Hi Al, On Thu, Jun 12, 2014 at 8:14 PM, Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx> wrote: > Gitweb: http://git.kernel.org/linus/;a=commit;h=8d0207652cbe27d1f962050737848e5ad4671958 > Commit: 8d0207652cbe27d1f962050737848e5ad4671958 > ->splice_write() via ->write_iter() > > iter_file_splice_write() - a ->splice_write() instance that gathers the > pipe buffers, builds a bio_vec-based iov_iter covering those and feeds > it to ->write_iter(). A bunch of simple cases coverted to that... > > [AV: fixed the braino spotted by Cyrill] > > Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > @@ -1052,6 +1053,145 @@ generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out, > > EXPORT_SYMBOL(generic_file_splice_write); > > +/** > + * iter_file_splice_write - splice data from a pipe to a file > + * @pipe: pipe info > + * @out: file to write to > + * @ppos: position in @out > + * @len: number of bytes to splice > + * @flags: splice modifier flags > + * > + * Description: > + * Will either move or copy pages (determined by @flags options) from > + * the given pipe inode to the given file. > + * This one is ->write_iter-based. What's the meaning of the return value? This is not documented. > +ssize_t > +iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out, > + loff_t *ppos, size_t len, unsigned int flags) > +{ > + struct splice_desc sd = { > + .total_len = len, > + .flags = flags, > + .pos = *ppos, > + .u.file = out, > + }; > + int nbufs = pipe->buffers; > + struct bio_vec *array = kcalloc(nbufs, sizeof(struct bio_vec), > + GFP_KERNEL); > + ssize_t ret; fs/splice.c:954: warning: ‘ret’ may be used uninitialized in this function > + > + if (unlikely(!array)) > + return -ENOMEM; > + > + pipe_lock(pipe); > + > + splice_from_pipe_begin(&sd); > + while (sd.total_len) { If the "len" parameter is zero, this loop will be skipped, and "ret" will be uninitialized. What should it return? 0? -EINVAL? > + } > +done: > + kfree(array); > + splice_from_pipe_end(pipe, &sd); > + > + pipe_unlock(pipe); > + > + if (sd.num_spliced) > + ret = sd.num_spliced; > + > + return ret; > +} Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- 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
