From patchwork Mon Jun 1 08:21:14 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Nicholas A. 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[67.23.28.174]) by mx.google.com with ESMTPSA id sm8sm7268025obb.13.2015.06.01.01.24.21 (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 01 Jun 2015 01:24:21 -0700 (PDT) From: "Nicholas A. Bellinger" To: target-devel Cc: linux-scsi , linux-kernel , Christoph Hellwig , Hannes Reinecke , Sagi Grimberg , "Paul E. McKenney" , Nicholas Bellinger , Chris Boot Subject: [PATCH-v3 2/4] target: Drop lun_sep_lock for se_lun->lun_se_dev RCU usage Date: Mon, 1 Jun 2015 08:21:14 +0000 Message-Id: <1433146876-20188-3-git-send-email-nab@daterainc.com> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: <1433146876-20188-1-git-send-email-nab@daterainc.com> References: <1433146876-20188-1-git-send-email-nab@daterainc.com> Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Nicholas Bellinger 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 Reviewed-by: Hannes Reinecke Cc: Paul E. McKenney Cc: Chris Boot Signed-off-by: Nicholas Bellinger --- drivers/target/sbp/sbp_target.c | 7 +- drivers/target/target_core_alua.c | 12 +++- drivers/target/target_core_device.c | 47 ++++++++----- drivers/target/target_core_file.c | 11 ++- drivers/target/target_core_iblock.c | 10 ++- drivers/target/target_core_pscsi.c | 11 ++- drivers/target/target_core_rd.c | 10 ++- drivers/target/target_core_spc.c | 2 +- drivers/target/target_core_stat.c | 123 +++++++++++++++++---------------- drivers/target/target_core_tpg.c | 16 ++--- drivers/target/target_core_transport.c | 20 ++---- drivers/target/target_core_user.c | 11 ++- include/target/target_core_base.h | 10 +-- 13 files changed, 175 insertions(+), 115 deletions(-) diff --git a/drivers/target/sbp/sbp_target.c b/drivers/target/sbp/sbp_target.c index 47fb12f..28e3adf 100644 --- a/drivers/target/sbp/sbp_target.c +++ b/drivers/target/sbp/sbp_target.c @@ -1905,8 +1905,11 @@ static int sbp_update_unit_directory(struct sbp_tport *tport) hlist_for_each_entry_rcu(lun, &tport->tpg->se_tpg.tpg_lun_hlist, link) { struct se_device *dev; int type; - - dev = lun->lun_se_dev; + /* + * rcu_dereference_raw protected by se_lun->lun_group symlink + * reference to se_device->dev_group. + */ + dev = rcu_dereference_raw(lun->lun_se_dev); type = dev->transport->get_device_type(dev); /* logical_unit_number */ diff --git a/drivers/target/target_core_alua.c b/drivers/target/target_core_alua.c index 1109c28..0a00873 100644 --- a/drivers/target/target_core_alua.c +++ b/drivers/target/target_core_alua.c @@ -1935,7 +1935,11 @@ ssize_t core_alua_store_tg_pt_gp_info( size_t count) { struct se_portal_group *tpg = lun->lun_tpg; - struct se_device *dev = lun->lun_se_dev; + /* + * rcu_dereference_raw protected by se_lun->lun_group symlink + * reference to se_device->dev_group. + */ + struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev); struct t10_alua_tg_pt_gp *tg_pt_gp = NULL, *tg_pt_gp_new = NULL; unsigned char buf[TG_PT_GROUP_NAME_BUF]; int move = 0; @@ -2189,7 +2193,11 @@ ssize_t core_alua_store_offline_bit( const char *page, size_t count) { - struct se_device *dev = lun->lun_se_dev; + /* + * rcu_dereference_raw protected by se_lun->lun_group symlink + * reference to se_device->dev_group. + */ + struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev); unsigned long tmp; int ret; diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c index 8485e9a..3baa6cd 100644 --- a/drivers/target/target_core_device.c +++ b/drivers/target/target_core_device.c @@ -61,7 +61,6 @@ 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; struct se_dev_entry *deve; if (unpacked_lun >= TRANSPORT_MAX_LUNS_PER_TPG) @@ -128,16 +127,21 @@ 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; } + /* + * RCU reference protected by percpu se_lun->lun_ref taken above that + * must drop to zero (including initial reference) before this se_lun + * pointer can be kfree_rcu() by the final se_lun->lun_group put via + * target_core_fabric_configfs.c:target_fabric_port_release + */ + se_cmd->se_dev = rcu_dereference_raw(se_lun->lun_se_dev); + atomic_long_inc(&se_cmd->se_dev->num_cmds); - /* Directly associate cmd with se_dev */ - se_cmd->se_dev = se_lun->lun_se_dev; - - dev = se_lun->lun_se_dev; - atomic_long_inc(&dev->num_cmds); if (se_cmd->data_direction == DMA_TO_DEVICE) - atomic_long_add(se_cmd->data_length, &dev->write_bytes); + atomic_long_add(se_cmd->data_length, + &se_cmd->se_dev->write_bytes); else if (se_cmd->data_direction == DMA_FROM_DEVICE) - atomic_long_add(se_cmd->data_length, &dev->read_bytes); + atomic_long_add(se_cmd->data_length, + &se_cmd->se_dev->read_bytes); return 0; } @@ -173,10 +177,11 @@ int transport_lookup_tmr_lun(struct se_cmd *se_cmd, u32 unpacked_lun) unpacked_lun); return -ENODEV; } - - /* Directly associate cmd with se_dev */ - se_cmd->se_dev = se_lun->lun_se_dev; - se_tmr->tmr_dev = se_lun->lun_se_dev; + /* + * XXX: Add percpu se_lun->lun_ref reference count for TMR + */ + se_cmd->se_dev = rcu_dereference_raw(se_lun->lun_se_dev); + se_tmr->tmr_dev = rcu_dereference_raw(se_lun->lun_se_dev); spin_lock_irqsave(&se_tmr->tmr_dev->se_tmr_lock, flags); list_add_tail(&se_tmr->tmr_list, &se_tmr->tmr_dev->dev_tmr_list); @@ -390,6 +395,11 @@ void core_disable_device_list_for_node( struct se_portal_group *tpg) { /* + * rcu_dereference_raw protected by se_lun->lun_group symlink + * reference to se_device->dev_group. + */ + struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev); + /* * If the MappedLUN entry is being disabled, the entry in * lun->lun_deve_list must be removed now before clearing the * struct se_dev_entry pointers below as logic in @@ -426,7 +436,7 @@ void core_disable_device_list_for_node( kfree_rcu(orig, rcu_head); - core_scsi3_free_pr_reg_from_nacl(lun->lun_se_dev, nacl); + core_scsi3_free_pr_reg_from_nacl(dev, nacl); } /* core_clear_lun_from_tpg(): @@ -629,6 +639,11 @@ int core_dev_add_initiator_node_lun_acl( u32 lun_access) { struct se_node_acl *nacl = lacl->se_lun_nacl; + /* + * rcu_dereference_raw protected by se_lun->lun_group symlink + * reference to se_device->dev_group. + */ + struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev); if (!nacl) return -EINVAL; @@ -652,7 +667,7 @@ int core_dev_add_initiator_node_lun_acl( * Check to see if there are any existing persistent reservation APTPL * pre-registrations that need to be enabled for this LUN ACL.. */ - core_scsi3_check_aptpl_registration(lun->lun_se_dev, tpg, lun, nacl, + core_scsi3_check_aptpl_registration(dev, tpg, lun, nacl, lacl->mapped_lun); return 0; } @@ -746,6 +761,7 @@ struct se_device *target_alloc_device(struct se_hba *hba, const char *name) dev->se_hba = hba; dev->transport = hba->backend->ops; dev->prot_length = sizeof(struct se_dif_v1_tuple); + dev->hba_index = hba->hba_index; INIT_LIST_HEAD(&dev->dev_list); INIT_LIST_HEAD(&dev->dev_sep_list); @@ -802,8 +818,7 @@ struct se_device *target_alloc_device(struct se_hba *hba, const char *name) dev->dev_attrib.max_write_same_len = DA_MAX_WRITE_SAME_LEN; xcopy_lun = &dev->xcopy_lun; - xcopy_lun->lun_se_dev = dev; - spin_lock_init(&xcopy_lun->lun_sep_lock); + rcu_assign_pointer(xcopy_lun->lun_se_dev, dev); init_completion(&xcopy_lun->lun_ref_comp); INIT_LIST_HEAD(&xcopy_lun->lun_deve_list); INIT_LIST_HEAD(&xcopy_lun->lun_dev_link); diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c index 948b61f..238e3a2 100644 --- a/drivers/target/target_core_file.c +++ b/drivers/target/target_core_file.c @@ -241,6 +241,14 @@ fail: return ret; } +static void fd_dev_call_rcu(struct rcu_head *p) +{ + struct se_device *dev = container_of(p, struct se_device, rcu_head); + struct fd_dev *fd_dev = FD_DEV(dev); + + kfree(fd_dev); +} + static void fd_free_device(struct se_device *dev) { struct fd_dev *fd_dev = FD_DEV(dev); @@ -249,8 +257,7 @@ static void fd_free_device(struct se_device *dev) filp_close(fd_dev->fd_file, NULL); fd_dev->fd_file = NULL; } - - kfree(fd_dev); + call_rcu(&dev->rcu_head, fd_dev_call_rcu); } static int fd_do_rw(struct se_cmd *cmd, struct file *fd, diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c index 6d47382..ae8ad2d 100644 --- a/drivers/target/target_core_iblock.c +++ b/drivers/target/target_core_iblock.c @@ -191,6 +191,14 @@ out: return ret; } +static void iblock_dev_call_rcu(struct rcu_head *p) +{ + struct se_device *dev = container_of(p, struct se_device, rcu_head); + struct iblock_dev *ib_dev = IBLOCK_DEV(dev); + + kfree(ib_dev); +} + static void iblock_free_device(struct se_device *dev) { struct iblock_dev *ib_dev = IBLOCK_DEV(dev); @@ -200,7 +208,7 @@ static void iblock_free_device(struct se_device *dev) if (ib_dev->ibd_bio_set != NULL) bioset_free(ib_dev->ibd_bio_set); - kfree(ib_dev); + call_rcu(&dev->rcu_head, iblock_dev_call_rcu); } static unsigned long long iblock_emulate_read_cap_with_block_size( diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c index afb87a8..c673980 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, diff --git a/drivers/target/target_core_rd.c b/drivers/target/target_core_rd.c index 55dd73e..e984327 100644 --- a/drivers/target/target_core_rd.c +++ b/drivers/target/target_core_rd.c @@ -350,12 +350,20 @@ fail: return ret; } +static void rd_dev_call_rcu(struct rcu_head *p) +{ + struct se_device *dev = container_of(p, struct se_device, rcu_head); + struct rd_dev *rd_dev = RD_DEV(dev); + + kfree(rd_dev); +} + static void rd_free_device(struct se_device *dev) { struct rd_dev *rd_dev = RD_DEV(dev); rd_release_device_space(rd_dev); - kfree(rd_dev); + call_rcu(&dev->rcu_head, rd_dev_call_rcu); } static struct rd_dev_sg_table *rd_get_sg_table(struct rd_dev *rd_dev, u32 page) diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c index 34d8292..a2b377e 100644 --- a/drivers/target/target_core_spc.c +++ b/drivers/target/target_core_spc.c @@ -692,7 +692,7 @@ spc_emulate_inquiry(struct se_cmd *cmd) return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE; } - if (dev == tpg->tpg_virt_lun0->lun_se_dev) + if (dev == rcu_access_pointer(tpg->tpg_virt_lun0->lun_se_dev)) buf[0] = 0x3f; /* Not connected */ else buf[0] = dev->transport->get_device_type(dev); diff --git a/drivers/target/target_core_stat.c b/drivers/target/target_core_stat.c index 8e080ef..79c7852 100644 --- a/drivers/target/target_core_stat.c +++ b/drivers/target/target_core_stat.c @@ -545,11 +545,11 @@ static ssize_t target_stat_scsi_port_show_attr_inst( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) - ret = snprintf(page, PAGE_SIZE, "%u\n", dev->se_hba->hba_index); - spin_unlock(&lun->lun_sep_lock); + ret = snprintf(page, PAGE_SIZE, "%u\n", dev->hba_index); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_PORT_ATTR_RO(inst); @@ -561,11 +561,11 @@ static ssize_t target_stat_scsi_port_show_attr_dev( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) ret = snprintf(page, PAGE_SIZE, "%u\n", dev->dev_index); - spin_unlock(&lun->lun_sep_lock); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_PORT_ATTR_RO(dev); @@ -577,11 +577,11 @@ static ssize_t target_stat_scsi_port_show_attr_indx( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) ret = snprintf(page, PAGE_SIZE, "%u\n", lun->lun_rtpi); - spin_unlock(&lun->lun_sep_lock); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_PORT_ATTR_RO(indx); @@ -593,11 +593,11 @@ static ssize_t target_stat_scsi_port_show_attr_role( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) ret = snprintf(page, PAGE_SIZE, "%s%u\n", "Device", dev->dev_index); - spin_unlock(&lun->lun_sep_lock); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_PORT_ATTR_RO(role); @@ -609,13 +609,13 @@ static ssize_t target_stat_scsi_port_show_attr_busy_count( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) { /* FIXME: scsiPortBusyStatuses */ ret = snprintf(page, PAGE_SIZE, "%u\n", 0); } - spin_unlock(&lun->lun_sep_lock); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_PORT_ATTR_RO(busy_count); @@ -666,11 +666,11 @@ static ssize_t target_stat_scsi_tgt_port_show_attr_inst( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) - ret = snprintf(page, PAGE_SIZE, "%u\n", dev->se_hba->hba_index); - spin_unlock(&lun->lun_sep_lock); + ret = snprintf(page, PAGE_SIZE, "%u\n", dev->hba_index); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_TGT_PORT_ATTR_RO(inst); @@ -682,11 +682,11 @@ static ssize_t target_stat_scsi_tgt_port_show_attr_dev( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) ret = snprintf(page, PAGE_SIZE, "%u\n", dev->dev_index); - spin_unlock(&lun->lun_sep_lock); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_TGT_PORT_ATTR_RO(dev); @@ -698,11 +698,11 @@ static ssize_t target_stat_scsi_tgt_port_show_attr_indx( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) ret = snprintf(page, PAGE_SIZE, "%u\n", lun->lun_rtpi); - spin_unlock(&lun->lun_sep_lock); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_TGT_PORT_ATTR_RO(indx); @@ -715,13 +715,13 @@ static ssize_t target_stat_scsi_tgt_port_show_attr_name( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) ret = snprintf(page, PAGE_SIZE, "%sPort#%u\n", tpg->se_tpg_tfo->get_fabric_name(), lun->lun_rtpi); - spin_unlock(&lun->lun_sep_lock); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_TGT_PORT_ATTR_RO(name); @@ -734,13 +734,13 @@ static ssize_t target_stat_scsi_tgt_port_show_attr_port_index( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) ret = snprintf(page, PAGE_SIZE, "%s%s%d\n", tpg->se_tpg_tfo->tpg_get_wwn(tpg), "+t+", tpg->se_tpg_tfo->tpg_get_tag(tpg)); - spin_unlock(&lun->lun_sep_lock); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_TGT_PORT_ATTR_RO(port_index); @@ -752,11 +752,12 @@ static ssize_t target_stat_scsi_tgt_port_show_attr_in_cmds( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) - ret = snprintf(page, PAGE_SIZE, "%u\n", lun->lun_stats.cmd_pdus); - spin_unlock(&lun->lun_sep_lock); + ret = snprintf(page, PAGE_SIZE, "%lu\n", + atomic_long_read(&lun->lun_stats.cmd_pdus)); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_TGT_PORT_ATTR_RO(in_cmds); @@ -768,12 +769,12 @@ static ssize_t target_stat_scsi_tgt_port_show_attr_write_mbytes( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) ret = snprintf(page, PAGE_SIZE, "%u\n", - (u32)(lun->lun_stats.rx_data_octets >> 20)); - spin_unlock(&lun->lun_sep_lock); + (u32)(atomic_long_read(&lun->lun_stats.rx_data_octets) >> 20)); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_TGT_PORT_ATTR_RO(write_mbytes); @@ -785,12 +786,12 @@ static ssize_t target_stat_scsi_tgt_port_show_attr_read_mbytes( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) ret = snprintf(page, PAGE_SIZE, "%u\n", - (u32)(lun->lun_stats.tx_data_octets >> 20)); - spin_unlock(&lun->lun_sep_lock); + (u32)(atomic_long_read(&lun->lun_stats.tx_data_octets) >> 20)); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_TGT_PORT_ATTR_RO(read_mbytes); @@ -802,13 +803,13 @@ static ssize_t target_stat_scsi_tgt_port_show_attr_hs_in_cmds( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) { /* FIXME: scsiTgtPortHsInCommands */ ret = snprintf(page, PAGE_SIZE, "%u\n", 0); } - spin_unlock(&lun->lun_sep_lock); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_TGT_PORT_ATTR_RO(hs_in_cmds); @@ -865,11 +866,11 @@ static ssize_t target_stat_scsi_transport_show_attr_inst( struct se_device *dev; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) - ret = snprintf(page, PAGE_SIZE, "%u\n", dev->se_hba->hba_index); - spin_unlock(&lun->lun_sep_lock); + ret = snprintf(page, PAGE_SIZE, "%u\n", dev->hba_index); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_TRANSPORT_ATTR_RO(inst); @@ -882,14 +883,14 @@ static ssize_t target_stat_scsi_transport_show_attr_device( struct se_portal_group *tpg = lun->lun_tpg; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) { /* scsiTransportType */ ret = snprintf(page, PAGE_SIZE, "scsiTransport%s\n", tpg->se_tpg_tfo->get_fabric_name()); } - spin_unlock(&lun->lun_sep_lock); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_TRANSPORT_ATTR_RO(device); @@ -902,12 +903,12 @@ static ssize_t target_stat_scsi_transport_show_attr_indx( struct se_portal_group *tpg = lun->lun_tpg; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) ret = snprintf(page, PAGE_SIZE, "%u\n", tpg->se_tpg_tfo->tpg_get_inst_index(tpg)); - spin_unlock(&lun->lun_sep_lock); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_TRANSPORT_ATTR_RO(indx); @@ -916,13 +917,13 @@ static ssize_t target_stat_scsi_transport_show_attr_dev_name( struct se_port_stat_grps *pgrps, char *page) { struct se_lun *lun = container_of(pgrps, struct se_lun, port_stat_grps); - struct se_device *dev = lun->lun_se_dev; + struct se_device *dev; struct se_portal_group *tpg = lun->lun_tpg; struct t10_wwn *wwn; ssize_t ret = -ENODEV; - spin_lock(&lun->lun_sep_lock); - dev = lun->lun_se_dev; + rcu_read_lock(); + dev = rcu_dereference(lun->lun_se_dev); if (dev) { wwn = &dev->t10_wwn; /* scsiTransportDevName */ @@ -931,7 +932,7 @@ static ssize_t target_stat_scsi_transport_show_attr_dev_name( (strlen(wwn->unit_serial)) ? wwn->unit_serial : wwn->vendor); } - spin_unlock(&lun->lun_sep_lock); + rcu_read_unlock(); return ret; } DEV_STAT_SCSI_TRANSPORT_ATTR_RO(dev_name); diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c index 499b139..5b30940 100644 --- a/drivers/target/target_core_tpg.c +++ b/drivers/target/target_core_tpg.c @@ -102,7 +102,8 @@ void core_tpg_add_node_to_devs( if (lun_orig && lun != lun_orig) continue; - dev = lun->lun_se_dev; + dev = rcu_dereference_check(lun->lun_se_dev, + lockdep_is_held(&tpg->tpg_lun_mutex)); /* * By default in LIO-Target $FABRIC_MOD, * demo_mode_write_protect is ON, or READ_ONLY; @@ -598,7 +599,6 @@ struct se_lun *core_tpg_alloc_lun( lun->unpacked_lun = unpacked_lun; lun->lun_link_magic = SE_LUN_LINK_MAGIC; atomic_set(&lun->lun_acl_count, 0); - spin_lock_init(&lun->lun_sep_lock); init_completion(&lun->lun_ref_comp); INIT_LIST_HEAD(&lun->lun_deve_list); INIT_LIST_HEAD(&lun->lun_dev_link); @@ -636,12 +636,8 @@ int core_tpg_add_lun( mutex_lock(&tpg->tpg_lun_mutex); - spin_lock(&lun->lun_sep_lock); - lun->lun_index = dev->dev_index; - lun->lun_se_dev = dev; - spin_unlock(&lun->lun_sep_lock); - spin_lock(&dev->se_port_lock); + lun->lun_index = dev->dev_index; rcu_assign_pointer(lun->lun_se_dev, dev); dev->export_count++; list_add_tail(&lun->lun_dev_link, &dev->dev_sep_list); @@ -664,7 +660,11 @@ void core_tpg_remove_lun( struct se_portal_group *tpg, struct se_lun *lun) { - struct se_device *dev = lun->lun_se_dev; + /* + * rcu_dereference_raw protected by se_lun->lun_group symlink + * reference to se_device->dev_group. + */ + struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev); core_clear_lun_from_tpg(lun, tpg); transport_clear_lun_ref(lun); diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index ef6fdd8..d8a5912 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1261,10 +1261,7 @@ target_setup_cmd_from_cdb(struct se_cmd *cmd, unsigned char *cdb) return ret; cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE; - - spin_lock(&cmd->se_lun->lun_sep_lock); - cmd->se_lun->lun_stats.cmd_pdus++; - spin_unlock(&cmd->se_lun->lun_sep_lock); + atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus); return 0; } EXPORT_SYMBOL(target_setup_cmd_from_cdb); @@ -2060,9 +2057,8 @@ static void target_complete_ok_work(struct work_struct *work) queue_rsp: switch (cmd->data_direction) { case DMA_FROM_DEVICE: - spin_lock(&cmd->se_lun->lun_sep_lock); - cmd->se_lun->lun_stats.tx_data_octets += cmd->data_length; - spin_unlock(&cmd->se_lun->lun_sep_lock); + atomic_long_add(cmd->data_length, + &cmd->se_lun->lun_stats.tx_data_octets); /* * Perform READ_STRIP of PI using software emulation when * backend had PI enabled, if the transport will not be @@ -2085,16 +2081,14 @@ queue_rsp: goto queue_full; break; case DMA_TO_DEVICE: - spin_lock(&cmd->se_lun->lun_sep_lock); - cmd->se_lun->lun_stats.rx_data_octets += cmd->data_length; - spin_unlock(&cmd->se_lun->lun_sep_lock); + atomic_long_add(cmd->data_length, + &cmd->se_lun->lun_stats.rx_data_octets); /* * Check if we need to send READ payload for BIDI-COMMAND */ if (cmd->se_cmd_flags & SCF_BIDI) { - spin_lock(&cmd->se_lun->lun_sep_lock); - cmd->se_lun->lun_stats.tx_data_octets += cmd->data_length; - spin_unlock(&cmd->se_lun->lun_sep_lock); + atomic_long_add(cmd->data_length, + &cmd->se_lun->lun_stats.tx_data_octets); ret = cmd->se_tfo->queue_data_in(cmd); if (ret == -EAGAIN || ret == -ENOMEM) goto queue_full; diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index aebaad5..949e616 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -950,6 +950,14 @@ static int tcmu_check_pending_cmd(int id, void *p, void *data) return -EINVAL; } +static void tcmu_dev_call_rcu(struct rcu_head *p) +{ + struct se_device *dev = container_of(p, struct se_device, rcu_head); + struct tcmu_dev *udev = TCMU_DEV(dev); + + kfree(udev); +} + static void tcmu_free_device(struct se_device *dev) { struct tcmu_dev *udev = TCMU_DEV(dev); @@ -975,8 +983,7 @@ static void tcmu_free_device(struct se_device *dev) kfree(udev->uio_info.name); kfree(udev->name); } - - kfree(udev); + call_rcu(&dev->rcu_head, tcmu_dev_call_rcu); } enum { diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h index 1927dd5..b82a989 100644 --- a/include/target/target_core_base.h +++ b/include/target/target_core_base.h @@ -690,9 +690,9 @@ struct se_port_stat_grps { }; struct scsi_port_stats { - u32 cmd_pdus; - u64 tx_data_octets; - u64 rx_data_octets; + atomic_long_t cmd_pdus; + atomic_long_t tx_data_octets; + atomic_long_t rx_data_octets; }; struct se_lun { @@ -705,7 +705,6 @@ struct se_lun { u32 unpacked_lun; u32 lun_index; atomic_t lun_acl_count; - spinlock_t lun_sep_lock; struct se_device __rcu *lun_se_dev; struct list_head lun_deve_list; @@ -818,6 +817,9 @@ struct se_device { struct se_lun xcopy_lun; /* Protection Information */ int prot_length; + /* For se_lun->lun_se_dev RCU read-side critical access */ + u32 hba_index; + struct rcu_head rcu_head; }; struct se_hba {