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staging: et131x: Avoid unnecessary calculations in for loop
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In et131x_rx_dma_memory_alloc(), we loop over fbr_entries - the values of
fbr_align and fbr_chunksize calculated in the loop do not depend on the
loop counter and are the same for all loop iterations.

Take the calculations of these values out of the loop, as we only
need to calculate them once per loop, not once per loop iteration.

Signed-off-by: Mark Einon <mark.einon@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Mark Einon authored and Greg Kroah-Hartman committed Nov 13, 2012
1 parent 9d10b22 commit 8764893
Showing 1 changed file with 11 additions and 9 deletions.
20 changes: 11 additions & 9 deletions drivers/staging/et131x/et131x.c
Original file line number Diff line number Diff line change
Expand Up @@ -2266,7 +2266,9 @@ static int et131x_rx_dma_memory_alloc(struct et131x_adapter *adapter)
u8 id;
u32 i, j;
u32 bufsize;
u32 pktstat_ringsize, fbr_chunksize;
u32 pktstat_ringsize;
u32 fbr_chunksize;
u32 fbr_align;
struct rx_ring *rx_ring;

/* Setup some convenience pointers */
Expand Down Expand Up @@ -2341,10 +2343,17 @@ static int et131x_rx_dma_memory_alloc(struct et131x_adapter *adapter)
}

for (id = 0; id < NUM_FBRS; id++) {
if (id == 0 && rx_ring->fbr[id]->buffsize > 4096)
fbr_align = 4096;
else
fbr_align = rx_ring->fbr[id]->buffsize;

fbr_chunksize = (FBR_CHUNKS *
rx_ring->fbr[id]->buffsize) + fbr_align - 1;

for (i = 0; i < (rx_ring->fbr[id]->num_entries / FBR_CHUNKS); i++) {
dma_addr_t fbr_tmp_physaddr;
dma_addr_t fbr_offset;
u32 fbr_align;

/* This code allocates an area of memory big enough for
* N free buffers + (buffer_size - 1) so that the
Expand All @@ -2353,13 +2362,6 @@ static int et131x_rx_dma_memory_alloc(struct et131x_adapter *adapter)
* effect would be to double the size of FBR0. By
* allocating N buffers at once, we reduce this overhead
*/
if (id == 0 && rx_ring->fbr[id]->buffsize > 4096)
fbr_align = 4096;
else
fbr_align = rx_ring->fbr[id]->buffsize;

fbr_chunksize = (FBR_CHUNKS *
rx_ring->fbr[id]->buffsize) + fbr_align - 1;
rx_ring->fbr[id]->mem_virtaddrs[i] = dma_alloc_coherent(
&adapter->pdev->dev, fbr_chunksize,
&rx_ring->fbr[id]->mem_physaddrs[i],
Expand Down

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