Re: [PATCH 03/12] target/configfs: Convert mappedlun + SCSI MIBs to RCU reader

From: Andy Grover
Date: Tue May 12 2015 - 16:58:54 EST


On 05/12/2015 02:25 AM, Nicholas A. Bellinger wrote:
From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

This patch converts fabric independent configfs link/unlink to use
RCU read path macros for se_node_acl->lun_entry_hlist access.

It also converts SCSI MIB configfs show attribute code to use
RCU read path macros for se_node_acl->lun_entry_hlist access.

Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_fabric_configfs.c | 35 +++---
drivers/target/target_core_stat.c | 180 +++++++++++++--------------
2 files changed, 110 insertions(+), 105 deletions(-)

diff --git a/drivers/target/target_core_fabric_configfs.c b/drivers/target/target_core_fabric_configfs.c
index 6cb4828..0dab6d5 100644
--- a/drivers/target/target_core_fabric_configfs.c
+++ b/drivers/target/target_core_fabric_configfs.c
@@ -123,16 +123,16 @@ static int target_fabric_mappedlun_link(
* which be will write protected (READ-ONLY) when
* tpg_1/attrib/demo_mode_write_protect=1
*/
- spin_lock_irq(&lacl->se_lun_nacl->device_list_lock);
- deve = lacl->se_lun_nacl->device_list[lacl->mapped_lun];
- if (deve->lun_flags & TRANSPORT_LUNFLAGS_INITIATOR_ACCESS)
+ rcu_read_lock();
+ deve = target_nacl_find_deve(lacl->se_lun_nacl, lacl->mapped_lun);
+ if (deve && deve->lun_flags & TRANSPORT_LUNFLAGS_INITIATOR_ACCESS)

Why do we still need TRANSPORT_LUNFLAGS_INITIATOR_ACCESS? Isn't deve being not-NULL enough?

-- Andy

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