firewire: core: optimize Topology Map creation

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>

diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index f58130789990a03da4643da4ead8e779d99169ee..7083bcc1b9c7c282fe1a56c7a7dba65e1ea9543e 100644 (file)
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -38,7 +38,7 @@
 
 #include "core.h"
 
-static int __compute_block_crc(__be32 *block)
+int fw_compute_block_crc(__be32 *block)
 {
        int length;
        u16 crc;
@@ -50,19 +50,6 @@ static int __compute_block_crc(__be32 *block)
        return length;
 }
 
-int fw_compute_block_crc(u32 *block)
-{
-       __be32 be32_block[256];
-       int i, length;
-
-       length = (*block >> 16) & 0xff;
-       for (i = 0; i < length; i++)
-               be32_block[i] = cpu_to_be32(block[i + 1]);
-       *block |= crc_itu_t(0, (u8 *) be32_block, length * 4);
-
-       return length;
-}
-
 static DEFINE_MUTEX(card_mutex);
 static LIST_HEAD(card_list);
 
@@ -141,7 +128,7 @@ static size_t generate_config_rom(struct fw_card *card, __be32 *config_rom)
         * the bus info block, which is always the case for this
         * implementation. */
        for (i = 0; i < j; i += length + 1)
-               length = __compute_block_crc(config_rom + i);
+               length = fw_compute_block_crc(config_rom + i);
 
        return j;
 }

diff --git a/drivers/firewire/core-topology.c b/drivers/firewire/core-topology.c
index fddf2b358936bd7b223a79bea5b4bd41147291d8..9a5f38c80b0e4cd5cd18991fb201b429a622c963 100644 (file)
--- a/drivers/firewire/core-topology.c
+++ b/drivers/firewire/core-topology.c
@@ -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);
 }
 

diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c
index da628c72a4621da3db2cdaf1cd564a555d5dde3f..203e6428bada373f1b649eec7cc4b8ff816136e7 100644 (file)
--- a/drivers/firewire/core-transaction.c
+++ b/drivers/firewire/core-transaction.c
@@ -810,8 +810,7 @@ static void handle_topology_map(struct fw_card *card, struct fw_request *request
                int speed, unsigned long long offset,
                void *payload, size_t length, void *callback_data)
 {
-       int i, start, end;
-       __be32 *map;
+       int start;
 
        if (!TCODE_IS_READ_REQUEST(tcode)) {
                fw_send_response(card, request, RCODE_TYPE_ERROR);
@@ -824,11 +823,7 @@ static void handle_topology_map(struct fw_card *card, struct fw_request *request
        }
 
        start = (offset - topology_map_region.start) / 4;
-       end = start + length / 4;
-       map = payload;
-
-       for (i = 0; i < length / 4; i++)
-               map[i] = cpu_to_be32(card->topology_map[start + i]);
+       memcpy(payload, &card->topology_map[start], length);
 
        fw_send_response(card, request, RCODE_COMPLETE);
 }

diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h
index 7adca7cb9f55056b4132e6100166ede3aba0fb7c..ed3b1a765c006887f9e338bb6c6457cb9c0f2f49 100644 (file)
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -94,7 +94,7 @@ int fw_card_add(struct fw_card *card,
                u32 max_receive, u32 link_speed, u64 guid);
 void fw_core_remove_card(struct fw_card *card);
 int fw_core_initiate_bus_reset(struct fw_card *card, int short_reset);
-int fw_compute_block_crc(u32 *block);
+int fw_compute_block_crc(__be32 *block);
 void fw_schedule_bm_work(struct fw_card *card, unsigned long delay);
 
 static inline struct fw_card *fw_card_get(struct fw_card *card)

diff --git a/include/linux/firewire.h b/include/linux/firewire.h
index 53b9217de86ce9741040bf32027f93e750c99c77..211a5d7d87b3e37cb2f07bd6f6d8edba2bb9066f 100644 (file)
--- a/include/linux/firewire.h
+++ b/include/linux/firewire.h
@@ -117,7 +117,7 @@ struct fw_card {
 
        bool broadcast_channel_allocated;
        u32 broadcast_channel;
-       u32 topology_map[(CSR_TOPOLOGY_MAP_END - CSR_TOPOLOGY_MAP) / 4];
+       __be32 topology_map[(CSR_TOPOLOGY_MAP_END - CSR_TOPOLOGY_MAP) / 4];
 };
 
 struct fw_attribute_group {