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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Emmanuel Grumbach <emmanuel.grumbach@intel.com>,
        Luca Coelho <luciano.coelho@intel.com>
Subject: [PATCH 4.9 086/223] iwlwifi: pcie: dont service an interrupt that was masked
Date:   Fri,  2 Aug 2019 11:35:11 +0200
Message-Id: <20190802092244.613286921@linuxfoundation.org>
In-Reply-To: <20190802092238.692035242@linuxfoundation.org>
References: <20190802092238.692035242@linuxfoundation.org>
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From: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

commit 3b57a10ca14c619707398dc58fe5ece18c95b20b upstream.

Sometimes the register status can include interrupts that
were masked. We can, for example, get the RF-Kill bit set
in the interrupt status register although this interrupt
was masked. Then if we get the ALIVE interrupt (for example)
that was not masked, we need to *not* service the RF-Kill
interrupt.
Fix this in the MSI-X interrupt handler.

Cc: stable@vger.kernel.org
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/wireless/intel/iwlwifi/pcie/rx.c |   27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

--- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
@@ -1901,10 +1901,18 @@ irqreturn_t iwl_pcie_irq_msix_handler(in
 		return IRQ_NONE;
 	}
 
-	if (iwl_have_debug_level(IWL_DL_ISR))
-		IWL_DEBUG_ISR(trans, "ISR inta_fh 0x%08x, enabled 0x%08x\n",
-			      inta_fh,
+	if (iwl_have_debug_level(IWL_DL_ISR)) {
+		IWL_DEBUG_ISR(trans,
+			      "ISR inta_fh 0x%08x, enabled (sw) 0x%08x (hw) 0x%08x\n",
+			      inta_fh, trans_pcie->fh_mask,
 			      iwl_read32(trans, CSR_MSIX_FH_INT_MASK_AD));
+		if (inta_fh & ~trans_pcie->fh_mask)
+			IWL_DEBUG_ISR(trans,
+				      "We got a masked interrupt (0x%08x)\n",
+				      inta_fh & ~trans_pcie->fh_mask);
+	}
+
+	inta_fh &= trans_pcie->fh_mask;
 
 	if ((trans_pcie->shared_vec_mask & IWL_SHARED_IRQ_NON_RX) &&
 	    inta_fh & MSIX_FH_INT_CAUSES_Q0) {
@@ -1943,11 +1951,18 @@ irqreturn_t iwl_pcie_irq_msix_handler(in
 	}
 
 	/* After checking FH register check HW register */
-	if (iwl_have_debug_level(IWL_DL_ISR))
+	if (iwl_have_debug_level(IWL_DL_ISR)) {
 		IWL_DEBUG_ISR(trans,
-			      "ISR inta_hw 0x%08x, enabled 0x%08x\n",
-			      inta_hw,
+			      "ISR inta_hw 0x%08x, enabled (sw) 0x%08x (hw) 0x%08x\n",
+			      inta_hw, trans_pcie->hw_mask,
 			      iwl_read32(trans, CSR_MSIX_HW_INT_MASK_AD));
+		if (inta_hw & ~trans_pcie->hw_mask)
+			IWL_DEBUG_ISR(trans,
+				      "We got a masked interrupt 0x%08x\n",
+				      inta_hw & ~trans_pcie->hw_mask);
+	}
+
+	inta_hw &= trans_pcie->hw_mask;
 
 	/* Alive notification via Rx interrupt will do the real work */
 	if (inta_hw & MSIX_HW_INT_CAUSES_REG_ALIVE) {