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net/smc: separate locks for SMCD and SMCR link group lists
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This patch introduces separate locks for the split SMCD and SMCR
link group lists.

Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
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Ursula Braun authored and Jakub Kicinski committed Oct 10, 2019
1 parent a2351c5 commit a0a62ee
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Showing 3 changed files with 44 additions and 15 deletions.
1 change: 1 addition & 0 deletions include/net/smc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,7 @@ struct smcd_dev {
u8 pnetid[SMC_MAX_PNETID_LEN];
bool pnetid_by_user;
struct list_head lgr_list;
spinlock_t lgr_lock;
};

struct smcd_dev *smcd_alloc_dev(struct device *parent, const char *name,
Expand Down
57 changes: 42 additions & 15 deletions net/smc/smc_core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,19 @@ static struct smc_lgr_list smc_lgr_list = { /* established link groups */
static void smc_buf_free(struct smc_link_group *lgr, bool is_rmb,
struct smc_buf_desc *buf_desc);

/* return head of link group list and its lock for a given link group */
static inline struct list_head *smc_lgr_list_head(struct smc_link_group *lgr,
spinlock_t **lgr_lock)
{
if (lgr->is_smcd) {
*lgr_lock = &lgr->smcd->lgr_lock;
return &lgr->smcd->lgr_list;
}

*lgr_lock = &smc_lgr_list.lock;
return &smc_lgr_list.list;
}

static void smc_lgr_schedule_free_work(struct smc_link_group *lgr)
{
/* client link group creation always follows the server link group
Expand Down Expand Up @@ -157,19 +170,21 @@ static void smc_lgr_free_work(struct work_struct *work)
struct smc_link_group *lgr = container_of(to_delayed_work(work),
struct smc_link_group,
free_work);
spinlock_t *lgr_lock;
bool conns;

spin_lock_bh(&smc_lgr_list.lock);
smc_lgr_list_head(lgr, &lgr_lock);
spin_lock_bh(lgr_lock);
read_lock_bh(&lgr->conns_lock);
conns = RB_EMPTY_ROOT(&lgr->conns_all);
read_unlock_bh(&lgr->conns_lock);
if (!conns) { /* number of lgr connections is no longer zero */
spin_unlock_bh(&smc_lgr_list.lock);
spin_unlock_bh(lgr_lock);
return;
}
if (!list_empty(&lgr->list))
list_del_init(&lgr->list); /* remove from smc_lgr_list */
spin_unlock_bh(&smc_lgr_list.lock);
spin_unlock_bh(lgr_lock);

if (!lgr->is_smcd && !lgr->terminating) {
struct smc_link *lnk = &lgr->lnk[SMC_SINGLE_LINK];
Expand Down Expand Up @@ -200,6 +215,7 @@ static int smc_lgr_create(struct smc_sock *smc, struct smc_init_info *ini)
struct smc_link_group *lgr;
struct list_head *lgr_list;
struct smc_link *lnk;
spinlock_t *lgr_lock;
u8 rndvec[3];
int rc = 0;
int i;
Expand Down Expand Up @@ -235,6 +251,7 @@ static int smc_lgr_create(struct smc_sock *smc, struct smc_init_info *ini)
lgr->peer_gid = ini->ism_gid;
lgr->smcd = ini->ism_dev;
lgr_list = &ini->ism_dev->lgr_list;
lgr_lock = &lgr->smcd->lgr_lock;
} else {
/* SMC-R specific settings */
lgr->role = smc->listen_smc ? SMC_SERV : SMC_CLNT;
Expand All @@ -248,6 +265,7 @@ static int smc_lgr_create(struct smc_sock *smc, struct smc_init_info *ini)
lnk->smcibdev = ini->ib_dev;
lnk->ibport = ini->ib_port;
lgr_list = &smc_lgr_list.list;
lgr_lock = &smc_lgr_list.lock;
lnk->path_mtu =
ini->ib_dev->pattr[ini->ib_port - 1].active_mtu;
if (!ini->ib_dev->initialized)
Expand Down Expand Up @@ -277,9 +295,9 @@ static int smc_lgr_create(struct smc_sock *smc, struct smc_init_info *ini)
goto destroy_qp;
}
smc->conn.lgr = lgr;
spin_lock_bh(&smc_lgr_list.lock);
spin_lock_bh(lgr_lock);
list_add(&lgr->list, lgr_list);
spin_unlock_bh(&smc_lgr_list.lock);
spin_unlock_bh(lgr_lock);
return 0;

destroy_qp:
Expand Down Expand Up @@ -442,11 +460,15 @@ static void smc_lgr_free(struct smc_link_group *lgr)

void smc_lgr_forget(struct smc_link_group *lgr)
{
spin_lock_bh(&smc_lgr_list.lock);
struct list_head *lgr_list;
spinlock_t *lgr_lock;

lgr_list = smc_lgr_list_head(lgr, &lgr_lock);
spin_lock_bh(lgr_lock);
/* do not use this link group for new connections */
if (!list_empty(&lgr->list))
list_del_init(&lgr->list);
spin_unlock_bh(&smc_lgr_list.lock);
if (!list_empty(lgr_list))
list_del_init(lgr_list);
spin_unlock_bh(lgr_lock);
}

/* terminate linkgroup abnormally */
Expand Down Expand Up @@ -487,9 +509,12 @@ static void __smc_lgr_terminate(struct smc_link_group *lgr)

void smc_lgr_terminate(struct smc_link_group *lgr)
{
spin_lock_bh(&smc_lgr_list.lock);
spinlock_t *lgr_lock;

smc_lgr_list_head(lgr, &lgr_lock);
spin_lock_bh(lgr_lock);
__smc_lgr_terminate(lgr);
spin_unlock_bh(&smc_lgr_list.lock);
spin_unlock_bh(lgr_lock);
}

/* Called when IB port is terminated */
Expand All @@ -514,15 +539,15 @@ void smc_smcd_terminate(struct smcd_dev *dev, u64 peer_gid, unsigned short vlan)
LIST_HEAD(lgr_free_list);

/* run common cleanup function and build free list */
spin_lock_bh(&smc_lgr_list.lock);
spin_lock_bh(&dev->lgr_lock);
list_for_each_entry_safe(lgr, l, &dev->lgr_list, list) {
if ((!peer_gid || lgr->peer_gid == peer_gid) &&
(vlan == VLAN_VID_MASK || lgr->vlan_id == vlan)) {
__smc_lgr_terminate(lgr);
list_move(&lgr->list, &lgr_free_list);
}
}
spin_unlock_bh(&smc_lgr_list.lock);
spin_unlock_bh(&dev->lgr_lock);

/* cancel the regular free workers and actually free lgrs */
list_for_each_entry_safe(lgr, l, &lgr_free_list, list) {
Expand Down Expand Up @@ -609,17 +634,19 @@ int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini)
struct list_head *lgr_list;
struct smc_link_group *lgr;
enum smc_lgr_role role;
spinlock_t *lgr_lock;
int rc = 0;

lgr_list = ini->is_smcd ? &ini->ism_dev->lgr_list : &smc_lgr_list.list;
lgr_lock = ini->is_smcd ? &ini->ism_dev->lgr_lock : &smc_lgr_list.lock;
ini->cln_first_contact = SMC_FIRST_CONTACT;
role = smc->listen_smc ? SMC_SERV : SMC_CLNT;
if (role == SMC_CLNT && ini->srv_first_contact)
/* create new link group as well */
goto create;

/* determine if an existing link group can be reused */
spin_lock_bh(&smc_lgr_list.lock);
spin_lock_bh(lgr_lock);
list_for_each_entry(lgr, lgr_list, list) {
write_lock_bh(&lgr->conns_lock);
if ((ini->is_smcd ?
Expand All @@ -640,7 +667,7 @@ int smc_conn_create(struct smc_sock *smc, struct smc_init_info *ini)
}
write_unlock_bh(&lgr->conns_lock);
}
spin_unlock_bh(&smc_lgr_list.lock);
spin_unlock_bh(lgr_lock);

if (role == SMC_CLNT && !ini->srv_first_contact &&
ini->cln_first_contact == SMC_FIRST_CONTACT) {
Expand Down
1 change: 1 addition & 0 deletions net/smc/smc_ism.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -286,6 +286,7 @@ struct smcd_dev *smcd_alloc_dev(struct device *parent, const char *name,
smc_pnetid_by_dev_port(parent, 0, smcd->pnetid);

spin_lock_init(&smcd->lock);
spin_lock_init(&smcd->lgr_lock);
INIT_LIST_HEAD(&smcd->vlan);
INIT_LIST_HEAD(&smcd->lgr_list);
smcd->event_wq = alloc_ordered_workqueue("ism_evt_wq-%s)",
Expand Down

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