On 11/25/20 5:46 AM, Alexandre Courbot wrote:
> On Fri, Nov 20, 2020 at 9:12 AM Stanimir Varbanov
> <stanimir.varbanov@xxxxxxxxxx> wrote:
>>
>> Currently we rely on firmware to return error when we reach the maximum
>> supported number of sessions. But this errors are happened at reqbuf
>> time which is a bit later. The more reasonable way looks like is to
>> return the error on driver open.
>>
>> To achieve that modify hfi_session_create to return error when we reach
>> maximum count of sessions and thus refuse open.
>>
>> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx>
>> ---
>> drivers/media/platform/qcom/venus/core.h | 1 +
>> drivers/media/platform/qcom/venus/hfi.c | 19 +++++++++++++++----
>> .../media/platform/qcom/venus/hfi_parser.c | 3 +++
>> 3 files changed, 19 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/media/platform/qcom/venus/core.h b/drivers/media/platform/qcom/venus/core.h
>> index db0e6738281e..3a477fcdd3a8 100644
>> --- a/drivers/media/platform/qcom/venus/core.h
>> +++ b/drivers/media/platform/qcom/venus/core.h
>> @@ -96,6 +96,7 @@ struct venus_format {
>> #define MAX_CAP_ENTRIES 32
>> #define MAX_ALLOC_MODE_ENTRIES 16
>> #define MAX_CODEC_NUM 32
>> +#define MAX_SESSIONS 16
>>
>> struct raw_formats {
>> u32 buftype;
>> diff --git a/drivers/media/platform/qcom/venus/hfi.c b/drivers/media/platform/qcom/venus/hfi.c
>> index 638ed5cfe05e..8420be6d3991 100644
>> --- a/drivers/media/platform/qcom/venus/hfi.c
>> +++ b/drivers/media/platform/qcom/venus/hfi.c
>> @@ -175,6 +175,7 @@ static int wait_session_msg(struct venus_inst *inst)
>> int hfi_session_create(struct venus_inst *inst, const struct hfi_inst_ops *ops)
>> {
>> struct venus_core *core = inst->core;
>> + int ret;
>>
>> if (!ops)
>> return -EINVAL;
>> @@ -183,12 +184,22 @@ int hfi_session_create(struct venus_inst *inst, const struct hfi_inst_ops *ops)
>> init_completion(&inst->done);
>> inst->ops = ops;
>>
>> - mutex_lock(&core->lock);
>> - list_add_tail(&inst->list, &core->instances);
>> - atomic_inc(&core->insts_count);
>> + ret = mutex_lock_interruptible(&core->lock);
>> + if (ret)
>> + return ret;
>
> Why do we change to mutex_lock_interruptible() here? This makes this
Because mutex_lock_interruptible is preferable in kernel docs, but I
agree that changing mutex_lock with mutex_lock_interruptible should be
subject of another lock related patches. I will drop this in next patch
version.
> function return an error even though we could obtain the lock just by
> trying a bit harder.
I didn't get that. The behavior of mutex_lock_interruptible is that same
as mutex_lock, i.e. the it will sleep to acquire the lock. The
difference is that the sleep could be interrupted by a signal. You might
think about mutex_trylock?
>
>> +
>> + ret = atomic_read(&core->insts_count);
>> + if (ret + 1 > core->max_sessions_supported) {
>> + ret = -EAGAIN;
>> + } else {
>> + atomic_inc(&core->insts_count);
>> + list_add_tail(&inst->list, &core->instances);
>> + ret = 0;
>> + }
>> +
>> mutex_unlock(&core->lock);
>>
>> - return 0;
>> + return ret;
>> }
>> EXPORT_SYMBOL_GPL(hfi_session_create);
>>
>> diff --git a/drivers/media/platform/qcom/venus/hfi_parser.c b/drivers/media/platform/qcom/venus/hfi_parser.c
>> index 363ee2a65453..52898633a8e6 100644
>> --- a/drivers/media/platform/qcom/venus/hfi_parser.c
>> +++ b/drivers/media/platform/qcom/venus/hfi_parser.c
>> @@ -276,6 +276,9 @@ u32 hfi_parser(struct venus_core *core, struct venus_inst *inst, void *buf,
>> words_count--;
>> }
>>
>> + if (!core->max_sessions_supported)
>> + core->max_sessions_supported = MAX_SESSIONS;
>> +
>> parser_fini(inst, codecs, domain);
>>
>> return HFI_ERR_NONE;
>> --
>> 2.17.1
>>
--
regards,
Stan
