Re: queue_flag_clear warnings with the latest git tree

[Bartlomiej Zolnierkiewicz]

On Tuesday 29 April 2008, Jens Axboe wrote:
> On Tue, Apr 29 2008, Bartlomiej Zolnierkiewicz wrote:
> > 
> > They happen both with IDE and SCSI/libata...
> > 
> > IDE:
> > 
> > Linux version 2.6.25-06476-gc9a3f6d-dirty (bzolnier@xxxxxxxxxxxxxxxxxxxxx) (gcc version 4.1.2 20070925 (Red Hat 4.1.2-27)) #225 PREEMPT Tue Apr 29 20:53:53 CEST 2008
> > BIOS-provided physical RAM map:
> >  BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
> >  BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
> >  BIOS-e820: 00000000000e8000 - 0000000000100000 (reserved)
> >  BIOS-e820: 0000000000100000 - 0000000007ff0000 (usable)
> >  BIOS-e820: 0000000007ff0000 - 0000000008000000 (ACPI data)
> >  BIOS-e820: 00000000fffc0000 - 0000000100000000 (reserved)
> > 127MB LOWMEM available.
> > Zone PFN ranges:
> >   DMA             0 ->     4096
> >   Normal       4096 ->    32752
> > Movable zone start PFN for each node
> > early_node_map[1] active PFN ranges
> >     0:        0 ->    32752
> > DMI not present or invalid.
> > ACPI: RSDP 000FA5D0, 0014 (r0 QEMU  )
> > ACPI: RSDT 07FF0000, 002C (r0 QEMU   QEMURSDT        1 QEMU        1)
> > ACPI: FACP 07FF002C, 0074 (r0 QEMU   QEMUFACP        1 QEMU        1)
> > ACPI: DSDT 07FF0100, 0832 (r1   BXPC   BXDSDT        1 INTL 20060912)
> > ACPI: FACS 07FF00C0, 0040
> > ACPI: APIC 07FF0938, 0040 (r0 QEMU   QEMUAPIC        1 QEMU        1)
> > ACPI: PM-Timer IO Port: 0xb008
> > ACPI: LAPIC (acpi_id[0x00] lapic_id[0x00] enabled)
> > BIOS bug, APIC version is 0 for CPU#0! fixing up to 0x10. (tell your hw vendor)
> > ACPI: IOAPIC (id[0x01] address[0xfec00000] gsi_base[0])
> > IOAPIC[0]: apic_id 1, version 17, address 0xfec00000, GSI 0-23
> > Enabling APIC mode:  Flat.  Using 1 I/O APICs
> > Using ACPI (MADT) for SMP configuration information
> > Allocating PCI resources starting at 10000000 (gap: 08000000:f7fc0000)
> > Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 32497
> > Kernel command line: root=/dev/hda init=/bin/sh  console=ttyS0,115200
> > Enabling fast FPU save and restore... done.
> > Enabling unmasked SIMD FPU exception support... done.
> > Initializing CPU#0
> > CPU 0 irqstacks, hard=c03e1000 soft=c03e0000
> > PID hash table entries: 512 (order: 9, 2048 bytes)
> > Detected 1495.172 MHz processor.
> > Console: colour VGA+ 80x25
> > console [ttyS0] enabled
> > Dentry cache hash table entries: 16384 (order: 4, 65536 bytes)
> > Inode-cache hash table entries: 8192 (order: 3, 32768 bytes)
> > Memory: 126096k/131008k available (1912k kernel code, 4432k reserved, 832k data, 180k init, 0k highmem)
> > virtual kernel memory layout:
> >     fixmap  : 0xfffb5000 - 0xfffff000   ( 296 kB)
> >     vmalloc : 0xc8800000 - 0xfffb3000   ( 887 MB)
> >     lowmem  : 0xc0000000 - 0xc7ff0000   ( 127 MB)
> >       .init : 0xc03b0000 - 0xc03dd000   ( 180 kB)
> >       .data : 0xc02de117 - 0xc03ae1e0   ( 832 kB)
> >       .text : 0xc0100000 - 0xc02de117   (1912 kB)
> > Checking if this processor honours the WP bit even in supervisor mode...Ok.
> > Calibrating delay using timer specific routine.. 3012.98 BogoMIPS (lpj=6025962)
> > Mount-cache hash table entries: 512
> > CPU: L1 I cache: 8K
> > CPU: L2 cache: 128K
> > Compat vDSO mapped to ffffe000.
> > CPU: Intel Pentium II (Klamath) stepping 03
> > Checking 'hlt' instruction... OK.
> > Freeing SMP alternatives: 0k freed
> > ACPI: Core revision 20070126
> > ENABLING IO-APIC IRQs
> > ..TIMER: vector=0x31 apic1=0 pin1=0 apic2=-1 pin2=-1
> > APIC calibration not consistent with PM Timer: 52ms instead of 100ms
> > APIC delta adjusted to PM-Timer: 6250026 (3292476)
> > net_namespace: 480 bytes
> > NET: Registered protocol family 16
> > No dock devices found.
> > ACPI: bus type pci registered
> > PCI: PCI BIOS revision 2.10 entry at 0xfa110, last bus=0
> > PCI: Using configuration type 1 for base access
> > Setting up standard PCI resources
> > ACPI: Interpreter enabled
> > ACPI: (supports S0 S5)
> > ACPI: Using IOAPIC for interrupt routing
> > ACPI: PCI Root Bridge [PCI0] (0000:00)
> > * Found PM-Timer Bug on the chipset. Due to workarounds for a bug,
> > * this clock source is slow. Consider trying other clock sources
> > pci 0000:00:01.3: quirk: region b000-b03f claimed by PIIX4 ACPI
> > pci 0000:00:01.3: quirk: region b100-b10f claimed by PIIX4 SMB
> > ACPI: PCI Interrupt Link [LNKA] (IRQs 3 4 5 6 7 9 10 *11 12)
> > ACPI: PCI Interrupt Link [LNKB] (IRQs 3 4 5 6 7 *9 10 11 12)
> > ACPI: PCI Interrupt Link [LNKC] (IRQs 3 4 5 6 7 9 10 *11 12)
> > ACPI: PCI Interrupt Link [LNKD] (IRQs 3 4 5 6 7 *9 10 11 12)
> > Linux Plug and Play Support v0.97 (c) Adam Belay
> > pnp: PnP ACPI init
> > ACPI: bus type pnp registered
> > pnp: PnP ACPI: found 6 devices
> > ACPI: ACPI bus type pnp unregistered
> > SCSI subsystem initialized
> > usbcore: registered new interface driver usbfs
> > usbcore: registered new interface driver hub
> > usbcore: registered new device driver usb
> > PCI: Using ACPI for IRQ routing
> > NET: Registered protocol family 2
> > IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
> > TCP established hash table entries: 4096 (order: 3, 32768 bytes)
> > TCP bind hash table entries: 4096 (order: 2, 16384 bytes)
> > TCP: Hash tables configured (established 4096 bind 4096)
> > TCP reno registered
> > NET: Registered protocol family 1
> > audit: initializing netlink socket (disabled)
> > type=2000 audit(1209495511.389:1): initialized
> > Total HugeTLB memory allocated, 0
> > fuse init (API version 7.9)
> > msgmni has been set to 246 for ipc namespace c0394260
> > io scheduler noop registered
> > io scheduler anticipatory registered (default)
> > io scheduler deadline registered
> > io scheduler cfq registered
> > pci 0000:00:00.0: Limiting direct PCI/PCI transfers
> > pci 0000:00:01.0: PIIX3: Enabling Passive Release
> > pci 0000:00:01.0: Activating ISA DMA hang workarounds
> > isapnp: Scanning for PnP cards...
> > isapnp: No Plug & Play device found
> > Real Time Clock Driver v1.12ac
> > Linux agpgart interface v0.103
> > Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing enabled
> > Switched to NOHz mode on CPU #0
> > ?serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16450
> > 00:05: ttyS0 at I/O 0x3f8 (irq = 4) is a 16450
> > Uniform Multi-Platform E-IDE driver
> > PIIX3: IDE controller (0x8086:0x7010 rev 0x00) at  PCI slot 0000:00:01.1
> > PIIX3: not 100% native mode: will probe irqs later
> >     ide0: BM-DMA at 0xc000-0xc007
> >     ide1: BM-DMA at 0xc008-0xc00f
> > hda: QEMU HARDDISK, ATA DISK drive
> > Clocksource tsc unstable (delta = -713139329 ns)
> > hda: MWDMA2 mode selected
> > hdc: QEMU CD-ROM, ATAPI CD/DVD-ROM drive
> > hdc: MWDMA2 mode selected
> > ide0 at 0x1f0-0x1f7,0x3f6 on irq 14
> > ide1 at 0x170-0x177,0x376 on irq 15
> > ide_generic: I/O resource 0x1F0-0x1F7 not free.
> > ide_generic: I/O resource 0x170-0x177 not free.
> > hda: max request size: 512KiB
> > hda: 102400 sectors (52 MB) w/256KiB Cache, CHS=101/255/63
> > hda: cache flushes supported
> >  hda:<4>------------[ cut here ]------------
> > WARNING: at include/linux/blkdev.h:439 queue_flag_clear+0x1e/0x3e()
> > Modules linked in:
> > Pid: 1, comm: swapper Not tainted 2.6.25-06476-gc9a3f6d-dirty #225
> >  [<c011a21e>] warn_on_slowpath+0x40/0x67
> >  [<c01b6ce3>] elv_rb_add+0x47/0x4f
> >  [<c01bda3e>] as_add_request+0x92/0xbe
> >  [<c01b6b8a>] elv_insert+0x11a/0x142
> >  [<c01b8b30>] __make_request+0x24e/0x292
> >  [<c01b8b53>] __make_request+0x271/0x292
> >  [<c01b7cb0>] generic_make_request+0x163/0x190
> 
> Hmm, I'm guessing UP and spin_is_locked() doesn't work there? I was
> pretty sure that was 'fixed' years ago. I lieu of a better fix,
> something like this should suffice.
> 
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 669b65c..9e2e23b 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -418,8 +418,12 @@ struct request_queue
>  
>  static inline int queue_is_locked(struct request_queue *q)
>  {
> +#ifdef CONFIG_SMP
>  	spinlock_t *lock = q->queue_lock;
>  	return lock && spin_is_locked(lock);
> +#else
> +	return 1;
> +#endif
>  }
>  
>  static inline void queue_flag_set_unlocked(unsigned int flag,

Yeah, all warnings are gone.

Thanks,
Bart
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