On 26/01/2022 13:42, Hanna Reitz wrote:
> On 21.01.22 18:05, Emanuele Giuseppe Esposito wrote:
>> Signed-off-by: Emanuele Giuseppe Esposito <eespo...@redhat.com>
>> ---
>> include/block/block_int-common.h | 67 +++++++++++++++++++-------------
>> 1 file changed, 40 insertions(+), 27 deletions(-)
>>
>> diff --git a/include/block/block_int-common.h
>> b/include/block/block_int-common.h
>> index e007dbf768..cc8c8835ba 100644
>> --- a/include/block/block_int-common.h
>> +++ b/include/block/block_int-common.h
>> @@ -815,12 +815,16 @@ struct BdrvChildClass {
>> */
>> bool parent_is_bds;
>> + /*
>> + * Global state (GS) API. These functions run under the BQL lock.
>> + *
>> + * See include/block/block-global-state.h for more information about
>> + * the GS API.
>> + */
>> void (*inherit_options)(BdrvChildRole role, bool parent_is_format,
>> int *child_flags, QDict *child_options,
>> int parent_flags, QDict *parent_options);
>> -
>> void (*change_media)(BdrvChild *child, bool load);
>> - void (*resize)(BdrvChild *child);
>> /*
>> * Returns a name that is supposedly more useful for human users
>> than the
>
> The method this comment belongs to is `.get_name()`. It’s exposed
> through `bdrv_get_parent_name()`, which is called by
> `bdrv_get_device_name()` and `bdrv_get_device_or_node_name()` – so I
> think it should be classified as I/O.
Agree on this, and also on comment on patch 23 about bdrv_probe.
>
>> @@ -837,6 +841,40 @@ struct BdrvChildClass {
>> */
>> char *(*get_parent_desc)(BdrvChild *child);
>
> This function is very similar, so we might also want to reconsider
> classifying it as I/O. There’s no need, because all of its callers do
> run in the main thread, but at the same time I don’t believe there’s
> anything stopping us (and it starts to sound to me like all functions of
> the “get name” kind perhaps should ideally be I/O, in that they
> shouldn’t require the GS context).
>
> Up to you. O:)
I understand what you mean, but I would like to leave it in global
state. Seeing the assertion/definition as GS tells me that it is already
under BQL, and I should not worry about I/O in that function. If no such
assert was present, it would lead me to think that there might be I/O
concurrently using it, and complicate the logic of whatever I want to do
there.
Thank you,
Emanuele
>
> (Rest of this patch looks good!)
>
> Hanna
>
