diff options
author | Nicholas Bellinger <nab@linux-iscsi.org> | 2015-03-22 20:42:19 -0700 |
---|---|---|
committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2015-06-01 00:23:46 -0700 |
commit | 29a05deebf6c2e3010934fb78ee65cab3d329470 (patch) | |
tree | 5b91d971e31c45919ef212513104350877807c3c /drivers/target/target_core_spc.c | |
parent | d2c27f0d0b7eb18f40b9b1a0d793c8ba074e5c23 (diff) | |
download | op-kernel-dev-29a05deebf6c2e3010934fb78ee65cab3d329470.zip op-kernel-dev-29a05deebf6c2e3010934fb78ee65cab3d329470.tar.gz |
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_spc.c')
-rw-r--r-- | drivers/target/target_core_spc.c | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c index 78c0b40..9f995b87 100644 --- a/drivers/target/target_core_spc.c +++ b/drivers/target/target_core_spc.c @@ -981,6 +981,7 @@ static sense_reason_t spc_emulate_modesense(struct se_cmd *cmd) int length = 0; int ret; int i; + bool read_only = target_lun_is_rdonly(cmd);; memset(buf, 0, SE_MODE_PAGE_BUF); @@ -991,9 +992,7 @@ static sense_reason_t spc_emulate_modesense(struct se_cmd *cmd) length = ten ? 3 : 2; /* DEVICE-SPECIFIC PARAMETER */ - if ((cmd->se_lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) || - (cmd->se_deve && - (cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY))) + if ((cmd->se_lun->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) || read_only) spc_modesense_write_protect(&buf[length], type); /* @@ -1211,8 +1210,9 @@ sense_reason_t spc_emulate_report_luns(struct se_cmd *cmd) { struct se_dev_entry *deve; struct se_session *sess = cmd->se_sess; + struct se_node_acl *nacl; unsigned char *buf; - u32 lun_count = 0, offset = 8, i; + u32 lun_count = 0, offset = 8; if (cmd->data_length < 16) { pr_warn("REPORT LUNS allocation length %u too small\n", @@ -1234,12 +1234,10 @@ sense_reason_t spc_emulate_report_luns(struct se_cmd *cmd) lun_count = 1; goto done; } + nacl = sess->se_node_acl; - spin_lock_irq(&sess->se_node_acl->device_list_lock); - for (i = 0; i < TRANSPORT_MAX_LUNS_PER_TPG; i++) { - deve = sess->se_node_acl->device_list[i]; - if (!(deve->lun_flags & TRANSPORT_LUNFLAGS_INITIATOR_ACCESS)) - continue; + rcu_read_lock(); + hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link) { /* * We determine the correct LUN LIST LENGTH even once we * have reached the initial allocation length. @@ -1252,7 +1250,7 @@ sense_reason_t spc_emulate_report_luns(struct se_cmd *cmd) int_to_scsilun(deve->mapped_lun, (struct scsi_lun *)&buf[offset]); offset += 8; } - spin_unlock_irq(&sess->se_node_acl->device_list_lock); + rcu_read_unlock(); /* * See SPC3 r07, page 159. |