Re: [PATCH v5 4/7] fs/fuse: support compiling out splice

[Pieter Smith <pieter@boesman.nl>]

On Tue, Nov 25, 2014 at 03:17:13PM +0100, Miklos Szeredi wrote:
> [Trimming CC.  Please do the same for other patches.  I for one am not
> interested in the general tinification discussion]
> 
> On Tue, Nov 25, 2014 at 08:19:39AM +0100, Pieter Smith wrote:
> > To implement splice support, fs/fuse makes use of nosteal_pipe_buf_ops. This
> > struct is exported by fs/splice. The goal of the larger patch set is to
> > completely compile out fs/splice, so uses of the exported struct need to be
> > compiled out along with fs/splice.
> > 
> > This patch therefore compiles out splice support in fs/fuse when
> > CONFIG_SYSCALL_SPLICE is undefined.
> > 
> > Signed-off-by: Pieter Smith <pieter@boesman.nl>
> > ---
> >  fs/fuse/dev.c | 9 +++++++--
> >  1 file changed, 7 insertions(+), 2 deletions(-)
> > 
> > diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
> > index ca88731..e984302 100644
> > --- a/fs/fuse/dev.c
> > +++ b/fs/fuse/dev.c
> > @@ -1191,8 +1191,9 @@ __releases(fc->lock)
> >   * request_end().  Otherwise add it to the processing list, and set
> >   * the 'sent' flag.
> >   */
> > -static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
> > -				struct fuse_copy_state *cs, size_t nbytes)
> > +static ssize_t __maybe_unused
> > +fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
> > +		 struct fuse_copy_state *cs, size_t nbytes)
> 
> fuse_dev_do_read() is definitely going to remain used.  So no point in adding
> __maybe_unused.

Off course, but at least gcc now also is aware that this is intentional and
nicely refrains from nagging you with a warning.

> >  {
> >  	int err;
> >  	struct fuse_req *req;
> > @@ -1291,6 +1292,7 @@ static ssize_t fuse_dev_read(struct kiocb *iocb, const struct iovec *iov,
> >  	return fuse_dev_do_read(fc, file, &cs, iov_length(iov, nr_segs));
> >  }
> >  
> > +#ifdef CONFIG_SYSCALL_SPLICE
> >  static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
> >  				    struct pipe_inode_info *pipe,
> >  				    size_t len, unsigned int flags)
> > @@ -1368,6 +1370,9 @@ out:
> >  	kfree(bufs);
> >  	return ret;
> >  }
> > +#else /* CONFIG_SYSCALL_SPLICE */
> > +#define fuse_dev_splice_read NULL
> > +#endif
> 
> This looks fine.
> 
> Thanks,
> Miklos
> 
> >  
> >  static int fuse_notify_poll(struct fuse_conn *fc, unsigned int size,
> >  			    struct fuse_copy_state *cs)
> > -- 
> > 2.1.0
> >