From c66ab6fa705e1b2887a6d9246b798bdc526839e2 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 12 Jun 2007 21:17:17 +0200 Subject: splice: abstract out actor data For direct splicing (or private splicing), the output may not be a file. So abstract out the handling into a specified actor function and put the data in the splice_desc structure earlier, so we can build on top of that. This is the first step in better splice handling for drivers, and also for implementing vmsplice _to_ user memory. Signed-off-by: Jens Axboe --- fs/splice.c | 99 +++++++++++++++++++++++++++++++++++++++++++------------------ 1 file changed, 70 insertions(+), 29 deletions(-) (limited to 'fs/splice.c') diff --git a/fs/splice.c b/fs/splice.c index e7d7080de2f9..68f6328236a6 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -668,31 +668,24 @@ out_ret: * key here is the 'actor' worker passed in that actually moves the data * to the wanted destination. See pipe_to_file/pipe_to_sendpage above. */ -ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, - struct file *out, loff_t *ppos, size_t len, - unsigned int flags, splice_actor *actor) +ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd, + splice_actor *actor) { int ret, do_wakeup, err; - struct splice_desc sd; ret = 0; do_wakeup = 0; - sd.total_len = len; - sd.flags = flags; - sd.file = out; - sd.pos = *ppos; - for (;;) { if (pipe->nrbufs) { struct pipe_buffer *buf = pipe->bufs + pipe->curbuf; const struct pipe_buf_operations *ops = buf->ops; - sd.len = buf->len; - if (sd.len > sd.total_len) - sd.len = sd.total_len; + sd->len = buf->len; + if (sd->len > sd->total_len) + sd->len = sd->total_len; - err = actor(pipe, buf, &sd); + err = actor(pipe, buf, sd); if (err <= 0) { if (!ret && err != -ENODATA) ret = err; @@ -704,10 +697,10 @@ ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, buf->offset += err; buf->len -= err; - sd.len -= err; - sd.pos += err; - sd.total_len -= err; - if (sd.len) + sd->len -= err; + sd->pos += err; + sd->total_len -= err; + if (sd->len) continue; if (!buf->len) { @@ -719,7 +712,7 @@ ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, do_wakeup = 1; } - if (!sd.total_len) + if (!sd->total_len) break; } @@ -732,7 +725,7 @@ ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, break; } - if (flags & SPLICE_F_NONBLOCK) { + if (sd->flags & SPLICE_F_NONBLOCK) { if (!ret) ret = -EAGAIN; break; @@ -772,6 +765,12 @@ ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, { ssize_t ret; struct inode *inode = out->f_mapping->host; + struct splice_desc sd = { + .total_len = len, + .flags = flags, + .pos = *ppos, + .file = out, + }; /* * The actor worker might be calling ->prepare_write and @@ -780,7 +779,7 @@ ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out, * pipe->inode, we have to order lock acquiry here. */ inode_double_lock(inode, pipe->inode); - ret = __splice_from_pipe(pipe, out, ppos, len, flags, actor); + ret = __splice_from_pipe(pipe, &sd, actor); inode_double_unlock(inode, pipe->inode); return ret; @@ -804,6 +803,12 @@ generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out, { struct address_space *mapping = out->f_mapping; struct inode *inode = mapping->host; + struct splice_desc sd = { + .total_len = len, + .flags = flags, + .pos = *ppos, + .file = out, + }; ssize_t ret; int err; @@ -811,7 +816,7 @@ generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out, if (unlikely(err)) return err; - ret = __splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_file); + ret = __splice_from_pipe(pipe, &sd, pipe_to_file); if (ret > 0) { unsigned long nr_pages; @@ -956,14 +961,17 @@ static long do_splice_to(struct file *in, loff_t *ppos, return in->f_op->splice_read(in, ppos, pipe, len, flags); } -long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, - size_t len, unsigned int flags) +/* + * Splices from an input file to an actor, using a 'direct' pipe. + */ +ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd, + splice_direct_actor *actor) { struct pipe_inode_info *pipe; long ret, bytes; - loff_t out_off; umode_t i_mode; - int i; + size_t len; + int i, flags; /* * We require the input being a regular file, as we don't want to @@ -999,7 +1007,13 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, */ ret = 0; bytes = 0; - out_off = 0; + len = sd->total_len; + flags = sd->flags; + + /* + * Don't block on output, we have to drain the direct pipe. + */ + sd->flags &= ~SPLICE_F_NONBLOCK; while (len) { size_t read_len, max_read_len; @@ -1009,19 +1023,19 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, */ max_read_len = min(len, (size_t)(PIPE_BUFFERS*PAGE_SIZE)); - ret = do_splice_to(in, ppos, pipe, max_read_len, flags); + ret = do_splice_to(in, &sd->pos, pipe, max_read_len, flags); if (unlikely(ret < 0)) goto out_release; read_len = ret; + sd->total_len = read_len; /* * NOTE: nonblocking mode only applies to the input. We * must not do the output in nonblocking mode as then we * could get stuck data in the internal pipe: */ - ret = do_splice_from(pipe, out, &out_off, read_len, - flags & ~SPLICE_F_NONBLOCK); + ret = actor(pipe, sd); if (unlikely(ret < 0)) goto out_release; @@ -1066,6 +1080,33 @@ out_release: return bytes; return ret; + +} +EXPORT_SYMBOL(splice_direct_to_actor); + +static int direct_splice_actor(struct pipe_inode_info *pipe, + struct splice_desc *sd) +{ + struct file *file = sd->file; + + return do_splice_from(pipe, file, &sd->pos, sd->total_len, sd->flags); +} + +long do_splice_direct(struct file *in, loff_t *ppos, struct file *out, + size_t len, unsigned int flags) +{ + struct splice_desc sd = { + .len = len, + .total_len = len, + .flags = flags, + .pos = *ppos, + .file = out, + }; + size_t ret; + + ret = splice_direct_to_actor(in, &sd, direct_splice_actor); + *ppos = sd.pos; + return ret; } /* -- cgit v1.2.3-55-g7522