From 08234e3adc7a299c9213bcfa0b5e97c359129670 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?J=C3=B6rn=20Engel?= Date: Wed, 12 Jun 2013 16:27:54 -0400 Subject: [PATCH] qla_target: remove qlt_check_fcport_exist Comment from original 2012 patch: In all our testing this function has never returned true. However, the dropping of hardware_lock necessary to call this function seems to cause a use-after-free we manage to hit rather frequently. Given this cost-benefit ratio, I'm willing to remove some 100 lines of code. And since the same problem exists around shutdown_sess and put_sess, this patch changes them from taking the hardware_lock to requiring the hardware_lock to be taken. In most cases the caller already had the lock and had to drop it for the called method to reacquire it. At best that hurts performance and in rare instances it causes races with fatal consequences. We dropped the original 2012 patch when upgrading our kernel and it took us nearly half a year to discover we still need it. (nab: Fix qla_tgt_sess reference in tcm_qla2xxx_put_sess) Signed-off-by: Joern Engel Cc: Giridhar Malavali Cc: Chad Dupuis Signed-off-by: Nicholas Bellinger --- drivers/scsi/qla2xxx/qla_target.c | 151 +++-------------------------- drivers/scsi/qla2xxx/tcm_qla2xxx.c | 6 +- 2 files changed, 17 insertions(+), 140 deletions(-) diff --git a/drivers/scsi/qla2xxx/qla_target.c b/drivers/scsi/qla2xxx/qla_target.c index fcdc22306cab..83a8f7a9ec76 100644 --- a/drivers/scsi/qla2xxx/qla_target.c +++ b/drivers/scsi/qla2xxx/qla_target.c @@ -544,102 +544,6 @@ out_free_id_list: return res; } -static bool qlt_check_fcport_exist(struct scsi_qla_host *vha, - struct qla_tgt_sess *sess) -{ - struct qla_hw_data *ha = vha->hw; - struct qla_port_24xx_data *pmap24; - bool res, found = false; - int rc, i; - uint16_t loop_id = 0xFFFF; /* to eliminate compiler's warning */ - uint16_t entries; - void *pmap; - int pmap_len; - fc_port_t *fcport; - int global_resets; - unsigned long flags; - -retry: - global_resets = atomic_read(&ha->tgt.qla_tgt->tgt_global_resets_count); - - rc = qla2x00_get_node_name_list(vha, &pmap, &pmap_len); - if (rc != QLA_SUCCESS) { - res = false; - goto out; - } - - pmap24 = pmap; - entries = pmap_len/sizeof(*pmap24); - - for (i = 0; i < entries; ++i) { - if (!memcmp(sess->port_name, pmap24[i].port_name, WWN_SIZE)) { - loop_id = le16_to_cpu(pmap24[i].loop_id); - found = true; - break; - } - } - - kfree(pmap); - - if (!found) { - res = false; - goto out; - } - - ql_dbg(ql_dbg_tgt_mgt, vha, 0xf046, - "qlt_check_fcport_exist(): loop_id %d", loop_id); - - fcport = kzalloc(sizeof(*fcport), GFP_KERNEL); - if (fcport == NULL) { - ql_dbg(ql_dbg_tgt_mgt, vha, 0xf047, - "qla_target(%d): Allocation of tmp FC port failed", - vha->vp_idx); - res = false; - goto out; - } - - fcport->loop_id = loop_id; - - rc = qla2x00_get_port_database(vha, fcport, 0); - if (rc != QLA_SUCCESS) { - ql_dbg(ql_dbg_tgt_mgt, vha, 0xf048, - "qla_target(%d): Failed to retrieve fcport " - "information -- get_port_database() returned %x " - "(loop_id=0x%04x)", vha->vp_idx, rc, loop_id); - res = false; - goto out_free_fcport; - } - - if (global_resets != - atomic_read(&ha->tgt.qla_tgt->tgt_global_resets_count)) { - ql_dbg(ql_dbg_tgt_mgt, vha, 0xf002, - "qla_target(%d): global reset during session discovery" - " (counter was %d, new %d), retrying", - vha->vp_idx, global_resets, - atomic_read(&ha->tgt.qla_tgt->tgt_global_resets_count)); - goto retry; - } - - ql_dbg(ql_dbg_tgt_mgt, vha, 0xf003, - "Updating sess %p s_id %x:%x:%x, loop_id %d) to d_id %x:%x:%x, " - "loop_id %d", sess, sess->s_id.b.domain, sess->s_id.b.al_pa, - sess->s_id.b.area, sess->loop_id, fcport->d_id.b.domain, - fcport->d_id.b.al_pa, fcport->d_id.b.area, fcport->loop_id); - - spin_lock_irqsave(&ha->hardware_lock, flags); - ha->tgt.tgt_ops->update_sess(sess, fcport->d_id, fcport->loop_id, - (fcport->flags & FCF_CONF_COMP_SUPPORTED)); - spin_unlock_irqrestore(&ha->hardware_lock, flags); - - res = true; - -out_free_fcport: - kfree(fcport); - -out: - return res; -} - /* ha->hardware_lock supposed to be held on entry */ static void qlt_undelete_sess(struct qla_tgt_sess *sess) { @@ -663,43 +567,13 @@ static void qlt_del_sess_work_fn(struct delayed_work *work) sess = list_entry(tgt->del_sess_list.next, typeof(*sess), del_list_entry); if (time_after_eq(jiffies, sess->expires)) { - bool cancel; - qlt_undelete_sess(sess); - spin_unlock_irqrestore(&ha->hardware_lock, flags); - cancel = qlt_check_fcport_exist(vha, sess); - - if (cancel) { - if (sess->deleted) { - /* - * sess was again deleted while we were - * discovering it - */ - spin_lock_irqsave(&ha->hardware_lock, - flags); - continue; - } - - ql_dbg(ql_dbg_tgt_mgt, vha, 0xf049, - "qla_target(%d): cancel deletion of " - "session for port %02x:%02x:%02x:%02x:%02x:" - "%02x:%02x:%02x (loop ID %d), because " - " it isn't deleted by firmware", - vha->vp_idx, sess->port_name[0], - sess->port_name[1], sess->port_name[2], - sess->port_name[3], sess->port_name[4], - sess->port_name[5], sess->port_name[6], - sess->port_name[7], sess->loop_id); - } else { - ql_dbg(ql_dbg_tgt_mgt, vha, 0xf004, - "Timeout: sess %p about to be deleted\n", - sess); - ha->tgt.tgt_ops->shutdown_sess(sess); - ha->tgt.tgt_ops->put_sess(sess); - } - - spin_lock_irqsave(&ha->hardware_lock, flags); + ql_dbg(ql_dbg_tgt_mgt, vha, 0xf004, + "Timeout: sess %p about to be deleted\n", + sess); + ha->tgt.tgt_ops->shutdown_sess(sess); + ha->tgt.tgt_ops->put_sess(sess); } else { schedule_delayed_work(&tgt->sess_del_work, jiffies - sess->expires); @@ -884,9 +758,8 @@ void qlt_fc_port_added(struct scsi_qla_host *vha, fc_port_t *fcport) sess->loop_id); sess->local = 0; } - spin_unlock_irqrestore(&ha->hardware_lock, flags); - ha->tgt.tgt_ops->put_sess(sess); + spin_unlock_irqrestore(&ha->hardware_lock, flags); } void qlt_fc_port_deleted(struct scsi_qla_host *vha, fc_port_t *fcport) @@ -2706,7 +2579,9 @@ static void qlt_do_work(struct work_struct *work) /* * Drop extra session reference from qla_tgt_handle_cmd_for_atio*( */ + spin_lock_irqsave(&ha->hardware_lock, flags); ha->tgt.tgt_ops->put_sess(sess); + spin_unlock_irqrestore(&ha->hardware_lock, flags); return; out_term: @@ -2718,9 +2593,9 @@ out_term: spin_lock_irqsave(&ha->hardware_lock, flags); qlt_send_term_exchange(vha, NULL, &cmd->atio, 1); kmem_cache_free(qla_tgt_cmd_cachep, cmd); - spin_unlock_irqrestore(&ha->hardware_lock, flags); if (sess) ha->tgt.tgt_ops->put_sess(sess); + spin_unlock_irqrestore(&ha->hardware_lock, flags); } /* ha->hardware_lock supposed to be held on entry */ @@ -4169,16 +4044,16 @@ static void qlt_abort_work(struct qla_tgt *tgt, rc = __qlt_24xx_handle_abts(vha, &prm->abts, sess); if (rc != 0) goto out_term; - spin_unlock_irqrestore(&ha->hardware_lock, flags); ha->tgt.tgt_ops->put_sess(sess); + spin_unlock_irqrestore(&ha->hardware_lock, flags); return; out_term: qlt_24xx_send_abts_resp(vha, &prm->abts, FCP_TMF_REJECTED, false); - spin_unlock_irqrestore(&ha->hardware_lock, flags); if (sess) ha->tgt.tgt_ops->put_sess(sess); + spin_unlock_irqrestore(&ha->hardware_lock, flags); } static void qlt_tmr_work(struct qla_tgt *tgt, @@ -4226,16 +4101,16 @@ static void qlt_tmr_work(struct qla_tgt *tgt, rc = qlt_issue_task_mgmt(sess, unpacked_lun, fn, iocb, 0); if (rc != 0) goto out_term; - spin_unlock_irqrestore(&ha->hardware_lock, flags); ha->tgt.tgt_ops->put_sess(sess); + spin_unlock_irqrestore(&ha->hardware_lock, flags); return; out_term: qlt_send_term_exchange(vha, NULL, &prm->tm_iocb2, 1); - spin_unlock_irqrestore(&ha->hardware_lock, flags); if (sess) ha->tgt.tgt_ops->put_sess(sess); + spin_unlock_irqrestore(&ha->hardware_lock, flags); } static void qlt_sess_work_fn(struct work_struct *work) diff --git a/drivers/scsi/qla2xxx/tcm_qla2xxx.c b/drivers/scsi/qla2xxx/tcm_qla2xxx.c index 7a3870f385f6..bb7eb909f0b1 100644 --- a/drivers/scsi/qla2xxx/tcm_qla2xxx.c +++ b/drivers/scsi/qla2xxx/tcm_qla2xxx.c @@ -795,12 +795,14 @@ static void tcm_qla2xxx_put_session(struct se_session *se_sess) static void tcm_qla2xxx_put_sess(struct qla_tgt_sess *sess) { - tcm_qla2xxx_put_session(sess->se_sess); + assert_spin_locked(&sess->vha->hw->hardware_lock); + kref_put(&sess->se_sess->sess_kref, tcm_qla2xxx_release_session); } static void tcm_qla2xxx_shutdown_sess(struct qla_tgt_sess *sess) { - tcm_qla2xxx_shutdown_session(sess->se_sess); + assert_spin_locked(&sess->vha->hw->hardware_lock); + target_sess_cmd_list_set_waiting(sess->se_sess); } static struct se_node_acl *tcm_qla2xxx_make_nodeacl(