The driver creates its own per-CPU threads which are updated based on
CPU hotplug events. It is also possible to delegate this task to the
smpboot-thread infrastructure and get the same job done while saving a
few lines of code.
The code checked ->iothread to decide if there is an active per-CPU
thread. With the smpboot infrastructure this is no longer possible and I
replaced its logic with the ->active member. The thread pointer is saved
in `kthread' instead of `iothread' so anything trying to use `thread' is
caught by the compiler.
The remaining part of the conversion is mostly straightforward.
This patch was only compile-tested due to -ENODEV.
Cc: QLogic-Storage-Upstream@xxxxxxxxxx
Cc: "James E.J. Bottomley" <JBottomley@xxxxxxxx>
Cc: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: linux-scsi@xxxxxxxxxxxxxxx
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
drivers/scsi/bnx2i/bnx2i.h | 4 +-
drivers/scsi/bnx2i/bnx2i_hwi.c | 45 +----------
drivers/scsi/bnx2i/bnx2i_init.c | 162 ++++++++++++++++------------------------
3 files changed, 69 insertions(+), 142 deletions(-)
diff --git a/drivers/scsi/bnx2i/bnx2i.h b/drivers/scsi/bnx2i/bnx2i.h
index ed7f3228e234..2bbccf571a18 100644
--- a/drivers/scsi/bnx2i/bnx2i.h
+++ b/drivers/scsi/bnx2i/bnx2i.h
@@ -775,9 +775,10 @@ struct bnx2i_work {
};
struct bnx2i_percpu_s {
- struct task_struct *iothread;
+ struct task_struct *kthread;
struct list_head work_list;
spinlock_t p_work_lock;
+ bool active;
};
@@ -875,7 +876,6 @@ extern void bnx2i_print_active_cmd_queue(struct bnx2i_conn *conn);
extern void bnx2i_print_xmit_pdu_queue(struct bnx2i_conn *conn);
extern void bnx2i_print_recv_state(struct bnx2i_conn *conn);
-extern int bnx2i_percpu_io_thread(void *arg);
extern int bnx2i_process_scsi_cmd_resp(struct iscsi_session *session,
struct bnx2i_conn *bnx2i_conn,
struct cqe *cqe);
diff --git a/drivers/scsi/bnx2i/bnx2i_hwi.c b/drivers/scsi/bnx2i/bnx2i_hwi.c
index fb072cc5e9fd..ec3969732846 100644
--- a/drivers/scsi/bnx2i/bnx2i_hwi.c
+++ b/drivers/scsi/bnx2i/bnx2i_hwi.c
@@ -1860,47 +1860,6 @@ static void bnx2i_process_cmd_cleanup_resp(struct iscsi_session *session,
complete(&bnx2i_conn->cmd_cleanup_cmpl);
}
-
-/**
- * bnx2i_percpu_io_thread - thread per cpu for ios
- *
- * @arg: ptr to bnx2i_percpu_info structure
- */
-int bnx2i_percpu_io_thread(void *arg)
-{
- struct bnx2i_percpu_s *p = arg;
- struct bnx2i_work *work, *tmp;
- LIST_HEAD(work_list);
-
- set_user_nice(current, MIN_NICE);
-
- while (!kthread_should_stop()) {
- spin_lock_bh(&p->p_work_lock);
- while (!list_empty(&p->work_list)) {
- list_splice_init(&p->work_list, &work_list);
- spin_unlock_bh(&p->p_work_lock);
-
- list_for_each_entry_safe(work, tmp, &work_list, list) {
- list_del_init(&work->list);
- /* work allocated in the bh, freed here */
- bnx2i_process_scsi_cmd_resp(work->session,
- work->bnx2i_conn,
- &work->cqe);
- atomic_dec(&work->bnx2i_conn->work_cnt);
- kfree(work);
- }
- spin_lock_bh(&p->p_work_lock);
- }
- set_current_state(TASK_INTERRUPTIBLE);
- spin_unlock_bh(&p->p_work_lock);
- schedule();
- }
- __set_current_state(TASK_RUNNING);
-
- return 0;
-}
-
-
/**
* bnx2i_queue_scsi_cmd_resp - queue cmd completion to the percpu thread
* @bnx2i_conn: bnx2i connection
@@ -1941,7 +1900,7 @@ static int bnx2i_queue_scsi_cmd_resp(struct iscsi_session *session,
p = &per_cpu(bnx2i_percpu, cpu);
spin_lock(&p->p_work_lock);
- if (unlikely(!p->iothread)) {
+ if (unlikely(!p->active)) {
rc = -EINVAL;
goto err;
}
@@ -1954,7 +1913,7 @@ static int bnx2i_queue_scsi_cmd_resp(struct iscsi_session *session,
memcpy(&bnx2i_work->cqe, cqe, sizeof(struct cqe));
list_add_tail(&bnx2i_work->list, &p->work_list);
atomic_inc(&bnx2i_conn->work_cnt);
- wake_up_process(p->iothread);
+ wake_up_process(p->kthread);
spin_unlock(&p->p_work_lock);
goto done;
} else
diff --git a/drivers/scsi/bnx2i/bnx2i_init.c b/drivers/scsi/bnx2i/bnx2i_init.c
index c8b410c24cf0..4ec8c552cc95 100644
--- a/drivers/scsi/bnx2i/bnx2i_init.c
+++ b/drivers/scsi/bnx2i/bnx2i_init.c
@@ -13,8 +13,8 @@
* Previously Maintained by: Eddie Wai (eddie.wai@xxxxxxxxxxxx)
* Maintained by: QLogic-Storage-Upstream@xxxxxxxxxx
*/
-
#include "bnx2i.h"
+#include <linux/smpboot.h>
static struct list_head adapter_list = LIST_HEAD_INIT(adapter_list);
static u32 adapter_count;
@@ -70,14 +70,6 @@ u64 iscsi_error_mask = 0x00;
DEFINE_PER_CPU(struct bnx2i_percpu_s, bnx2i_percpu);
-static int bnx2i_cpu_callback(struct notifier_block *nfb,
- unsigned long action, void *hcpu);
-/* notification function for CPU hotplug events */
-static struct notifier_block bnx2i_cpu_notifier = {
- .notifier_call = bnx2i_cpu_callback,
-};
-
-
/**
* bnx2i_identify_device - identifies NetXtreme II device type
* @hba: Adapter structure pointer
@@ -410,92 +402,95 @@ int bnx2i_get_stats(void *handle)
return 0;
}
-
-/**
- * bnx2i_percpu_thread_create - Create a receive thread for an
- * online CPU
- *
- * @cpu: cpu index for the online cpu
- */
-static void bnx2i_percpu_thread_create(unsigned int cpu)
+static void bnx2i_thread_io_process(unsigned int cpu)
{
- struct bnx2i_percpu_s *p;
- struct task_struct *thread;
+ struct bnx2i_percpu_s *p = per_cpu_ptr(&bnx2i_percpu, cpu);
+ struct bnx2i_work *work, *tmp;
+ LIST_HEAD(work_list);
- p = &per_cpu(bnx2i_percpu, cpu);
+ spin_lock_bh(&p->p_work_lock);
+ while (!list_empty(&p->work_list)) {
+ list_splice_init(&p->work_list, &work_list);
+ spin_unlock_bh(&p->p_work_lock);
- thread = kthread_create_on_node(bnx2i_percpu_io_thread, (void *)p,
- cpu_to_node(cpu),
- "bnx2i_thread/%d", cpu);
- /* bind thread to the cpu */
- if (likely(!IS_ERR(thread))) {
- kthread_bind(thread, cpu);
- p->iothread = thread;
- wake_up_process(thread);
+ list_for_each_entry_safe(work, tmp, &work_list, list) {
+ list_del_init(&work->list);
+ /* work allocated in the bh, freed here */
+ bnx2i_process_scsi_cmd_resp(work->session,
+ work->bnx2i_conn,
+ &work->cqe);
+ atomic_dec(&work->bnx2i_conn->work_cnt);
+ kfree(work);
+ }
+ spin_lock_bh(&p->p_work_lock);
}
+ spin_unlock_bh(&p->p_work_lock);
}
+static void bnx2i_thread_setup(unsigned int cpu)
+{
+ struct bnx2i_percpu_s *p = per_cpu_ptr(&bnx2i_percpu, cpu);
-static void bnx2i_percpu_thread_destroy(unsigned int cpu)
+ set_user_nice(current, MIN_NICE);
+ INIT_LIST_HEAD(&p->work_list);
+ spin_lock_init(&p->p_work_lock);
+}
+
+static int bnx2i_thread_should_run(unsigned int cpu)
+{
+ struct bnx2i_percpu_s *p = per_cpu_ptr(&bnx2i_percpu, cpu);
+ /*
+ * A lockless peek at the list. The real check is done in
+ * bnx2i_thread_io_process()
+ */
+ return !list_empty(&p->work_list);
+}
+
+static void bnx2i_thread_park(unsigned int cpu)
{
struct bnx2i_percpu_s *p;
- struct task_struct *thread;
struct bnx2i_work *work, *tmp;
/* Prevent any new work from being queued for this CPU */
p = &per_cpu(bnx2i_percpu, cpu);
spin_lock_bh(&p->p_work_lock);
- thread = p->iothread;
- p->iothread = NULL;
+ p->active = false;
/* Free all work in the list */
list_for_each_entry_safe(work, tmp, &p->work_list, list) {
list_del_init(&work->list);
- bnx2i_process_scsi_cmd_resp(work->session,
- work->bnx2i_conn, &work->cqe);
+ bnx2i_process_scsi_cmd_resp(work->session, work->bnx2i_conn,
+ &work->cqe);
kfree(work);
}
spin_unlock_bh(&p->p_work_lock);
- if (thread)
- kthread_stop(thread);
}
-
-/**
- * bnx2i_cpu_callback - Handler for CPU hotplug events
- *
- * @nfb: The callback data block
- * @action: The event triggering the callback
- * @hcpu: The index of the CPU that the event is for
- *
- * This creates or destroys per-CPU data for iSCSI
- *
- * Returns NOTIFY_OK always.
- */
-static int bnx2i_cpu_callback(struct notifier_block *nfb,
- unsigned long action, void *hcpu)
+static void bnx2i_thread_cleanup(unsigned int cpu, bool online)
{
- unsigned cpu = (unsigned long)hcpu;
-
- switch (action) {
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- printk(KERN_INFO "bnx2i: CPU %x online: Create Rx thread\n",
- cpu);
- bnx2i_percpu_thread_create(cpu);
- break;
- case CPU_DEAD:
- case CPU_DEAD_FROZEN:
- printk(KERN_INFO "CPU %x offline: Remove Rx thread\n", cpu);
- bnx2i_percpu_thread_destroy(cpu);
- break;
- default:
- break;
- }
- return NOTIFY_OK;
+ if (!online)
+ return;
+ bnx2i_thread_park(cpu);
}
+static void bnx2i_thread_unpark(unsigned int cpu)
+{
+ struct bnx2i_percpu_s *p = per_cpu_ptr(&bnx2i_percpu, cpu);
+
+ p->active = true;
+}
+
+static struct smp_hotplug_thread bnx2i_threads = {
+ .store = &bnx2i_percpu.kthread,
+ .setup = bnx2i_thread_setup,
+ .cleanup = bnx2i_thread_cleanup,
+ .thread_should_run = bnx2i_thread_should_run,
+ .thread_fn = bnx2i_thread_io_process,
+ .park = bnx2i_thread_park,
+ .unpark = bnx2i_thread_unpark,
+ .thread_comm = "bnx2i_thread/%u",
+};
/**
* bnx2i_mod_init - module init entry point
@@ -507,8 +502,6 @@ static int bnx2i_cpu_callback(struct notifier_block *nfb,
static int __init bnx2i_mod_init(void)
{
int err;
- unsigned cpu = 0;
- struct bnx2i_percpu_s *p;
printk(KERN_INFO "%s", version);
@@ -531,24 +524,7 @@ static int __init bnx2i_mod_init(void)
goto unreg_xport;
}
- /* Create percpu kernel threads to handle iSCSI I/O completions */
- for_each_possible_cpu(cpu) {
- p = &per_cpu(bnx2i_percpu, cpu);
- INIT_LIST_HEAD(&p->work_list);
- spin_lock_init(&p->p_work_lock);
- p->iothread = NULL;
- }
-
- cpu_notifier_register_begin();
-
- for_each_online_cpu(cpu)
- bnx2i_percpu_thread_create(cpu);
-
- /* Initialize per CPU interrupt thread */
- __register_hotcpu_notifier(&bnx2i_cpu_notifier);
-
- cpu_notifier_register_done();
-
+ smpboot_register_percpu_thread(&bnx2i_threads);
return 0;
unreg_xport:
@@ -569,7 +545,6 @@ static int __init bnx2i_mod_init(void)
static void __exit bnx2i_mod_exit(void)
{
struct bnx2i_hba *hba;
- unsigned cpu = 0;
mutex_lock(&bnx2i_dev_lock);
while (!list_empty(&adapter_list)) {
@@ -587,14 +562,7 @@ static void __exit bnx2i_mod_exit(void)
}
mutex_unlock(&bnx2i_dev_lock);
- cpu_notifier_register_begin();
-
- for_each_online_cpu(cpu)
- bnx2i_percpu_thread_destroy(cpu);
-
- __unregister_hotcpu_notifier(&bnx2i_cpu_notifier);
-
- cpu_notifier_register_done();
+ smpboot_unregister_percpu_thread(&bnx2i_threads);
iscsi_unregister_transport(&bnx2i_iscsi_transport);
cnic_unregister_driver(CNIC_ULP_ISCSI);
--
2.7.0
--
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