ACPI, APEI, Fix acpi_pre_map() return value

After we ioremap() a new region, we call __acpi_try_ioremap() to
see whether another thread has already mapped the same region.
This check clobbers "vaddr",  so compute the return value of
acpi_pre_map() using the ioremap() result "map->vaddr" instead.

v2:
    Modified the unsuitable description of patch.

v3:
    Removed unlikely() check and made description simpler.

Signed-off-by: Jin Dongming <jin.dongming@np.css.fujitsu.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/acpi/atomicio.c b/drivers/acpi/atomicio.c
index 8f8bd736d4f..542e5390389 100644
--- a/drivers/acpi/atomicio.c
+++ b/drivers/acpi/atomicio.c
@@ -142,7 +142,7 @@ static void __iomem *acpi_pre_map(phys_addr_t paddr,
         list_add_tail_rcu(&map->list, &acpi_iomaps);
         spin_unlock_irqrestore(&acpi_iomaps_lock, flags);
 
-        return vaddr + (paddr - pg_off);
+        return map->vaddr + (paddr - map->paddr);
 err_unmap:
         iounmap(vaddr);
         return NULL;