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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-10-07 15:36:58 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-10-07 15:36:58 -0700 |
commit | d1f5323370fceaed43a7ee38f4c7bfc7e70f28d0 (patch) | |
tree | cadb1dc22207a4e1838b7af31ac3fc15363e809b /kernel/relay.c | |
parent | 2eee010d092903ee95716b6c2fbd9d3289839aa4 (diff) | |
parent | a949e63992469fed87aef197347960ced31701b8 (diff) | |
download | lwn-d1f5323370fceaed43a7ee38f4c7bfc7e70f28d0.tar.gz lwn-d1f5323370fceaed43a7ee38f4c7bfc7e70f28d0.zip |
Merge branch 'work.splice_read' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
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
Diffstat (limited to 'kernel/relay.c')
-rw-r--r-- | kernel/relay.c | 78 |
1 files changed, 20 insertions, 58 deletions
diff --git a/kernel/relay.c b/kernel/relay.c index fc9b4a4af463..9988f5cc2d46 100644 --- a/kernel/relay.c +++ b/kernel/relay.c @@ -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); - inode_unlock(file_inode(filp)); + buffer += ret; + written += ret; + count -= ret; - return desc->written; -} + 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)); -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) |