Date: Sat, 29 Nov 2008 19:00:56 +0100 (CET) From: Stefan Richter Subject: firewire: reorder struct fw_card for better cache efficiency topology_map is by far the largest member in struct fw_card. Move it to the very end of the struct so that card pointer dereferences have better chances to hit the CPU cache. This requires to increase the topology_map backing store to the size specified in IEEE 1394, i.e. 256 rather than 255 quadlets. Otherwise the topology_map response handler may access invalid memory. Signed-off-by: Stefan Richter --- drivers/firewire/fw-transaction.h | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) Index: linux/drivers/firewire/fw-transaction.h =================================================================== --- linux.orig/drivers/firewire/fw-transaction.h +++ linux/drivers/firewire/fw-transaction.h @@ -237,13 +237,6 @@ struct fw_card { int link_speed; int config_rom_generation; - /* - * We need to store up to 4 self ID for a maximum of 63 - * devices plus 3 words for the topology map header. - */ - u32 topology_map[252 + 3]; - u32 broadcast_channel; - spinlock_t lock; /* Take this lock when handling the lists in * this struct. */ struct fw_node *local_node; @@ -261,6 +254,9 @@ struct fw_card { struct delayed_work work; int bm_retries; int bm_generation; + + u32 broadcast_channel; + u32 topology_map[(CSR_TOPOLOGY_MAP_END - CSR_TOPOLOGY_MAP) / 4]; }; static inline struct fw_card *fw_card_get(struct fw_card *card)