Merge tag 'driver-core-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here's the "big" driver core update for 4.7-rc1.

  Mostly just debugfs changes, the long-known and messy races with
  removing debugfs files should be fixed thanks to the great work of
  Nicolai Stange.  We also have some isa updates in here (the x86
  maintainers told me to take it through this tree), a new warning when
  we run out of dynamic char major numbers, and a few other assorted
  changes, details in the shortlog.

  All have been in linux-next for some time with no reported issues"

* tag 'driver-core-4.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (32 commits)
  Revert "base: dd: don't remove driver_data in -EPROBE_DEFER case"
  gpio: ws16c48: Utilize the ISA bus driver
  gpio: 104-idio-16: Utilize the ISA bus driver
  gpio: 104-idi-48: Utilize the ISA bus driver
  gpio: 104-dio-48e: Utilize the ISA bus driver
  watchdog: ebc-c384_wdt: Utilize the ISA bus driver
  iio: stx104: Utilize the module_isa_driver and max_num_isa_dev macros
  iio: stx104: Add X86 dependency to STX104 Kconfig option
  Documentation: Add ISA bus driver documentation
  isa: Implement the max_num_isa_dev macro
  isa: Implement the module_isa_driver macro
  pnp: pnpbios: Add explicit X86_32 dependency to PNPBIOS
  isa: Decouple X86_32 dependency from the ISA Kconfig option
  driver-core: use 'dev' argument in dev_dbg_ratelimited stub
  base: dd: don't remove driver_data in -EPROBE_DEFER case
  kernfs: Move faulting copy_user operations outside of the mutex
  devcoredump: add scatterlist support
  debugfs: unproxify files created through debugfs_create_u32_array()
  debugfs: unproxify files created through debugfs_create_blob()
  debugfs: unproxify files created through debugfs_create_bool()
  ...

3 files changed, 44 insertions, 30 deletions

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 68a44315d949..8a652404eef6 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -753,7 +753,8 @@ int kernfs_add_one(struct kernfs_node *kn)
 	ps_iattr = parent->iattr;
 	if (ps_iattr) {
 		struct iattr *ps_iattrs = &ps_iattr->ia_iattr;
-		ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
+		ktime_get_real_ts(&ps_iattrs->ia_ctime);
+		ps_iattrs->ia_mtime = ps_iattrs->ia_ctime;
 	}
 
 	mutex_unlock(&kernfs_mutex);
@@ -1279,8 +1280,9 @@ static void __kernfs_remove(struct kernfs_node *kn)
 
 			/* update timestamps on the parent */
 			if (ps_iattr) {
-				ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
-				ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
+				ktime_get_real_ts(&ps_iattr->ia_iattr.ia_ctime);
+				ps_iattr->ia_iattr.ia_mtime =
+					ps_iattr->ia_iattr.ia_ctime;
 			}
 
 			kernfs_put(pos);
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index 7247252ee9b1..e1574008adc9 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -190,15 +190,16 @@ static ssize_t kernfs_file_direct_read(struct kernfs_open_file *of,
 	char *buf;
 
 	buf = of->prealloc_buf;
-	if (!buf)
+	if (buf)
+		mutex_lock(&of->prealloc_mutex);
+	else
 		buf = kmalloc(len, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 
 	/*
 	 * @of->mutex nests outside active ref and is used both to ensure that
-	 * the ops aren't called concurrently for the same open file, and
-	 * to provide exclusive access to ->prealloc_buf (when that exists).
+	 * the ops aren't called concurrently for the same open file.
 	 */
 	mutex_lock(&of->mutex);
 	if (!kernfs_get_active(of->kn)) {
@@ -214,21 +215,23 @@ static ssize_t kernfs_file_direct_read(struct kernfs_open_file *of,
 	else
 		len = -EINVAL;
 
+	kernfs_put_active(of->kn);
+	mutex_unlock(&of->mutex);
+
 	if (len < 0)
-		goto out_unlock;
+		goto out_free;
 
 	if (copy_to_user(user_buf, buf, len)) {
 		len = -EFAULT;
-		goto out_unlock;
+		goto out_free;
 	}
 
 	*ppos += len;
 
- out_unlock:
-	kernfs_put_active(of->kn);
-	mutex_unlock(&of->mutex);
  out_free:
-	if (buf != of->prealloc_buf)
+	if (buf == of->prealloc_buf)
+		mutex_unlock(&of->prealloc_mutex);
+	else
 		kfree(buf);
 	return len;
 }
@@ -284,15 +287,22 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf,
 	}
 
 	buf = of->prealloc_buf;
-	if (!buf)
+	if (buf)
+		mutex_lock(&of->prealloc_mutex);
+	else
 		buf = kmalloc(len + 1, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
 
+	if (copy_from_user(buf, user_buf, len)) {
+		len = -EFAULT;
+		goto out_free;
+	}
+	buf[len] = '\0';	/* guarantee string termination */
+
 	/*
 	 * @of->mutex nests outside active ref and is used both to ensure that
-	 * the ops aren't called concurrently for the same open file, and
-	 * to provide exclusive access to ->prealloc_buf (when that exists).
+	 * the ops aren't called concurrently for the same open file.
 	 */
 	mutex_lock(&of->mutex);
 	if (!kernfs_get_active(of->kn)) {
@@ -301,26 +311,22 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf,
 		goto out_free;
 	}
 
-	if (copy_from_user(buf, user_buf, len)) {
-		len = -EFAULT;
-		goto out_unlock;
-	}
-	buf[len] = '\0';	/* guarantee string termination */
-
 	ops = kernfs_ops(of->kn);
 	if (ops->write)
 		len = ops->write(of, buf, len, *ppos);
 	else
 		len = -EINVAL;
 
+	kernfs_put_active(of->kn);
+	mutex_unlock(&of->mutex);
+
 	if (len > 0)
 		*ppos += len;
 
-out_unlock:
-	kernfs_put_active(of->kn);
-	mutex_unlock(&of->mutex);
 out_free:
-	if (buf != of->prealloc_buf)
+	if (buf == of->prealloc_buf)
+		mutex_unlock(&of->prealloc_mutex);
+	else
 		kfree(buf);
 	return len;
 }
@@ -687,6 +693,7 @@ static int kernfs_fop_open(struct inode *inode, struct file *file)
 		error = -ENOMEM;
 		if (!of->prealloc_buf)
 			goto err_free;
+		mutex_init(&of->prealloc_mutex);
 	}
 
 	/*
diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
index b5247226732b..1719649d7ad7 100644
--- a/fs/kernfs/inode.c
+++ b/fs/kernfs/inode.c
@@ -54,7 +54,10 @@ static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn)
 	iattrs->ia_mode = kn->mode;
 	iattrs->ia_uid = GLOBAL_ROOT_UID;
 	iattrs->ia_gid = GLOBAL_ROOT_GID;
-	iattrs->ia_atime = iattrs->ia_mtime = iattrs->ia_ctime = CURRENT_TIME;
+
+	ktime_get_real_ts(&iattrs->ia_atime);
+	iattrs->ia_mtime = iattrs->ia_atime;
+	iattrs->ia_ctime = iattrs->ia_atime;
 
 	simple_xattrs_init(&kn->iattr->xattrs);
 out_unlock:
@@ -236,16 +239,18 @@ ssize_t kernfs_iop_listxattr(struct dentry *dentry, char *buf, size_t size)
 static inline void set_default_inode_attr(struct inode *inode, umode_t mode)
 {
 	inode->i_mode = mode;
-	inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+	inode->i_atime = inode->i_mtime =
+		inode->i_ctime = current_fs_time(inode->i_sb);
 }
 
 static inline void set_inode_attr(struct inode *inode, struct iattr *iattr)
 {
+	struct super_block *sb = inode->i_sb;
 	inode->i_uid = iattr->ia_uid;
 	inode->i_gid = iattr->ia_gid;
-	inode->i_atime = iattr->ia_atime;
-	inode->i_mtime = iattr->ia_mtime;
-	inode->i_ctime = iattr->ia_ctime;
+	inode->i_atime = timespec_trunc(iattr->ia_atime, sb->s_time_gran);
+	inode->i_mtime = timespec_trunc(iattr->ia_mtime, sb->s_time_gran);
+	inode->i_ctime = timespec_trunc(iattr->ia_ctime, sb->s_time_gran);
 }
 
 static void kernfs_refresh_inode(struct kernfs_node *kn, struct inode *inode)