Re: [PATCH] ipr: fix lockdep warning from ipr_ioa_reset_done

[Brian King <brking@linux.vnet.ibm.com>]

Acked by: Brian King <brking@linux.vnet.ibm.com>

Mark Nelson wrote:
> To fix the following lockdep warning we turn the spin_unlock_irq() into
> a spin_unlock() and similarly for the corresponding spin_lock_irq(). We
> can do this because there is no need to enable interrupts in this path
> (thanks to Bring King for the tip).
> 
> Badness at kernel/lockdep.c:2193
> NIP: c0000000000855d0 LR: c0000000000855b4 CTR: c0000000000482d0
> REGS: c00000000fffb8d0 TRAP: 0700   Not tainted  (2.6.28-rc5-autokern1)
> MSR: 8000000000021032 <ME,IR,DR>  CR: 28000022  XER: 00000004
> TASK = c00000000091fa80[0] 'swapper' THREAD: c000000000a3c000 CPU: 0
> GPR00: 0000000000000000 c00000000fffbb50 c000000000a3c2e0 0000000000000001
> GPR04: 000000000000a580 c0000000003870d4 0000000000000000 0000000000000001
> GPR08: 0000000000000000 c00000000112fdf0 c0000000008ed918 c000000000abcfd0
> GPR12: 0000000048000088 c000000000a7f300 0000000000000000 0000000002100000
> GPR16: c000000000644bd0 c000000000643390 0000000000000000 00000000003d0c00
> GPR20: 00000000028372d8 c0000000007372d8 0000000002837548 c000000000737548
> GPR24: c000000000644660 00000000028372d8 000000000000001a c000000076760000
> GPR28: 0000000000000004 c0000000004e8450 c0000000009aafb0 c00000000091fa80
> NIP [c0000000000855d0] .trace_hardirqs_on_caller+0x10c/0x194
> LR [c0000000000855b4] .trace_hardirqs_on_caller+0xf0/0x194
> Call Trace:
> [c00000000fffbb50] [c00000000fffbbe0] 0xc00000000fffbbe0 (unreliable)
> [c00000000fffbbe0] [c0000000004e8450] ._spin_unlock_irq+0x38/0x5c
> [c00000000fffbc70] [c0000000003870d4] .ipr_ioa_reset_done+0x204/0x284
> [c00000000fffbd10] [c00000000037d234] .ipr_reset_ioa_job+0xc4/0xec
> [c00000000fffbda0] [c000000000385ce0] .ipr_isr+0x208/0x484
> [c00000000fffbe50] [c0000000000aaf3c] .handle_IRQ_event+0x58/0xd4
> [c00000000fffbef0] [c0000000000ad978] .handle_fasteoi_irq+0x110/0x1ac
> [c00000000fffbf90] [c000000000025214] .call_handle_irq+0x1c/0x2c
> [c000000000a3f9a0] [c00000000000d168] .do_IRQ+0x120/0x210
> [c000000000a3fa40] [c000000000004804] hardware_interrupt_entry+0x1c/0x98
> --- Exception: 501 at .pseries_dedicated_idle_sleep+0xec/0x1cc
>     LR = .pseries_dedicated_idle_sleep+0xdc/0x1cc
> [c000000000a3fd30] [c000000000038208] .pseries_dedicated_idle_sleep+0x74/0x1cc (unreliable)
> [c000000000a3fdd0] [c000000000012134] .cpu_idle+0x114/0x1dc
> [c000000000a3fe60] [c0000000004ecb18] .rest_init+0x7c/0x94
> [c000000000a3fee0] [c000000000700a40] .start_kernel+0x4b8/0x4e0
> [c000000000a3ff90] [c000000000008368] .start_here_common+0x1c/0x34
> Instruction dump:
> e92d01b0 80090894 2f800000 41be002c 481ed1d1 60000000 2fa30000 419e0080
> e93e8090 80090000 2f800000 409e0070 <0fe00000> 48000068 7fe3fb78 38800001
> 
> Signed-off-by: Mark Nelson <markn@au1.ibm.com>
> ---
> 	Is this patch OK? It makes silences the warning and so far has no side effects
> 
>  drivers/scsi/ipr.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> Index: upstream/drivers/scsi/ipr.c
> ===================================================================
> --- upstream.orig/drivers/scsi/ipr.c
> +++ upstream/drivers/scsi/ipr.c
> @@ -5389,9 +5389,9 @@ static int ipr_ioa_reset_done(struct ipr
>  	list_add_tail(&ipr_cmd->queue, &ioa_cfg->free_q);
>  	wake_up_all(&ioa_cfg->reset_wait_q);
> 
> -	spin_unlock_irq(ioa_cfg->host->host_lock);
> +	spin_unlock(ioa_cfg->host->host_lock);
>  	scsi_unblock_requests(ioa_cfg->host);
> -	spin_lock_irq(ioa_cfg->host->host_lock);
> +	spin_lock(ioa_cfg->host->host_lock);
> 
>  	if (!ioa_cfg->allow_cmds)
>  		scsi_block_requests(ioa_cfg->host);
> --
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-- 
Brian King
Linux on Power Virtualization
IBM Linux Technology Center