Re: [PATCH RFC v5 3/6] iommu/arm-smmu-v3: Delay stream allocation to inside the mutex

[Peng Fan]

On Wed, Oct 07, 2026 at 04:55:37PM -0700, Nicolin Chen wrote:
>On Tue, Oct 06, 2026 at 08:19:09PM +0800, Peng Fan (OSS) wrote:
>> @@ -4110,52 +4110,29 @@ static int arm_smmu_insert_master(struct arm_smmu_device *smmu,
>[...]
>> -		/* Insert into SID tree */
>> -		existing = rb_find_add(&new_stream->node, &smmu->streams,
>> -				       arm_smmu_streams_cmp_node);
>> +		existing = rb_find(&sid, &smmu->streams,
>> +				   arm_smmu_streams_cmp_key);
>>  		if (existing) {
>>  			struct arm_smmu_master *existing_master =
>>  				rb_entry(existing, struct arm_smmu_stream, node)
>>  					->master;
>>  
>>  			/* Bridged PCI devices may end up with duplicated IDs */
>> -			if (existing_master == master)
>> +			if (existing_master == master) {
>> +				master->streams[i] = rb_entry(existing,
>> +					struct arm_smmu_stream, node);
>
>This can be cleaned a bit by moving the arm_smmu_find_stream()
>from PATCH-4 to this patch.
>
>>  	if (ret) {

...

>> +		}
>
>Add a helper to share with arm_smmu_remove_master():

For both comments, I will address them in V6.

Thanks
Peng

>
>static void arm_smmu_free_master_streams(struct arm_smmu_master *master)
>{
>	struct arm_smmu_device *smmu = master->smmu;
>	int i;
>
>	lockdep_assert_held(&smmu->streams_mutex);
>
>	for (i = 0; i < master->num_streams; i++) {
>		int j;
>
>		if (!master->streams[i])
>			continue;
>		/* 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]);
>	}
>}
>
>Nicolin
>