scsi: qla2xxx: Remove in_interrupt() from qla83xx-specific code

qla83xx_wait_logic() is used to control the frequency of device IDC lock
retries. If in_interrupt() is true, it does 20 loops of cpu_relax().
Otherwise, it sleeps for 100ms and yields the CPU.

While in_interrupt() is ill-defined and does not provide what the name
suggests, it is not needed here: that qla83xx_wait_logic() is exclusively
called by qla83xx_idc_lock() / unlock(), and they always run from process
context. Below is an analysis of all the idc lock/unlock callers, in order
of appearance:

  - qla_os.c:
      qla83xx_nic_core_unrecoverable_work(),
      qla83xx_idc_state_handler_work(),
      qla83xx_nic_core_reset_work(),
      qla83xx_service_idc_aen(), all workqueue context

  - qla_os.c: qla83xx_check_nic_core_fw_alive(), has msleep()

  - qla_os.c: qla83xx_set_drv_presence(), called once from
    qla2x00_abort_isp(), which is bound to process-context ->abort_isp()
    hook. It also invokes wait_for_completion_timeout() through the chain
    qla2x00_configure_hba() => qla24xx_link_initialize() =>
    qla2x00_mailbox_command().

  - qla_os.c: qla83xx_clear_drv_presence(), which is called from
    qla2x00_abort_isp() discussed above, and from qla2x00_remove_one()
    which is PCI process-context ->remove() hook.

  - qla_os.c: qla83xx_need_reset_handler(), has a one second msleep() in
    a loop.

  - qla_os.c: qla83xx_device_bootstrap(), called only by
    qla83xx_idc_state_handler(), which has multiple msleep()
    invocations.

  - qla_os.c: qla83xx_idc_state_handler(), multiple msleep()
    invocations.

  - qla_attr.c: qla2x00_sysfs_write_reset(), sysfs bin_attribute
    ->write() hook, process context

  - qla_init.c: qla83xx_nic_core_fw_load()
      => qla_init.c: qla2x00_initialize_adapter()
        => bound to isp_operations ->initialize_adapter() hook
        ** => qla_os.c: qla2x00_probe_one(), PCI ->probe() process ctx

  - qla_init.c: qla83xx_initiating_reset(), msleep() in a loop.

  - qla_init.c: qla83xx_nic_core_reset(), called by
    qla83xx_nic_core_reset_work(), workqueue context.

Remove the in_interrupt() check, and thus replace the entirety of
qla83xx_wait_logic() with an msleep(QLA83XX_WAIT_LOGIC_MS).

Mark qla83xx_idc_lock() / unlock() with "Context: task, can sleep".

Link: https://lore.kernel.org/r/20201126132952.2287996-7-bigeasy@linutronix.de
Cc: Nilesh Javali <njavali@marvell.com>
Cc: GR-QLogic-Storage-Upstream@marvell.com
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qla2xxx/qla_os.c

@@ -5619,25 +5619,10 @@ qla83xx_service_idc_aen(struct work_struct *work)
 	}
 }
 
-static void
+/*
-qla83xx_wait_logic(void)
+ * Control the frequency of IDC lock retries
-{
+ */
-	int i;
+#define QLA83XX_WAIT_LOGIC_MS	100
-
-	/* Yield CPU */
-	if (!in_interrupt()) {
-		/*
-		 * Wait about 200ms before retrying again.
-		 * This controls the number of retries for single
-		 * lock operation.
-		 */
-		msleep(100);
-		schedule();
-	} else {
-		for (i = 0; i < 20; i++)
-			cpu_relax(); /* This a nop instr on i386 */
-	}
-}
 
 static int
 qla83xx_force_lock_recovery(scsi_qla_host_t *base_vha)
@@ -5727,7 +5712,7 @@ retry_lockid:
 		goto exit;
 
 	if (o_drv_lockid == n_drv_lockid) {
-		qla83xx_wait_logic();
+		msleep(QLA83XX_WAIT_LOGIC_MS);
 		goto retry_lockid;
 	} else
 		return QLA_SUCCESS;
@@ -5736,6 +5721,9 @@ exit:
 	return rval;
 }
 
+/*
+ * Context: task, can sleep
+ */
 void
 qla83xx_idc_lock(scsi_qla_host_t *base_vha, uint16_t requester_id)
 {
@@ -5743,6 +5731,8 @@ qla83xx_idc_lock(scsi_qla_host_t *base_vha, uint16_t requester_id)
 	uint32_t lock_owner;
 	struct qla_hw_data *ha = base_vha->hw;
 
+	might_sleep();
+
 	/* IDC-lock implementation using driver-lock/lock-id remote registers */
 retry_lock:
 	if (qla83xx_rd_reg(base_vha, QLA83XX_DRIVER_LOCK, &data)
@@ -5761,7 +5751,7 @@ retry_lock:
 			/* Retry/Perform IDC-Lock recovery */
 			if (qla83xx_idc_lock_recovery(base_vha)
 			    == QLA_SUCCESS) {
-				qla83xx_wait_logic();
+				msleep(QLA83XX_WAIT_LOGIC_MS);
 				goto retry_lock;
 			} else
 				ql_log(ql_log_warn, base_vha, 0xb075,
@@ -6259,6 +6249,9 @@ void qla24xx_process_purex_list(struct purex_list *list)
 	}
 }
 
+/*
+ * Context: task, can sleep
+ */
 void
 qla83xx_idc_unlock(scsi_qla_host_t *base_vha, uint16_t requester_id)
 {
@@ -6269,6 +6262,8 @@ qla83xx_idc_unlock(scsi_qla_host_t *base_vha, uint16_t requester_id)
 	uint32_t data;
 	struct qla_hw_data *ha = base_vha->hw;
 
+	might_sleep();
+
 	/* IDC-unlock implementation using driver-unlock/lock-id
 	 * remote registers
 	 */
@@ -6284,7 +6279,7 @@ retry_unlock:
 			/* SV: XXX: IDC unlock retrying needed here? */
 
 			/* Retry for IDC-unlock */
-			qla83xx_wait_logic();
+			msleep(QLA83XX_WAIT_LOGIC_MS);
 			retry++;
 			ql_dbg(ql_dbg_p3p, base_vha, 0xb064,
 			    "Failed to release IDC lock, retrying=%d\n", retry);
@@ -6292,7 +6287,7 @@ retry_unlock:
 		}
 	} else if (retry < 10) {
 		/* Retry for IDC-unlock */
-		qla83xx_wait_logic();
+		msleep(QLA83XX_WAIT_LOGIC_MS);
 		retry++;
 		ql_dbg(ql_dbg_p3p, base_vha, 0xb065,
 		    "Failed to read drv-lockid, retrying=%d\n", retry);
@@ -6308,7 +6303,7 @@ retry_unlock2:
 	if (qla83xx_access_control(base_vha, options, 0, 0, NULL)) {
 		if (retry < 10) {
 			/* Retry for IDC-unlock */
-			qla83xx_wait_logic();
+			msleep(QLA83XX_WAIT_LOGIC_MS);
 			retry++;
 			ql_dbg(ql_dbg_p3p, base_vha, 0xb066,
 			    "Failed to release IDC lock, retrying=%d\n", retry);