radix-tree: must check __radix_tree_preload() return value

[mirror_ubuntu-artful-kernel.git] / lib / Kconfig

diff --git a/lib/Kconfig b/lib/Kconfig
index 6762529ad9e4597f473a07e9300bd0ac8a601c10..90be4c091128f9d5ad988250f0bf9ef1c99b646a 100644 (file)
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -59,6 +59,20 @@ config ARCH_USE_CMPXCHG_LOCKREF
 config ARCH_HAS_FAST_MULTIPLIER
        bool
 
+config LIBIO
+       bool "Generic logical IO management"
+       def_bool y if PCI && (ARM || UNICORE32 || MICROBLAZE || ARM64)
+       help
+         For some architectures, there are no IO space. To support the
+         accesses to legacy I/O devices on those architectures, kernel
+         implemented the memory mapped I/O mechanism based on bridge bus
+         supports. But for some buses which do not support MMIO, the
+         peripherals there should be accessed with device-specific way.
+         To abstract those different I/O accesses into unified I/O accessors,
+         this option provide a generic I/O space management way after mapping
+         the device I/O to system logical/fake I/O and help to hide all the
+         hardware detail.
+
 config CRC_CCITT
        tristate "CRC-CCITT functions"
        help