[PATCH RFC v5 4/6] iommu/arm-smmu-v3: Support shared SIDs in insert/remove_master

[Peng Fan]

On Wed, Oct 07, 2026 at 06:02:03PM -0700, Nicolin Chen wrote:
>On Tue, Oct 06, 2026 at 08:19:10PM +0800, Peng Fan (OSS) wrote:
>> @@ -4193,17 +4213,31 @@ static void arm_smmu_remove_master(struct arm_smmu_master *master)
>>  		return;
>>  
>>  	mutex_lock(&smmu->streams_mutex);
>> -	for (i = 0; i < master->num_streams; i++) {
>> -		int j;
>> +	if (!list_empty(&master->shared_masters_elm)) {
>> +		struct arm_smmu_stream *stream = master->streams[0];
>>  
>> -		/* Skip duplicated SID pointers already freed */
>> -		for (j = 0; j < i; j++)
>> -			if (master->streams[j] == master->streams[i])
>> -				break;
>> -		if (j < i)
>> -			continue;
>> -		rb_erase(&master->streams[i]->node, &smmu->streams);
>> -		kfree(master->streams[i]);
>> +		list_del_init(&master->shared_masters_elm);
>> +		if (list_is_singular(&stream->shared_masters)) {
>> +			struct arm_smmu_master *last;
>> +
>> +			last = list_first_entry(&stream->shared_masters,
>> +					struct arm_smmu_master,
>> +					shared_masters_elm);
>> +			list_del_init(&last->shared_masters_elm);
>> +		}
>
>This doesn't look right: it still needs the for loop and also needs
>to compare master with stream->master:

My bad. Thanks for sharing the code. I will take care in V6.

Thanks
Peng
>
>		if (!list_empty(&stream->shared_masters)) {
>			struct arm_smmu_master *next;
>
>			list_del_init(&master->shared_masters_elm);
>			next = list_first_entry(&stream->shared_masters,
>						struct arm_smmu_master,
>						shared_masters_elm);
>			if (stream->master == master)
>				stream->master = next;
>			if (list_is_singular(&stream->shared_masters))
>				list_del_init(&next->shared_masters_elm);
>			continue;
>		}
>		rb_erase(&stream->node, &smmu->streams);
>		kfree(stream);
>
>Nicolin
>