intel_th: Fix freeing IRQs

Commit aac8da6517 ("intel_th: msu: Start handling IRQs") implicitly
relies on the use of devm_request_irq() to subsequently free the irqs on
device removal, but in case of the pci_free_irq_vectors() API, the
handlers need to be freed before it is called. Therefore, at the moment
the driver's remove path trips a BUG_ON(irq_has_action()):

> kernel BUG at drivers/pci/msi.c:375!
> invalid opcode: 0000 1 SMP
> CPU: 2 PID: 818 Comm: rmmod Not tainted 5.5.0-rc1+ #1
> RIP: 0010:free_msi_irqs+0x67/0x1c0
> pci_disable_msi+0x116/0x150
> pci_free_irq_vectors+0x1b/0x20
> intel_th_pci_remove+0x22/0x30 [intel_th_pci]
> pci_device_remove+0x3e/0xb0
> device_release_driver_internal+0xf0/0x1c0
> driver_detach+0x4c/0x8f
> bus_remove_driver+0x5c/0xd0
> driver_unregister+0x31/0x50
> pci_unregister_driver+0x40/0x90
> intel_th_pci_driver_exit+0x10/0xad6 [intel_th_pci]
> __x64_sys_delete_module+0x147/0x290
> ? exit_to_usermode_loop+0xd7/0x120
> do_syscall_64+0x57/0x1b0
> entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix this by explicitly freeing irqs before freeing the vectors. We keep
using the devm_* variants because they are still useful in early error
paths.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Fixes: aac8da6517 ("intel_th: msu: Start handling IRQs")
Reported-by: Ammy Yi <ammy.yi@intel.com>
Tested-by: Ammy Yi <ammy.yi@intel.com>
Cc: stable@vger.kernel.org # v5.2+
Link: https://lore.kernel.org/r/20191217115527.74383-4-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/intel_th/core.c

@@ -834,9 +834,6 @@ static irqreturn_t intel_th_irq(int irq, void *data)
 			ret |= d->irq(th->thdev[i]);
 	}
 
-	if (ret == IRQ_NONE)
-		pr_warn_ratelimited("nobody cared for irq\n");
-
 	return ret;
 }
 
@@ -887,6 +884,7 @@ intel_th_alloc(struct device *dev, struct intel_th_drvdata *drvdata,
 
 			if (th->irq == -1)
 				th->irq = devres[r].start;
+			th->num_irqs++;
 			break;
 		default:
 			dev_warn(dev, "Unknown resource type %lx\n",
@@ -940,6 +938,9 @@ void intel_th_free(struct intel_th *th)
 
 	th->num_thdevs = 0;
 
+	for (i = 0; i < th->num_irqs; i++)
+		devm_free_irq(th->dev, th->irq + i, th);
+
 	pm_runtime_get_sync(th->dev);
 	pm_runtime_forbid(th->dev);
 

drivers/hwtracing/intel_th/intel_th.h

@@ -261,6 +261,7 @@ enum th_mmio_idx {
  * @num_thdevs:	number of devices in the @thdev array
  * @num_resources:	number of resources in the @resource array
  * @irq:	irq number
+ * @num_irqs:	number of IRQs is use
  * @id:		this Intel TH controller's device ID in the system
  * @major:	device node major for output devices
  */
@@ -277,6 +278,7 @@ struct intel_th {
 	unsigned int		num_thdevs;
 	unsigned int		num_resources;
 	int			irq;
+	int			num_irqs;
 
 	int			id;
 	int			major;