anonfd: Allow making anon files read-only

It seems a couple places such as arch/ia64/kernel/perfmon.c and
drivers/infiniband/core/uverbs_main.c could use anon_inode_getfile()
instead of a private pseudo-fs + alloc_file(), if only there were a way
to get a read-only file.  So provide this by having anon_inode_getfile()
create a read-only file if we pass O_RDONLY in flags.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/timerfd.c b/fs/timerfd.c
index b042bd7034b1..1bfc95ad5f71 100644
--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -200,7 +200,7 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags)
         hrtimer_init(&ctx->tmr, clockid, HRTIMER_MODE_ABS);
 
         ufd = anon_inode_getfd("[timerfd]", &timerfd_fops, ctx,
-                               flags & TFD_SHARED_FCNTL_FLAGS);
+                               O_RDWR | (flags & TFD_SHARED_FCNTL_FLAGS));
         if (ufd < 0)
                 kfree(ctx);