[PATCH] powerpc/pci: Fix get_phb_number() locking

[Michael Ellerman]

On Mon, 15 Aug 2022 16:55:50 +1000, Michael Ellerman wrote:
> The recent change to get_phb_number() causes a DEBUG_ATOMIC_SLEEP
> warning on some systems:
> 
>   BUG: sleeping function called from invalid context at kernel/locking/mutex.c:580
>   in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: swapper
>   preempt_count: 1, expected: 0
>   RCU nest depth: 0, expected: 0
>   1 lock held by swapper/1:
>    #0: c157efb0 (hose_spinlock){+.+.}-{2:2}, at: pcibios_alloc_controller+0x64/0x220
>   Preemption disabled at:
>   [<00000000>] 0x0
>   CPU: 0 PID: 1 Comm: swapper Not tainted 5.19.0-yocto-standard+ #1
>   Call Trace:
>   [d101dc90] [c073b264] dump_stack_lvl+0x50/0x8c (unreliable)
>   [d101dcb0] [c0093b70] __might_resched+0x258/0x2a8
>   [d101dcd0] [c0d3e634] __mutex_lock+0x6c/0x6ec
>   [d101dd50] [c0a84174] of_alias_get_id+0x50/0xf4
>   [d101dd80] [c002ec78] pcibios_alloc_controller+0x1b8/0x220
>   [d101ddd0] [c140c9dc] pmac_pci_init+0x198/0x784
>   [d101de50] [c140852c] discover_phbs+0x30/0x4c
>   [d101de60] [c0007fd4] do_one_initcall+0x94/0x344
>   [d101ded0] [c1403b40] kernel_init_freeable+0x1a8/0x22c
>   [d101df10] [c00086e0] kernel_init+0x34/0x160
>   [d101df30] [c001b334] ret_from_kernel_thread+0x5c/0x64
> 
> [...]

Applied to powerpc/fixes.

[1/1] powerpc/pci: Fix get_phb_number() locking
      https://git.kernel.org/powerpc/c/8d48562a2729742f767b0fdd994d6b2a56a49c63

cheers