On Tuesday 01 July 2008 09:32, Andrew Morton wrote: > > I noticed that read/write/rdwr_pipe_fops are (1) const and > > (2) exactly identical to xxx_fifo_fops, which are also const. > > > > Attached patch #defines xxx_pipe_fops as aliases to xxx_fifo_fops. > > Size difference: > > > > # size linux-2.6.25-rc6*/*/pipe.o > > text data bss dec hex filename > > 6534 144 0 6678 1a16 linux-2.6.25-rc6/fs/pipe.o > > 5862 144 0 6006 1776 linux-2.6.25-rc6-pt/fs/pipe.o > > > > Run-tested on 2.6.26-rc8. Please apply. > > > > Signed-off-by: Denys Vlasenko <vda.linux@xxxxxxxxxxxxxx> > > <argh, an attachment. save-as, read, edit..> Let's see how KMail will cope with inline cut-n-paste... > > -static const struct file_operations rdwr_pipe_fops = { > > - .llseek = no_llseek, > > - .read = do_sync_read, > > - .aio_read = pipe_read, > > - .write = do_sync_write, > > - .aio_write = pipe_write, > > - .poll = pipe_poll, > > - .unlocked_ioctl = pipe_ioctl, > > - .open = pipe_rdwr_open, > > - .release = pipe_rdwr_release, > > - .fasync = pipe_rdwr_fasync, > > -}; > > +#define read_pipe_fops read_fifo_fops > > +#define write_pipe_fops write_fifo_fops > > +#define rdwr_pipe_fops rdwr_fifo_fops > > Well OK. But there's a risk that someone will go and modify > read_fifo_fops without realising that they're also modifying > read_pipe_fops. Yes, it is possible. > So it'd be better to rename read_fifo_fops to (say) shared_read_fops > then do > > #define read_pipe_fops shared_read_fops > #define read_fifo_fops shared_read_fops I think since XXX_pipe_fops are only used in this file, just explaining this in the comment would be enough. Please take a look at the version below. Signed-off-by: Denys Vlasenko <vda.linux@xxxxxxxxxxxxxx> -- vda --- linux-2.6.26-rc8/fs/pipe.c.org Tue Jul 1 11:52:28 2008 +++ linux-2.6.26-rc8/fs/pipe.c Tue Jul 1 11:58:23 2008 @@ -777,6 +777,8 @@ /* * The file_operations structs are not static because they * are also used in linux/fs/fifo.c to do operations on FIFOs. + * + * Pipes reuse fifos' file_operations structs. */ const struct file_operations read_fifo_fops = { .llseek = no_llseek, @@ -815,43 +817,6 @@ .fasync = pipe_rdwr_fasync, }; -static const struct file_operations read_pipe_fops = { - .llseek = no_llseek, - .read = do_sync_read, - .aio_read = pipe_read, - .write = bad_pipe_w, - .poll = pipe_poll, - .unlocked_ioctl = pipe_ioctl, - .open = pipe_read_open, - .release = pipe_read_release, - .fasync = pipe_read_fasync, -}; - -static const struct file_operations write_pipe_fops = { - .llseek = no_llseek, - .read = bad_pipe_r, - .write = do_sync_write, - .aio_write = pipe_write, - .poll = pipe_poll, - .unlocked_ioctl = pipe_ioctl, - .open = pipe_write_open, - .release = pipe_write_release, - .fasync = pipe_write_fasync, -}; - -static const struct file_operations rdwr_pipe_fops = { - .llseek = no_llseek, - .read = do_sync_read, - .aio_read = pipe_read, - .write = do_sync_write, - .aio_write = pipe_write, - .poll = pipe_poll, - .unlocked_ioctl = pipe_ioctl, - .open = pipe_rdwr_open, - .release = pipe_rdwr_release, - .fasync = pipe_rdwr_fasync, -}; - struct pipe_inode_info * alloc_pipe_info(struct inode *inode) { struct pipe_inode_info *pipe; @@ -927,7 +892,7 @@ inode->i_pipe = pipe; pipe->readers = pipe->writers = 1; - inode->i_fop = &rdwr_pipe_fops; + inode->i_fop = &rdwr_fifo_fops; /* * Mark the inode dirty from the very beginning, @@ -978,7 +943,7 @@ d_instantiate(dentry, inode); err = -ENFILE; - f = alloc_file(pipe_mnt, dentry, FMODE_WRITE, &write_pipe_fops); + f = alloc_file(pipe_mnt, dentry, FMODE_WRITE, &write_fifo_fops); if (!f) goto err_dentry; f->f_mapping = inode->i_mapping; @@ -1021,7 +986,7 @@ f->f_pos = 0; f->f_flags = O_RDONLY; - f->f_op = &read_pipe_fops; + f->f_op = &read_fifo_fops; f->f_mode = FMODE_READ; f->f_version = 0; -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html