From 4cc987eaff9144182cde88d6d132420c28d3f81b Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Tue, 19 May 2015 00:03:07 -0700 Subject: target: Drop lun_sep_lock for se_lun->lun_se_dev RCU usage With se_port and t10_alua_tg_pt_gp_member being absored into se_lun, there is no need for an extra lock to protect se_lun->lun_se_dev assignment. This patch also converts backend drivers to use call_rcu() release to allow any se_device readers to complete. The call_rcu() instead of kfree_rcu() is required here because se_device is embedded into the backend driver specific structure. Also, convert se_lun->lun_stats to use atomic_long_t within the target_complete_ok_work() completion callback, and add FIXME for transport_lookup_tmr_lun() with se_lun->lun_ref. Finally, update sbp_update_unit_directory() special case usage with proper rcu_dereference_raw() and configfs symlink comment. Reported-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Cc: Paul E. McKenney Cc: Chris Boot Signed-off-by: Nicholas Bellinger --- include/target/target_core_base.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h index 1927dd5947a7..b82a989a4d3b 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -690,9 +690,9 @@ struct se_port_stat_grps { }; struct scsi_port_stats { - u32 cmd_pdus; - u64 tx_data_octets; - u64 rx_data_octets; + atomic_long_t cmd_pdus; + atomic_long_t tx_data_octets; + atomic_long_t rx_data_octets; }; struct se_lun { @@ -705,7 +705,6 @@ struct se_lun { u32 unpacked_lun; u32 lun_index; atomic_t lun_acl_count; - spinlock_t lun_sep_lock; struct se_device __rcu *lun_se_dev; struct list_head lun_deve_list; @@ -818,6 +817,9 @@ struct se_device { struct se_lun xcopy_lun; /* Protection Information */ int prot_length; + /* For se_lun->lun_se_dev RCU read-side critical access */ + u32 hba_index; + struct rcu_head rcu_head; }; struct se_hba { -- cgit v1.2.3