Sanitize f_flags helpers

* pull ACC_MODE to fs.h; we have several copies all over the place
* nightmarish expression calculating f_mode by f_flags deserves a helper
too (OPEN_FMODE(flags))
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/anon_inodes.c

@@ -89,19 +89,11 @@ struct file *anon_inode_getfile(const char *name,
 	struct qstr this;
 	struct path path;
 	struct file *file;
-	fmode_t mode;
 	int error;
 
 	if (IS_ERR(anon_inode_inode))
 		return ERR_PTR(-ENODEV);
 
-	switch (flags & O_ACCMODE) {
-	case O_RDONLY: mode = FMODE_READ;		break;
-	case O_WRONLY: mode = FMODE_WRITE;		break;
-	case O_RDWR:   mode = FMODE_READ | FMODE_WRITE;	break;
-	default:       return ERR_PTR(-EINVAL);
-	}
-
 	if (fops->owner && !try_module_get(fops->owner))
 		return ERR_PTR(-ENOENT);
 
@@ -129,7 +121,7 @@ struct file *anon_inode_getfile(const char *name,
 	d_instantiate(path.dentry, anon_inode_inode);
 
 	error = -ENFILE;
-	file = alloc_file(&path, mode, fops);
+	file = alloc_file(&path, OPEN_FMODE(flags), fops);
 	if (!file)
 		goto err_dput;
 	file->f_mapping = anon_inode_inode->i_mapping;

fs/namei.c

@@ -37,8 +37,6 @@
 
 #include "internal.h"
 
-#define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE])
-
 /* [Feb-1997 T. Schoebel-Theuer]
  * Fundamental changes in the pathname lookup mechanisms (namei)
  * were necessary because of omirr.  The reason is that omirr needs

fs/open.c

@@ -828,7 +828,7 @@ static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt,
 	struct inode *inode;
 	int error;
 
-	f->f_mode = (__force fmode_t)((f->f_flags+1) & O_ACCMODE) | FMODE_LSEEK |
+	f->f_mode = OPEN_FMODE(f->f_flags) | FMODE_LSEEK |
 				FMODE_PREAD | FMODE_PWRITE;
 	inode = dentry->d_inode;
 	if (f->f_mode & FMODE_WRITE) {

include/linux/fs.h

@@ -2464,5 +2464,8 @@ int proc_nr_files(struct ctl_table *table, int write,
 
 int __init get_filesystem_list(char *buf);
 
+#define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE])
+#define OPEN_FMODE(flag) ((__force fmode_t)((flag + 1) & O_ACCMODE))
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_FS_H */

kernel/auditsc.c

@@ -250,7 +250,6 @@ struct audit_context {
 #endif
 };
 
-#define ACC_MODE(x) ("\004\002\006\006"[(x)&O_ACCMODE])
 static inline int open_arg(int flags, int mask)
 {
 	int n = ACC_MODE(flags);

security/tomoyo/file.c

@@ -12,7 +12,6 @@
 #include "common.h"
 #include "tomoyo.h"
 #include "realpath.h"
-#define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE])
 
 /*
  * tomoyo_globally_readable_file_entry is a structure which is used for holding