Messages in this thread | | | Date | Thu, 11 Sep 2008 13:34:12 -0700 | From | "Yinghai Lu" <> | Subject | Re: [PATCH 6 of 7] x86: use early_ioremap in __acpi_map_table |
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On Wed, Sep 10, 2008 at 9:49 AM, Jeremy Fitzhardinge <jeremy@goop.org> wrote: > Ingo Molnar wrote: >>> So i'd suggest a different, more carful approach: keep the new code >>> you wrote, but print a WARN()ing if prev_map is not unmapped yet when >>> the next mapping is acquired. That way the ACPI code can be fixed >>> gradually and without breaking existing functionality. >>> >> >> ok, i stuck in your patches into tip/master today and -tip testing >> quickly found an early-ioremap leak: >> >> [ 36.625100] calling check_early_ioremap_leak+0x0/0x3d >> [ 36.630253] ------------[ cut here ]------------ >> [ 36.634884] WARNING: at arch/x86/mm/ioremap.c:577 check_early_ioremap_leak+0x28/0x3d() >> [ 36.642811] Debug warning: early ioremap leak of 1 areas detected. >> >> find the full log below with ioremap-leak-tracing turned on. I've >> excluded these commits for now from tip/master. >> > > Yes, that leak is expected, unfortunately. __acpi_map_table() has no > corresponding unmap, and only maintains one mapping. So it will leak > its last mapping when it switches over from using __acpi_map_table() to > ioremap(). > > So, yes, its ugly, but its guaranteed to be a single leaked mapping. > But I'm not sure what the best approach to deal with it is. > > (All those other backtraces are just informational, right?) >
acpi_os_map_memory is the only user for __acpi_map_table (except es7000_32.c)
void __iomem *__init_refok acpi_os_map_memory(acpi_physical_address phys, acpi_size size) { if (phys > ULONG_MAX) { printk(KERN_ERR PREFIX "Cannot map memory that high\n"); return NULL; } if (acpi_gbl_permanent_mmap) /* * ioremap checks to ensure this is in reserved space */ return ioremap((unsigned long)phys, size); else return __acpi_map_table((unsigned long)phys, size); } EXPORT_SYMBOL_GPL(acpi_os_map_memory);
void acpi_os_unmap_memory(void __iomem * virt, acpi_size size) { if (acpi_gbl_permanent_mmap) { iounmap(virt); } } EXPORT_SYMBOL_GPL(acpi_os_unmap_memory);
just let acpi_os_unmap_memory to call __acpi_unmap_table...
YH
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