acpi: remove final __acpi_map_table mapping before setting acpi_gbl_permanent_mmap

On x86, __acpi_map_table uses early_ioremap() to create the mapping,
replacing the previous mapping with a new one.  Once enough of the
kernel is up an running it switches to using normal ioremap().  At
that point, we need to clean up the final mapping to avoid a warning
from the early_ioremap subsystem.

This can be removed after all the instances in the ACPI code are fixed
that rely on early-ioremap's implicit overmapping of previously
mapped tables.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Len Brown <len.brown@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 11 insertions, 3 deletions

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 5424a18f2e4e..7217834f6b1d 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -124,12 +124,14 @@ char *__init __acpi_map_table(unsigned long phys, unsigned long size)
         static char *prev_map;
         static unsigned long prev_size;
 
+        if (prev_map) {
+                early_iounmap(prev_map, prev_size);
+                prev_map = NULL;
+        }
+
         if (!phys || !size)
                 return NULL;
 
-        if (prev_map)
-                early_iounmap(prev_map, prev_size);
-
         prev_size = size;
         prev_map = early_ioremap(phys, size);
 
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 765fd1c56cd6..fb1be7b5dbc1 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -694,6 +694,12 @@ void __init acpi_early_init(void)
         if (!acpi_strict)
                 acpi_gbl_enable_interpreter_slack = TRUE;
 
+        /*
+         * Doing a zero-sized mapping will clear out the previous
+         * __acpi_map_table() mapping, if any.
+         */
+        __acpi_map_table(0, 0);
+
         acpi_gbl_permanent_mmap = 1;
 
         status = acpi_reallocate_root_table();