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firewire: core: optimize Topology Map creation

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The Topology Map of the local node was created in CPU byte order,
then a temporary big endian copy was created to compute the CRC,
and when a read request to the Topology Map arrived it had to be
converted to big endian byte order again.

We now generate it in big endian byte order in the first place.
This also rids us of 1000 bytes stack usage in tasklet context.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
This commit is contained in:
Stefan Richter
2009-10-08 00:42:53 +02:00
parent fe242579e9
commit cb7c96da36
5 changed files with 16 additions and 31 deletions
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17
drivers/firewire/core-topology.c
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@@ -28,9 +28,9 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <asm/atomic.h>
#include <asm/byteorder.h>
#include <asm/system.h>
#include "core.h"
@@ -510,13 +510,16 @@ static void update_tree(struct fw_card *card, struct fw_node *root)
static void update_topology_map(struct fw_card *card,
u32 *self_ids, int self_id_count)
{
int node_count;
int node_count = (card->root_node->node_id & 0x3f) + 1;
__be32 *map = card->topology_map;
*map++ = cpu_to_be32((self_id_count + 2) << 16);
*map++ = cpu_to_be32(be32_to_cpu(card->topology_map[1]) + 1);
*map++ = cpu_to_be32((node_count << 16) | self_id_count);
while (self_id_count--)
*map++ = cpu_to_be32p(self_ids++);
card->topology_map[1]++;
node_count = (card->root_node->node_id & 0x3f) + 1;
card->topology_map[2] = (node_count << 16) | self_id_count;
card->topology_map[0] = (self_id_count + 2) << 16;
memcpy(&card->topology_map[3], self_ids, self_id_count * 4);
fw_compute_block_crc(card->topology_map);
}