Re: [PATCH 04/15] target/iscsi: move session_index to common se_session

[Mike Christie <mchristi@redhat.com>]

On 07/18/2018 05:19 PM, Bart Van Assche wrote:
> On Sun, 2018-07-15 at 18:16 -0500, Mike Christie wrote:
>> diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
>> index 75ddbbb..97a1ee5 100644
>> --- a/drivers/target/target_core_transport.c
>> +++ b/drivers/target/target_core_transport.c
>> @@ -55,6 +55,8 @@
>>  
>>  static struct workqueue_struct *target_completion_wq;
>>  static struct kmem_cache *se_sess_cache;
>> +static DEFINE_SPINLOCK(se_sess_idr_lock);
>> +static DEFINE_IDR(se_sess_idr);
> 
> Is it necessary that se_sess_idr_lock and se_sess_idr are global? Could these
> two data structures be members of the data structure associated with
> /sys/kernel/config/target/iscsi/$port/$tpg (struct se_portal_group?)?

For tcmu we have a problem where we pass the scsi commands to userspace
but then we need to know what I_T nexus it was sent through or what
target port it was received on.

I thought I could reuse the sid for tcmu commands where I could embed
the sid in the tcmu_cmd and then userspace can look up the sid and know
what session the command came in on. If the device is exported through 2
tpgs then we need the sid target wide in case sessions on different tpgs
have the same sid. And, then I thought if you exported the device
through 2 fabrics then I thought you need it set globally.

I am still working on that part with Bodo, so I can make it per tpg when
I resend then do another path to change it later.