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: [email protected] Cc: "James E.J. Bottomley" <[email protected]> Cc: "Martin K. Petersen" <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: [email protected] Signed-off-by: Sebastian Andrzej Siewior <[email protected]> --- 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 ([email protected]) * Maintained by: [email protected] */ - #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 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
