[PATCH 4.9 086/223] iwlwifi: pcie: dont service an interrupt that was masked

Greg Kroah-Hartman
2019-08-02T09:44:37Z

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) {