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wctc4xxp: Reduce the number of locks grabbed when sending commands

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Not only does this make it atomic when moving commands from the
waiting_for_response_list to the command_list if the descriptor is full, it will
also make the entire process of submitting a packet the packet transmission
logic atomic.

Signed-off-by: Shaun Ruffell <sruffell@digium.com>
Signed-off-by: Russ Meyerriecks <rmeyerriecks@digium.com>
This commit is contained in:
Shaun Ruffell
2014-05-09 09:40:24 -05:00
committed by Russ Meyerriecks
parent cbe4825d1a
commit 67e422c1ef
1 changed files with 6 additions and 34 deletions
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40
drivers/dahdi/wctc4xxp/base.c
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@@ -1548,41 +1548,11 @@ static void wctc4xxp_cleanup_command_list(struct wcdte *wc)
}
}
/**
* The command list is used to store commands that couldn't fit in the tx
* descriptor list when they were requested.
*/
static void
wctc4xxp_add_to_command_list(struct wcdte *wc, struct tcb *cmd)
{
unsigned long flags;
spin_lock_irqsave(&wc->cmd_list_lock, flags);
list_add_tail(&cmd->node, &wc->cmd_list);
spin_unlock_irqrestore(&wc->cmd_list_lock, flags);
}
static void
wctc4xxp_add_to_response_list(struct wcdte *wc, struct tcb *cmd)
{
unsigned long flags;
spin_lock_irqsave(&wc->cmd_list_lock, flags);
list_add_tail(&cmd->node, &wc->waiting_for_response_list);
spin_unlock_irqrestore(&wc->cmd_list_lock, flags);
}
static void
wctc4xxp_remove_from_response_list(struct wcdte *wc, struct tcb *cmd)
{
unsigned long flags;
spin_lock_irqsave(&wc->cmd_list_lock, flags);
list_del_init(&cmd->node);
spin_unlock_irqrestore(&wc->cmd_list_lock, flags);
}
static void
wctc4xxp_transmit_cmd(struct wcdte *wc, struct tcb *cmd)
{
int res;
unsigned long flags;
/* If we're shutdown all commands will timeout. Just complete the
* command here with the timeout flag */
@@ -1606,6 +1576,8 @@ wctc4xxp_transmit_cmd(struct wcdte *wc, struct tcb *cmd)
WARN_ON(cmd->response);
WARN_ON(cmd->flags & TX_COMPLETE);
cmd->timeout = jiffies + HZ/4;
spin_lock_irqsave(&wc->cmd_list_lock, flags);
if (cmd->flags & (WAIT_FOR_ACK | WAIT_FOR_RESPONSE)) {
if (cmd->flags & WAIT_FOR_RESPONSE) {
/* We don't need both an ACK and a response. Let's
@@ -1616,7 +1588,7 @@ wctc4xxp_transmit_cmd(struct wcdte *wc, struct tcb *cmd)
hdr->control |= SUPPRESS_ACK;
}
WARN_ON(!list_empty(&cmd->node));
wctc4xxp_add_to_response_list(wc, cmd);
list_add_tail(&cmd->node, &wc->waiting_for_response_list);
mod_timer(&wc->watchdog, jiffies + HZ/2);
}
res = wctc4xxp_submit(wc->txd, cmd);
@@ -1626,8 +1598,7 @@ wctc4xxp_transmit_cmd(struct wcdte *wc, struct tcb *cmd)
* and the interrupt service routine will pull from
* this list as it clears up room in the descriptor
* ring. */
wctc4xxp_remove_from_response_list(wc, cmd);
wctc4xxp_add_to_command_list(wc, cmd);
list_move_tail(&cmd->node, &wc->cmd_list);
} else if (0 == res) {
if (!(cmd->flags & DO_NOT_CAPTURE))
wctc4xxp_net_capture_cmd(wc, cmd);
@@ -1636,6 +1607,7 @@ wctc4xxp_transmit_cmd(struct wcdte *wc, struct tcb *cmd)
/* Unknown return value... */
WARN_ON(1);
}
spin_unlock_irqrestore(&wc->cmd_list_lock, flags);
}
static int