From 874020f8adce535cd318af1768ffe744251b6593 Mon Sep 17 00:00:00 2001
From: Johannes Berg <johannes.berg@intel.com>
Date: Wed, 10 Feb 2021 13:56:27 +0200
Subject: [PATCH] iwlwifi: pcie: don't disable interrupts for reg_lock
Git-commit: 874020f8adce535cd318af1768ffe744251b6593
Patch-mainline: v5.12-rc1
References: bsc#1187495

The only thing we do touching the device in hard interrupt context
is, at most, writing an interrupt ACK register, which isn't racing
in with anything protected by the reg_lock.

Thus, avoid disabling interrupts here for potentially long periods
of time, particularly long periods have been observed with dumping
of firmware memory (leading to lockup warnings on some devices.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20210210135352.da916ab91298.I064c3e7823b616647293ed97da98edefb9ce9435@changeid
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/net/wireless/intel/iwlwifi/pcie/trans.c   |   11 +++++------
 drivers/net/wireless/intel/iwlwifi/pcie/tx-gen2.c |    5 ++---
 drivers/net/wireless/intel/iwlwifi/pcie/tx.c      |   22 +++++++++-------------
 3 files changed, 16 insertions(+), 22 deletions(-)

--- a/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/trans.c
@@ -2026,7 +2026,7 @@ static bool iwl_trans_pcie_grab_nic_acce
 	int ret;
 	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
 
-	spin_lock_irqsave(&trans_pcie->reg_lock, *flags);
+	spin_lock_bh(&trans_pcie->reg_lock);
 
 	if (trans_pcie->cmd_hold_nic_awake)
 		goto out;
@@ -2111,7 +2111,7 @@ static bool iwl_trans_pcie_grab_nic_acce
 		}
 
 err:
-		spin_unlock_irqrestore(&trans_pcie->reg_lock, *flags);
+		spin_unlock_bh(&trans_pcie->reg_lock);
 		return false;
 	}
 
@@ -2149,7 +2149,7 @@ static void iwl_trans_pcie_release_nic_a
 	 * scheduled on different CPUs (after we drop reg_lock).
 	 */
 out:
-	spin_unlock_irqrestore(&trans_pcie->reg_lock, *flags);
+	spin_unlock_bh(&trans_pcie->reg_lock);
 }
 
 static int iwl_trans_pcie_read_mem(struct iwl_trans *trans, u32 addr,
@@ -2403,11 +2403,10 @@ static void iwl_trans_pcie_set_bits_mask
 					 u32 mask, u32 value)
 {
 	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
-	unsigned long flags;
 
-	spin_lock_irqsave(&trans_pcie->reg_lock, flags);
+	spin_lock_bh(&trans_pcie->reg_lock);
 	__iwl_trans_pcie_set_bits_mask(trans, reg, mask, value);
-	spin_unlock_irqrestore(&trans_pcie->reg_lock, flags);
+	spin_unlock_bh(&trans_pcie->reg_lock);
 }
 
 static const char *get_csr_string(int cmd)
--- a/drivers/net/wireless/intel/iwlwifi/pcie/tx-gen2.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/tx-gen2.c
@@ -78,7 +78,6 @@ static int iwl_pcie_gen2_enqueue_hcmd(st
 	struct iwl_txq *txq = trans->txqs.txq[trans->txqs.cmd.q_id];
 	struct iwl_device_cmd *out_cmd;
 	struct iwl_cmd_meta *out_meta;
-	unsigned long flags;
 	void *dup_buf = NULL;
 	dma_addr_t phys_addr;
 	int i, cmd_pos, idx;
@@ -291,11 +290,11 @@ static int iwl_pcie_gen2_enqueue_hcmd(st
 	if (txq->read_ptr == txq->write_ptr && txq->wd_timeout)
 		mod_timer(&txq->stuck_timer, jiffies + txq->wd_timeout);
 
-	spin_lock_irqsave(&trans_pcie->reg_lock, flags);
+	spin_lock(&trans_pcie->reg_lock);
 	/* Increment and update queue's write index */
 	txq->write_ptr = iwl_txq_inc_wrap(trans, txq->write_ptr);
 	iwl_txq_inc_wr_ptr(trans, txq);
-	spin_unlock_irqrestore(&trans_pcie->reg_lock, flags);
+	spin_unlock(&trans_pcie->reg_lock);
 
 out:
 	spin_unlock_bh(&txq->lock);
--- a/drivers/net/wireless/intel/iwlwifi/pcie/tx.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/tx.c
@@ -321,12 +321,10 @@ static void iwl_pcie_txq_unmap(struct iw
 		txq->read_ptr = iwl_txq_inc_wrap(trans, txq->read_ptr);
 
 		if (txq->read_ptr == txq->write_ptr) {
-			unsigned long flags;
-
-			spin_lock_irqsave(&trans_pcie->reg_lock, flags);
+			spin_lock(&trans_pcie->reg_lock);
 			if (txq_id == trans->txqs.cmd.q_id)
 				iwl_pcie_clear_cmd_in_flight(trans);
-			spin_unlock_irqrestore(&trans_pcie->reg_lock, flags);
+			spin_unlock(&trans_pcie->reg_lock);
 		}
 	}
 
@@ -931,7 +929,6 @@ static void iwl_pcie_cmdq_reclaim(struct
 {
 	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
 	struct iwl_txq *txq = trans->txqs.txq[txq_id];
-	unsigned long flags;
 	int nfreed = 0;
 	u16 r;
 
@@ -962,9 +959,10 @@ static void iwl_pcie_cmdq_reclaim(struct
 	}
 
 	if (txq->read_ptr == txq->write_ptr) {
-		spin_lock_irqsave(&trans_pcie->reg_lock, flags);
+		/* BHs are also disabled due to txq->lock */
+		spin_lock(&trans_pcie->reg_lock);
 		iwl_pcie_clear_cmd_in_flight(trans);
-		spin_unlock_irqrestore(&trans_pcie->reg_lock, flags);
+		spin_unlock(&trans_pcie->reg_lock);
 	}
 
 	iwl_pcie_txq_progress(txq);
@@ -1173,7 +1171,6 @@ static int iwl_pcie_enqueue_hcmd(struct
 	struct iwl_txq *txq = trans->txqs.txq[trans->txqs.cmd.q_id];
 	struct iwl_device_cmd *out_cmd;
 	struct iwl_cmd_meta *out_meta;
-	unsigned long flags;
 	void *dup_buf = NULL;
 	dma_addr_t phys_addr;
 	int idx;
@@ -1416,20 +1413,19 @@ static int iwl_pcie_enqueue_hcmd(struct
 	if (txq->read_ptr == txq->write_ptr && txq->wd_timeout)
 		mod_timer(&txq->stuck_timer, jiffies + txq->wd_timeout);
 
-	spin_lock_irqsave(&trans_pcie->reg_lock, flags);
+	spin_lock(&trans_pcie->reg_lock);
 	ret = iwl_pcie_set_cmd_in_flight(trans, cmd);
 	if (ret < 0) {
 		idx = ret;
-		spin_unlock_irqrestore(&trans_pcie->reg_lock, flags);
-		goto out;
+		goto unlock_reg;
 	}
 
 	/* Increment and update queue's write index */
 	txq->write_ptr = iwl_txq_inc_wrap(trans, txq->write_ptr);
 	iwl_pcie_txq_inc_wr_ptr(trans, txq);
 
-	spin_unlock_irqrestore(&trans_pcie->reg_lock, flags);
-
+ unlock_reg:
+	spin_unlock(&trans_pcie->reg_lock);
  out:
 	spin_unlock_bh(&txq->lock);
  free_dup_buf: