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authorNicholas Bellinger <nab@linux-iscsi.org>2013-06-06 01:35:18 -0700
committerNicholas Bellinger <nab@linux-iscsi.org>2013-06-20 14:10:39 -0700
commit862e6389a78992d4ee44bf4f60051fe560470320 (patch)
tree0b0cceedf17564748ca12e5b25d37ff1f9ac050f
parent670caa9f762647802a1b19749f127ac28949ca5a (diff)
target: Add transport_cmd_check_stop write_pending bit
This patch adds a new transport_cmd_check_stop() parameter for signaling when TRANSPORT_WRITE_PENDING needs to be set. This allows transport_generic_new_cmd() to avoid the extra lock acquire/release of ->t_state_lock in the fast path for DMA_TO_DEVICE operations ahead of transport_cmd_check_stop() + se_tfo->write_pending(). Cc: Christoph Hellwig <hch@lst.de> Cc: Roland Dreier <roland@kernel.org> Cc: Kent Overstreet <koverstreet@google.com> Cc: Or Gerlitz <ogerlitz@mellanox.com> Cc: Moussa Ba <moussaba@micron.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
-rw-r--r--drivers/target/target_core_transport.c19
1 files changed, 9 insertions, 10 deletions
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 21e315874a5..39319efe50c 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -446,11 +446,15 @@ static void target_remove_from_state_list(struct se_cmd *cmd)
spin_unlock_irqrestore(&dev->execute_task_lock, flags);
}
-static int transport_cmd_check_stop(struct se_cmd *cmd, bool remove_from_lists)
+static int transport_cmd_check_stop(struct se_cmd *cmd, bool remove_from_lists,
+ bool write_pending)
{
unsigned long flags;
spin_lock_irqsave(&cmd->t_state_lock, flags);
+ if (write_pending)
+ cmd->t_state = TRANSPORT_WRITE_PENDING;
+
/*
* Determine if IOCTL context caller in requesting the stopping of this
* command for LUN shutdown purposes.
@@ -515,7 +519,7 @@ static int transport_cmd_check_stop(struct se_cmd *cmd, bool remove_from_lists)
static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
{
- return transport_cmd_check_stop(cmd, true);
+ return transport_cmd_check_stop(cmd, true, false);
}
static void transport_lun_remove_cmd(struct se_cmd *cmd)
@@ -2116,12 +2120,7 @@ transport_generic_new_cmd(struct se_cmd *cmd)
target_execute_cmd(cmd);
return 0;
}
-
- spin_lock_irq(&cmd->t_state_lock);
- cmd->t_state = TRANSPORT_WRITE_PENDING;
- spin_unlock_irq(&cmd->t_state_lock);
-
- transport_cmd_check_stop(cmd, false);
+ transport_cmd_check_stop(cmd, false, true);
ret = cmd->se_tfo->write_pending(cmd);
if (ret == -EAGAIN || ret == -ENOMEM)
@@ -2319,7 +2318,7 @@ static int transport_lun_wait_for_tasks(struct se_cmd *cmd, struct se_lun *lun)
pr_debug("ConfigFS ITT[0x%08x] - CMD_T_STOP, skipping\n",
cmd->se_tfo->get_task_tag(cmd));
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
- transport_cmd_check_stop(cmd, false);
+ transport_cmd_check_stop(cmd, false, false);
return -EPERM;
}
cmd->transport_state |= CMD_T_LUN_FE_STOP;
@@ -2427,7 +2426,7 @@ check_cond:
spin_unlock_irqrestore(&cmd->t_state_lock,
cmd_flags);
- transport_cmd_check_stop(cmd, false);
+ transport_cmd_check_stop(cmd, false, false);
complete(&cmd->transport_lun_fe_stop_comp);
spin_lock_irqsave(&lun->lun_cmd_lock, lun_flags);
continue;