| Message ID | 1427443512-8925-2-git-send-email-nab@daterainc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 3/27/2015 11:04 AM, Nicholas A. Bellinger wrote: > From: Nicholas Bellinger <nab@linux-iscsi.org> > > This patch converts transport_lookup_*_lun() fast-path code to > use RCU read path primitives when looking up se_dev_entry. It > adds a new array of pointers in 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. > > Cc: Hannes Reinecke <hare@suse.de> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Sagi Grimberg <sagig@mellanox.com> > Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> > --- > drivers/target/target_core_device.c | 45 +++++++++++++++++++++++++------------ > drivers/target/target_core_tpg.c | 10 +++++---- > include/target/target_core_base.h | 2 ++ > 3 files changed, 39 insertions(+), 18 deletions(-) > > diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c > index 37449bd..be893c8 100644 > --- a/drivers/target/target_core_device.c > +++ b/drivers/target/target_core_device.c > @@ -59,17 +59,24 @@ transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun) > { > struct se_lun *se_lun = NULL; > struct se_session *se_sess = se_cmd->se_sess; > + struct se_node_acl *nacl = se_sess->se_node_acl; > struct se_device *dev; > - unsigned long flags; > + struct se_dev_entry *deve; > > if (unpacked_lun >= TRANSPORT_MAX_LUNS_PER_TPG) > return TCM_NON_EXISTENT_LUN; > > - spin_lock_irqsave(&se_sess->se_node_acl->device_list_lock, flags); > - se_cmd->se_deve = se_sess->se_node_acl->device_list[unpacked_lun]; > - if (se_cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_INITIATOR_ACCESS) { > - struct se_dev_entry *deve = se_cmd->se_deve; > - > + rcu_read_lock(); > + deve = rcu_dereference(nacl->lun_entry_hlist[unpacked_lun]); > + if (deve->lun_flags & TRANSPORT_LUNFLAGS_INITIATOR_ACCESS) { > + /* > + * Make sure that target_enable_device_list_for_node() > + * has not already cleared the RCU protected pointers. > + */ > + if (!deve->se_lun) { > + rcu_read_unlock(); > + goto check_lun; > + } > deve->total_cmds++; > > if ((se_cmd->data_direction == DMA_TO_DEVICE) && > @@ -78,7 +85,7 @@ transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun) > " Access for 0x%08x\n", > se_cmd->se_tfo->get_fabric_name(), > unpacked_lun); > - spin_unlock_irqrestore(&se_sess->se_node_acl->device_list_lock, flags); > + rcu_read_unlock(); > return TCM_WRITE_PROTECTED; > } > > @@ -96,8 +103,9 @@ transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun) > percpu_ref_get(&se_lun->lun_ref); > se_cmd->lun_ref_active = true; > } > - spin_unlock_irqrestore(&se_sess->se_node_acl->device_list_lock, flags); > + rcu_read_unlock(); > > +check_lun: > if (!se_lun) { > /* > * Use the se_portal_group->tpg_virt_lun0 to allow for > @@ -146,25 +154,34 @@ int transport_lookup_tmr_lun(struct se_cmd *se_cmd, u32 unpacked_lun) > struct se_dev_entry *deve; > struct se_lun *se_lun = NULL; > struct se_session *se_sess = se_cmd->se_sess; > + struct se_node_acl *nacl = se_sess->se_node_acl; > struct se_tmr_req *se_tmr = se_cmd->se_tmr_req; > unsigned long flags; > > if (unpacked_lun >= TRANSPORT_MAX_LUNS_PER_TPG) > return -ENODEV; > > - spin_lock_irqsave(&se_sess->se_node_acl->device_list_lock, flags); > - se_cmd->se_deve = se_sess->se_node_acl->device_list[unpacked_lun]; > - deve = se_cmd->se_deve; > + rcu_read_lock(); > + deve = rcu_dereference(nacl->lun_entry_hlist[unpacked_lun]); > > if (deve->lun_flags & TRANSPORT_LUNFLAGS_INITIATOR_ACCESS) { > + /* > + * Make sure that target_enable_device_list_for_node() > + * has not already cleared the RCU protected pointers. > + */ > + if (!deve->se_lun) { > + rcu_read_unlock(); > + goto check_lun; > + } > se_tmr->tmr_lun = deve->se_lun; > se_cmd->se_lun = deve->se_lun; > se_lun = deve->se_lun; > se_cmd->pr_res_key = deve->pr_res_key; > se_cmd->orig_fe_lun = unpacked_lun; > } > - spin_unlock_irqrestore(&se_sess->se_node_acl->device_list_lock, flags); > + rcu_read_unlock(); > > +check_lun: > if (!se_lun) { > pr_debug("TARGET_CORE[%s]: Detected NON_EXISTENT_LUN" > " Access for 0x%08x\n", > @@ -267,8 +284,8 @@ int core_free_device_list_for_node( > } > spin_unlock_irq(&nacl->device_list_lock); > > - array_free(nacl->device_list, TRANSPORT_MAX_LUNS_PER_TPG); > - nacl->device_list = NULL; > + array_free(nacl->lun_entry_hlist, TRANSPORT_MAX_LUNS_PER_TPG); > + nacl->lun_entry_hlist = NULL; > > return 0; > } > diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c > index 0696de9..b2fdba5 100644 > --- a/drivers/target/target_core_tpg.c > +++ b/drivers/target/target_core_tpg.c > @@ -234,15 +234,15 @@ static int core_create_device_list_for_node(struct se_node_acl *nacl) > struct se_dev_entry *deve; > int i; > > - nacl->device_list = array_zalloc(TRANSPORT_MAX_LUNS_PER_TPG, > + nacl->lun_entry_hlist = array_zalloc(TRANSPORT_MAX_LUNS_PER_TPG, > sizeof(struct se_dev_entry), GFP_KERNEL); > - if (!nacl->device_list) { > + if (!nacl->lun_entry_hlist) { > pr_err("Unable to allocate memory for" > - " struct se_node_acl->device_list\n"); > + " struct se_node_acl->lun_entry_hlist\n"); > return -ENOMEM; > } > for (i = 0; i < TRANSPORT_MAX_LUNS_PER_TPG; i++) { > - deve = nacl->device_list[i]; > + deve = nacl->lun_entry_hlist[i]; > > atomic_set(&deve->ua_count, 0); > atomic_set(&deve->pr_ref_count, 0); > @@ -281,6 +281,7 @@ struct se_node_acl *core_tpg_check_initiator_node_acl( > init_completion(&acl->acl_free_comp); > spin_lock_init(&acl->device_list_lock); > spin_lock_init(&acl->nacl_sess_lock); > + spin_lock_init(&acl->lun_entry_lock); > atomic_set(&acl->acl_pr_ref_count, 0); > acl->queue_depth = tpg->se_tpg_tfo->tpg_get_default_depth(tpg); > snprintf(acl->initiatorname, TRANSPORT_IQN_LEN, "%s", initiatorname); > @@ -408,6 +409,7 @@ struct se_node_acl *core_tpg_add_initiator_node_acl( > init_completion(&acl->acl_free_comp); > spin_lock_init(&acl->device_list_lock); > spin_lock_init(&acl->nacl_sess_lock); > + spin_lock_init(&acl->lun_entry_lock); > atomic_set(&acl->acl_pr_ref_count, 0); > acl->queue_depth = queue_depth; > snprintf(acl->initiatorname, TRANSPORT_IQN_LEN, "%s", initiatorname); > diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h > index fe25a78..06ecd7b 100644 > --- a/include/target/target_core_base.h > +++ b/include/target/target_core_base.h > @@ -595,10 +595,12 @@ struct se_node_acl { > char acl_tag[MAX_ACL_TAG_SIZE]; > /* Used for PR SPEC_I_PT=1 and REGISTER_AND_MOVE */ > atomic_t acl_pr_ref_count; > + struct se_dev_entry __rcu **lun_entry_hlist; > struct se_dev_entry **device_list; Shouldn't device_list be removed here? > struct se_session *nacl_sess; > struct se_portal_group *se_tpg; > spinlock_t device_list_lock; > + spinlock_t lun_entry_lock; This lock is unused in this patch, it should be introduced with its usage. 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diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c index 37449bd..be893c8 100644 --- a/drivers/target/target_core_device.c +++ b/drivers/target/target_core_device.c @@ -59,17 +59,24 @@ transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun) { struct se_lun *se_lun = NULL; struct se_session *se_sess = se_cmd->se_sess; + struct se_node_acl *nacl = se_sess->se_node_acl; struct se_device *dev; - unsigned long flags; + struct se_dev_entry *deve; if (unpacked_lun >= TRANSPORT_MAX_LUNS_PER_TPG) return TCM_NON_EXISTENT_LUN; - spin_lock_irqsave(&se_sess->se_node_acl->device_list_lock, flags); - se_cmd->se_deve = se_sess->se_node_acl->device_list[unpacked_lun]; - if (se_cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_INITIATOR_ACCESS) { - struct se_dev_entry *deve = se_cmd->se_deve; - + rcu_read_lock(); + deve = rcu_dereference(nacl->lun_entry_hlist[unpacked_lun]); + if (deve->lun_flags & TRANSPORT_LUNFLAGS_INITIATOR_ACCESS) { + /* + * Make sure that target_enable_device_list_for_node() + * has not already cleared the RCU protected pointers. + */ + if (!deve->se_lun) { + rcu_read_unlock(); + goto check_lun; + } deve->total_cmds++; if ((se_cmd->data_direction == DMA_TO_DEVICE) && @@ -78,7 +85,7 @@ transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun) " Access for 0x%08x\n", se_cmd->se_tfo->get_fabric_name(), unpacked_lun); - spin_unlock_irqrestore(&se_sess->se_node_acl->device_list_lock, flags); + rcu_read_unlock(); return TCM_WRITE_PROTECTED; } @@ -96,8 +103,9 @@ transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun) percpu_ref_get(&se_lun->lun_ref); se_cmd->lun_ref_active = true; } - spin_unlock_irqrestore(&se_sess->se_node_acl->device_list_lock, flags); + rcu_read_unlock(); +check_lun: if (!se_lun) { /* * Use the se_portal_group->tpg_virt_lun0 to allow for @@ -146,25 +154,34 @@ int transport_lookup_tmr_lun(struct se_cmd *se_cmd, u32 unpacked_lun) struct se_dev_entry *deve; struct se_lun *se_lun = NULL; struct se_session *se_sess = se_cmd->se_sess; + struct se_node_acl *nacl = se_sess->se_node_acl; struct se_tmr_req *se_tmr = se_cmd->se_tmr_req; unsigned long flags; if (unpacked_lun >= TRANSPORT_MAX_LUNS_PER_TPG) return -ENODEV; - spin_lock_irqsave(&se_sess->se_node_acl->device_list_lock, flags); - se_cmd->se_deve = se_sess->se_node_acl->device_list[unpacked_lun]; - deve = se_cmd->se_deve; + rcu_read_lock(); + deve = rcu_dereference(nacl->lun_entry_hlist[unpacked_lun]); if (deve->lun_flags & TRANSPORT_LUNFLAGS_INITIATOR_ACCESS) { + /* + * Make sure that target_enable_device_list_for_node() + * has not already cleared the RCU protected pointers. + */ + if (!deve->se_lun) { + rcu_read_unlock(); + goto check_lun; + } se_tmr->tmr_lun = deve->se_lun; se_cmd->se_lun = deve->se_lun; se_lun = deve->se_lun; se_cmd->pr_res_key = deve->pr_res_key; se_cmd->orig_fe_lun = unpacked_lun; } - spin_unlock_irqrestore(&se_sess->se_node_acl->device_list_lock, flags); + rcu_read_unlock(); +check_lun: if (!se_lun) { pr_debug("TARGET_CORE[%s]: Detected NON_EXISTENT_LUN" " Access for 0x%08x\n", @@ -267,8 +284,8 @@ int core_free_device_list_for_node( } spin_unlock_irq(&nacl->device_list_lock); - array_free(nacl->device_list, TRANSPORT_MAX_LUNS_PER_TPG); - nacl->device_list = NULL; + array_free(nacl->lun_entry_hlist, TRANSPORT_MAX_LUNS_PER_TPG); + nacl->lun_entry_hlist = NULL; return 0; } diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c index 0696de9..b2fdba5 100644 --- a/drivers/target/target_core_tpg.c +++ b/drivers/target/target_core_tpg.c @@ -234,15 +234,15 @@ static int core_create_device_list_for_node(struct se_node_acl *nacl) struct se_dev_entry *deve; int i; - nacl->device_list = array_zalloc(TRANSPORT_MAX_LUNS_PER_TPG, + nacl->lun_entry_hlist = array_zalloc(TRANSPORT_MAX_LUNS_PER_TPG, sizeof(struct se_dev_entry), GFP_KERNEL); - if (!nacl->device_list) { + if (!nacl->lun_entry_hlist) { pr_err("Unable to allocate memory for" - " struct se_node_acl->device_list\n"); + " struct se_node_acl->lun_entry_hlist\n"); return -ENOMEM; } for (i = 0; i < TRANSPORT_MAX_LUNS_PER_TPG; i++) { - deve = nacl->device_list[i]; + deve = nacl->lun_entry_hlist[i]; atomic_set(&deve->ua_count, 0); atomic_set(&deve->pr_ref_count, 0); @@ -281,6 +281,7 @@ struct se_node_acl *core_tpg_check_initiator_node_acl( init_completion(&acl->acl_free_comp); spin_lock_init(&acl->device_list_lock); spin_lock_init(&acl->nacl_sess_lock); + spin_lock_init(&acl->lun_entry_lock); atomic_set(&acl->acl_pr_ref_count, 0); acl->queue_depth = tpg->se_tpg_tfo->tpg_get_default_depth(tpg); snprintf(acl->initiatorname, TRANSPORT_IQN_LEN, "%s", initiatorname); @@ -408,6 +409,7 @@ struct se_node_acl *core_tpg_add_initiator_node_acl( init_completion(&acl->acl_free_comp); spin_lock_init(&acl->device_list_lock); spin_lock_init(&acl->nacl_sess_lock); + spin_lock_init(&acl->lun_entry_lock); atomic_set(&acl->acl_pr_ref_count, 0); acl->queue_depth = queue_depth; snprintf(acl->initiatorname, TRANSPORT_IQN_LEN, "%s", initiatorname); diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h index fe25a78..06ecd7b 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -595,10 +595,12 @@ struct se_node_acl { char acl_tag[MAX_ACL_TAG_SIZE]; /* Used for PR SPEC_I_PT=1 and REGISTER_AND_MOVE */ atomic_t acl_pr_ref_count; + struct se_dev_entry __rcu **lun_entry_hlist; struct se_dev_entry **device_list; struct se_session *nacl_sess; struct se_portal_group *se_tpg; spinlock_t device_list_lock; + spinlock_t lun_entry_lock; spinlock_t nacl_sess_lock; struct config_group acl_group; struct config_group acl_attrib_group;