[PATCH 3.16 248/328] ARM: 8799/1: mm: fix pci_ioremap_io() offset check

[Ben Hutchings]

3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>

commit 3a58ac65e2d7969bcdf1b6acb70fa4d12a88e53e upstream.

IO_SPACE_LIMIT is the ending address of the PCI IO space, i.e
something like 0xfffff (and not 0x100000).

Therefore, when offset = 0xf0000 is passed as argument, this function
fails even though the offset + SZ_64K fits below the
IO_SPACE_LIMIT. This makes the last chunk of 64 KB of the I/O space
not usable as it cannot be mapped.

This patch fixes that by substracing 1 to offset + SZ_64K, so that we
compare the addrss of the last byte of the I/O space against
IO_SPACE_LIMIT instead of the address of the first byte of what is
after the I/O space.

Fixes: c2794437091a4 ("ARM: Add fixed PCI i/o mapping")
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxx>
Acked-by: Nicolas Pitre <nico@xxxxxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 arch/arm/mm/ioremap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -447,7 +447,7 @@ void pci_ioremap_set_mem_type(int mem_ty
 
 int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr)
 {
-	BUG_ON(offset + SZ_64K > IO_SPACE_LIMIT);
+	BUG_ON(offset + SZ_64K - 1 > IO_SPACE_LIMIT);
 
 	return ioremap_page_range(PCI_IO_VIRT_BASE + offset,
 				  PCI_IO_VIRT_BASE + offset + SZ_64K,