Hello, Greg.
On Fri, Nov 01, 2013 at 08:04:48AM -0700, Greg Kroah-Hartman wrote:
> > @@ -800,7 +800,7 @@ EXPORT_SYMBOL_GPL(sysfs_notify);
> > const struct file_operations sysfs_file_operations = {
> > .read = seq_read,
> > .write = sysfs_write_file,
> > - .llseek = seq_lseek,
> > + .llseek = generic_file_llseek,
>
> Does that mean that seq_lseek can't handle SEEK_END? Shouldn't we fix
> that instead?
As the files are dynamic, seq_file has no way of knowing whether the
file is gonna end at all. It's perfectly valid to have an infinite
file. The only benefits of using seq_lseek() instead of
generic_file_llseek() are
* Early failure. For whatever reason, traversing to certain file
position should fail, seq_lseek() will report such failure on
seek(2) instead of the following read/write operations.
* EOF detection. While SEEK_END is not supported, SEEK_SET/CUR +
large offset can be used to detect eof - eof at the time of the last
seek anyway as the file size may change dynamically.
I don't think either would matter for sysfs or for prospect kernfs
users and sticking with genefic_file_llseek() should be fine.
Thanks.
--
tejun
--
To unsubscribe from this list: send the line "unsubscribe linux-next" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
