From 621f6dd715209d3c3c27841943ae71fc2c75c9f5 Mon Sep 17 00:00:00 2001 From: Stefan Richter Date: Sun, 26 Oct 2008 11:04:20 +0100 Subject: [PATCH] firewire: fw-sbp2: remove unnecessary locking What was I thinking when I added sbp2_set_generation()? Its locking did nothing (except for implicitly providing the necessary barrier between node IDs update and generation update). Signed-off-by: Stefan Richter --- drivers/firewire/fw-sbp2.c | 21 ++++++--------------- 1 file changed, 6 insertions(+), 15 deletions(-) diff --git a/drivers/firewire/fw-sbp2.c b/drivers/firewire/fw-sbp2.c index e54403ee59e7..e88d5067448c 100644 --- a/drivers/firewire/fw-sbp2.c +++ b/drivers/firewire/fw-sbp2.c @@ -670,17 +670,6 @@ static void sbp2_agent_reset_no_wait(struct sbp2_logical_unit *lu) &d, sizeof(d), complete_agent_reset_write_no_wait, t); } -static void sbp2_set_generation(struct sbp2_logical_unit *lu, int generation) -{ - struct fw_card *card = fw_device(lu->tgt->unit->device.parent)->card; - unsigned long flags; - - /* serialize with comparisons of lu->generation and card->generation */ - spin_lock_irqsave(&card->lock, flags); - lu->generation = generation; - spin_unlock_irqrestore(&card->lock, flags); -} - static inline void sbp2_allow_block(struct sbp2_logical_unit *lu) { /* @@ -884,7 +873,7 @@ static void sbp2_login(struct work_struct *work) goto out; generation = device->generation; - smp_rmb(); /* node_id must not be older than generation */ + smp_rmb(); /* node IDs must not be older than generation */ node_id = device->node_id; local_node_id = device->card->node_id; @@ -908,7 +897,8 @@ static void sbp2_login(struct work_struct *work) tgt->node_id = node_id; tgt->address_high = local_node_id << 16; - sbp2_set_generation(lu, generation); + smp_wmb(); /* node IDs must not be older than generation */ + lu->generation = generation; lu->command_block_agent_address = ((u64)(be32_to_cpu(response.command_block_agent.high) & 0xffff) @@ -1201,7 +1191,7 @@ static void sbp2_reconnect(struct work_struct *work) goto out; generation = device->generation; - smp_rmb(); /* node_id must not be older than generation */ + smp_rmb(); /* node IDs must not be older than generation */ node_id = device->node_id; local_node_id = device->card->node_id; @@ -1228,7 +1218,8 @@ static void sbp2_reconnect(struct work_struct *work) tgt->node_id = node_id; tgt->address_high = local_node_id << 16; - sbp2_set_generation(lu, generation); + smp_wmb(); /* node IDs must not be older than generation */ + lu->generation = generation; fw_notify("%s: reconnected to LUN %04x (%d retries)\n", tgt->bus_id, lu->lun, lu->retries);