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authorNicholas Bellinger <nab@linux-iscsi.org>2015-05-19 00:03:07 -0700
committerNicholas Bellinger <nab@linux-iscsi.org>2015-06-01 00:27:38 -0700
commit4cc987eaff9144182cde88d6d132420c28d3f81b (patch)
tree15cf7d432599e1e09446462968ef01c4d10a087e /drivers/target/target_core_pscsi.c
parentadf653f92f38e80a78bb77e912d49bcc8055330f (diff)
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 <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Chris Boot <bootc@bootc.net> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target/target_core_pscsi.c')
-rw-r--r--drivers/target/target_core_pscsi.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index afb87a8d5668..c673980ded04 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -579,6 +579,14 @@ static int pscsi_configure_device(struct se_device *dev)
return -ENODEV;
}
+static void pscsi_dev_call_rcu(struct rcu_head *p)
+{
+ struct se_device *dev = container_of(p, struct se_device, rcu_head);
+ struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
+
+ kfree(pdv);
+}
+
static void pscsi_free_device(struct se_device *dev)
{
struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
@@ -610,8 +618,7 @@ static void pscsi_free_device(struct se_device *dev)
pdv->pdv_sd = NULL;
}
-
- kfree(pdv);
+ call_rcu(&dev->rcu_head, pscsi_dev_call_rcu);
}
static void pscsi_transport_complete(struct se_cmd *cmd, struct scatterlist *sg,

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