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SubjectRe: [PATCH v1 07/10] powerpc/mm: move iounmap() into ioremap.c and drop __iounmap()
Date
Christophe Leroy <christophe.leroy@c-s.fr> writes:
> diff --git a/arch/powerpc/mm/ioremap.c b/arch/powerpc/mm/ioremap.c
> index 0c23660522ca..57d742509cec 100644
> --- a/arch/powerpc/mm/ioremap.c
> +++ b/arch/powerpc/mm/ioremap.c
> @@ -72,3 +75,31 @@ void __iomem *ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long f
> return __ioremap_caller(addr, size, pte_pgprot(pte), caller);
> }
> EXPORT_SYMBOL(ioremap_prot);
> +
> +/*
> + * Unmap an IO region and remove it from vmalloc'd list.
> + * Access to IO memory should be serialized by driver.
> + */
> +void iounmap(volatile void __iomem *token)
> +{
> + void *addr;
> +
> + /*
> + * If mapped by BATs then there is nothing to do.
> + */
> + if (v_block_mapped((unsigned long)token))
> + return;
> +
> + if (!slab_is_available())
> + return;
> +
> + addr = (void *)((unsigned long __force)PCI_FIX_ADDR(token) & PAGE_MASK);
> + if (WARN_ON((unsigned long)addr < IOREMAP_BASE))
> + return;

This pops a bunch, as we seem to have various places that want to call
iounmap(NULL) in error paths, much like kfree().

One example:

[ 85.062269] WARNING: CPU: 6 PID: 3643 at arch/powerpc/mm/ioremap.c:97 .iounmap+0x58/0xb0
[ 85.062276] Modules linked in: snd_powermac(+) snd_pcm snd_timer snd soundcore
[ 85.062314] CPU: 6 PID: 3643 Comm: modprobe Tainted: G W 5.3.0-rc2-gcc-8.2.0-00051-ga8e8d67f314c #655
[ 85.062325] NIP: c000000000078e08 LR: c000000000078dd0 CTR: c000000000078db0
[ 85.062335] REGS: c0000000f44f6e40 TRAP: 0700 Tainted: G W (5.3.0-rc2-gcc-8.2.0-00051-ga8e8d67f314c)
[ 85.062342] MSR: 8000000002029032 <SF,VEC,EE,ME,IR,DR,RI> CR: 24228884 XER: 00000000
[ 85.062377] CFAR: c000000000339650 IRQMASK: 0
GPR00: c000000000078dd0 c0000000f44f70d0 c000000001a2ff00 0000000000000000
GPR04: c008000000336518 0000000000000000 c000000001a66b80 0000000000000001
GPR08: c0000000013296c8 c00a000080000000 0000000000000001 c00800000032ba08
GPR12: c000000000078db0 c00000003fff8e80 0000000000000004 c008000000350000
GPR16: c000000002637730 c000000000d69868 0000000000000000 c000000002637740
GPR20: c00000000197ad08 0000000000000000 0000000000000100 0000000000000028
GPR24: c0000000f736eac0 c0000000f44f7370 c0000000f5065000 c008000000336510
GPR28: c0000000026aafc8 ffffffffffffffed 0000000000000000 0000000000000000
[ 85.062554] NIP [c000000000078e08] .iounmap+0x58/0xb0
[ 85.062564] LR [c000000000078dd0] .iounmap+0x20/0xb0
[ 85.062572] Call Trace:
[ 85.062591] [c0000000f44f70d0] [c000000000078dd0] .iounmap+0x20/0xb0 (unreliable)
[ 85.062623] [c0000000f44f7150] [c008000000321e24] .snd_pmac_free+0x164/0x270 [snd_powermac]
[ 85.062709] [c0000000f44f71e0] [c008000000322fa4] .snd_pmac_new+0x884/0xf30 [snd_powermac]
[ 85.062798] [c0000000f44f72f0] [c00800000032015c] .snd_pmac_probe+0x7c/0x450 [snd_powermac]
[ 85.062849] [c0000000f44f73a0] [c0000000007b0628] .platform_drv_probe+0x68/0x100
[ 85.062863] [c0000000f44f7430] [c0000000007aca94] .really_probe+0x144/0x3c0
[ 85.062880] [c0000000f44f74d0] [c0000000007acfe0] .driver_probe_device+0x80/0x170
[ 85.062899] [c0000000f44f7560] [c0000000007a9be4] .bus_for_each_drv+0xb4/0x130
[ 85.062922] [c0000000f44f7610] [c0000000007ac89c] .__device_attach+0x11c/0x1a0
[ 85.062941] [c0000000f44f76c0] [c0000000007ab3d8] .bus_probe_device+0xe8/0x100
[ 85.062961] [c0000000f44f7750] [c0000000007a6164] .device_add+0x504/0x7d0
[ 85.062978] [c0000000f44f7820] [c0000000007b02fc] .platform_device_add+0x14c/0x310
[ 85.062994] [c0000000f44f78c0] [c0000000007b14c0] .platform_device_register_full+0x130/0x210
[ 85.063084] [c0000000f44f7940] [c00800000032b850] .alsa_card_pmac_init+0x80/0xc4 [snd_powermac]
[ 85.063106] [c0000000f44f7a10] [c000000000010e58] .do_one_initcall+0x88/0x448
[ 85.063158] [c0000000f44f7b00] [c0000000002416e4] .do_init_module+0x74/0x2e0
[ 85.063203] [c0000000f44f7ba0] [c000000000243bd4] .load_module+0x20b4/0x26d0
[ 85.063219] [c0000000f44f7cf0] [c000000000244470] .__se_sys_finit_module+0xe0/0x140
[ 85.063237] [c0000000f44f7e20] [c00000000000c46c] system_call+0x5c/0x70



I think we can just do:

void iounmap(volatile void __iomem *token)
{
void *addr;

if (!addr)
return;

...

??

cheers

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