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/eventfd.c b/fs/eventfd.c
index 8b47e4200e65..d26402ff06ea 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -339,7 +339,7 @@ struct file *eventfd_file_create(unsigned int count, int flags)
         ctx->flags = flags;
 
         file = anon_inode_getfile("[eventfd]", &eventfd_fops, ctx,
-                                  flags & EFD_SHARED_FCNTL_FLAGS);
+                                  O_RDWR | (flags & EFD_SHARED_FCNTL_FLAGS));
         if (IS_ERR(file))
                 eventfd_free_ctx(ctx);