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authorNicholas Bellinger <nab@linux-iscsi.org>2015-03-22 20:42:19 -0700
committerNicholas Bellinger <nab@linux-iscsi.org>2015-06-01 00:23:46 -0700
commit29a05deebf6c2e3010934fb78ee65cab3d329470 (patch)
tree5b91d971e31c45919ef212513104350877807c3c /drivers/target/target_core_pscsi.c
parentd2c27f0d0b7eb18f40b9b1a0d793c8ba074e5c23 (diff)
target: Convert se_node_acl->device_list[] to RCU hlist
This patch converts se_node_acl->device_list[] table for mappedluns to modern RCU hlist_head usage in order to support an arbitrary number of node_acl lun mappings. It converts transport_lookup_*_lun() fast-path code to use RCU read path primitives when looking up se_dev_entry. It adds a new hlist_head at se_node_acl->lun_entry_hlist for this purpose. For transport_lookup_cmd_lun() code, it works with existing per-cpu se_lun->lun_ref when associating se_cmd with se_lun + se_device. Also, go ahead and update core_create_device_list_for_node() + core_free_device_list_for_node() to use ->lun_entry_hlist. It also converts se_dev_entry->pr_ref_count access to use modern struct kref counting, and updates core_disable_device_list_for_node() to kref_put() and block on se_deve->pr_comp waiting for outstanding PR special-case PR references to drop, then invoke kfree_rcu() to wait for the RCU grace period to complete before releasing memory. So now that se_node_acl->lun_entry_hlist fast path access uses RCU protected pointers, go ahead and convert remaining non-fast path RCU updater code using ->lun_entry_lock to struct mutex to allow callers to block while walking se_node_acl->lun_entry_hlist. Finally drop the left-over core_clear_initiator_node_from_tpg() that originally cleared lun_access during se_node_acl shutdown, as post RCU conversion it now becomes duplicated logic. Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Sagi Grimberg <sagig@mellanox.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> 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.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index ecc5eaef13d6..21db991b4465 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -47,6 +47,7 @@
#include <target/target_core_backend_configfs.h>
#include "target_core_alua.h"
+#include "target_core_internal.h"
#include "target_core_pscsi.h"
#define ISPRINT(a) ((a >= ' ') && (a <= '~'))
@@ -637,12 +638,14 @@ static void pscsi_transport_complete(struct se_cmd *cmd, struct scatterlist *sg,
* Hack to make sure that Write-Protect modepage is set if R/O mode is
* forced.
*/
- if (!cmd->se_deve || !cmd->data_length)
+ if (!cmd->data_length)
goto after_mode_sense;
if (((cdb[0] == MODE_SENSE) || (cdb[0] == MODE_SENSE_10)) &&
(status_byte(result) << 1) == SAM_STAT_GOOD) {
- if (cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY) {
+ bool read_only = target_lun_is_rdonly(cmd);
+
+ if (read_only) {
unsigned char *buf;
buf = transport_kmap_data_sg(cmd);

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