Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Subject | [PATCH] compat_ioctl: introduce generic_compat_ioctl helper | Date | Sat, 20 Oct 2007 17:50:57 +0200 |
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Many drivers use only compatible ioctl numbers. In order to avoid having to write a special compat_ioctl handler for each of them or listing every ioctl number in fs/compat_ioctl.c, let's introduce a generic handler that simply calls the driver specific f_op->unlocked_ioctl() or f_op->ioctl() handler.
Signed-off-by: Arnd Bergman <arnd@arndb.de> --- On Saturday 13 October 2007, Al Viro wrote: > Just how many instances of that sucker do we need? It's nothing but > > struct inode *inode = file->f_path.dentry->d_inode; > return file->f_op->ioctl(inode, file, cmd, compat_ptr(arg));
Is this what you had in mind? I've been meaning to do something like it for some time, but had forgotten about it.
I guess we can kill a significant amount of COMPATIBLE_IOCTL lines in fs/compat_ioctl.c with this.
Index: linux-2.6/fs/compat_ioctl.c =================================================================== --- linux-2.6.orig/fs/compat_ioctl.c +++ linux-2.6/fs/compat_ioctl.c @@ -1877,6 +1877,30 @@ lp_timeout_trans(unsigned int fd, unsign return sys_ioctl(fd, cmd, (unsigned long)tn); } +/* + * Helper function for device drivers that only have COMPATIBLE_IOCTL + * numbers. This can be used as f_op->compat_ioctl without any #ifdef + * and will simply call the native ioctl handler with the argument + * pointer. + * Don't use for drivers that interpret arg as an unsigned long instead + * of a pointer. + */ +long generic_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + int ret = -ENOTTY; + arg = (unsigned long)compat_ptr(arg); + + if (file->f_op->unlocked_ioctl) + ret = file->f_op->unlocked_ioctl(file, cmd, arg); + else if (file->f_op->ioctl) { + lock_kernel(); + ret = file->f_op->ioctl(file->f_dentry->d_inode, file, cmd, arg); + unlock_kernel(); + } + + return ret; +} +EXPORT_SYMBOL_GPL(generic_compat_ioctl); typedef int (*ioctl_trans_handler_t)(unsigned int, unsigned int, unsigned long, struct file *); Index: linux-2.6/include/linux/fs.h =================================================================== --- linux-2.6.orig/include/linux/fs.h +++ linux-2.6/include/linux/fs.h @@ -1807,6 +1807,12 @@ extern void do_generic_mapping_read(stru extern int generic_segment_checks(const struct iovec *iov, unsigned long *nr_segs, size_t *count, int access_flags); +#ifdef CONFIG_COMPAT +extern long generic_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg); +#else +#define generic_compat_ioctl (long (*)(struct file *, unsigned int, unsigned long))NULL +#endif + /* fs/splice.c */ extern ssize_t generic_file_splice_read(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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