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Merge branch 'work.splice_read' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

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Pull VFS splice updates from Al Viro:
 "There's a bunch of branches this cycle, both mine and from other folks
  and I'd rather send pull requests separately.

  This one is the conversion of ->splice_read() to ITER_PIPE iov_iter
  (and introduction of such). Gets rid of a lot of code in fs/splice.c
  and elsewhere; there will be followups, but these are for the next
  cycle...  Some pipe/splice-related cleanups from Miklos in the same
  branch as well"

* 'work.splice_read' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  pipe: fix comment in pipe_buf_operations
  pipe: add pipe_buf_steal() helper
  pipe: add pipe_buf_confirm() helper
  pipe: add pipe_buf_release() helper
  pipe: add pipe_buf_get() helper
  relay: simplify relay_file_read()
  switch default_file_splice_read() to use of pipe-backed iov_iter
  switch generic_file_splice_read() to use of ->read_iter()
  new iov_iter flavour: pipe-backed
  fuse_dev_splice_read(): switch to add_to_pipe()
  skb_splice_bits(): get rid of callback
  new helper: add_to_pipe()
  splice: lift pipe_lock out of splice_to_pipe()
  splice: switch get_iovec_page_array() to iov_iter
  splice_to_pipe(): don't open-code wakeup_pipe_readers()
  consistent treatment of EFAULT on O_DIRECT read/write
This commit is contained in:
Linus Torvalds 2016-10-07 15:36:58 -07:00
commit d1f5323370
30 changed files with 748 additions and 1079 deletions
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78
kernel/relay.c
View file

@ -1108,51 +1108,23 @@ static size_t relay_file_read_end_pos(struct rchan_buf *buf,
return end_pos;
}
/*
* subbuf_read_actor - read up to one subbuf's worth of data
*/
static int subbuf_read_actor(size_t read_start,
struct rchan_buf *buf,
size_t avail,
read_descriptor_t *desc)
{
void *from;
int ret = 0;
from = buf->start + read_start;
ret = avail;
if (copy_to_user(desc->arg.buf, from, avail)) {
desc->error = -EFAULT;
ret = 0;
}
desc->arg.data += ret;
desc->written += ret;
desc->count -= ret;
return ret;
}
typedef int (*subbuf_actor_t) (size_t read_start,
struct rchan_buf *buf,
size_t avail,
read_descriptor_t *desc);
/*
* relay_file_read_subbufs - read count bytes, bridging subbuf boundaries
*/
static ssize_t relay_file_read_subbufs(struct file *filp, loff_t *ppos,
subbuf_actor_t subbuf_actor,
read_descriptor_t *desc)
static ssize_t relay_file_read(struct file *filp,
char __user *buffer,
size_t count,
loff_t *ppos)
{
struct rchan_buf *buf = filp->private_data;
size_t read_start, avail;
size_t written = 0;
int ret;
if (!desc->count)
if (!count)
return 0;
inode_lock(file_inode(filp));
do {
void *from;
if (!relay_file_read_avail(buf, *ppos))
break;
@ -1161,32 +1133,22 @@ static ssize_t relay_file_read_subbufs(struct file *filp, loff_t *ppos,
if (!avail)
break;
avail = min(desc->count, avail);
ret = subbuf_actor(read_start, buf, avail, desc);
if (desc->error < 0)
avail = min(count, avail);
from = buf->start + read_start;
ret = avail;
if (copy_to_user(buffer, from, avail))
break;
if (ret) {
relay_file_read_consume(buf, read_start, ret);
*ppos = relay_file_read_end_pos(buf, read_start, ret);
}
} while (desc->count && ret);
buffer += ret;
written += ret;
count -= ret;
relay_file_read_consume(buf, read_start, ret);
*ppos = relay_file_read_end_pos(buf, read_start, ret);
} while (count);
inode_unlock(file_inode(filp));
return desc->written;
}
static ssize_t relay_file_read(struct file *filp,
char __user *buffer,
size_t count,
loff_t *ppos)
{
read_descriptor_t desc;
desc.written = 0;
desc.count = count;
desc.arg.buf = buffer;
desc.error = 0;
return relay_file_read_subbufs(filp, ppos, subbuf_read_actor, &desc);
return written;
}
static void relay_consume_bytes(struct rchan_buf *rbuf, int bytes_consumed)