52 lines
1.8 KiB
Diff
52 lines
1.8 KiB
Diff
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From b49ba04a3a0382e7314d990707c21094c410425a Mon Sep 17 00:00:00 2001
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From: Johannes Berg <johannes.berg@intel.com>
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Date: Thu, 19 Jan 2012 08:20:57 -0800
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Subject: [PATCH 8/8] iwlwifi: fix PCI-E transport "inta" race
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When an interrupt comes in, we read the reason
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bits and collect them into "trans_pcie->inta".
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This happens with the spinlock held. However,
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there's a bug resetting this variable -- that
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happens after the spinlock has been released.
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This means that it is possible for interrupts
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to be missed if the reset happens after some
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other interrupt reasons were already added to
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the variable.
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I found this by code inspection, looking for a
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reason that we sometimes see random commands
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time out. It seems possible that this causes
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such behaviour, but I can't say for sure right
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now since it happens extremely infrequently on
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my test systems.
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Cc: stable@vger.kernel.org [3.2]
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Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>
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Signed-off-by: John W. Linville <linville@tuxdriver.com>
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---
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drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c | 4 ++--
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1 files changed, 2 insertions(+), 2 deletions(-)
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diff --git a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
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index 752493f..65d1f05 100644
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--- a/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
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+++ b/drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c
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@@ -972,11 +972,11 @@ void iwl_irq_tasklet(struct iwl_trans *trans)
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}
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#endif
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- spin_unlock_irqrestore(&trans->shrd->lock, flags);
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-
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/* saved interrupt in inta variable now we can reset trans_pcie->inta */
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trans_pcie->inta = 0;
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+ spin_unlock_irqrestore(&trans->shrd->lock, flags);
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+
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/* Now service all interrupt bits discovered above. */
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if (inta & CSR_INT_BIT_HW_ERR) {
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IWL_ERR(trans, "Hardware error detected. Restarting.\n");
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--
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1.7.4.4
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