genirq: Remove the deprecated 'IRQF_DISABLED' request_irq() flag entirely

The IRQF_DISABLED flag is a NOOP and has been scheduled for removal
since Linux v2.6.36 by commit 6932bf37bed4 ("genirq: Remove
IRQF_DISABLED from core code").

According to commit e58aa3d2d0cc ("genirq: Run irq handlers with
interrupts disabled"), running IRQ handlers with interrupts
enabled can cause stack overflows when the interrupt line of the
issuing device is still active.

This patch ends the grace period for IRQF_DISABLED (i.e.,
SA_INTERRUPT in older versions of Linux) and removes the
definition and all remaining usages of this flag.

There's still a few non-functional references left in the kernel
source:

- The bigger hunk in Documentation/scsi/ncr53c8xx.txt is removed entirely
as IRQF_DISABLED is gone now; the usage in older kernel versions
(including the old SA_INTERRUPT flag) should be discouraged. The
trouble of using IRQF_SHARED is a general problem and not specific to
any driver.

- I left the reference in Documentation/PCI/MSI-HOWTO.txt untouched since
it has already been removed in linux-next.

- All remaining references are changelogs that I suggest to keep.

Signed-off-by: Valentin Rothberg <[e-mail]>
Cc: Afzal Mohammed <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Cc: Brian Norris <[e-mail]>
Cc: Christoph Hellwig <[e-mail]>
Cc: Dan Carpenter <[e-mail]>
Cc: David Woodhouse <[e-mail]>
Cc: Ewan Milne <[e-mail]>
Cc: Eyal Perry <[e-mail]>
Cc: Felipe Balbi <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: H. Peter Anvin <[e-mail]>
Cc: Hannes Reinecke <[e-mail]>
Cc: Hongliang Tao <[e-mail]>
Cc: Huacai Chen <[e-mail]>
Cc: Jiri Kosina <[e-mail]>
Cc: Jonathan Corbet <[e-mail]>
Cc: Keerthy <[e-mail]>
Cc: Laurent Pinchart <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Nishanth Menon <[e-mail]>
Cc: Paul Bolle <[e-mail]>
Cc: Peter Ujfalusi <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Quentin Lambert <[e-mail]>
Cc: Rajendra Nayak <[e-mail]>
Cc: Ralf Baechle <[e-mail]>
Cc: Santosh Shilimkar <[e-mail]>
Cc: Sricharan R <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: Tony Lindgren <[e-mail]>
Cc: Zhou Wang <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

Documentation/scsi/ncr53c8xx.txt

···
         irqm:1     same as initial settings (assumed BIOS settings)
         irqm:2     always totem pole
         irqm:0x10  driver will not use IRQF_SHARED flag when requesting irq
-        irqm:0x20  driver will not use IRQF_DISABLED flag when requesting irq
 
     (Bits 0x10 and 0x20 can be combined with hardware irq mode option)
 
···
 they only refer to system buffers that are well aligned. So, a work around 
 may only be needed under Linux when a scatter/gather list is not used and 
 when the SCSI DATA IN phase is reentered after a phase mismatch.
-
-14.5 IRQ sharing problems
-
-When an IRQ is shared by devices that are handled by different drivers, it 
-may happen that one driver complains about the request of the IRQ having 
-failed. Inder Linux-2.0, this may be due to one driver having requested the 
-IRQ using the IRQF_DISABLED flag but some other having requested the same IRQ
-without this flag. Under both Linux-2.0 and linux-2.2, this may be caused by 
-one driver not having requested the IRQ with the IRQF_SHARED flag.
-
-By default, the ncr53c8xx and sym53c8xx drivers request IRQs with both the 
-IRQF_DISABLED and the IRQF_SHARED flag under Linux-2.0 and with only the IRQF_SHARED
-flag under Linux-2.2.
-
-Under Linux-2.0, you can disable use of IRQF_DISABLED flag from the boot
-command line by using the following option:
-
-     ncr53c8xx=irqm:0x20   (for the generic ncr53c8xx driver)
-     sym53c8xx=irqm:0x20   (for the sym53c8xx driver)
-
-If this does not fix the problem, then you may want to check how all other 
-drivers are requesting the IRQ and report the problem. Note that if at least 
-a single driver does not request the IRQ with the IRQF_SHARED flag (share IRQ),
-then the request of the IRQ obviously will not succeed for all the drivers.
 
 15. SCSI problem troubleshooting
 

Documentation/scsi/tmscsim.txt

···
 MHz PCI bus works for me, though, but I don't recommend using higher clocks
 than the 33.33 MHz being in the PCI spec.
 
-If you want to share the IRQ with another device and the driver refuses to
-do so, you might succeed with changing the DC390_IRQ type in tmscsim.c to 
-IRQF_SHARED | IRQF_DISABLED.
-
 
 3.Features
 ----------

arch/mips/loongson/loongson-3/hpet.c

···
 
 static struct irqaction hpet_irq = {
 	.handler = hpet_irq_handler,
-	.flags = IRQF_DISABLED | IRQF_NOBALANCING | IRQF_TIMER,
+	.flags = IRQF_NOBALANCING | IRQF_TIMER,
 	.name = "hpet",
 };
 

drivers/block/cpqarray.c

···
 		goto Enomem4;
 	}
 	hba[i]->access.set_intr_mask(hba[i], 0);
-	if (request_irq(hba[i]->intr, do_ida_intr,
-		IRQF_DISABLED|IRQF_SHARED, hba[i]->devname, hba[i]))
+	if (request_irq(hba[i]->intr, do_ida_intr, IRQF_SHARED,
+			hba[i]->devname, hba[i]))
 	{
 		printk(KERN_ERR "cpqarray: Unable to get irq %d for %s\n",
 				hba[i]->intr, hba[i]->devname);

drivers/bus/omap_l3_noc.c

···
 	 */
 	l3->debug_irq = platform_get_irq(pdev, 0);
 	ret = devm_request_irq(l3->dev, l3->debug_irq, l3_interrupt_handler,
-			       IRQF_DISABLED, "l3-dbg-irq", l3);
+			       0x0, "l3-dbg-irq", l3);
 	if (ret) {
 		dev_err(l3->dev, "request_irq failed for %d\n",
 			l3->debug_irq);
···
 
 	l3->app_irq = platform_get_irq(pdev, 1);
 	ret = devm_request_irq(l3->dev, l3->app_irq, l3_interrupt_handler,
-			       IRQF_DISABLED, "l3-app-irq", l3);
+			       0x0, "l3-app-irq", l3);
 	if (ret)
 		dev_err(l3->dev, "request_irq failed for %d\n", l3->app_irq);
 

drivers/bus/omap_l3_smx.c

···
 	}
 
 	l3->debug_irq = platform_get_irq(pdev, 0);
-	ret = request_irq(l3->debug_irq, omap3_l3_app_irq,
-		IRQF_DISABLED | IRQF_TRIGGER_RISING,
-		"l3-debug-irq", l3);
+	ret = request_irq(l3->debug_irq, omap3_l3_app_irq, IRQF_TRIGGER_RISING,
+			  "l3-debug-irq", l3);
 	if (ret) {
 		dev_err(&pdev->dev, "couldn't request debug irq\n");
 		goto err1;
 	}
 
 	l3->app_irq = platform_get_irq(pdev, 1);
-	ret = request_irq(l3->app_irq, omap3_l3_app_irq,
-		IRQF_DISABLED | IRQF_TRIGGER_RISING,
-		"l3-app-irq", l3);
+	ret = request_irq(l3->app_irq, omap3_l3_app_irq, IRQF_TRIGGER_RISING,
+			  "l3-app-irq", l3);
 	if (ret) {
 		dev_err(&pdev->dev, "couldn't request app irq\n");
 		goto err2;

drivers/mtd/nand/hisi504_nand.c

···
 
 	hisi_nfc_host_init(host);
 
-	ret = devm_request_irq(dev, irq, hinfc_irq_handle, IRQF_DISABLED,
-				"nandc", host);
+	ret = devm_request_irq(dev, irq, hinfc_irq_handle, 0x0, "nandc", host);
 	if (ret) {
 		dev_err(dev, "failed to request IRQ\n");
 		goto err_res;

drivers/usb/isp1760/isp1760-core.c

···
 	}
 
 	if (IS_ENABLED(CONFIG_USB_ISP1761_UDC) && !udc_disabled) {
-		ret = isp1760_udc_register(isp, irq, irqflags | IRQF_SHARED |
-					   IRQF_DISABLED);
+		ret = isp1760_udc_register(isp, irq, irqflags | IRQF_SHARED);
 		if (ret < 0) {
 			isp1760_hcd_unregister(&isp->hcd);
 			return ret;

drivers/usb/isp1760/isp1760-udc.c

···
 
 	sprintf(udc->irqname, "%s (udc)", devname);
 
-	ret = request_irq(irq, isp1760_udc_irq, IRQF_SHARED | IRQF_DISABLED |
-			  irqflags, udc->irqname, udc);
+	ret = request_irq(irq, isp1760_udc_irq, IRQF_SHARED | irqflags,
+			  udc->irqname, udc);
 	if (ret < 0)
 		goto error;
 

include/linux/interrupt.h

···
  * These flags used only by the kernel as part of the
  * irq handling routines.
  *
- * IRQF_DISABLED - keep irqs disabled when calling the action handler.
- *                 DEPRECATED. This flag is a NOOP and scheduled to be removed
  * IRQF_SHARED - allow sharing the irq among several devices
  * IRQF_PROBE_SHARED - set by callers when they expect sharing mismatches to occur
  * IRQF_TIMER - Flag to mark this interrupt as timer interrupt
···
  * IRQF_EARLY_RESUME - Resume IRQ early during syscore instead of at device
  *                resume time.
  */
-#define IRQF_DISABLED		0x00000020
 #define IRQF_SHARED		0x00000080
 #define IRQF_PROBE_SHARED	0x00000100
 #define __IRQF_TIMER		0x00000200