commit: b49ba04a3a0382e7314d990707c21094c410425a From: Johannes Berg <[email protected]> Date: Thu, 19 Jan 2012 08:20:57 -0800 Subject: iwlwifi: fix PCI-E transport "inta" race
When an interrupt comes in, we read the reason bits and collect them into "trans_pcie->inta". This happens with the spinlock held. However, there's a bug resetting this variable -- that happens after the spinlock has been released. This means that it is possible for interrupts to be missed if the reset happens after some other interrupt reasons were already added to the variable. I found this by code inspection, looking for a reason that we sometimes see random commands time out. It seems possible that this causes such behaviour, but I can't say for sure right now since it happens extremely infrequently on my test systems. Cc: [email protected] [3.2] Signed-off-by: Johannes Berg <[email protected]> Signed-off-by: Wey-Yi Guy <[email protected]> Signed-off-by: John W. Linville <[email protected]> --- drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c index 752493f..65d1f05 100644 --- a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c +++ b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c @@ -972,11 +972,11 @@ void iwl_irq_tasklet(struct iwl_trans *trans) } #endif - spin_unlock_irqrestore(&trans->shrd->lock, flags); - /* saved interrupt in inta variable now we can reset trans_pcie->inta */ trans_pcie->inta = 0; + spin_unlock_irqrestore(&trans->shrd->lock, flags); + /* Now service all interrupt bits discovered above. */ if (inta & CSR_INT_BIT_HW_ERR) { IWL_ERR(trans, "Hardware error detected. Restarting.\n"); -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
