Re: [PATCH 01/08] idr: add idr_replace method for replacing pointers

[Jeff Mahoney <jeffm@suse.com>]

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Andrew Morton wrote:
> Jeff Mahoney <jeffm@suse.com> wrote:
>> +/**
>> + * idr_replace - replace pointer for given id
>> + * @idp: idr handle
>> + * @ptr: pointer you want associated with the ide
>> + * @id: lookup key
>> + *
>> + * Replace the pointer registered with the id.  A -ENOENT
>> + * return indicates that @id was not found.
>> + *
>> + * The caller must serialize vs idr_find(), idr_get_new(), and idr_remove().
>> + */
>> +int idr_replace(struct idr *idp, void *ptr, int id)
> 
> I'd have thought it would be more flexible were this to return the old
> pointer.
> 
> If there was no old item, we could return NULL and "succeed".  But that gets
> a bit ill-defined, because lack of an old pointer can occur if either a)
> there was a layer, but the slot was empty or b) there wasn't a layer for
> this new item.  So perhaps it's best to continue considering lack of an old
> pointer as an error, with ERR_PTR(-ENOENT).

Sure, I'll make those changes now.

- -Jeff


- --
Jeff Mahoney
SUSE Labs
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