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| author | Stanislav Yakovlev <stas.yakovlev@gmail.com> | 2012-04-19 15:55:09 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-05-07 08:56:40 -0700 |
| commit | b00c5b8d8590a0fe2713a4bee24e9562480ccb9e (patch) | |
| tree | 18b0ccebf6db040babda8beebedcfb719d20e17a | |
| parent | b476e58a834f099aa0f7b4d0a71853e6c61ee6d8 (diff) | |
| download | lwn-b00c5b8d8590a0fe2713a4bee24e9562480ccb9e.tar.gz lwn-b00c5b8d8590a0fe2713a4bee24e9562480ccb9e.zip | |
ipw2200: Fix race condition in the command completion acknowledge
commit dd447319895d0c0af423e483d9b63f84f3f8869a upstream.
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.
Signed-off-by: Stanislav Yakovlev <stas.yakovlev@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/net/wireless/ipw2x00/ipw2200.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/net/wireless/ipw2x00/ipw2200.c b/drivers/net/wireless/ipw2x00/ipw2200.c index 87813c33bdc2..b2707d733e92 100644 --- a/drivers/net/wireless/ipw2x00/ipw2200.c +++ b/drivers/net/wireless/ipw2x00/ipw2200.c @@ -2182,6 +2182,7 @@ 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) { @@ -2223,10 +2224,20 @@ 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) { |