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SubjectRe: Remove TO DO in jfs_xtree.c
On 12/27/2014 06:58 PM, nick wrote:
> Greetings Dave,
> I am wondering why there is a TO DO above this code:
> * ToDo: tlocks should be on doubly-linked list, so we can
> * quickly remove it and add it to the end.

I'm sure the idea was to avoid the for loop needed to find the previous
entry in the linked list. A doubly-linked list makes it much simpler to
remove an item from an arbitrary position in the list.

> */
>
> /*
> * Move parent page's tlock to the end of the tid's tlock list
> */
> if (log && mp->lid && (tblk->last != mp->lid) &&
> lid_to_tlock(mp->lid)->tid) {
> lid_t lid = mp->lid;
> struct tlock *prev;
>
> tlck = lid_to_tlock(lid);
>
> if (tblk->next == lid)
> tblk->next = tlck->next;
> else {
> for (prev = lid_to_tlock(tblk->next);
> prev->next != lid;
> prev = lid_to_tlock(prev->next)) {
> assert(prev->next);
> }
> prev->next = tlck->next;
> }
> lid_to_tlock(tblk->last)->next = lid;
> tlck->next = 0;
> tblk->last = lid;
> }
> As this code clearly moves the locks onto a linked list. Therefore I am recommend we remove this
> TO DO as this is clearly misleading and no longer needed.

That comment has been in the code forever and I don't have any intention
of changing things, but I don't think it's wrong. I don't mind removing
it, though. jfs has been barely maintained and there is a ton of cleanup
that can be done if someone were willing to take the time to do it.

Thanks,
Shaggy


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