vfs: make path_openat take a struct filename pointer

...and fix up the callers. For do_file_open_root, just declare a
struct filename on the stack and fill out the .name field. For
do_filp_open, make it also take a struct filename pointer, and fix up its
callers to call it appropriately.

For filp_open, add a variant that takes a struct filename pointer and turn
filp_open into a wrapper around it.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

7 files changed, 42 insertions, 21 deletions

diff --git a/fs/exec.c b/fs/exec.c
index 4e591e20e10..8b9011b6704 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -116,7 +116,7 @@ SYSCALL_DEFINE1(uselib, const char __user *, library)
         if (IS_ERR(tmp))
                 goto out;
 
-        file = do_filp_open(AT_FDCWD, tmp->name, &uselib_flags, LOOKUP_FOLLOW);
+        file = do_filp_open(AT_FDCWD, tmp, &uselib_flags, LOOKUP_FOLLOW);
         putname(tmp);
         error = PTR_ERR(file);
         if (IS_ERR(file))
@@ -751,13 +751,14 @@ struct file *open_exec(const char *name)
 {
         struct file *file;
         int err;
+        struct filename tmp = { .name = name };
         static const struct open_flags open_exec_flags = {
                 .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
                 .acc_mode = MAY_EXEC | MAY_OPEN,
                 .intent = LOOKUP_OPEN
         };
 
-        file = do_filp_open(AT_FDCWD, name, &open_exec_flags, LOOKUP_FOLLOW);
+        file = do_filp_open(AT_FDCWD, &tmp, &open_exec_flags, LOOKUP_FOLLOW);
         if (IS_ERR(file))
                 goto out;
 
diff --git a/fs/internal.h b/fs/internal.h
index 371bcc4b169..916b7cbf3e3 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -97,8 +97,8 @@ struct open_flags {
         int acc_mode;
         int intent;
 };
-extern struct file *do_filp_open(int dfd, const char *pathname,
-                const struct open_flags *op, int lookup_flags);
+extern struct file *do_filp_open(int dfd, struct filename *pathname,
+                const struct open_flags *op, int flags);
 extern struct file *do_file_open_root(struct dentry *, struct vfsmount *,
                 const char *, const struct open_flags *, int lookup_flags);
 
diff --git a/fs/namei.c b/fs/namei.c
index 8c14353fb75..6bbd8fdfb1f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2662,7 +2662,7 @@ out_dput:
  */
 static int do_last(struct nameidata *nd, struct path *path,
                    struct file *file, const struct open_flags *op,
-                   int *opened, const char *pathname)
+                   int *opened, struct filename *name)
 {
         struct dentry *dir = nd->path.dentry;
         int open_flag = op->open_flag;
@@ -2674,6 +2674,7 @@ static int do_last(struct nameidata *nd, struct path *path,
         struct path save_parent = { .dentry = NULL, .mnt = NULL };
         bool retried = false;
         int error;
+        const char *pathname = name->name;
 
         nd->flags &= ~LOOKUP_PARENT;
         nd->flags |= op->intent;
@@ -2908,7 +2909,7 @@ stale_open:
         goto retry_lookup;
 }
 
-static struct file *path_openat(int dfd, const char *pathname,
+static struct file *path_openat(int dfd, struct filename *pathname,
                 struct nameidata *nd, const struct open_flags *op, int flags)
 {
         struct file *base = NULL;
@@ -2923,12 +2924,12 @@ static struct file *path_openat(int dfd, const char *pathname,
 
         file->f_flags = op->open_flag;
 
-        error = path_init(dfd, pathname, flags | LOOKUP_PARENT, nd, &base);
+        error = path_init(dfd, pathname->name, flags | LOOKUP_PARENT, nd, &base);
         if (unlikely(error))
                 goto out;
 
         current->total_link_count = 0;
-        error = link_path_walk(pathname, nd);
+        error = link_path_walk(pathname->name, nd);
         if (unlikely(error))
                 goto out;
 
@@ -2974,7 +2975,7 @@ out:
         return file;
 }
 
-struct file *do_filp_open(int dfd, const char *pathname,
+struct file *do_filp_open(int dfd, struct filename *pathname,
                 const struct open_flags *op, int flags)
 {
         struct nameidata nd;
@@ -2993,6 +2994,7 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
 {
         struct nameidata nd;
         struct file *file;
+        struct filename filename = { .name = name };
 
         nd.root.mnt = mnt;
         nd.root.dentry = dentry;
@@ -3002,11 +3004,11 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
         if (dentry->d_inode->i_op->follow_link && op->intent & LOOKUP_OPEN)
                 return ERR_PTR(-ELOOP);
 
-        file = path_openat(-1, name, &nd, op, flags | LOOKUP_RCU);
+        file = path_openat(-1, &filename, &nd, op, flags | LOOKUP_RCU);
         if (unlikely(file == ERR_PTR(-ECHILD)))
-                file = path_openat(-1, name, &nd, op, flags);
+                file = path_openat(-1, &filename, &nd, op, flags);
         if (unlikely(file == ERR_PTR(-ESTALE)))
-                file = path_openat(-1, name, &nd, op, flags | LOOKUP_REVAL);
+                file = path_openat(-1, &filename, &nd, op, flags | LOOKUP_REVAL);
         return file;
 }
 
diff --git a/fs/open.c b/fs/open.c
index 81dd92ac10f..59071f55bf7 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -859,6 +859,24 @@ static inline int build_open_flags(int flags, umode_t mode, struct open_flags *o
 }
 
 /**
+ * file_open_name - open file and return file pointer
+ *
+ * @name:       struct filename containing path to open
+ * @flags:      open flags as per the open(2) second argument
+ * @mode:       mode for the new file if O_CREAT is set, else ignored
+ *
+ * This is the helper to open a file from kernelspace if you really
+ * have to.  But in generally you should not do this, so please move
+ * along, nothing to see here..
+ */
+struct file *file_open_name(struct filename *name, int flags, umode_t mode)
+{
+        struct open_flags op;
+        int lookup = build_open_flags(flags, mode, &op);
+        return do_filp_open(AT_FDCWD, name, &op, lookup);
+}
+
+/**
  * filp_open - open file and return file pointer
  *
  * @filename:   path to open
@@ -871,9 +889,8 @@ static inline int build_open_flags(int flags, umode_t mode, struct open_flags *o
  */
 struct file *filp_open(const char *filename, int flags, umode_t mode)
 {
-        struct open_flags op;
-        int lookup = build_open_flags(flags, mode, &op);
-        return do_filp_open(AT_FDCWD, filename, &op, lookup);
+        struct filename name = {.name = filename};
+        return file_open_name(&name, flags, mode);
 }
 EXPORT_SYMBOL(filp_open);
 
@@ -901,7 +918,7 @@ long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
         if (!IS_ERR(tmp)) {
                 fd = get_unused_fd_flags(flags);
                 if (fd >= 0) {
-                        struct file *f = do_filp_open(dfd, tmp->name, &op, lookup);
+                        struct file *f = do_filp_open(dfd, tmp, &op, lookup);
                         if (IS_ERR(f)) {
                                 put_unused_fd(fd);
                                 fd = PTR_ERR(f);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6c93b46f46d..b6b10e7f0ac 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2207,6 +2207,7 @@ extern int do_fallocate(struct file *file, int mode, loff_t offset,
                         loff_t len);
 extern long do_sys_open(int dfd, const char __user *filename, int flags,
                         umode_t mode);
+extern struct file *file_open_name(struct filename *, int, umode_t);
 extern struct file *filp_open(const char *, int, umode_t);
 extern struct file *file_open_root(struct dentry *, struct vfsmount *,
                                    const char *, int);
diff --git a/kernel/acct.c b/kernel/acct.c
index 08354195eec..051e071a06e 100644
--- a/kernel/acct.c
+++ b/kernel/acct.c
@@ -193,7 +193,7 @@ static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file,
         }
 }
 
-static int acct_on(const char *name)
+static int acct_on(struct filename *pathname)
 {
         struct file *file;
         struct vfsmount *mnt;
@@ -201,7 +201,7 @@ static int acct_on(const char *name)
         struct bsd_acct_struct *acct = NULL;
 
         /* Difference from BSD - they don't do O_APPEND */
-        file = filp_open(name, O_WRONLY|O_APPEND|O_LARGEFILE, 0);
+        file = file_open_name(pathname, O_WRONLY|O_APPEND|O_LARGEFILE, 0);
         if (IS_ERR(file))
                 return PTR_ERR(file);
 
@@ -263,7 +263,7 @@ SYSCALL_DEFINE1(acct, const char __user *, name)
                 struct filename *tmp = getname(name);
                 if (IS_ERR(tmp))
                         return (PTR_ERR(tmp));
-                error = acct_on(tmp->name);
+                error = acct_on(tmp);
                 putname(tmp);
         } else {
                 struct bsd_acct_struct *acct;
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 90d2ed591de..71cd288b200 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1498,7 +1498,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
         if (IS_ERR(pathname))
                 goto out;
 
-        victim = filp_open(pathname->name, O_RDWR|O_LARGEFILE, 0);
+        victim = file_open_name(pathname, O_RDWR|O_LARGEFILE, 0);
         err = PTR_ERR(victim);
         if (IS_ERR(victim))
                 goto out;
@@ -1966,7 +1966,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
                 name = NULL;
                 goto bad_swap;
         }
-        swap_file = filp_open(name->name, O_RDWR|O_LARGEFILE, 0);
+        swap_file = file_open_name(name, O_RDWR|O_LARGEFILE, 0);
         if (IS_ERR(swap_file)) {
                 error = PTR_ERR(swap_file);
                 swap_file = NULL;