[RFC][PATCH] kill do_filp_open()

[RFC][PATCH] kill do_filp_open()

[Dave Hansen]

This kills off the almost empty do_filp_open().  However,
let's keep filp_open() around.  It does the nameidata allocation
on the stack, and also adds the AT_FDCWD argument.  I think
that's enough to keep it around.

---

 lxc-dave/fs/open.c |   40 ++++++++++++++++++----------------------
 1 file changed, 18 insertions(+), 22 deletions(-)

diff -puN fs/open.c~kill-do_filp_open fs/open.c
--- lxc/fs/open.c~kill-do_filp_open	2007-09-27 12:03:24.000000000 -0700
+++ lxc-dave/fs/open.c	2007-09-27 12:05:31.000000000 -0700
@@ -840,18 +840,10 @@ cleanup_file:
 	return ERR_PTR(error);
 }
 
-static struct file *do_filp_open(int dfd, const char *filename, int flags,
-				 int mode)
-{
-	int error;
-	struct nameidata nd;
-
-	return open_namei(dfd, filename, flags, mode, &nd);
-}
-
 struct file *filp_open(const char *filename, int flags, int mode)
 {
-	return do_filp_open(AT_FDCWD, filename, flags, mode);
+	struct nameidata nd;
+	return open_namei(AT_FDCWD, filename, flags, mode, &nd);
 }
 EXPORT_SYMBOL(filp_open);
 
@@ -1050,20 +1042,24 @@ long do_sys_open(int dfd, const char __u
 	char *tmp = getname(filename);
 	int fd = PTR_ERR(tmp);
 
-	if (!IS_ERR(tmp)) {
-		fd = get_unused_fd_flags(flags);
-		if (fd >= 0) {
-			struct file *f = do_filp_open(dfd, tmp, flags, mode);
-			if (IS_ERR(f)) {
-				put_unused_fd(fd);
-				fd = PTR_ERR(f);
-			} else {
-				fsnotify_open(f->f_path.dentry);
-				fd_install(fd, f);
-			}
+	if (IS_ERR(tmp))
+		goto out;
+
+	fd = get_unused_fd_flags(flags);
+	if (fd >= 0) {
+		struct nameidata nd;
+		struct file *f = open_namei(dfd, tmp, flags, mode, &nd);
+
+		if (IS_ERR(f)) {
+			put_unused_fd(fd);
+			fd = PTR_ERR(f);
+		} else {
+			fsnotify_open(f->f_path.dentry);
+			fd_install(fd, f);
 		}
-		putname(tmp);
 	}
+	putname(tmp);
+out:
 	return fd;
 }
 
_

Re: [RFC][PATCH] kill do_filp_open()

[Christoph Hellwig]

On Thu, Sep 27, 2007 at 12:08:23PM -0700, Dave Hansen wrote:
> 
> This kills off the almost empty do_filp_open().  However,
> let's keep filp_open() around.  It does the nameidata allocation
> on the stack, and also adds the AT_FDCWD argument.  I think
> that's enough to keep it around.

So why would we not want to allocate the nameidata in open_namei?