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 --- drivers/target/target_core_rd.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'drivers/target/target_core_rd.c') diff --git a/drivers/target/target_core_rd.c b/drivers/target/target_core_rd.c index 55dd73e7f213..e98432705f39 100644 --- a/drivers/target/target_core_rd.c +++ b/drivers/target/target_core_rd.c @@ -350,12 +350,20 @@ fail: return ret; } +static void rd_dev_call_rcu(struct rcu_head *p) +{ + struct se_device *dev = container_of(p, struct se_device, rcu_head); + struct rd_dev *rd_dev = RD_DEV(dev); + + kfree(rd_dev); +} + static void rd_free_device(struct se_device *dev) { struct rd_dev *rd_dev = RD_DEV(dev); rd_release_device_space(rd_dev); - kfree(rd_dev); + call_rcu(&dev->rcu_head, rd_dev_call_rcu); } static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page) -- cgit v1.2.3