Linux-Fsdevel Archive on lore.kernel.org
 help / color / Atom feed
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dave Chinner <david@fromorbit.com>, CAI Qian <caiqian@redhat.com>,
	linux-xfs <linux-xfs@vger.kernel.org>,
	xfs@oss.sgi.com, Jens Axboe <axboe@kernel.dk>,
	Nick Piggin <npiggin@gmail.com>,
	linux-fsdevel@vger.kernel.org
Subject: [PATCH 06/11] new helper: add_to_pipe()
Date: Fri, 23 Sep 2016 20:04:23 +0100
Message-ID: <20160923190423.GD2356@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20160923190032.GA25771@ZenIV.linux.org.uk>

single-buffer analogue of splice_to_pipe(); vmsplice_to_pipe() switched
to that, leaving splice_to_pipe() only for ->splice_read() instances
(and that only until they are converted as well).

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/splice.c            | 109 ++++++++++++++++++++++++++++---------------------
 include/linux/splice.h |   2 +
 2 files changed, 64 insertions(+), 47 deletions(-)

diff --git a/fs/splice.c b/fs/splice.c
index 9ce6e62..085ad37 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -203,8 +203,6 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
 		buf->len = spd->partial[page_nr].len;
 		buf->private = spd->partial[page_nr].private;
 		buf->ops = spd->ops;
-		if (spd->flags & SPLICE_F_GIFT)
-			buf->flags |= PIPE_BUF_FLAG_GIFT;
 
 		pipe->nrbufs++;
 		page_nr++;
@@ -225,6 +223,27 @@ out:
 }
 EXPORT_SYMBOL_GPL(splice_to_pipe);
 
+ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
+{
+	int ret;
+
+	if (unlikely(!pipe->readers)) {
+		send_sig(SIGPIPE, current, 0);
+		ret = -EPIPE;
+	} else if (pipe->nrbufs == pipe->buffers) {
+		ret = -EAGAIN;
+	} else {
+		int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
+		pipe->bufs[newbuf] = *buf;
+		pipe->nrbufs++;
+		return buf->len;
+	}
+	buf->ops->release(pipe, buf);
+	buf->ops = NULL;
+	return ret;
+}
+EXPORT_SYMBOL(add_to_pipe);
+
 void spd_release_page(struct splice_pipe_desc *spd, unsigned int i)
 {
 	put_page(spd->pages[i]);
@@ -1436,33 +1455,50 @@ static long do_splice(struct file *in, loff_t __user *off_in,
 	return -EINVAL;
 }
 
-static int get_iovec_page_array(const struct iov_iter *from,
-				struct page **pages,
-				struct partial_page *partial,
-				unsigned int pipe_buffers)
+static int iter_to_pipe(struct iov_iter *from,
+			struct pipe_inode_info *pipe,
+			unsigned flags)
 {
-	struct iov_iter i = *from;
-	int buffers = 0;
-	while (iov_iter_count(&i)) {
+	struct pipe_buffer buf = {
+		.ops = &user_page_pipe_buf_ops,
+		.flags = flags
+	};
+	size_t total = 0;
+	int ret = 0;
+	bool failed = false;
+
+	while (iov_iter_count(from) && !failed) {
+		struct page *pages[16];
 		ssize_t copied;
 		size_t start;
+		int n;
 
-		copied = iov_iter_get_pages(&i, pages + buffers, ~0UL,
-					pipe_buffers - buffers, &start);
-		if (copied <= 0)
-			return buffers ? buffers : copied;
+		copied = iov_iter_get_pages(from, pages, ~0UL, 16, &start);
+		if (copied <= 0) {
+			ret = copied;
+			break;
+		}
 
-		iov_iter_advance(&i, copied);
-		while (copied) {
+		for (n = 0; copied; n++, start = 0) {
 			int size = min_t(int, copied, PAGE_SIZE - start);
-			partial[buffers].offset = start;
-			partial[buffers].len = size;
+			if (!failed) {
+				buf.page = pages[n];
+				buf.offset = start;
+				buf.len = size;
+				ret = add_to_pipe(pipe, &buf);
+				if (unlikely(ret < 0)) {
+					failed = true;
+				} else {
+					iov_iter_advance(from, ret);
+					total += ret;
+				}
+			} else {
+				put_page(pages[n]);
+			}
 			copied -= size;
-			start = 0;
-			buffers++;
 		}
 	}
-	return buffers;
+	return total ? total : ret;
 }
 
 static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
@@ -1523,19 +1559,13 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *uiov,
 	struct iovec iovstack[UIO_FASTIOV];
 	struct iovec *iov = iovstack;
 	struct iov_iter from;
-	struct page *pages[PIPE_DEF_BUFFERS];
-	struct partial_page partial[PIPE_DEF_BUFFERS];
-	struct splice_pipe_desc spd = {
-		.pages = pages,
-		.partial = partial,
-		.nr_pages_max = PIPE_DEF_BUFFERS,
-		.flags = flags,
-		.ops = &user_page_pipe_buf_ops,
-		.spd_release = spd_release_page,
-	};
 	long ret, total = 0;
+	unsigned buf_flag = 0;
 	int bogus_count;
 
+	if (flags & SPLICE_F_GIFT)
+		buf_flag = PIPE_BUF_FLAG_GIFT;
+
 	pipe = get_pipe_info(file);
 	if (!pipe)
 		return -EBADF;
@@ -1545,27 +1575,13 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *uiov,
 	if (ret < 0)
 		return ret;
 
-	if (splice_grow_spd(pipe, &spd)) {
-		kfree(iov);
-		return -ENOMEM;
-	}
-
 	pipe_lock(pipe);
 	bogus_count = pipe->buffers;
 	do {
 		bogus_count += pipe->nrbufs;
-		spd.nr_pages = get_iovec_page_array(&from, spd.pages,
-						    spd.partial,
-						    spd.nr_pages_max);
-		if (spd.nr_pages <= 0) {
-			ret = spd.nr_pages;
-			break;
-		}
-		ret = splice_to_pipe(pipe, &spd);
-		if (ret > 0) {
+		ret = iter_to_pipe(&from, pipe, buf_flag);
+		if (ret > 0)
 			total += ret;
-			iov_iter_advance(&from, ret);
-		}
 		bogus_count -= pipe->nrbufs;
 		if (bogus_count <= 0)
 			break;
@@ -1575,7 +1591,6 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *uiov,
 		wakeup_pipe_readers(pipe);
 		ret = total;
 	}
-	splice_shrink_spd(&spd);
 	kfree(iov);
 	return ret;
 }
diff --git a/include/linux/splice.h b/include/linux/splice.h
index da2751d..58b300f 100644
--- a/include/linux/splice.h
+++ b/include/linux/splice.h
@@ -72,6 +72,8 @@ extern ssize_t __splice_from_pipe(struct pipe_inode_info *,
 				  struct splice_desc *, splice_actor *);
 extern ssize_t splice_to_pipe(struct pipe_inode_info *,
 			      struct splice_pipe_desc *);
+extern ssize_t add_to_pipe(struct pipe_inode_info *,
+			      struct pipe_buffer *);
 extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
 				      splice_direct_actor *);
 
-- 
2.9.3


  parent reply index

Thread overview: 101+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20160908235521.GL2356@ZenIV.linux.org.uk>
     [not found] ` <20160909015324.GD30056@dastard>
     [not found]   ` <CA+55aFzohsUXj_3BeFNr2t50Wm=G+7toRDEz=Tk7VJqP3n1hXQ@mail.gmail.com>
     [not found]     ` <CA+55aFxrqCng2Qxasc9pyMrKUGFjo==fEaFT1vkH9Lncte3RgQ@mail.gmail.com>
     [not found]       ` <20160909023452.GO2356@ZenIV.linux.org.uk>
     [not found]         ` <CA+55aFwHQMjO4-vtfB9-ytc=o+DRo-HXVGckvXLboUxgpwb7_g@mail.gmail.com>
     [not found]           ` <20160909221945.GQ2356@ZenIV.linux.org.uk>
     [not found]             ` <CA+55aFzTOOB6oEVaaGD0N7Uznk-W9+ULPwzsxS_L_oZqGVSeLA@mail.gmail.com>
     [not found]               ` <20160914031648.GB2356@ZenIV.linux.org.uk>
     [not found]                 ` <20160914133925.2fba4629@roar.ozlabs.ibm.com>
2016-09-18  5:33                   ` xfs_file_splice_read: possible circular locking dependency detected Al Viro
2016-09-19  3:08                     ` Nicholas Piggin
2016-09-19  6:11                       ` Al Viro
2016-09-19  7:26                         ` Nicholas Piggin
     [not found]                 ` <CA+55aFznQaOWoSMNphgGJJWZ=8-odrc0DAUMzfGPQe+_N4UgNA@mail.gmail.com>
     [not found]                   ` <20160914042559.GC2356@ZenIV.linux.org.uk>
     [not found]                     ` <20160917082007.GA6489@ZenIV.linux.org.uk>
     [not found]                       ` <20160917190023.GA8039@ZenIV.linux.org.uk>
2016-09-18 19:31                         ` skb_splice_bits() and large chunks in pipe (was " Al Viro
2016-09-18 20:12                           ` Linus Torvalds
2016-09-18 22:31                             ` Al Viro
2016-09-19  0:18                               ` Linus Torvalds
2016-09-23 19:00                         ` [RFC][CFT] splice_read reworked Al Viro
2016-09-23 19:01                           ` [PATCH 01/11] fix memory leaks in tracing_buffers_splice_read() Al Viro
2016-09-23 19:02                           ` [PATCH 02/11] splice_to_pipe(): don't open-code wakeup_pipe_readers() Al Viro
2016-09-23 19:02                           ` [PATCH 03/11] splice: switch get_iovec_page_array() to iov_iter Al Viro
2016-09-23 19:03                           ` [PATCH 04/11] splice: lift pipe_lock out of splice_to_pipe() Al Viro
2016-09-23 19:45                             ` Linus Torvalds
2016-09-23 20:10                               ` Al Viro
2016-09-23 20:36                                 ` Linus Torvalds
2016-09-24  3:59                                   ` Al Viro
2016-09-24 17:29                                     ` Al Viro
2016-09-27 15:38                                       ` Nicholas Piggin
2016-09-27 15:53                                       ` Chuck Lever
2016-09-24  3:59                                   ` [PATCH 04/12] " Al Viro
2016-09-26 13:35                                     ` Miklos Szeredi
2016-09-27  4:14                                       ` Al Viro
2016-12-17 19:54                                     ` Andreas Schwab
2016-12-18 19:28                                       ` Linus Torvalds
2016-12-18 19:57                                         ` Andreas Schwab
2016-12-18 20:12                                         ` Al Viro
2016-12-18 20:30                                           ` Al Viro
2016-12-18 22:10                                             ` Linus Torvalds
2016-12-18 22:18                                               ` Al Viro
2016-12-18 22:22                                                 ` Linus Torvalds
2016-12-18 22:49                                               ` Andreas Schwab
2016-12-21 18:56                                               ` Andreas Schwab
2016-12-21 19:12                                                 ` Linus Torvalds
2016-09-24  4:00                                   ` [PATCH 06/12] new helper: add_to_pipe() Al Viro
2016-09-26 13:49                                     ` Miklos Szeredi
2016-09-24  4:01                                   ` [PATCH 10/12] new iov_iter flavour: pipe-backed Al Viro
2016-09-29 20:53                                     ` Miklos Szeredi
2016-09-29 22:50                                       ` Al Viro
2016-09-30  7:30                                         ` Miklos Szeredi
2016-10-03  3:34                                           ` [RFC] O_DIRECT vs EFAULT (was Re: [PATCH 10/12] new iov_iter flavour: pipe-backed) Al Viro
2016-10-03 17:07                                             ` Linus Torvalds
2016-10-03 18:54                                               ` Al Viro
2016-09-24  4:01                                   ` [PATCH 11/12] switch generic_file_splice_read() to use of ->read_iter() Al Viro
2016-09-24  4:02                                   ` [PATCH 12/12] switch default_file_splice_read() to use of pipe-backed iov_iter Al Viro
2016-09-23 19:03                           ` [PATCH 05/11] skb_splice_bits(): get rid of callback Al Viro
2016-09-23 19:04                           ` Al Viro [this message]
2016-09-23 19:04                           ` [PATCH 07/11] fuse_dev_splice_read(): switch to add_to_pipe() Al Viro
2016-09-23 19:06                           ` [PATCH 08/11] cifs: don't use memcpy() to copy struct iov_iter Al Viro
2016-09-23 19:08                           ` [PATCH 09/11] fuse_ioctl_copy_user(): don't open-code copy_page_{to,from}_iter() Al Viro
2016-09-26  9:31                             ` Miklos Szeredi
2016-09-23 19:09                           ` [PATCH 10/11] new iov_iter flavour: pipe-backed Al Viro
2016-09-23 19:10                           ` [PATCH 11/11] switch generic_file_splice_read() to use of ->read_iter() Al Viro
2016-09-30 13:32                           ` [RFC][CFT] splice_read reworked CAI Qian
2016-09-30 17:42                             ` CAI Qian
2016-09-30 18:33                               ` CAI Qian
2016-10-03  1:37                                 ` Al Viro
2016-10-03 17:49                                   ` CAI Qian
2016-10-04 17:39                                     ` local DoS - systemd hang or timeout (WAS: Re: [RFC][CFT] splice_read reworked) CAI Qian
2016-10-04 21:42                                       ` tj
2016-10-05 14:09                                         ` CAI Qian
2016-10-05 15:30                                           ` tj
2016-10-05 15:54                                             ` CAI Qian
2016-10-05 18:57                                               ` CAI Qian
2016-10-05 20:05                                                 ` Al Viro
2016-10-06 12:20                                                   ` CAI Qian
2016-10-06 12:25                                                     ` CAI Qian
2016-10-06 16:11                                                       ` CAI Qian
2016-10-06 17:00                                                         ` Linus Torvalds
2016-10-06 18:12                                                           ` CAI Qian
2016-10-07  9:57                                                           ` Dave Chinner
2016-10-07 15:25                                                             ` Linus Torvalds
2016-10-07  7:08                                                       ` Jan Kara
2016-10-07 14:43                                                         ` CAI Qian
2016-10-07 15:27                                                           ` CAI Qian
2016-10-07 18:56                                                             ` CAI Qian
2016-10-09 21:54                                                               ` Dave Chinner
2016-10-10 14:10                                                                 ` CAI Qian
2016-10-10 20:14                                                                   ` CAI Qian
2016-10-10 21:57                                                                   ` Dave Chinner
2016-10-12 19:50                                                                     ` [bisected] " CAI Qian
2016-10-12 20:59                                                                       ` Dave Chinner
2016-10-13 16:25                                                                         ` CAI Qian
2016-10-13 20:49                                                                           ` Dave Chinner
2016-10-13 20:56                                                                             ` CAI Qian
2016-10-09 21:51                                                           ` Dave Chinner
2016-10-21 15:38                                                         ` [4.9-rc1+] overlayfs lockdep CAI Qian
2016-10-24 12:57                                                           ` Miklos Szeredi
2016-10-07  9:27                                                     ` local DoS - systemd hang or timeout (WAS: Re: [RFC][CFT] splice_read reworked) Dave Chinner
2016-10-03  1:42                               ` [RFC][CFT] splice_read reworked Al Viro
2016-10-03 14:06                                 ` CAI Qian
2016-10-03 15:20                                   ` CAI Qian
2016-10-03 21:12                                     ` Dave Chinner
2016-10-04 13:57                                       ` CAI Qian
2016-10-03 20:32                                   ` CAI Qian
2016-10-03 20:35                                     ` Al Viro
2016-10-04 13:29                                       ` CAI Qian
2016-10-04 14:28                                         ` Al Viro
2016-10-04 16:21                                           ` CAI Qian
2016-10-04 20:12                                             ` Al Viro
2016-10-05 14:30                                               ` CAI Qian
2016-10-05 16:07                                                 ` Al Viro
2016-09-19  0:22 skb_splice_bits() and large chunks in pipe (was Re: xfs_file_splice_read: possible circular locking dependency detected Al Viro
2016-09-20  9:51 ` Herbert Xu

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20160923190423.GD2356@ZenIV.linux.org.uk \
    --to=viro@zeniv.linux.org.uk \
    --cc=axboe@kernel.dk \
    --cc=caiqian@redhat.com \
    --cc=david@fromorbit.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-xfs@vger.kernel.org \
    --cc=npiggin@gmail.com \
    --cc=torvalds@linux-foundation.org \
    --cc=xfs@oss.sgi.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Fsdevel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-fsdevel/0 linux-fsdevel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-fsdevel linux-fsdevel/ https://lore.kernel.org/linux-fsdevel \
		linux-fsdevel@vger.kernel.org
	public-inbox-index linux-fsdevel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-fsdevel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git