[PATCH-v4 03/10] target/pr: Change alloc_registration to avoid pr_reg_tg_pt_lun

From: Nicholas A. Bellinger
Date: Mon Jun 01 2015 - 04:13:54 EST

From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

This patch changes __core_scsi3_do_alloc_registration() code to
drop pr_reg->pr_reg_tg_pt_lun pointer usage in favor of a new
pr_reg RPTI + existing pr_reg->pr_aptpl_target_lun used by
APTPL metadata logic.

It also includes changes to REGISTER, REGISTER_AND_MOVE and APTPL
feature bit codepaths to use rcu_dereference_check() with the
expected non-zero se_dev_entry->pr_kref reference held.

Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_configfs.c | 6 +-
drivers/target/target_core_pr.c | 131 ++++++++++++++++++----------------
include/target/target_core_base.h | 4 +-
3 files changed, 72 insertions(+), 69 deletions(-)

diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index 798386a..4a31d47 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -817,7 +817,6 @@ static ssize_t target_core_dev_pr_show_attr_res_pr_holder_tg_port(
struct se_device *dev, char *page)
{
struct se_node_acl *se_nacl;
- struct se_lun *lun;
struct se_portal_group *se_tpg;
struct t10_pr_registration *pr_reg;
const struct target_core_fabric_ops *tfo;
@@ -832,7 +831,6 @@ static ssize_t target_core_dev_pr_show_attr_res_pr_holder_tg_port(

se_nacl = pr_reg->pr_reg_nacl;
se_tpg = se_nacl->se_tpg;
- lun = pr_reg->pr_reg_tg_pt_lun;
tfo = se_tpg->se_tpg_tfo;

len += sprintf(page+len, "SPC-3 Reservation: %s"
@@ -840,9 +838,9 @@ static ssize_t target_core_dev_pr_show_attr_res_pr_holder_tg_port(
tfo->tpg_get_wwn(se_tpg));
len += sprintf(page+len, "SPC-3 Reservation: Relative Port"
" Identifier Tag: %hu %s Portal Group Tag: %hu"
- " %s Logical Unit: %u\n", lun->lun_sep->sep_rtpi,
+ " %s Logical Unit: %u\n", pr_reg->tg_pt_sep_rtpi,
tfo->get_fabric_name(), tfo->tpg_get_tag(se_tpg),
- tfo->get_fabric_name(), lun->unpacked_lun);
+ tfo->get_fabric_name(), pr_reg->pr_aptpl_target_lun);

out_unlock:
spin_unlock(&dev->dev_reservation_lock);
diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
index 66e686b..48ed5d2 100644
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c
@@ -44,11 +44,10 @@
* Used for Specify Initiator Ports Capable Bit (SPEC_I_PT)
*/
struct pr_transport_id_holder {
- int dest_local_nexus;
struct t10_pr_registration *dest_pr_reg;
struct se_portal_group *dest_tpg;
struct se_node_acl *dest_node_acl;
- struct se_dev_entry __rcu *dest_se_deve;
+ struct se_dev_entry *dest_se_deve;
struct list_head dest_list;
};

@@ -625,7 +624,9 @@ static u32 core_scsi3_pr_generation(struct se_device *dev)
static struct t10_pr_registration *__core_scsi3_do_alloc_registration(
struct se_device *dev,
struct se_node_acl *nacl,
+ struct se_lun *lun,
struct se_dev_entry *deve,
+ u32 mapped_lun,
unsigned char *isid,
u64 sa_res_key,
int all_tg_pt,
@@ -647,12 +648,12 @@ static struct t10_pr_registration *__core_scsi3_do_alloc_registration(
atomic_set(&pr_reg->pr_res_holders, 0);
pr_reg->pr_reg_nacl = nacl;
pr_reg->pr_reg_deve = deve;
- pr_reg->pr_res_mapped_lun = deve->mapped_lun;
- pr_reg->pr_aptpl_target_lun = deve->se_lun->unpacked_lun;
+ pr_reg->pr_res_mapped_lun = mapped_lun;
+ pr_reg->pr_aptpl_target_lun = lun->unpacked_lun;
+ pr_reg->tg_pt_sep_rtpi = lun->lun_sep->sep_rtpi;
pr_reg->pr_res_key = sa_res_key;
pr_reg->pr_reg_all_tg_pt = all_tg_pt;
pr_reg->pr_reg_aptpl = aptpl;
- pr_reg->pr_reg_tg_pt_lun = deve->se_lun;
/*
* If an ISID value for this SCSI Initiator Port exists,
* save it to the registration now.
@@ -676,7 +677,9 @@ static void core_scsi3_lunacl_undepend_item(struct se_dev_entry *);
static struct t10_pr_registration *__core_scsi3_alloc_registration(
struct se_device *dev,
struct se_node_acl *nacl,
+ struct se_lun *lun,
struct se_dev_entry *deve,
+ u32 mapped_lun,
unsigned char *isid,
u64 sa_res_key,
int all_tg_pt,
@@ -684,6 +687,8 @@ static struct t10_pr_registration *__core_scsi3_alloc_registration(
{
struct se_dev_entry *deve_tmp;
struct se_node_acl *nacl_tmp;
+ struct se_lun_acl *lacl_tmp;
+ struct se_lun *lun_tmp;
struct se_port *port, *port_tmp;
const struct target_core_fabric_ops *tfo = nacl->se_tpg->se_tpg_tfo;
struct t10_pr_registration *pr_reg, *pr_reg_atp, *pr_reg_tmp, *pr_reg_tmp_safe;
@@ -692,8 +697,9 @@ static struct t10_pr_registration *__core_scsi3_alloc_registration(
* Create a registration for the I_T Nexus upon which the
* PROUT REGISTER was received.
*/
- pr_reg = __core_scsi3_do_alloc_registration(dev, nacl, deve, isid,
- sa_res_key, all_tg_pt, aptpl);
+ pr_reg = __core_scsi3_do_alloc_registration(dev, nacl, lun, deve, mapped_lun,
+ isid, sa_res_key, all_tg_pt,
+ aptpl);
if (!pr_reg)
return NULL;
/*
@@ -721,7 +727,9 @@ static struct t10_pr_registration *__core_scsi3_alloc_registration(
if (!deve_tmp->se_lun_acl)
continue;

- nacl_tmp = deve_tmp->se_lun_acl->se_lun_nacl;
+ lacl_tmp = rcu_dereference_check(deve_tmp->se_lun_acl,
+ lockdep_is_held(&port->sep_alua_lock));
+ nacl_tmp = lacl_tmp->se_lun_nacl;
/*
* Skip the matching struct se_node_acl that is allocated
* above..
@@ -764,8 +772,12 @@ static struct t10_pr_registration *__core_scsi3_alloc_registration(
* the original *pr_reg is processed in
* __core_scsi3_add_registration()
*/
+ lun_tmp = rcu_dereference_check(deve_tmp->se_lun,
+ atomic_read(&deve_tmp->pr_kref.refcount) != 0);
+
pr_reg_atp = __core_scsi3_do_alloc_registration(dev,
- nacl_tmp, deve_tmp, NULL,
+ nacl_tmp, lun_tmp, deve_tmp,
+ deve_tmp->mapped_lun, NULL,
sa_res_key, all_tg_pt, aptpl);
if (!pr_reg_atp) {
atomic_dec_mb(&port->sep_tg_pt_ref_cnt);
@@ -835,7 +847,6 @@ int core_scsi3_alloc_aptpl_registration(
pr_reg->pr_res_key = sa_res_key;
pr_reg->pr_reg_all_tg_pt = all_tg_pt;
pr_reg->pr_reg_aptpl = 1;
- pr_reg->pr_reg_tg_pt_lun = NULL;
pr_reg->pr_res_scope = 0; /* Always LUN_SCOPE */
pr_reg->pr_res_type = type;
/*
@@ -935,7 +946,7 @@ static int __core_scsi3_check_aptpl_registration(
(pr_reg->pr_aptpl_target_lun == target_lun)) {

pr_reg->pr_reg_nacl = nacl;
- pr_reg->pr_reg_tg_pt_lun = lun;
+ pr_reg->tg_pt_sep_rtpi = lun->lun_sep->sep_rtpi;

list_del(&pr_reg->pr_reg_aptpl_list);
spin_unlock(&pr_tmpl->aptpl_reg_lock);
@@ -1090,7 +1101,9 @@ static void __core_scsi3_add_registration(
static int core_scsi3_alloc_registration(
struct se_device *dev,
struct se_node_acl *nacl,
+ struct se_lun *lun,
struct se_dev_entry *deve,
+ u32 mapped_lun,
unsigned char *isid,
u64 sa_res_key,
int all_tg_pt,
@@ -1100,8 +1113,9 @@ static int core_scsi3_alloc_registration(
{
struct t10_pr_registration *pr_reg;

- pr_reg = __core_scsi3_alloc_registration(dev, nacl, deve, isid,
- sa_res_key, all_tg_pt, aptpl);
+ pr_reg = __core_scsi3_alloc_registration(dev, nacl, lun, deve, mapped_lun,
+ isid, sa_res_key, all_tg_pt,
+ aptpl);
if (!pr_reg)
return -EPERM;

@@ -1411,12 +1425,14 @@ static void core_scsi3_nodeacl_undepend_item(struct se_node_acl *nacl)

static int core_scsi3_lunacl_depend_item(struct se_dev_entry *se_deve)
{
- struct se_lun_acl *lun_acl = se_deve->se_lun_acl;
+ struct se_lun_acl *lun_acl;
struct se_node_acl *nacl;
struct se_portal_group *tpg;
/*
* For nacl->dynamic_node_acl=1
*/
+ lun_acl = rcu_dereference_check(se_deve->se_lun_acl,
+ atomic_read(&se_deve->pr_kref.refcount) != 0);
if (!lun_acl)
return 0;

@@ -1434,7 +1450,8 @@ static void core_scsi3_lunacl_undepend_item(struct se_dev_entry *se_deve)
/*
* For nacl->dynamic_node_acl=1
*/
- lun_acl = se_deve->se_lun_acl;
+ lun_acl = rcu_dereference_check(se_deve->se_lun_acl,
+ atomic_read(&se_deve->pr_kref.refcount) != 0);
if (!lun_acl) {
kref_put(&se_deve->pr_kref, target_pr_kref_release);
return;
@@ -1450,7 +1467,6 @@ static sense_reason_t
core_scsi3_decode_spec_i_port(
struct se_cmd *cmd,
struct se_portal_group *tpg,
- struct se_dev_entry *local_se_deve,
unsigned char *l_isid,
u64 sa_res_key,
int all_tg_pt,
@@ -1461,7 +1477,7 @@ core_scsi3_decode_spec_i_port(
struct se_portal_group *dest_tpg = NULL, *tmp_tpg;
struct se_session *se_sess = cmd->se_sess;
struct se_node_acl *dest_node_acl = NULL;
- struct se_dev_entry __rcu *dest_se_deve = NULL;
+ struct se_dev_entry *dest_se_deve = NULL;
struct t10_pr_registration *dest_pr_reg, *local_pr_reg, *pr_reg_e;
struct t10_pr_registration *pr_reg_tmp, *pr_reg_tmp_safe;
LIST_HEAD(tid_dest_list);
@@ -1471,14 +1487,12 @@ core_scsi3_decode_spec_i_port(
char *iport_ptr = NULL, i_buf[PR_REG_ISID_ID_LEN];
sense_reason_t ret;
u32 tpdl, tid_len = 0;
- int dest_local_nexus;
u32 dest_rtpi = 0;

/*
* Allocate a struct pr_transport_id_holder and setup the
- * local_node_acl and local_se_deve pointers and add to
- * struct list_head tid_dest_list for add registration
- * processing in the loop of tid_dest_list below.
+ * local_node_acl pointer and add to struct list_head tid_dest_list
+ * for add registration processing in the loop of tid_dest_list below.
*/
tidh_new = kzalloc(sizeof(struct pr_transport_id_holder), GFP_KERNEL);
if (!tidh_new) {
@@ -1490,20 +1504,20 @@ core_scsi3_decode_spec_i_port(
tidh_new->dest_node_acl = se_sess->se_node_acl;

local_pr_reg = __core_scsi3_alloc_registration(cmd->se_dev,
- se_sess->se_node_acl, local_se_deve, l_isid,
+ se_sess->se_node_acl, cmd->se_lun,
+ NULL, cmd->orig_fe_lun, l_isid,
sa_res_key, all_tg_pt, aptpl);
if (!local_pr_reg) {
kfree(tidh_new);
return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
}
- rcu_assign_pointer(tidh_new->dest_se_deve, local_se_deve);
tidh_new->dest_pr_reg = local_pr_reg;
/*
* The local I_T nexus does not hold any configfs dependances,
- * so we set tid_h->dest_local_nexus=1 to prevent the
+ * so we set tidh_new->dest_se_deve to NULL to prevent the
* configfs_undepend_item() calls in the tid_dest_list loops below.
*/
- tidh_new->dest_local_nexus = 1;
+ tidh_new->dest_se_deve = NULL;
list_add_tail(&tidh_new->dest_list, &tid_dest_list);

if (cmd->data_length < 28) {
@@ -1544,6 +1558,8 @@ core_scsi3_decode_spec_i_port(
ptr = &buf[28];

while (tpdl > 0) {
+ struct se_lun *dest_lun;
+
proto_ident = (ptr[0] & 0x0f);
dest_tpg = NULL;

@@ -1720,9 +1736,13 @@ core_scsi3_decode_spec_i_port(
* and then call __core_scsi3_add_registration() in the
* 2nd loop which will never fail.
*/
+ dest_lun = rcu_dereference_check(dest_se_deve->se_lun,
+ atomic_read(&dest_se_deve->pr_kref.refcount) != 0);
+
dest_pr_reg = __core_scsi3_alloc_registration(cmd->se_dev,
- dest_node_acl, dest_se_deve, iport_ptr,
- sa_res_key, all_tg_pt, aptpl);
+ dest_node_acl, dest_lun, dest_se_deve,
+ dest_se_deve->mapped_lun, iport_ptr,
+ sa_res_key, all_tg_pt, aptpl);
if (!dest_pr_reg) {
core_scsi3_lunacl_undepend_item(dest_se_deve);
core_scsi3_nodeacl_undepend_item(dest_node_acl);
@@ -1760,7 +1780,6 @@ core_scsi3_decode_spec_i_port(
dest_node_acl = tidh->dest_node_acl;
dest_se_deve = tidh->dest_se_deve;
dest_pr_reg = tidh->dest_pr_reg;
- dest_local_nexus = tidh->dest_local_nexus;

list_del(&tidh->dest_list);
kfree(tidh);
@@ -1774,9 +1793,10 @@ core_scsi3_decode_spec_i_port(
pr_debug("SPC-3 PR [%s] SPEC_I_PT: Successfully"
" registered Transport ID for Node: %s%s Mapped LUN:"
" %u\n", dest_tpg->se_tpg_tfo->get_fabric_name(),
- dest_node_acl->initiatorname, i_buf, dest_se_deve->mapped_lun);
+ dest_node_acl->initiatorname, i_buf, (dest_se_deve) ?
+ dest_se_deve->mapped_lun : 0);

- if (dest_local_nexus)
+ if (!dest_se_deve)
continue;

core_scsi3_lunacl_undepend_item(dest_se_deve);
@@ -1797,7 +1817,6 @@ out:
dest_node_acl = tidh->dest_node_acl;
dest_se_deve = tidh->dest_se_deve;
dest_pr_reg = tidh->dest_pr_reg;
- dest_local_nexus = tidh->dest_local_nexus;

list_del(&tidh->dest_list);
kfree(tidh);
@@ -1815,7 +1834,7 @@ out:

kmem_cache_free(t10_pr_reg_cache, dest_pr_reg);

- if (dest_local_nexus)
+ if (!dest_se_deve)
continue;

core_scsi3_lunacl_undepend_item(dest_se_deve);
@@ -1830,7 +1849,6 @@ static int core_scsi3_update_aptpl_buf(
unsigned char *buf,
u32 pr_aptpl_buf_len)
{
- struct se_lun *lun;
struct se_portal_group *tpg;
struct t10_pr_registration *pr_reg;
unsigned char tmp[512], isid_buf[32];
@@ -1849,7 +1867,6 @@ static int core_scsi3_update_aptpl_buf(
tmp[0] = '\0';
isid_buf[0] = '\0';
tpg = pr_reg->pr_reg_nacl->se_tpg;
- lun = pr_reg->pr_reg_tg_pt_lun;
/*
* Write out any ISID value to APTPL metadata that was included
* in the original registration.
@@ -1901,7 +1918,8 @@ static int core_scsi3_update_aptpl_buf(
" %d\n", tpg->se_tpg_tfo->get_fabric_name(),
tpg->se_tpg_tfo->tpg_get_wwn(tpg),
tpg->se_tpg_tfo->tpg_get_tag(tpg),
- lun->lun_sep->sep_rtpi, lun->unpacked_lun, reg_count);
+ pr_reg->tg_pt_sep_rtpi, pr_reg->pr_aptpl_target_lun,
+ reg_count);

if ((len + strlen(tmp) >= pr_aptpl_buf_len)) {
pr_err("Unable to update renaming APTPL metadata,"
@@ -2011,9 +2029,7 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
bool aptpl, bool all_tg_pt, bool spec_i_pt, enum register_type register_type)
{
struct se_session *se_sess = cmd->se_sess;
- struct se_node_acl *nacl = se_sess->se_node_acl;
struct se_device *dev = cmd->se_dev;
- struct se_dev_entry *se_deve;
struct se_lun *se_lun = cmd->se_lun;
struct se_portal_group *se_tpg;
struct t10_pr_registration *pr_reg, *pr_reg_p, *pr_reg_tmp;
@@ -2028,14 +2044,6 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
}
se_tpg = se_sess->se_tpg;

- rcu_read_lock();
- se_deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
- if (!se_deve) {
- pr_err("Unable to locate se_deve for PRO-REGISTER\n");
- rcu_read_unlock();
- return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
- }
-
if (se_tpg->se_tpg_tfo->sess_get_initiator_sid) {
memset(&isid_buf[0], 0, PR_REG_ISID_LEN);
se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess, &isid_buf[0],
@@ -2050,16 +2058,14 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
if (res_key) {
pr_warn("SPC-3 PR: Reservation Key non-zero"
" for SA REGISTER, returning CONFLICT\n");
- rcu_read_unlock();
return TCM_RESERVATION_CONFLICT;
}
/*
* Do nothing but return GOOD status.
*/
- if (!sa_res_key) {
- rcu_read_unlock();
+ if (!sa_res_key)
return 0;
- }
+
if (!spec_i_pt) {
/*
* Perform the Service Action REGISTER on the Initiator
@@ -2067,12 +2073,12 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
* Logical Unit of the SCSI device server.
*/
if (core_scsi3_alloc_registration(cmd->se_dev,
- se_sess->se_node_acl, se_deve, isid_ptr,
+ se_sess->se_node_acl, cmd->se_lun,
+ NULL, cmd->orig_fe_lun, isid_ptr,
sa_res_key, all_tg_pt, aptpl,
register_type, 0)) {
pr_err("Unable to allocate"
" struct t10_pr_registration\n");
- rcu_read_unlock();
return TCM_INVALID_PARAMETER_LIST;
}
} else {
@@ -2084,17 +2090,13 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key,
* logic from of core_scsi3_alloc_registration() for
* each TransportID provided SCSI Initiator Port/Device
*/
- ret = core_scsi3_decode_spec_i_port(cmd, se_tpg, se_deve,
+ ret = core_scsi3_decode_spec_i_port(cmd, se_tpg,
isid_ptr, sa_res_key, all_tg_pt, aptpl);
- if (ret != 0) {
- rcu_read_unlock();
+ if (ret != 0)
return ret;
- }
}
- rcu_read_unlock();
return core_scsi3_update_and_write_aptpl(dev, aptpl);
}
- rcu_read_unlock();

/* ok, existing registration */

@@ -3440,10 +3442,13 @@ after_iport_check:
dest_pr_reg = __core_scsi3_locate_pr_reg(dev, dest_node_acl,
iport_ptr);
if (!dest_pr_reg) {
+ struct se_lun *dest_lun = rcu_dereference_check(dest_se_deve->se_lun,
+ atomic_read(&dest_se_deve->pr_kref.refcount) != 0);
+
spin_unlock(&dev->dev_reservation_lock);
- if (core_scsi3_alloc_registration(cmd->se_dev,
- dest_node_acl, dest_se_deve, iport_ptr,
- sa_res_key, 0, aptpl, 2, 1)) {
+ if (core_scsi3_alloc_registration(cmd->se_dev, dest_node_acl,
+ dest_lun, dest_se_deve, dest_se_deve->mapped_lun,
+ iport_ptr, sa_res_key, 0, aptpl, 2, 1)) {
ret = TCM_INVALID_PARAMETER_LIST;
goto out;
}
@@ -4011,10 +4016,10 @@ core_scsi3_pri_read_full_status(struct se_cmd *cmd)
* IDENTIFIER field are not defined by this standard.
*/
if (!pr_reg->pr_reg_all_tg_pt) {
- struct se_port *port = pr_reg->pr_reg_tg_pt_lun->lun_sep;
+ u16 sep_rtpi = pr_reg->tg_pt_sep_rtpi;

- buf[off++] = ((port->sep_rtpi >> 8) & 0xff);
- buf[off++] = (port->sep_rtpi & 0xff);
+ buf[off++] = ((sep_rtpi >> 8) & 0xff);
+ buf[off++] = (sep_rtpi & 0xff);
} else
off += 2; /* Skip over RELATIVE TARGET PORT IDENTIFIER */

diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 508528a..cf3c6ad 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -372,13 +372,14 @@ struct t10_pr_registration {
bool isid_present_at_reg;
u32 pr_res_mapped_lun;
u32 pr_aptpl_target_lun;
+ u16 tg_pt_sep_rtpi;
u32 pr_res_generation;
u64 pr_reg_bin_isid;
u64 pr_res_key;
atomic_t pr_res_holders;
struct se_node_acl *pr_reg_nacl;
+ /* Used by ALL_TG_PT=1 registration with deve->pr_ref taken */
struct se_dev_entry *pr_reg_deve;
- struct se_lun *pr_reg_tg_pt_lun;
struct list_head pr_reg_list;
struct list_head pr_reg_abort_list;
struct list_head pr_reg_aptpl_list;
@@ -498,7 +499,6 @@ struct se_cmd {
struct list_head se_delayed_node;
struct list_head se_qf_node;
struct se_device *se_dev;
- struct se_dev_entry *se_deve;
struct se_lun *se_lun;
/* Only used for internal passthrough and legacy TCM fabric modules */
struct se_session *se_sess;
--
1.9.1

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