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/eventpoll.c b/fs/eventpoll.c
index 366c503f9657..bd056a5b4efc 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1206,7 +1206,7 @@ SYSCALL_DEFINE1(epoll_create1, int, flags)
          * a file structure and a free file descriptor.
          */
         error = anon_inode_getfd("[eventpoll]", &eventpoll_fops, ep,
-                                 flags & O_CLOEXEC);
+                                 O_RDWR | (flags & O_CLOEXEC));
         if (error < 0)
                 ep_free(ep);