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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: Stanislav Yakovlev <stas.yakovlev@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Stanislav Yakovlev 2012-04-19 15:55:09 -04:00 committed by John W. Linville
parent 8db4c7e25d
commit dd44731989
1 changed files with 12 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/net/wireless/ipw2x00/ipw2200.c
View File

@ -2191,6 +2191,7 @@ static int __ipw_send_cmd(struct ipw_priv *priv, struct host_cmd *cmd)
{ {
int rc = 0; int rc = 0;
unsigned long flags; unsigned long flags;
unsigned long now, end;
spin_lock_irqsave(&priv->lock, flags); spin_lock_irqsave(&priv->lock, flags);
if (priv->status & STATUS_HCMD_ACTIVE) { 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); spin_unlock_irqrestore(&priv->lock, flags);
now = jiffies;
end = now + HOST_COMPLETE_TIMEOUT;
again:
rc = wait_event_interruptible_timeout(priv->wait_command_queue, rc = wait_event_interruptible_timeout(priv->wait_command_queue,
!(priv-> !(priv->
status & STATUS_HCMD_ACTIVE), 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) { if (rc == 0) {
spin_lock_irqsave(&priv->lock, flags); spin_lock_irqsave(&priv->lock, flags);
if (priv->status & STATUS_HCMD_ACTIVE) { if (priv->status & STATUS_HCMD_ACTIVE) {