lkml.org 
[lkml]   [2018]   [Feb]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: Change in register_blkdev() behavior


On 01/02/18 05:23 PM, Srivatsa S. Bhat wrote:
> static int find_dynamic_major(void)
> {
> int i;
> struct char_device_struct *cd;
>
> for (i = ARRAY_SIZE(chrdevs)-1; i > CHRDEV_MAJOR_DYN_END; i--) {
> ^^^^
> As far as I can see, _DYN_END is inclusive, so shouldn't this be >= ?

Yes, it looks like _DYN_END should have been inclusive based on the way
I documented it.

>
> for (cd = chrdevs[major_to_index(i)]; cd; cd = cd->next)
> if (cd->major == i)
> break;
>
> if (cd == NULL || cd->major != i)
> ^^^^^^^^
> It seems that this latter condition is unnecessary, as it will never be
> true. (We'll reach here only if cd == NULL or cd->major == i).

Not quite. chrdevs[] may contain majors that also hit on the hash but
don't equal 'i'. So the for loop will iterate through all hashes
matching 'i' and if there is one or more and they all don't match 'i',
it will fall through the loop and cd will be set to something non-null
and not equal to i.

Thanks for the review!

Logan

\
 
 \ /
  Last update: 2018-02-02 02:12    [W:0.049 / U:0.772 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site