Merge branch 'for-rmk' of git://git.pengutronix.de/git/imx/linux-2.6

15 files changed, 349 insertions, 277 deletions

diff --git a/fs/bio.c b/fs/bio.c
index e0c9e545bbf..cd42bb882f3 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -348,6 +348,24 @@ err:
 	return NULL;
 }
 
+/**
+ * bio_alloc - allocate a bio for I/O
+ * @gfp_mask:   the GFP_ mask given to the slab allocator
+ * @nr_iovecs:	number of iovecs to pre-allocate
+ *
+ * Description:
+ *   bio_alloc will allocate a bio and associated bio_vec array that can hold
+ *   at least @nr_iovecs entries. Allocations will be done from the
+ *   fs_bio_set. Also see @bio_alloc_bioset.
+ *
+ *   If %__GFP_WAIT is set, then bio_alloc will always be able to allocate
+ *   a bio. This is due to the mempool guarantees. To make this work, callers
+ *   must never allocate more than 1 bio at the time from this pool. Callers
+ *   that need to allocate more than 1 bio must always submit the previously
+ *   allocate bio for IO before attempting to allocate a new one. Failure to
+ *   do so can cause livelocks under memory pressure.
+ *
+ **/
 struct bio *bio_alloc(gfp_t gfp_mask, int nr_iovecs)
 {
 	struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
diff --git a/fs/buffer.c b/fs/buffer.c
index 13edf7ad3ff..ff8bb1f2333 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -547,7 +547,7 @@ repeat:
 	return err;
 }
 
-void do_thaw_all(unsigned long unused)
+void do_thaw_all(struct work_struct *work)
 {
 	struct super_block *sb;
 	char b[BDEVNAME_SIZE];
@@ -567,6 +567,7 @@ restart:
 			goto restart;
 	}
 	spin_unlock(&sb_lock);
+	kfree(work);
 	printk(KERN_WARNING "Emergency Thaw complete\n");
 }
 
@@ -577,7 +578,13 @@ restart:
  */
 void emergency_thaw_all(void)
 {
-	pdflush_operation(do_thaw_all, 0);
+	struct work_struct *work;
+
+	work = kmalloc(sizeof(*work), GFP_ATOMIC);
+	if (work) {
+		INIT_WORK(work, do_thaw_all);
+		schedule_work(work);
+	}
 }
 
 /**
diff --git a/fs/direct-io.c b/fs/direct-io.c
index da258e7249c..05763bbc205 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -307,8 +307,6 @@ dio_bio_alloc(struct dio *dio, struct block_device *bdev,
 	struct bio *bio;
 
 	bio = bio_alloc(GFP_KERNEL, nr_vecs);
-	if (bio == NULL)
-		return -ENOMEM;
 
 	bio->bi_bdev = bdev;
 	bio->bi_sector = first_sector;
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 6132353dcf6..2a1cb097976 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2416,8 +2416,6 @@ static int ext4_ext_zeroout(struct inode *inode, struct ext4_extent *ex)
 			len = ee_len;
 
 		bio = bio_alloc(GFP_NOIO, len);
-		if (!bio)
-			return -ENOMEM;
 		bio->bi_sector = ee_pblock;
 		bio->bi_bdev   = inode->i_sb->s_bdev;
 
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 3984e47d1d3..1afd9f26bcb 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -597,7 +597,6 @@ __acquires(&gl->gl_spin)
 
 	GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
 
-	down_read(&gfs2_umount_flush_sem);
 	if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
 	    gl->gl_demote_state != gl->gl_state) {
 		if (find_first_holder(gl))
@@ -614,15 +613,14 @@ __acquires(&gl->gl_spin)
 		if (ret == 0)
 			goto out_unlock;
 		if (ret == 2)
-			goto out_sem;
+			goto out;
 		gh = find_first_waiter(gl);
 		gl->gl_target = gh->gh_state;
 		if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
 			do_error(gl, 0); /* Fail queued try locks */
 	}
 	do_xmote(gl, gh, gl->gl_target);
-out_sem:
-	up_read(&gfs2_umount_flush_sem);
+out:
 	return;
 
 out_sched:
@@ -631,7 +629,7 @@ out_sched:
 		gfs2_glock_put(gl);
 out_unlock:
 	clear_bit(GLF_LOCK, &gl->gl_flags);
-	goto out_sem;
+	goto out;
 }
 
 static void glock_work_func(struct work_struct *work)
@@ -641,6 +639,7 @@ static void glock_work_func(struct work_struct *work)
 
 	if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags))
 		finish_xmote(gl, gl->gl_reply);
+	down_read(&gfs2_umount_flush_sem);
 	spin_lock(&gl->gl_spin);
 	if (test_and_clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
 	    gl->gl_state != LM_ST_UNLOCKED &&
@@ -653,6 +652,7 @@ static void glock_work_func(struct work_struct *work)
 	}
 	run_queue(gl, 0);
 	spin_unlock(&gl->gl_spin);
+	up_read(&gfs2_umount_flush_sem);
 	if (!delay ||
 	    queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
 		gfs2_glock_put(gl);
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 7b277d44915..5a31d426116 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -137,15 +137,15 @@ void gfs2_set_iop(struct inode *inode)
 	if (S_ISREG(mode)) {
 		inode->i_op = &gfs2_file_iops;
 		if (gfs2_localflocks(sdp))
-			inode->i_fop = gfs2_file_fops_nolock;
+			inode->i_fop = &gfs2_file_fops_nolock;
 		else
-			inode->i_fop = gfs2_file_fops;
+			inode->i_fop = &gfs2_file_fops;
 	} else if (S_ISDIR(mode)) {
 		inode->i_op = &gfs2_dir_iops;
 		if (gfs2_localflocks(sdp))
-			inode->i_fop = gfs2_dir_fops_nolock;
+			inode->i_fop = &gfs2_dir_fops_nolock;
 		else
-			inode->i_fop = gfs2_dir_fops;
+			inode->i_fop = &gfs2_dir_fops;
 	} else if (S_ISLNK(mode)) {
 		inode->i_op = &gfs2_symlink_iops;
 	} else {
diff --git a/fs/gfs2/inode.h b/fs/gfs2/inode.h
index dca4fee3078..c30be2b6658 100644
--- a/fs/gfs2/inode.h
+++ b/fs/gfs2/inode.h
@@ -101,21 +101,23 @@ void gfs2_dinode_print(const struct gfs2_inode *ip);
 extern const struct inode_operations gfs2_file_iops;
 extern const struct inode_operations gfs2_dir_iops;
 extern const struct inode_operations gfs2_symlink_iops;
-extern const struct file_operations *gfs2_file_fops_nolock;
-extern const struct file_operations *gfs2_dir_fops_nolock;
+extern const struct file_operations gfs2_file_fops_nolock;
+extern const struct file_operations gfs2_dir_fops_nolock;
 
 extern void gfs2_set_inode_flags(struct inode *inode);
  
 #ifdef CONFIG_GFS2_FS_LOCKING_DLM
-extern const struct file_operations *gfs2_file_fops;
-extern const struct file_operations *gfs2_dir_fops;
+extern const struct file_operations gfs2_file_fops;
+extern const struct file_operations gfs2_dir_fops;
+
 static inline int gfs2_localflocks(const struct gfs2_sbd *sdp)
 {
 	return sdp->sd_args.ar_localflocks;
 }
 #else /* Single node only */
-#define gfs2_file_fops NULL
-#define gfs2_dir_fops NULL
+#define gfs2_file_fops gfs2_file_fops_nolock
+#define gfs2_dir_fops gfs2_dir_fops_nolock
+
 static inline int gfs2_localflocks(const struct gfs2_sbd *sdp)
 {
 	return 1;
diff --git a/fs/gfs2/ops_file.c b/fs/gfs2/ops_file.c
index 70b9b854894..101caf3ee86 100644
--- a/fs/gfs2/ops_file.c
+++ b/fs/gfs2/ops_file.c
@@ -705,7 +705,7 @@ static int gfs2_flock(struct file *file, int cmd, struct file_lock *fl)
 	}
 }
 
-const struct file_operations *gfs2_file_fops = &(const struct file_operations){
+const struct file_operations gfs2_file_fops = {
 	.llseek		= gfs2_llseek,
 	.read		= do_sync_read,
 	.aio_read	= generic_file_aio_read,
@@ -723,7 +723,7 @@ const struct file_operations *gfs2_file_fops = &(const struct file_operations){
 	.setlease	= gfs2_setlease,
 };
 
-const struct file_operations *gfs2_dir_fops = &(const struct file_operations){
+const struct file_operations gfs2_dir_fops = {
 	.readdir	= gfs2_readdir,
 	.unlocked_ioctl	= gfs2_ioctl,
 	.open		= gfs2_open,
@@ -735,7 +735,7 @@ const struct file_operations *gfs2_dir_fops = &(const struct file_operations){
 
 #endif /* CONFIG_GFS2_FS_LOCKING_DLM */
 
-const struct file_operations *gfs2_file_fops_nolock = &(const struct file_operations){
+const struct file_operations gfs2_file_fops_nolock = {
 	.llseek		= gfs2_llseek,
 	.read		= do_sync_read,
 	.aio_read	= generic_file_aio_read,
@@ -751,7 +751,7 @@ const struct file_operations *gfs2_file_fops_nolock = &(const struct file_operat
 	.setlease	= generic_setlease,
 };
 
-const struct file_operations *gfs2_dir_fops_nolock = &(const struct file_operations){
+const struct file_operations gfs2_dir_fops_nolock = {
 	.readdir	= gfs2_readdir,
 	.unlocked_ioctl	= gfs2_ioctl,
 	.open		= gfs2_open,
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 51883b3ad89..650a730707b 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -272,11 +272,6 @@ static int gfs2_read_super(struct gfs2_sbd *sdp, sector_t sector)
 	lock_page(page);
 
 	bio = bio_alloc(GFP_NOFS, 1);
-	if (unlikely(!bio)) {
-		__free_page(page);
-		return -ENOBUFS;
-	}
-
 	bio->bi_sector = sector * (sb->s_blocksize >> 9);
 	bio->bi_bdev = sb->s_bdev;
 	bio_add_page(bio, page, PAGE_SIZE, 0);
diff --git a/fs/gfs2/ops_inode.c b/fs/gfs2/ops_inode.c
index abd5429ae28..1c70fa5168d 100644
--- a/fs/gfs2/ops_inode.c
+++ b/fs/gfs2/ops_inode.c
@@ -371,6 +371,7 @@ static int gfs2_symlink(struct inode *dir, struct dentry *dentry,
 	ip = ghs[1].gh_gl->gl_object;
 
 	ip->i_disksize = size;
+	i_size_write(inode, size);
 
 	error = gfs2_meta_inode_buffer(ip, &dibh);
 
diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index 8d53f66b5bc..152e6c4a0dc 100644
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -81,7 +81,7 @@ struct gfs2_quota_change_host {
 
 static LIST_HEAD(qd_lru_list);
 static atomic_t qd_lru_count = ATOMIC_INIT(0);
-static spinlock_t qd_lru_lock = SPIN_LOCK_UNLOCKED;
+static DEFINE_SPINLOCK(qd_lru_lock);
 
 int gfs2_shrink_qd_memory(int nr, gfp_t gfp_mask)
 {
@@ -1364,7 +1364,7 @@ int gfs2_quotad(void *data)
 			refrigerator();
 		t = min(quotad_timeo, statfs_timeo);
 
-		prepare_to_wait(&sdp->sd_quota_wait, &wait, TASK_UNINTERRUPTIBLE);
+		prepare_to_wait(&sdp->sd_quota_wait, &wait, TASK_INTERRUPTIBLE);
 		spin_lock(&sdp->sd_trunc_lock);
 		empty = list_empty(&sdp->sd_trunc_list);
 		spin_unlock(&sdp->sd_trunc_lock);
diff --git a/fs/inode.c b/fs/inode.c
index d06d6d268de..6ad14a1cd8c 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1470,42 +1470,6 @@ static void __wait_on_freeing_inode(struct inode *inode)
 	spin_lock(&inode_lock);
 }
 
-/*
- * We rarely want to lock two inodes that do not have a parent/child
- * relationship (such as directory, child inode) simultaneously. The
- * vast majority of file systems should be able to get along fine
- * without this. Do not use these functions except as a last resort.
- */
-void inode_double_lock(struct inode *inode1, struct inode *inode2)
-{
-	if (inode1 == NULL || inode2 == NULL || inode1 == inode2) {
-		if (inode1)
-			mutex_lock(&inode1->i_mutex);
-		else if (inode2)
-			mutex_lock(&inode2->i_mutex);
-		return;
-	}
-
-	if (inode1 < inode2) {
-		mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
-		mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
-	} else {
-		mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT);
-		mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD);
-	}
-}
-EXPORT_SYMBOL(inode_double_lock);
-
-void inode_double_unlock(struct inode *inode1, struct inode *inode2)
-{
-	if (inode1)
-		mutex_unlock(&inode1->i_mutex);
-
-	if (inode2 && inode2 != inode1)
-		mutex_unlock(&inode2->i_mutex);
-}
-EXPORT_SYMBOL(inode_double_unlock);
-
 static __initdata unsigned long ihash_entries;
 static int __init set_ihash_entries(char *str)
 {
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 8672b953603..c2a87c885b7 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1912,6 +1912,22 @@ out_sems:
 	return written ? written : ret;
 }
 
+static int ocfs2_splice_to_file(struct pipe_inode_info *pipe,
+				struct file *out,
+				struct splice_desc *sd)
+{
+	int ret;
+
+	ret = ocfs2_prepare_inode_for_write(out->f_path.dentry,	&sd->pos,
+					    sd->total_len, 0, NULL);
+	if (ret < 0) {
+		mlog_errno(ret);
+		return ret;
+	}
+
+	return splice_from_pipe_feed(pipe, sd, pipe_to_file);
+}
+
 static ssize_t ocfs2_file_splice_write(struct pipe_inode_info *pipe,
 				       struct file *out,
 				       loff_t *ppos,
@@ -1919,38 +1935,76 @@ static ssize_t ocfs2_file_splice_write(struct pipe_inode_info *pipe,
 				       unsigned int flags)
 {
 	int ret;
-	struct inode *inode = out->f_path.dentry->d_inode;
+	struct address_space *mapping = out->f_mapping;
+	struct inode *inode = mapping->host;
+	struct splice_desc sd = {
+		.total_len = len,
+		.flags = flags,
+		.pos = *ppos,
+		.u.file = out,
+	};
 
 	mlog_entry("(0x%p, 0x%p, %u, '%.*s')\n", out, pipe,
 		   (unsigned int)len,
 		   out->f_path.dentry->d_name.len,
 		   out->f_path.dentry->d_name.name);
 
-	mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
+	if (pipe->inode)
+		mutex_lock_nested(&pipe->inode->i_mutex, I_MUTEX_PARENT);
 
-	ret = ocfs2_rw_lock(inode, 1);
-	if (ret < 0) {
-		mlog_errno(ret);
-		goto out;
-	}
+	splice_from_pipe_begin(&sd);
+	do {
+		ret = splice_from_pipe_next(pipe, &sd);
+		if (ret <= 0)
+			break;
 
-	ret = ocfs2_prepare_inode_for_write(out->f_path.dentry, ppos, len, 0,
-					    NULL);
-	if (ret < 0) {
-		mlog_errno(ret);
-		goto out_unlock;
-	}
+		mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
+		ret = ocfs2_rw_lock(inode, 1);
+		if (ret < 0)
+			mlog_errno(ret);
+		else {
+			ret = ocfs2_splice_to_file(pipe, out, &sd);
+			ocfs2_rw_unlock(inode, 1);
+		}
+		mutex_unlock(&inode->i_mutex);
+	} while (ret > 0);
+	splice_from_pipe_end(pipe, &sd);
 
 	if (pipe->inode)
-		mutex_lock_nested(&pipe->inode->i_mutex, I_MUTEX_CHILD);
-	ret = generic_file_splice_write_nolock(pipe, out, ppos, len, flags);
-	if (pipe->inode)
 		mutex_unlock(&pipe->inode->i_mutex);
 
-out_unlock:
-	ocfs2_rw_unlock(inode, 1);
-out:
-	mutex_unlock(&inode->i_mutex);
+	if (sd.num_spliced)
+		ret = sd.num_spliced;
+
+	if (ret > 0) {
+		unsigned long nr_pages;
+
+		*ppos += ret;
+		nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+
+		/*
+		 * If file or inode is SYNC and we actually wrote some data,
+		 * sync it.
+		 */
+		if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) {
+			int err;
+
+			mutex_lock(&inode->i_mutex);
+			err = ocfs2_rw_lock(inode, 1);
+			if (err < 0) {
+				mlog_errno(err);
+			} else {
+				err = generic_osync_inode(inode, mapping,
+						  OSYNC_METADATA|OSYNC_DATA);
+				ocfs2_rw_unlock(inode, 1);
+			}
+			mutex_unlock(&inode->i_mutex);
+
+			if (err)
+				ret = err;
+		}
+		balance_dirty_pages_ratelimited_nr(mapping, nr_pages);
+	}
 
 	mlog_exit(ret);
 	return ret;
diff --git a/fs/pipe.c b/fs/pipe.c
index 4af7aa52181..13414ec45b8 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -37,6 +37,42 @@
  * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09
  */
 
+static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass)
+{
+	if (pipe->inode)
+		mutex_lock_nested(&pipe->inode->i_mutex, subclass);
+}
+
+void pipe_lock(struct pipe_inode_info *pipe)
+{
+	/*
+	 * pipe_lock() nests non-pipe inode locks (for writing to a file)
+	 */
+	pipe_lock_nested(pipe, I_MUTEX_PARENT);
+}
+EXPORT_SYMBOL(pipe_lock);
+
+void pipe_unlock(struct pipe_inode_info *pipe)
+{
+	if (pipe->inode)
+		mutex_unlock(&pipe->inode->i_mutex);
+}
+EXPORT_SYMBOL(pipe_unlock);
+
+void pipe_double_lock(struct pipe_inode_info *pipe1,
+		      struct pipe_inode_info *pipe2)
+{
+	BUG_ON(pipe1 == pipe2);
+
+	if (pipe1 < pipe2) {
+		pipe_lock_nested(pipe1, I_MUTEX_PARENT);
+		pipe_lock_nested(pipe2, I_MUTEX_CHILD);
+	} else {
+		pipe_lock_nested(pipe2, I_MUTEX_CHILD);
+		pipe_lock_nested(pipe1, I_MUTEX_PARENT);
+	}
+}
+
 /* Drop the inode semaphore and wait for a pipe event, atomically */
 void pipe_wait(struct pipe_inode_info *pipe)
 {
@@ -47,12 +83,10 @@ void pipe_wait(struct pipe_inode_info *pipe)
 	 * is considered a noninteractive wait:
 	 */
 	prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE);
-	if (pipe->inode)
-		mutex_unlock(&pipe->inode->i_mutex);
+	pipe_unlock(pipe);
 	schedule();
 	finish_wait(&pipe->wait, &wait);
-	if (pipe->inode)
-		mutex_lock(&pipe->inode->i_mutex);
+	pipe_lock(pipe);
 }
 
 static int
diff --git a/fs/splice.c b/fs/splice.c
index c18aa7e03e2..5384a90665d 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -182,8 +182,7 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
 	do_wakeup = 0;
 	page_nr = 0;
 
-	if (pipe->inode)
-		mutex_lock(&pipe->inode->i_mutex);
+	pipe_lock(pipe);
 
 	for (;;) {
 		if (!pipe->readers) {
@@ -245,15 +244,13 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
 		pipe->waiting_writers--;
 	}
 
-	if (pipe->inode) {
-		mutex_unlock(&pipe->inode->i_mutex);
+	pipe_unlock(pipe);
 
-		if (do_wakeup) {
-			smp_mb();
-			if (waitqueue_active(&pipe->wait))
-				wake_up_interruptible(&pipe->wait);
-			kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
-		}
+	if (do_wakeup) {
+		smp_mb();
+		if (waitqueue_active(&pipe->wait))
+			wake_up_interruptible(&pipe->wait);
+		kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
 	}
 
 	while (page_nr < spd_pages)
@@ -555,8 +552,8 @@ static int pipe_to_sendpage(struct pipe_inode_info *pipe,
  * SPLICE_F_MOVE isn't set, or we cannot move the page, we simply create
  * a new page in the output file page cache and fill/dirty that.
  */
-static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
-			struct splice_desc *sd)
+int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
+		 struct splice_desc *sd)
 {
 	struct file *file = sd->u.file;
 	struct address_space *mapping = file->f_mapping;
@@ -600,108 +597,178 @@ static int pipe_to_file(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 out:
 	return ret;
 }
+EXPORT_SYMBOL(pipe_to_file);
+
+static void wakeup_pipe_writers(struct pipe_inode_info *pipe)
+{
+	smp_mb();
+	if (waitqueue_active(&pipe->wait))
+		wake_up_interruptible(&pipe->wait);
+	kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
+}
 
 /**
- * __splice_from_pipe - splice data from a pipe to given actor
+ * splice_from_pipe_feed - feed available data from a pipe to a file
  * @pipe:	pipe to splice from
  * @sd:		information to @actor
  * @actor:	handler that splices the data
  *
  * Description:
- *    This function does little more than loop over the pipe and call
- *    @actor to do the actual moving of a single struct pipe_buffer to
- *    the desired destination. See pipe_to_file, pipe_to_sendpage, or
- *    pipe_to_user.
+
+ *    This function loops over the pipe and calls @actor to do the
+ *    actual moving of a single struct pipe_buffer to the desired
+ *    destination.  It returns when there's no more buffers left in
+ *    the pipe or if the requested number of bytes (@sd->total_len)
+ *    have been copied.  It returns a positive number (one) if the
+ *    pipe needs to be filled with more data, zero if the required
+ *    number of bytes have been copied and -errno on error.
  *
+ *    This, together with splice_from_pipe_{begin,end,next}, may be
+ *    used to implement the functionality of __splice_from_pipe() when
+ *    locking is required around copying the pipe buffers to the
+ *    destination.
  */
-ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd,
-			   splice_actor *actor)
+int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd,
+			  splice_actor *actor)
 {
-	int ret, do_wakeup, err;
-
-	ret = 0;
-	do_wakeup = 0;
-
-	for (;;) {
-		if (pipe->nrbufs) {
-			struct pipe_buffer *buf = pipe->bufs + pipe->curbuf;
-			const struct pipe_buf_operations *ops = buf->ops;
+	int ret;
 
-			sd->len = buf->len;
-			if (sd->len > sd->total_len)
-				sd->len = sd->total_len;
+	while (pipe->nrbufs) {
+		struct pipe_buffer *buf = pipe->bufs + pipe->curbuf;
+		const struct pipe_buf_operations *ops = buf->ops;
 
-			err = actor(pipe, buf, sd);
-			if (err <= 0) {
-				if (!ret && err != -ENODATA)
-					ret = err;
+		sd->len = buf->len;
+		if (sd->len > sd->total_len)
+			sd->len = sd->total_len;
 
-				break;
-			}
+		ret = actor(pipe, buf, sd);
+		if (ret <= 0) {
+			if (ret == -ENODATA)
+				ret = 0;
+			return ret;
+		}
+		buf->offset += ret;
+		buf->len -= ret;
 
-			ret += err;
-			buf->offset += err;
-			buf->len -= err;
+		sd->num_spliced += ret;
+		sd->len -= ret;
+		sd->pos += ret;
+		sd->total_len -= ret;
 
-			sd->len -= err;
-			sd->pos += err;
-			sd->total_len -= err;
-			if (sd->len)
-				continue;
+		if (!buf->len) {
+			buf->ops = NULL;
+			ops->release(pipe, buf);
+			pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1);
+			pipe->nrbufs--;
+			if (pipe->inode)
+				sd->need_wakeup = true;
+		}
 
-			if (!buf->len) {
-				buf->ops = NULL;
-				ops->release(pipe, buf);
-				pipe->curbuf = (pipe->curbuf + 1) & (PIPE_BUFFERS - 1);
-				pipe->nrbufs--;
-				if (pipe->inode)
-					do_wakeup = 1;
-			}
+		if (!sd->total_len)
+			return 0;
+	}
 
-			if (!sd->total_len)
-				break;
-		}
+	return 1;
+}
+EXPORT_SYMBOL(splice_from_pipe_feed);
 
-		if (pipe->nrbufs)
-			continue;
+/**
+ * splice_from_pipe_next - wait for some data to splice from
+ * @pipe:	pipe to splice from
+ * @sd:		information about the splice operation
+ *
+ * Description:
+ *    This function will wait for some data and return a positive
+ *    value (one) if pipe buffers are available.  It will return zero
+ *    or -errno if no more data needs to be spliced.
+ */
+int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd)
+{
+	while (!pipe->nrbufs) {
 		if (!pipe->writers)
-			break;
-		if (!pipe->waiting_writers) {
-			if (ret)
-				break;
-		}
+			return 0;
 
-		if (sd->flags & SPLICE_F_NONBLOCK) {
-			if (!ret)
-				ret = -EAGAIN;
-			break;
-		}
+		if (!pipe->waiting_writers && sd->num_spliced)
+			return 0;
 
-		if (signal_pending(current)) {
-			if (!ret)
-				ret = -ERESTARTSYS;
-			break;
-		}
+		if (sd->flags & SPLICE_F_NONBLOCK)
+			return -EAGAIN;
 
-		if (do_wakeup) {
-			smp_mb();
-			if (waitqueue_active(&pipe->wait))
-				wake_up_interruptible_sync(&pipe->wait);
-			kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
-			do_wakeup = 0;
+		if (signal_pending(current))
+			return -ERESTARTSYS;
+
+		if (sd->need_wakeup) {
+			wakeup_pipe_writers(pipe);
+			sd->need_wakeup = false;
 		}
 
 		pipe_wait(pipe);
 	}
 
-	if (do_wakeup) {
-		smp_mb();
-		if (waitqueue_active(&pipe->wait))
-			wake_up_interruptible(&pipe->wait);
-		kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
-	}
+	return 1;
+}
+EXPORT_SYMBOL(splice_from_pipe_next);
 
-	return ret;
+/**
+ * splice_from_pipe_begin - start splicing from pipe
+ * @pipe:	pipe to splice from
+ *
+ * Description:
+ *    This function should be called before a loop containing
+ *    splice_from_pipe_next() and splice_from_pipe_feed() to
+ *    initialize the necessary fields of @sd.
+ */
+void splice_from_pipe_begin(struct splice_desc *sd)
+{
+	sd->num_spliced = 0;
+	sd->need_wakeup = false;
+}
+EXPORT_SYMBOL(splice_from_pipe_begin);
+
+/**
+ * splice_from_pipe_end - finish splicing from pipe
+ * @pipe:	pipe to splice from
+ * @sd:		information about the splice operation
+ *
+ * Description:
+ *    This function will wake up pipe writers if necessary.  It should
+ *    be called after a loop containing splice_from_pipe_next() and
+ *    splice_from_pipe_feed().
+ */
+void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd)
+{
+	if (sd->need_wakeup)
+		wakeup_pipe_writers(pipe);
+}
+EXPORT_SYMBOL(splice_from_pipe_end);
+
+/**
+ * __splice_from_pipe - splice data from a pipe to given actor
+ * @pipe:	pipe to splice from
+ * @sd:		information to @actor
+ * @actor:	handler that splices the data
+ *
+ * Description:
+ *    This function does little more than loop over the pipe and call
+ *    @actor to do the actual moving of a single struct pipe_buffer to
+ *    the desired destination. See pipe_to_file, pipe_to_sendpage, or
+ *    pipe_to_user.
+ *
+ */
+ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd,
+			   splice_actor *actor)
+{
+	int ret;
+
+	splice_from_pipe_begin(sd);
+	do {
+		ret = splice_from_pipe_next(pipe, sd);
+		if (ret > 0)
+			ret = splice_from_pipe_feed(pipe, sd, actor);
+	} while (ret > 0);
+	splice_from_pipe_end(pipe, sd);
+
+	return sd->num_spliced ? sd->num_spliced : ret;
 }
 EXPORT_SYMBOL(__splice_from_pipe);
 
@@ -715,7 +782,7 @@ EXPORT_SYMBOL(__splice_from_pipe);
  * @actor:	handler that splices the data
  *
  * Description:
- *    See __splice_from_pipe. This function locks the input and output inodes,
+ *    See __splice_from_pipe. This function locks the pipe inode,
  *    otherwise it's identical to __splice_from_pipe().
  *
  */
@@ -724,7 +791,6 @@ ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
 			 splice_actor *actor)
 {
 	ssize_t ret;
-	struct inode *inode = out->f_mapping->host;
 	struct splice_desc sd = {
 		.total_len = len,
 		.flags = flags,
@@ -732,30 +798,15 @@ ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
 		.u.file = out,
 	};
 
-	/*
-	 * The actor worker might be calling ->write_begin and
-	 * ->write_end. Most of the time, these expect i_mutex to
-	 * be held. Since this may result in an ABBA deadlock with
-	 * pipe->inode, we have to order lock acquiry here.
-	 *
-	 * Outer lock must be inode->i_mutex, as pipe_wait() will
-	 * release and reacquire pipe->inode->i_mutex, AND inode must
-	 * never be a pipe.
-	 */
-	WARN_ON(S_ISFIFO(inode->i_mode));
-	mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
-	if (pipe->inode)
-		mutex_lock_nested(&pipe->inode->i_mutex, I_MUTEX_CHILD);
+	pipe_lock(pipe);
 	ret = __splice_from_pipe(pipe, &sd, actor);
-	if (pipe->inode)
-		mutex_unlock(&pipe->inode->i_mutex);
-	mutex_unlock(&inode->i_mutex);
+	pipe_unlock(pipe);
 
 	return ret;
 }
 
 /**
- * generic_file_splice_write_nolock - generic_file_splice_write without mutexes
+ * generic_file_splice_write - splice data from a pipe to a file
  * @pipe:	pipe info
  * @out:	file to write to
  * @ppos:	position in @out
@@ -764,13 +815,12 @@ ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
  *
  * Description:
  *    Will either move or copy pages (determined by @flags options) from
- *    the given pipe inode to the given file. The caller is responsible
- *    for acquiring i_mutex on both inodes.
+ *    the given pipe inode to the given file.
  *
  */
 ssize_t
-generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out,
-				 loff_t *ppos, size_t len, unsigned int flags)
+generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
+			  loff_t *ppos, size_t len, unsigned int flags)
 {
 	struct address_space *mapping = out->f_mapping;
 	struct inode *inode = mapping->host;
@@ -781,76 +831,28 @@ generic_file_splice_write_nolock(struct pipe_inode_info *pipe, struct file *out,
 		.u.file = out,
 	};
 	ssize_t ret;
-	int err;
-
-	err = file_remove_suid(out);
-	if (unlikely(err))
-		return err;
-
-	ret = __splice_from_pipe(pipe, &sd, pipe_to_file);
-	if (ret > 0) {
-		unsigned long nr_pages;
 
-		*ppos += ret;
-		nr_pages = (ret + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+	pipe_lock(pipe);
 
-		/*
-		 * If file or inode is SYNC and we actually wrote some data,
-		 * sync it.
-		 */
-		if (unlikely((out->f_flags & O_SYNC) || IS_SYNC(inode))) {
-			err = generic_osync_inode(inode, mapping,
-						  OSYNC_METADATA|OSYNC_DATA);
-
-			if (err)
-				ret = err;
-		}
-		balance_dirty_pages_ratelimited_nr(mapping, nr_pages);
-	}
+	splice_from_pipe_begin(&sd);
+	do {
+		ret = splice_from_pipe_next(pipe, &sd);
+		if (ret <= 0)
+			break;
 
-	return ret;
-}
+		mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
+		ret = file_remove_suid(out);
+		if (!ret)
+			ret = splice_from_pipe_feed(pipe, &sd, pipe_to_file);
+		mutex_unlock(&inode->i_mutex);
+	} while (ret > 0);
+	splice_from_pipe_end(pipe, &sd);
 
-EXPORT_SYMBOL(generic_file_splice_write_nolock);
+	pipe_unlock(pipe);
 
-/**
- * generic_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.
- *
- */
-ssize_t
-generic_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
-			  loff_t *ppos, size_t len, unsigned int flags)
-{
-	struct address_space *mapping = out->f_mapping;
-	struct inode *inode = mapping->host;
-	struct splice_desc sd = {
-		.total_len = len,
-		.flags = flags,
-		.pos = *ppos,
-		.u.file = out,
-	};
-	ssize_t ret;
+	if (sd.num_spliced)
+		ret = sd.num_spliced;
 
-	WARN_ON(S_ISFIFO(inode->i_mode));
-	mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
-	ret = file_remove_suid(out);
-	if (likely(!ret)) {
-		if (pipe->inode)
-			mutex_lock_nested(&pipe->inode->i_mutex, I_MUTEX_CHILD);
-		ret = __splice_from_pipe(pipe, &sd, pipe_to_file);
-		if (pipe->inode)
-			mutex_unlock(&pipe->inode->i_mutex);
-	}
-	mutex_unlock(&inode->i_mutex);
 	if (ret > 0) {
 		unsigned long nr_pages;
 
@@ -1339,8 +1341,7 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *iov,
 	if (!pipe)
 		return -EBADF;
 
-	if (pipe->inode)
-		mutex_lock(&pipe->inode->i_mutex);
+	pipe_lock(pipe);
 
 	error = ret = 0;
 	while (nr_segs) {
@@ -1395,8 +1396,7 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *iov,
 		iov++;
 	}
 
-	if (pipe->inode)
-		mutex_unlock(&pipe->inode->i_mutex);
+	pipe_unlock(pipe);
 
 	if (!ret)
 		ret = error;
@@ -1524,7 +1524,7 @@ static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
 		return 0;
 
 	ret = 0;
-	mutex_lock(&pipe->inode->i_mutex);
+	pipe_lock(pipe);
 
 	while (!pipe->nrbufs) {
 		if (signal_pending(current)) {
@@ -1542,7 +1542,7 @@ static int link_ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
 		pipe_wait(pipe);
 	}
 
-	mutex_unlock(&pipe->inode->i_mutex);
+	pipe_unlock(pipe);
 	return ret;
 }
 
@@ -1562,7 +1562,7 @@ static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
 		return 0;
 
 	ret = 0;
-	mutex_lock(&pipe->inode->i_mutex);
+	pipe_lock(pipe);
 
 	while (pipe->nrbufs >= PIPE_BUFFERS) {
 		if (!pipe->readers) {
@@ -1583,7 +1583,7 @@ static int link_opipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
 		pipe->waiting_writers--;
 	}
 
-	mutex_unlock(&pipe->inode->i_mutex);
+	pipe_unlock(pipe);
 	return ret;
 }
 
@@ -1599,10 +1599,10 @@ static int link_pipe(struct pipe_inode_info *ipipe,
 
 	/*
 	 * Potential ABBA deadlock, work around it by ordering lock
-	 * grabbing by inode address. Otherwise two different processes
+	 * grabbing by pipe info address. Otherwise two different processes
 	 * could deadlock (one doing tee from A -> B, the other from B -> A).
 	 */
-	inode_double_lock(ipipe->inode, opipe->inode);
+	pipe_double_lock(ipipe, opipe);
 
 	do {
 		if (!opipe->readers) {
@@ -1653,7 +1653,8 @@ static int link_pipe(struct pipe_inode_info *ipipe,
 	if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK))
 		ret = -EAGAIN;
 
-	inode_double_unlock(ipipe->inode, opipe->inode);
+	pipe_unlock(ipipe);
+	pipe_unlock(opipe);
 
 	/*
 	 * If we put data in the output pipe, wakeup any potential readers.