On 11/8/18 10:47 AM, Jens Axboe wrote:
> On 11/8/18 10:35 AM, Bart Van Assche wrote:
>> On Thu, 2018-11-08 at 09:31 -0700, Jens Axboe wrote:
>>> On 11/8/18 9:28 AM, Bart Van Assche wrote:
>>>> On Thu, 2018-11-08 at 09:06 -0700, Jens Axboe wrote:
>>>>> --- a/block/blk-mq-debugfs.c
>>>>> +++ b/block/blk-mq-debugfs.c
>>>>> @@ -424,13 +424,15 @@ struct show_busy_params {
>>>>> * Note: the state of a request may change while this function is in progress,
>>>>> * e.g. due to a concurrent blk_mq_finish_request() call.
>>>>> */
>>>>> -static void hctx_show_busy_rq(struct request *rq, void *data, bool reserved)
>>>>> +static bool hctx_show_busy_rq(struct request *rq, void *data, bool reserved)
>>>>> {
>>>>
>>>> Please update the kdoc header above hctx_show_busy_rq() such that it reflects
>>>> the new behavior. I'm referring to the "will be called for each request" part.
>>>> Otherwise this patch looks fine to me.
>>>
>>> Took a look at the comment, and what do you want changed? There's no change
>>> in behavior for hctx_show_busy_rq(), it loops all requests just like before.
>>> We just return true to ensure we continue iterating.
>>
>> Oops, I added my reply below the wrong function. I wanted to refer to the
>> following comment above blk_mq_queue_tag_busy_iter():
>>
>> * @fn: Pointer to the function that will be called for each request
>>
>> Additionally, how about similar comments above bt_for_each(), bt_tags_for_each()
>> blk_mq_all_tag_busy_iter() and blk_mq_tagset_busy_iter()? I think this patch
>> affects all these functions.
>
> Fair enough, I'll add a documentation patch. Didn't consider it a big deal
> since this is how it's always worked internally, but we haven't exposed
> this break/continue functionality outside the sbitmap core until now.
How about this incremental?
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 097e9a67d5f5..87bc5df72d48 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -248,7 +248,8 @@ static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
* @fn: Pointer to the function that will be called for each request
* associated with @hctx that has been assigned a driver tag.
* @fn will be called as follows: @fn(@hctx, rq, @data, @reserved)
- * where rq is a pointer to a request.
+ * where rq is a pointer to a request. Return true to continue
+ * iterating tags, false to stop.
* @data: Will be passed as third argument to @fn.
* @reserved: Indicates whether @bt is the breserved_tags member or the
* bitmap_tags member of struct blk_mq_tags.
@@ -301,7 +302,8 @@ static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
* or the bitmap_tags member of struct blk_mq_tags.
* @fn: Pointer to the function that will be called for each started
* request. @fn will be called as follows: @fn(rq, @data,
- * @reserved) where rq is a pointer to a request.
+ * @reserved) where rq is a pointer to a request. Return true
+ * to continue iterating tags, false to stop.
* @data: Will be passed as second argument to @fn.
* @reserved: Indicates whether @bt is the breserved_tags member or the
* bitmap_tags member of struct blk_mq_tags.
@@ -326,7 +328,8 @@ static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt,
* @fn: Pointer to the function that will be called for each started
* request. @fn will be called as follows: @fn(rq, @priv,
* reserved) where rq is a pointer to a request. 'reserved'
- * indicates whether or not @rq is a reserved request.
+ * indicates whether or not @rq is a reserved request. Return
+ * true to continue iterating tags, false to stop.
* @priv: Will be passed as second argument to @fn.
*/
static void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags,
@@ -343,7 +346,8 @@ static void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags,
* @fn: Pointer to the function that will be called for each started
* request. @fn will be called as follows: @fn(rq, @priv,
* reserved) where rq is a pointer to a request. 'reserved'
- * indicates whether or not @rq is a reserved request.
+ * indicates whether or not @rq is a reserved request. Return
+ * true to continue iterating tags, false to stop.
* @priv: Will be passed as second argument to @fn.
*/
void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
--
Jens Axboe
