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

Pull vfs updates from Al Viro:
 "Assorted bits and pieces"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  aio: drop needless assignment in aio_read()
  clean overflow checks in count_mounts() a bit
  seq_file: fix NULL pointer arithmetic warning
  uml/x86: use x86 load_unaligned_zeropad()
  asm/user.h: killed unused macros
  constify struct path argument of finish_automount()/do_add_mount()
  fs: Remove FIXME comment in generic_write_checks()

6 files changed, 16 insertions, 22 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 7b66b93d5bfa..3c249b938632 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1552,7 +1552,6 @@ static int aio_read(struct kiocb *req, const struct iocb *iocb,
 	file = req->ki_filp;
 	if (unlikely(!(file->f_mode & FMODE_READ)))
 		return -EBADF;
-	ret = -EINVAL;
 	if (unlikely(!file->f_op->read_iter))
 		return -EINVAL;
 
diff --git a/fs/internal.h b/fs/internal.h
index fb2c2ea807d7..08503dc68d2b 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -74,7 +74,7 @@ int do_linkat(int olddfd, struct filename *old, int newdfd,
  * namespace.c
  */
 extern struct vfsmount *lookup_mnt(const struct path *);
-extern int finish_automount(struct vfsmount *, struct path *);
+extern int finish_automount(struct vfsmount *, const struct path *);
 
 extern int sb_prepare_remount_readonly(struct super_block *);
 
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index 74067a73ff78..88423069407c 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -120,13 +120,8 @@ static void *kernfs_seq_start(struct seq_file *sf, loff_t *ppos)
 		if (next == ERR_PTR(-ENODEV))
 			kernfs_seq_stop_active(sf, next);
 		return next;
-	} else {
-		/*
-		 * The same behavior and code as single_open().  Returns
-		 * !NULL if pos is at the beginning; otherwise, NULL.
-		 */
-		return NULL + !*ppos;
 	}
+	return single_start(sf, ppos);
 }
 
 static void *kernfs_seq_next(struct seq_file *sf, void *v, loff_t *ppos)
diff --git a/fs/namespace.c b/fs/namespace.c
index 6e9844b8c6fb..a0a36bfa3aa0 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2112,22 +2112,23 @@ static int invent_group_ids(struct mount *mnt, bool recurse)
 int count_mounts(struct mnt_namespace *ns, struct mount *mnt)
 {
 	unsigned int max = READ_ONCE(sysctl_mount_max);
-	unsigned int mounts = 0, old, pending, sum;
+	unsigned int mounts = 0;
 	struct mount *p;
 
+	if (ns->mounts >= max)
+		return -ENOSPC;
+	max -= ns->mounts;
+	if (ns->pending_mounts >= max)
+		return -ENOSPC;
+	max -= ns->pending_mounts;
+
 	for (p = mnt; p; p = next_mnt(p, mnt))
 		mounts++;
 
-	old = ns->mounts;
-	pending = ns->pending_mounts;
-	sum = old + pending;
-	if ((old > sum) ||
-	    (pending > sum) ||
-	    (max < sum) ||
-	    (mounts > (max - sum)))
+	if (mounts > max)
 		return -ENOSPC;
 
-	ns->pending_mounts = pending + mounts;
+	ns->pending_mounts += mounts;
 	return 0;
 }
 
@@ -2921,7 +2922,7 @@ static int do_move_mount_old(struct path *path, const char *old_name)
  * add a mount into a namespace's mount tree
  */
 static int do_add_mount(struct mount *newmnt, struct mountpoint *mp,
-			struct path *path, int mnt_flags)
+			const struct path *path, int mnt_flags)
 {
 	struct mount *parent = real_mount(path->mnt);
 
@@ -3044,7 +3045,7 @@ static int do_new_mount(struct path *path, const char *fstype, int sb_flags,
 	return err;
 }
 
-int finish_automount(struct vfsmount *m, struct path *path)
+int finish_automount(struct vfsmount *m, const struct path *path)
 {
 	struct dentry *dentry = path->dentry;
 	struct mountpoint *mp;
diff --git a/fs/read_write.c b/fs/read_write.c
index dc5000173b80..e643aec2b0ef 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1630,7 +1630,6 @@ int generic_write_checks_count(struct kiocb *iocb, loff_t *count)
 	if (!*count)
 		return 0;
 
-	/* FIXME: this is for backwards compatibility with 2.4 */
 	if (iocb->ki_flags & IOCB_APPEND)
 		iocb->ki_pos = i_size_read(inode);
 
diff --git a/fs/seq_file.c b/fs/seq_file.c
index f8e1f4ee87ff..7ab8a58c29b6 100644
--- a/fs/seq_file.c
+++ b/fs/seq_file.c
@@ -554,9 +554,9 @@ int seq_dentry(struct seq_file *m, struct dentry *dentry, const char *esc)
 }
 EXPORT_SYMBOL(seq_dentry);
 
-static void *single_start(struct seq_file *p, loff_t *pos)
+void *single_start(struct seq_file *p, loff_t *pos)
 {
-	return NULL + (*pos == 0);
+	return *pos ? NULL : SEQ_START_TOKEN;
 }
 
 static void *single_next(struct seq_file *p, void *v, loff_t *pos)