From: Rafał Bilski <rafalbilski@interia.pl>

I mistyped
# echo /dev/hdc1 >/sys/module/block2mtd/parameters/block2mt
instead of sdc1. There is no /dev/hdc1. I have DVD-ROM as /dev/hdc.
# dmesg
block2mtd: version $Revision: 1.30 $
block2mtd: error: cannot open device /dev/hdc1
Looks right, but tray is locked. And it doesn't want to get out.
# eject
hdc: irq timeout: status=0xd0 { Busy }
ide: failed opcode was: unknown
WARNING: at kernel/irq/resend.c:70 check_irq_resend()
 [<c013444b>] check_irq_resend+0xab/0xc0
 [<c0133e2a>] enable_irq+0x4a/0xa0
 [<c02c26e7>] ide_error+0x47/0xa0
 [<c02d1e60>] cdrom_newpc_intr+0x0/0x300
 [<c02c2bc0>] ide_timer_expiry+0x1e0/0x2d0
 [<c02c29e0>] ide_timer_expiry+0x0/0x2d0
 [<c011b986>] run_timer_softirq+0x116/0x160
 [<c0127e75>] hrtimer_interrupt+0x165/0x1a0
 [<c0118772>] __do_softirq+0x42/0x90
 [<c01187e6>] do_softirq+0x26/0x30
 [<c0118aaa>] irq_exit+0x5a/0x60
 [<c0104817>] do_IRQ+0x47/0x80
 [<c0102c23>] common_interrupt+0x23/0x30
 [<c0281a46>] acpi_processor_idle+0x162/0x380
 [<c0100d0e>] cpu_idle+0x4e/0x70
 [<c0524ac5>] start_kernel+0x1f5/0x240
 [<c05243a0>] unknown_bootoption+0x0/0x1e0
 =======================

Removing bdput from do_open() in fs/block_dev.c seems to be a cure for irq
timeout.

Signed-off-by: Rafał Bilski <rafalbilski@interia.pl>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/block_dev.c |    1 -
 1 files changed, 1 deletion(-)

diff -puN fs/block_dev.c~remove-bdput-from-do_open-in-fs-block_devc fs/block_dev.c
--- a/fs/block_dev.c~remove-bdput-from-do_open-in-fs-block_devc
+++ a/fs/block_dev.c
@@ -1120,7 +1120,6 @@ static int do_open(struct block_device *
 	disk = get_gendisk(bdev->bd_dev, &part);
 	if (!disk) {
 		unlock_kernel();
-		bdput(bdev);
 		return ret;
 	}
 	owner = disk->fops->owner;
_