2011-05-26 20:31:13

by Daniel Drake

Subject: [PATCH] libertas: Set command sequence number later to ensure consistency

Before this patch, the command sequence number is being set before
lbs_queue_cmd() adds the command to the queue. However, lbs_queue_cmd()
sometimes forces commands to queue-jump (e.g. CMD_802_11_WAKEUP_CONFIRM).
It currently does this without considering that sequence numbers might need
adjusting to keep things running in order.

Fix this by setting the sequence number at a later stage, just before
we're actually submitting the command to the hardware. Also fixes a
possible race where seqnum was being modified outside of the driver
lock.

Signed-off-by: Daniel Drake <[email protected]>
---
drivers/net/wireless/libertas/cmd.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/libertas/cmd.c b/drivers/net/wireless/libertas/cmd.c
index 84566db..71c8f3f 100644
--- a/drivers/net/wireless/libertas/cmd.c
+++ b/drivers/net/wireless/libertas/cmd.c
@@ -994,6 +994,8 @@ static void lbs_submit_command(struct lbs_private *priv,
cmd = cmdnode->cmdbuf;

spin_lock_irqsave(&priv->driver_lock, flags);
+ priv->seqnum++;
+ cmd->seqnum = cpu_to_le16(priv->seqnum);
priv->cur_cmd = cmdnode;
spin_unlock_irqrestore(&priv->driver_lock, flags);

@@ -1621,11 +1623,9 @@ struct cmd_ctrl_node *__lbs_cmd_async(struct lbs_private *priv,
/* Copy the incoming command to the buffer */
memcpy(cmdnode->cmdbuf, in_cmd, in_cmd_size);

- /* Set sequence number, clean result, move to buffer */
- priv->seqnum++;
+ /* Set command, clean result, move to buffer */
cmdnode->cmdbuf->command = cpu_to_le16(command);
cmdnode->cmdbuf->size = cpu_to_le16(in_cmd_size);
- cmdnode->cmdbuf->seqnum = cpu_to_le16(priv->seqnum);
cmdnode->cmdbuf->result = 0;

lbs_deb_host("PREP_CMD: command 0x%04x\n", command);
--
1.7.5.1

2011-05-27 14:52:06

by Dan Williams

Subject: Re: [PATCH] libertas: Set command sequence number later to ensure consistency

On Thu, 2011-05-26 at 21:31 +0100, Daniel Drake wrote:
> Before this patch, the command sequence number is being set before
> lbs_queue_cmd() adds the command to the queue. However, lbs_queue_cmd()
> sometimes forces commands to queue-jump (e.g. CMD_802_11_WAKEUP_CONFIRM).
> It currently does this without considering that sequence numbers might need
> adjusting to keep things running in order.
>
> Fix this by setting the sequence number at a later stage, just before
> we're actually submitting the command to the hardware. Also fixes a
> possible race where seqnum was being modified outside of the driver
> lock.
>
> Signed-off-by: Daniel Drake <[email protected]>

Acked-by: Dan Williams <[email protected]>

> ---
> drivers/net/wireless/libertas/cmd.c | 6 +++---
> 1 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/wireless/libertas/cmd.c b/drivers/net/wireless/libertas/cmd.c
> index 84566db..71c8f3f 100644
> --- a/drivers/net/wireless/libertas/cmd.c
> +++ b/drivers/net/wireless/libertas/cmd.c
> @@ -994,6 +994,8 @@ static void lbs_submit_command(struct lbs_private *priv,
> cmd = cmdnode->cmdbuf;
>
> spin_lock_irqsave(&priv->driver_lock, flags);
> + priv->seqnum++;
> + cmd->seqnum = cpu_to_le16(priv->seqnum);
> priv->cur_cmd = cmdnode;
> spin_unlock_irqrestore(&priv->driver_lock, flags);
>
> @@ -1621,11 +1623,9 @@ struct cmd_ctrl_node *__lbs_cmd_async(struct lbs_private *priv,
> /* Copy the incoming command to the buffer */
> memcpy(cmdnode->cmdbuf, in_cmd, in_cmd_size);
>
> - /* Set sequence number, clean result, move to buffer */
> - priv->seqnum++;
> + /* Set command, clean result, move to buffer */
> cmdnode->cmdbuf->command = cpu_to_le16(command);
> cmdnode->cmdbuf->size = cpu_to_le16(in_cmd_size);
> - cmdnode->cmdbuf->seqnum = cpu_to_le16(priv->seqnum);
> cmdnode->cmdbuf->result = 0;
>
> lbs_deb_host("PREP_CMD: command 0x%04x\n", command);