On Thu, Feb 9, 2012 at 4:08 PM, Myron Stowe <mstowe@xxxxxxxxxx> wrote: > On Thu, 2012-02-09 at 08:42 -0800, Bjorn Helgaas wrote: >> On Thu, Feb 9, 2012 at 8:36 AM, Myron Stowe <myron.stowe@xxxxxxxxxx> wrote: >> > From: Myron Stowe <mstowe@xxxxxxxxxx> >> > >> > Make sure the removal of mappings uses the same logic that put the >> > mappings in place. >> > >> > Signed-off-by: Myron Stowe <myron.stowe@xxxxxxxxxx> >> > --- >> > >> > drivers/acpi/osl.c | 2 +- >> > 1 files changed, 1 insertions(+), 1 deletions(-) >> > >> > diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c >> > index 412a1e0..5aef087 100644 >> > --- a/drivers/acpi/osl.c >> > +++ b/drivers/acpi/osl.c >> > @@ -347,7 +347,7 @@ static void acpi_unmap(acpi_physical_address pg_off, void __iomem *vaddr) >> > unsigned long pfn; >> > >> > pfn = pg_off >> PAGE_SHIFT; >> > - if (page_is_ram(pfn)) >> > + if (should_use_kmap(pfn)) >> > kunmap(pfn_to_page(pfn)); >> > else >> > iounmap(vaddr); >> > >> >> Whatever happened to the question of why we have arch-specific >> ioremap() behavior? It's good to make map/unmap symmetric, but it'd >> be better to get rid of the ioremap/kmap hack. > > +cc ingo > > We never received any explanation for why ioremap() failed for Ying with > RAM on x86. Last I saw Ying asked Ingo for some input here but there > was never any reply - > http://marc.info/?l=linux-acpi&m=132788392604738&w=2 > > I like your idea of possibly changing ioremap's implementation so that > it would handle requests related to RAM - by using kmap() internally > when necessary - so that a *user* wouldn't need to care what > architecture we're on. I, however, feel like I don't have enough > experience with the memory management subsystem to know if such a tactic > would fly or not so was uncomfortable proceeding along those lines. As > a result, I just wanted to get this in for the meantime. I dunno if you're comfortable with it, but you can always propose a patch doing it how you think it should be done. People are more apt to respond to a concrete patch than to an abstract question about why things are the way they are. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
