Can request_irq be called under spinlock?

[Jeremy Fitzhardinge]

Relatively recently, I've started seeing this report from my code:

BUG: sleeping function called from invalid context at /home/jeremy/git/linux-2.6/mm/slab.c:2982
in_atomic(): 1, irqs_disabled(): 1, pid: 2249, name: xenstored
Pid: 2249, comm: xenstored Not tainted 2.6.29-rc4-tip #22
Call Trace:
[<ffffffff80233e5d>] __might_sleep+0x113/0x115
[<ffffffff802a6f8c>] __kmalloc+0x67/0xe2
[<ffffffff802ebc85>] __proc_create+0x89/0x127
[<ffffffff803f1c5f>] ? bind_evtchn_to_cpu+0x4f/0xa0
[<ffffffff802ec0ad>] proc_mkdir_mode+0x2e/0x57
[<ffffffff802ec0ec>] proc_mkdir+0x16/0x18
[<ffffffff80270d99>] register_irq_proc+0x74/0xcf
[<ffffffff8026f5ab>] __setup_irq+0x19b/0x200
[<ffffffff8026f6e7>] request_irq+0xd7/0x100
[<ffffffff803f7d8e>] ? evtchn_interrupt+0x0/0xc1
[<ffffffff803f7d8e>] ? evtchn_interrupt+0x0/0xc1
[<ffffffff803f2856>] bind_evtchn_to_irqhandler+0x3d/0x5f
[<ffffffff803f7c8b>] evtchn_bind_to_user+0x54/0x72
[<ffffffff803f81cc>] evtchn_ioctl+0x180/0x39c
[<ffffffff802a8592>] ? __dentry_open+0x1a4/0x2a2
[<ffffffff802a9513>] ? nameidata_to_filp+0x46/0x57
[<ffffffff803f02ed>] ? pnpacpi_parse_allocated_resource+0x94/0x9b
[<ffffffff8020e6d9>] ? xen_force_evtchn_callback+0xd/0xf
[<ffffffff802b5f06>] vfs_ioctl+0x2f/0x7c
[<ffffffff802b63fe>] do_vfs_ioctl+0x4ab/0x503
[<ffffffff802aad0e>] ? __fput+0x1a1/0x1ae
[<ffffffff802b649d>] sys_ioctl+0x47/0x6a
[<ffffffff80212522>] system_call_fastpath+0x16/0x1b

because I'm calling request_irq() while holding a spinlock.

request_irq() itself looks like its OK with that (it allocates with 
GFP_ATOMIC, for example), but __setup_irq -> register_irq_proc -> 
proc_mkdir ends up doing a GFP_KERNEL allocation, which leads to this 
message.

I can rearrange this code to not do the call under lock, but it seems 
like there was an unintentional change in API here.

Thanks,
   J
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