32(ring->dma_addr);
desc->next = cpu_to_le32(ring->dma_addr);
/*
* barrier is meant to insure that all the writes to the dma descriptors