linux-kernel - [PATCH AUTOSEL for 4.15 064/102] iwlwifi: mvm: avoid dumping assert log when device is stopped

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Date:   Sat, 3 Mar 2018 22:24:46 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
CC:     Sara Sharon <sara.sharon@...el.com>,
        Luca Coelho <luciano.coelho@...el.com>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL for 4.15 064/102] iwlwifi: mvm: avoid dumping assert
 log when device is stopped

From: Sara Sharon <sara.sharon@...el.com>

[ Upstream commit 6362ab721ef5c4ecfa01f53ad4137d3d984f0c6c ]

We might erroneously get to error dumping code when the
device is already stopped.

In that case the driver will detect a defective value and will try to
reset the HW, assuming it is only a bus issue.  The driver than
proceeds with the dumping.

The result has two side effects:

1. The device won't be stopped again, since the transport status is
already stopped, so the device remains powered on while it actually
should be stopped.

2. The dump in that case is completely garbaged and useless.

Detect and avoid this.  It will also make debugging such issues
easier.

Signed-off-by: Sara Sharon <sara.sharon@...el.com>
Signed-off-by: Luca Coelho <luciano.coelho@...el.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 drivers/net/wireless/intel/iwlwifi/mvm/utils.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/utils.c b/drivers/net/wireless/intel/iwlwifi/mvm/utils.c
index 03ffd84786ca..50255944525e 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/utils.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/utils.c
@@ -595,6 +595,12 @@ static void iwl_mvm_dump_lmac_error_log(struct iwl_mvm *mvm, u32 base)
 
 void iwl_mvm_dump_nic_error_log(struct iwl_mvm *mvm)
 {
+	if (!test_bit(STATUS_DEVICE_ENABLED, &mvm->trans->status)) {
+		IWL_ERR(mvm,
+			"DEVICE_ENABLED bit is not set. Aborting dump.\n");
+		return;
+	}
+
 	iwl_mvm_dump_lmac_error_log(mvm, mvm->error_event_table[0]);
 
 	if (mvm->error_event_table[1])
-- 
2.14.1