target: Add percpu refcounting for se_lun access

This patch adds percpu refcounting for se_lun access that allows the
association of an se_lun + se_cmd in transport_lookup_cmd_lun() to
occur without an extra list_head for tracking outstanding I/O during
se_lun shutdown.

This effectively changes se_lun shutdown logic to wait for outstanding
I/O percpu references to complete in transport_lun_remove_cmd() using
se_lun->lun_ref_comp, instead of explicitly draining the per se_lun
command list and waiting for individual se_cmd descriptor processing
to complete.

Cc: Kent Overstreet <kmo@daterainc.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/target/target_core_internal.h b/drivers/target/target_core_internal.h
index 889af4df8562..47b63b094cdc 100644
--- a/drivers/target/target_core_internal.h
+++ b/drivers/target/target_core_internal.h
@@ -100,7 +100,7 @@ int	transport_dump_vpd_assoc(struct t10_vpd *, unsigned char *, int);
 int     transport_dump_vpd_ident_type(struct t10_vpd *, unsigned char *, int);
 int     transport_dump_vpd_ident(struct t10_vpd *, unsigned char *, int);
 bool    target_stop_cmd(struct se_cmd *cmd, unsigned long *flags);
-int     transport_clear_lun_from_sessions(struct se_lun *);
+int     transport_clear_lun_ref(struct se_lun *);
 void    transport_send_task_abort(struct se_cmd *);
 sense_reason_t  target_cmd_size_check(struct se_cmd *cmd, unsigned int size);
 void    target_qf_do_work(struct work_struct *work);