iwlwifi: pcie: avoid unnecessary work if NIC is disconnected

When the NIC is disconnected from PCI bus, we are not
able to access it anymore. Check the status to avoid
some unnecessary work so can improve the performance.
It will help to make PCI bus rescan to bring back the
device much faster.

The real test is able to improve 7 seconds.

[w/o patch] It takes around 9 seconds
..
2018-04-20T01:22:39.691929-07:00 WARNING kernel:
[   66.335881] Timeout waiting for hardware access (CSR_GP_CNTRL 0xffffffff)
..
2018-04-20T01:22:48.101094-07:00 INFO kernel:
[   74.747364] iwlwifi 0000:01:00.0: loaded firmware version 29.610311.0 op_mode iwlmvm

[w/a patch] It takes about 2 seconds.
..
2018-04-20T01:18:16.454087-07:00 WARNING kernel:
[   75.966860] Timeout waiting for hardware access (CSR_GP_CNTRL 0xffffffff)
..
2018-04-20T01:18:18.602717-07:00 INFO kernel:
[   78.116132] iwlwifi 0000:01:00.0: loaded firmware version 29.610311.0 op_mode iwlmvm
..

Fixes: 49564a806fc5 ("iwlwifi: pcie: remove non-responsive device")
Signed-off-by: Matt Chen <matt.chen@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
index 631f0015102b1e7b22993ab88f50fce3f1036a29..cf7d1acc8e7a64ebdcdf7306f8dff5be37a2a39e 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
@@ -2266,6 +2266,10 @@ static int iwl_trans_pcie_wait_txq_empty(struct iwl_trans *trans, int txq_idx)
        unsigned long now = jiffies;
        u8 wr_ptr;
 
+       /* Make sure the NIC is still alive in the bus */
+       if (trans_pcie->scheduled_for_removal)
+               return -EIO;
+
        if (!test_bit(txq_idx, trans_pcie->queue_used))
                return -EINVAL;
 

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/tx.c b/drivers/net/wireless/intel/iwlwifi/pcie/tx.c
index debff193016e88bcd9c95c2e6fcaa24b9f125930..d5aba9ebd84aaf7d84face36ac69b2f7d26d785b 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/pcie/tx.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/tx.c
@@ -1188,6 +1188,10 @@ static int iwl_pcie_set_cmd_in_flight(struct iwl_trans *trans,
 
        lockdep_assert_held(&trans_pcie->reg_lock);
 
+       /* Make sure the NIC is still alive in the bus */
+       if (trans_pcie->scheduled_for_removal)
+               return -EIO;
+
        if (!(cmd->flags & CMD_SEND_IN_IDLE) &&
            !trans_pcie->ref_cmd_in_flight) {
                trans_pcie->ref_cmd_in_flight = true;
@@ -1957,6 +1961,12 @@ cancel:
 
 int iwl_trans_pcie_send_hcmd(struct iwl_trans *trans, struct iwl_host_cmd *cmd)
 {
+       struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
+
+       /* Make sure the NIC is still alive in the bus */
+       if (trans_pcie->scheduled_for_removal)
+               return -EIO;
+
        if (!(cmd->flags & CMD_SEND_IN_RFKILL) &&
            test_bit(STATUS_RFKILL_OPMODE, &trans->status)) {
                IWL_DEBUG_RF_KILL(trans, "Dropping CMD 0x%x: RF KILL\n",