On 9/6/22 10:45 AM, Dmitry Bogdanov wrote:
> From: Roman Bolshakov <r.bolshakov@xxxxxxxxx>
>
> SAM-5 4.6.5.2 (Relative Port Identifier attribute) defines the attribute
> as unique across SCSI target ports.
>
> The change introduces RTPI attribute to se_portal group. The value is
> auto-incremented and unique across all SCSI target ports. It also limits
> number of SCSI target ports to 65535.
>
> Signed-off-by: Roman Bolshakov <r.bolshakov@xxxxxxxxx>
> Signed-off-by: Dmitry Bogdanov <d.bogdanov@xxxxxxxxx>
> ---
> drivers/target/target_core_tpg.c | 78 +++++++++++++++++++++++++++++--
> include/target/target_core_base.h | 4 ++
> 2 files changed, 77 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
> index f0d38d77edcc..325ef439fb42 100644
> --- a/drivers/target/target_core_tpg.c
> +++ b/drivers/target/target_core_tpg.c
> @@ -31,6 +31,10 @@
> #include "target_core_ua.h"
>
> extern struct se_device *g_lun0_dev;
> +static u16 g_tpg_count;
> +static u16 g_tpg_rtpi_counter = 1;
> +static LIST_HEAD(g_tpg_list);
> +static DEFINE_SPINLOCK(g_tpg_lock);
>
> /* __core_tpg_get_initiator_node_acl():
> *
> @@ -439,6 +443,57 @@ static void core_tpg_lun_ref_release(struct percpu_ref *ref)
> complete(&lun->lun_shutdown_comp);
> }
>
> +static int core_tpg_register_rtpi(struct se_portal_group *se_tpg)
> +{
> + struct se_portal_group *tpg;
> +
> + /*
> + * Allocate the next RELATIVE TARGET PORT IDENTIFIER.
> + * Here is the table from SPC-4 4.3.4:
> + *
> + * Table 34 -- Relative target port identifier values
> + *
> + * Value Description
> + * 0h Reserved
> + * 1h Relative port 1, historically known as port A
> + * 2h Relative port 2, historically known as port B
> + * 3h to FFFFh Relative port 3 through 65 535
> + */
> + spin_lock(&g_tpg_lock);
> +
> + if (g_tpg_count == 0xffff) {
> + spin_unlock(&g_tpg_lock);
> + pr_warn("Reached g_tpg_count == 0xffff\n");
> + return -ENOSPC;
> + }
> +again:
> + se_tpg->tpg_rtpi = g_tpg_rtpi_counter++;
> + if (!se_tpg->tpg_rtpi)
> + goto again;
> +
> + list_for_each_entry(tpg, &g_tpg_list, tpg_list) {
> + /*
> + * Make sure RELATIVE TARGET PORT IDENTIFIER is unique
> + * for 16-bit wrap..
> + */
> + if (se_tpg->tpg_rtpi == tpg->tpg_rtpi)
> + goto again;
> + }
> + list_add(&se_tpg->tpg_list, &g_tpg_list);
> + g_tpg_count++;
> + spin_unlock(&g_tpg_lock);
> +
I think you could just use an ida.
