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ib_srpt: Use a mutex instead of a spinlock to protect the channel list

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This is allowed because all CM callback functions are invoked from thread
context.


git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@5443 d57e44dd-8a1f-0410-8b47-8ef2f437770f
This commit is contained in:
Bart Van Assche
2014-04-18 12:10:47 +00:00
parent 97241d4e29
commit f234b9db8a
2 changed files with 24 additions and 51 deletions
Download Patch File Download Diff File Expand all files Collapse all files
srpt/src/ib_srpt.c
+21 -48
View File
@@ -2059,10 +2059,10 @@ static void srpt_unreg_sess(struct scst_session *scst_sess)
* Invoke wake_up() inside the lock to avoid that srpt_tgt disappears
* after list_del() and before wake_up() has been invoked.
*/
spin_lock_irq(&srpt_tgt->spinlock);
mutex_lock(&srpt_tgt->mutex);
list_del(&ch->list);
wake_up(&srpt_tgt->ch_releaseQ);
spin_unlock_irq(&srpt_tgt->spinlock);
mutex_unlock(&srpt_tgt->mutex);
kref_put(&ch->kref, srpt_free_ch);
}
@@ -2192,7 +2192,7 @@ static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch)
}
/**
* __srpt_close_ch() - Close an RDMA channel.
* srpt_close_ch() - Close an RDMA channel.
*
* Make sure all resources associated with the channel will be deallocated at
* an appropriate time.
@@ -2200,22 +2200,14 @@ static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch)
* Returns true if and only if the channel state has been modified from
* CH_CONNECTING or CH_LIVE into CH_DISCONNECTING.
*/
static bool __srpt_close_ch(struct srpt_rdma_ch *ch)
__releases(&ch->srpt_tgt->spinlock)
__acquires(&ch->srpt_tgt->spinlock)
static bool srpt_close_ch(struct srpt_rdma_ch *ch)
{
struct srpt_tgt *srpt_tgt = ch->srpt_tgt;
int ret;
bool was_live;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 32)
lockdep_assert_held(&srpt_tgt->spinlock);
#endif
was_live = srpt_set_ch_state(ch, CH_DISCONNECTING);
if (was_live) {
kref_get(&ch->kref);
spin_unlock_irq(&srpt_tgt->spinlock);
ret = srpt_ch_qp_err(ch);
if (ret < 0)
@@ -2230,35 +2222,20 @@ static bool __srpt_close_ch(struct srpt_rdma_ch *ch)
}
kref_put(&ch->kref, srpt_free_ch);
spin_lock_irq(&srpt_tgt->spinlock);
}
return was_live;
}
/**
* srpt_close_ch() - Close an RDMA channel.
*/
static void srpt_close_ch(struct srpt_rdma_ch *ch)
{
struct srpt_tgt *srpt_tgt = ch->srpt_tgt;
spin_lock_irq(&srpt_tgt->spinlock);
__srpt_close_ch(ch);
spin_unlock_irq(&srpt_tgt->spinlock);
}
static void __srpt_close_all_ch(struct srpt_tgt *srpt_tgt)
{
struct srpt_nexus *nexus;
struct srpt_rdma_ch *ch;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 32)
lockdep_assert_held(&srpt_tgt->spinlock);
lockdep_assert_held(&srpt_tgt->mutex);
#endif
restart:
list_for_each_entry(nexus, &srpt_tgt->nexus_list, entry) {
list_for_each_entry(ch, &nexus->ch_list, list) {
if (ib_send_cm_dreq(ch->ib_cm.cm_id, NULL, 0) < 0)
@@ -2266,7 +2243,6 @@ restart:
PRINT_INFO("Closing channel %s because target %s has"
" been disabled", ch->sess_name,
srpt_tgt->scst_tgt->tgt_name);
goto restart;
}
}
}
@@ -2295,11 +2271,10 @@ static struct srpt_nexus *srpt_get_nexus(struct srpt_tgt *srpt_tgt,
const u8 i_port_id[16],
const u8 t_port_id[16])
{
unsigned long flags;
struct srpt_nexus *nexus = NULL, *tmp_nexus = NULL, *n;
for (;;) {
spin_lock_irqsave(&srpt_tgt->spinlock, flags);
mutex_lock(&srpt_tgt->mutex);
list_for_each_entry(n, &srpt_tgt->nexus_list, entry) {
if (memcmp(n->i_port_id, i_port_id, 16) == 0 &&
memcmp(n->t_port_id, t_port_id, 16) == 0) {
@@ -2311,7 +2286,7 @@ static struct srpt_nexus *srpt_get_nexus(struct srpt_tgt *srpt_tgt,
list_add_tail(&tmp_nexus->entry, &srpt_tgt->nexus_list);
swap(nexus, tmp_nexus);
}
spin_unlock_irqrestore(&srpt_tgt->spinlock, flags);
mutex_unlock(&srpt_tgt->mutex);
if (nexus)
break;
@@ -2347,11 +2322,11 @@ static int srpt_enable_target(struct scst_tgt *scst_tgt, bool enable)
PRINT_INFO("%s target %s", enable ? "Enabling" : "Disabling",
scst_tgt->tgt_name);
spin_lock_irq(&srpt_tgt->spinlock);
mutex_lock(&srpt_tgt->mutex);
srpt_tgt->enabled = enable;
if (!enable)
__srpt_close_all_ch(srpt_tgt);
spin_unlock_irq(&srpt_tgt->spinlock);
mutex_unlock(&srpt_tgt->mutex);
res = 0;
@@ -2585,20 +2560,18 @@ static int srpt_cm_req_recv(struct ib_cm_id *ib_cm_id,
goto unreg_ch;
}
spin_lock_irq(&srpt_tgt->spinlock);
mutex_lock(&srpt_tgt->mutex);
if ((req->req_flags & SRP_MTCH_ACTION) == SRP_MULTICHAN_SINGLE) {
struct srpt_rdma_ch *ch2;
rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_NO_CHAN;
restart:
list_for_each_entry(ch2, &nexus->ch_list, list) {
if (ib_send_cm_dreq(ch2->ib_cm.cm_id, NULL, 0) < 0)
continue;
PRINT_INFO("Relogin - closed existing channel %s",
ch2->sess_name);
rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_TERMINATED;
goto restart;
}
} else {
rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_MAINTAINED;
@@ -2613,11 +2586,11 @@ restart:
PRINT_INFO("rejected SRP_LOGIN_REQ because the target %s (%s)"
" is not enabled",
srpt_tgt->scst_tgt->tgt_name, sdev->device->name);
spin_unlock_irq(&srpt_tgt->spinlock);
mutex_unlock(&srpt_tgt->mutex);
goto reject;
}
spin_unlock_irq(&srpt_tgt->spinlock);
mutex_unlock(&srpt_tgt->mutex);
ret = srpt_ch_qp_rtr(ch, ch->qp);
if (ret) {
@@ -3487,11 +3460,11 @@ static bool srpt_ch_list_empty(struct srpt_tgt *srpt_tgt)
struct srpt_nexus *nexus;
bool res = true;
spin_lock_irq(&srpt_tgt->spinlock);
mutex_lock(&srpt_tgt->mutex);
list_for_each_entry(nexus, &srpt_tgt->nexus_list, entry)
if (!list_empty(&nexus->ch_list))
res = false;
spin_unlock_irq(&srpt_tgt->spinlock);
mutex_unlock(&srpt_tgt->mutex);
return res;
}
@@ -3510,16 +3483,16 @@ static int srpt_release_sport(struct srpt_tgt *srpt_tgt)
BUG_ON(!srpt_tgt);
/* Disallow new logins and close all active sessions. */
spin_lock_irq(&srpt_tgt->spinlock);
mutex_lock(&srpt_tgt->mutex);
srpt_tgt->enabled = false;
__srpt_close_all_ch(srpt_tgt);
spin_unlock_irq(&srpt_tgt->spinlock);
mutex_unlock(&srpt_tgt->mutex);
while (wait_event_timeout(srpt_tgt->ch_releaseQ,
srpt_ch_list_empty(srpt_tgt), 5 * HZ) <= 0) {
PRINT_INFO("%s: waiting for session unregistration ...",
srpt_tgt->scst_tgt->tgt_name);
spin_lock_irq(&srpt_tgt->spinlock);
mutex_lock(&srpt_tgt->mutex);
list_for_each_entry(nexus, &srpt_tgt->nexus_list, entry) {
list_for_each_entry(ch, &nexus->ch_list, list) {
PRINT_INFO("%s: state %s; %d commands in"
@@ -3528,15 +3501,15 @@ static int srpt_release_sport(struct srpt_tgt *srpt_tgt)
atomic_read(&ch->scst_sess->sess_cmd_count));
}
}
spin_unlock_irq(&srpt_tgt->spinlock);
mutex_unlock(&srpt_tgt->mutex);
}
spin_lock_irq(&srpt_tgt->spinlock);
mutex_lock(&srpt_tgt->mutex);
list_for_each_entry_safe(nexus, next_n, &srpt_tgt->nexus_list, entry) {
list_del(&nexus->entry);
kfree(nexus);
}
spin_unlock_irq(&srpt_tgt->spinlock);
mutex_unlock(&srpt_tgt->mutex);
TRACE_EXIT();
return 0;
@@ -3784,7 +3757,7 @@ static void srpt_init_tgt(struct srpt_tgt *srpt_tgt)
{
INIT_LIST_HEAD(&srpt_tgt->nexus_list);
init_waitqueue_head(&srpt_tgt->ch_releaseQ);
spin_lock_init(&srpt_tgt->spinlock);
mutex_init(&srpt_tgt->mutex);
}
/**
srpt/src/ib_srpt.h
+3 -3
View File
@@ -368,7 +368,7 @@ struct srpt_rdma_ch {
/**
* struct srpt_nexus - I_T nexus
* @entry: srpt_tgt.nexus_list list node.
* @ch_list: struct srpt_rdma_ch list. Protected by srpt_tgt.spinlock
* @ch_list: struct srpt_rdma_ch list. Protected by srpt_tgt.mutex.
* @i_port_id: 128-bit initiator port identifier copied from SRP_LOGIN_REQ.
* @t_port_id: 128-bit target port identifier copied from SRP_LOGIN_REQ.
*/
@@ -382,14 +382,14 @@ struct srpt_nexus {
/**
* struct srpt_tgt
* @ch_releaseQ: Enables waiting for removal from nexus_list.
* @spinlock: Protects nexus_list.
* @mutex: Protects @nexus_list and srpt_nexus.ch_list.
* @nexus_list: Per-device I_T nexus list.
* @scst_tgt: SCST target information associated with this HCA.
* @enabled: Whether or not this SCST target is enabled.
*/
struct srpt_tgt {
wait_queue_head_t ch_releaseQ;
spinlock_t spinlock;
struct mutex mutex;
struct list_head nexus_list;
struct scst_tgt *scst_tgt;
bool enabled;