From c8a12d45d543905a2718fccafd612edbd73a1341 Mon Sep 17 00:00:00 2001
From: Stefan Richter <stefanr@s5r6.in-berlin.de>
Date: Sat, 29 Nov 2008 19:00:56 +0100
Subject: [PATCH] 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 <stefanr@s5r6.in-berlin.de>
---
drivers/firewire/fw-transaction.h | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/drivers/firewire/fw-transaction.h b/drivers/firewire/fw-transaction.h
index 5a57bb897e23..c9ab12a15f6e 100644
--- a/drivers/firewire/fw-transaction.h
+++ b/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)
--
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