NFS: Always enable NFS direct I/O

Since O_DIRECT is a standard feature that is enabled in most distros,
eliminate the CONFIG_NFS_DIRECTIO build option, and change the
fs/nfs/Makefile to always build in the NFS direct I/O engine.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 0 insertions, 24 deletions

diff --git a/fs/Kconfig b/fs/Kconfig
index d7312825592b..55c1a0374e13 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -1637,30 +1637,6 @@ config NFS_V4
 
           If unsure, say N.
 
-config NFS_DIRECTIO
-        bool "Allow direct I/O on NFS files"
-        depends on NFS_FS
-        help
-          This option enables applications to perform uncached I/O on files
-          in NFS file systems using the O_DIRECT open() flag.  When O_DIRECT
-          is set for a file, its data is not cached in the system's page
-          cache.  Data is moved to and from user-level application buffers
-          directly.  Unlike local disk-based file systems, NFS O_DIRECT has
-          no alignment restrictions.
-
-          Unless your program is designed to use O_DIRECT properly, you are
-          much better off allowing the NFS client to manage data caching for
-          you.  Misusing O_DIRECT can cause poor server performance or network
-          storms.  This kernel build option defaults OFF to avoid exposing
-          system administrators unwittingly to a potentially hazardous
-          feature.
-
-          For more details on NFS O_DIRECT, see fs/nfs/direct.c.
-
-          If unsure, say N.  This reduces the size of the NFS client, and
-          causes open() to return EINVAL if a file residing in NFS is
-          opened with the O_DIRECT flag.
-
 config NFSD
         tristate "NFS server support"
         depends on INET