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Commit dd447319 authored by Stanislav Yakovlev's avatar Stanislav Yakovlev Committed by John W. Linville
Browse files

ipw2200: Fix race condition in the command completion acknowledge 

Driver incorrectly validates command completion: instead of waiting
for a command to be acknowledged it continues execution.  Most of the
time driver gets acknowledge of the command completion in a tasklet
before it executes the next one. But sometimes it sends the next
command before it gets acknowledge for the previous one. In such a
case one of the following error messages appear in the log:

Failed to send SYSTEM_CONFIG: Already sending a command.
Failed to send ASSOCIATE: Already sending a command.
Failed to send TX_POWER: Already sending a command.

After that you need to reload the driver to get it working again.

This bug occurs during roaming (reported by Sam Varshavchik)
https://bugzilla.redhat.com/show_bug.cgi?id=738508
and machine booting (reported by Tom Gundersen and Mads Kiilerich)
https://bugs.archlinux.org/task/28097
https://bugzilla.redhat.com/show_bug.cgi?id=802106



This patch doesn't fix the delay issue during firmware load.
But at least device now works as usual after boot.

Cc: stable@kernel.org
Signed-off-by: default avatarStanislav Yakovlev <stas.yakovlev@gmail.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 8db4c7e2

drivers/net/wireless/ipw2x00/ipw2200.c

+12 −1
Original line number Diff line number Diff line
@@ -2191,6 +2191,7 @@ static int __ipw_send_cmd(struct ipw_priv *priv, struct host_cmd *cmd) 
{

	int rc = 0;

	unsigned long flags;

	unsigned long now, end;



	spin_lock_irqsave(&priv->lock, flags);

	if (priv->status & STATUS_HCMD_ACTIVE) {
@@ -2232,10 +2233,20 @@ static int __ipw_send_cmd(struct ipw_priv *priv, struct host_cmd *cmd) 
	}

	spin_unlock_irqrestore(&priv->lock, flags);



	now = jiffies;

	end = now + HOST_COMPLETE_TIMEOUT;

again:

	rc = wait_event_interruptible_timeout(priv->wait_command_queue,

					      !(priv->

						status & STATUS_HCMD_ACTIVE),

					      HOST_COMPLETE_TIMEOUT);

					      end - now);

	if (rc < 0) {

		now = jiffies;

		if (time_before(now, end))

			goto again;

		rc = 0;

	}



	if (rc == 0) {

		spin_lock_irqsave(&priv->lock, flags);

		if (priv->status & STATUS_HCMD_ACTIVE) {