[RFC/REFACT] Refactoring and significantly reducing code complexity

From: Wang Jinchao
Date: Thu Sep 28 2023 - 04:53:53 EST

This is a refactored version with the following main changes:

- The parallel workqueue no longer uses the WQ_UNBOUND attribute
- Removal of CPU-related logic, sysfs-related interfaces
- removal of structures like padata_cpumask, and deletion of parallel_data
- Using completion to maintain sequencing
- no longer using lists
- removing structures like padata_list and padata_serial_queue
- Removal of padata_do_serial()
- padata automatically ensures the calling sequence.

Testing was conducted using ltp's pcrypt_aead01, and the execution time
comparison between the old and new versions is as follows:

Old Version:
real 0m27.451s
user 0m0.031s
sys 0m0.260s

New Version:
real 0m21.351s
user 0m0.023s
sys 0m0.260s

Signed-off-by: Wang Jinchao <wangjinchao@xxxxxxxxxxx>
---
crypto/pcrypt.c | 34 +-
include/linux/padata.h | 95 +----
kernel/padata.c | 815 ++---------------------------------------
3 files changed, 43 insertions(+), 901 deletions(-)

diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c
index 8c1d0ca41213..db9a36c35229 100644
--- a/crypto/pcrypt.c
+++ b/crypto/pcrypt.c
@@ -70,8 +70,6 @@ static void pcrypt_aead_done(void *data, int err)
struct padata_priv *padata = pcrypt_request_padata(preq);

padata->info = err;
-
- padata_do_serial(padata);
}

static void pcrypt_aead_enc(struct padata_priv *padata)
@@ -86,7 +84,6 @@ static void pcrypt_aead_enc(struct padata_priv *padata)
return;

padata->info = ret;
- padata_do_serial(padata);
}

static int pcrypt_aead_encrypt(struct aead_request *req)
@@ -114,7 +111,7 @@ static int pcrypt_aead_encrypt(struct aead_request *req)
req->cryptlen, req->iv);
aead_request_set_ad(creq, req->assoclen);

- err = padata_do_parallel(ictx->psenc, padata, &ctx->cb_cpu);
+ err = padata_do_parallel(ictx->psenc, padata);
if (!err)
return -EINPROGRESS;

@@ -133,7 +130,6 @@ static void pcrypt_aead_dec(struct padata_priv *padata)
return;

padata->info = ret;
- padata_do_serial(padata);
}

static int pcrypt_aead_decrypt(struct aead_request *req)
@@ -161,7 +157,7 @@ static int pcrypt_aead_decrypt(struct aead_request *req)
req->cryptlen, req->iv);
aead_request_set_ad(creq, req->assoclen);

- err = padata_do_parallel(ictx->psdec, padata, &ctx->cb_cpu);
+ err = padata_do_parallel(ictx->psdec, padata);
if (!err)
return -EINPROGRESS;

@@ -304,31 +300,18 @@ static int pcrypt_create(struct crypto_template *tmpl, struct rtattr **tb)
return -EINVAL;
}

-static int pcrypt_sysfs_add(struct padata_instance *pinst, const char *name)
-{
- int ret;
-
- pinst->kobj.kset = pcrypt_kset;
- ret = kobject_add(&pinst->kobj, NULL, "%s", name);
- if (!ret)
- kobject_uevent(&pinst->kobj, KOBJ_ADD);
-
- return ret;
-}
-
static int pcrypt_init_padata(struct padata_instance **pinst, const char *name)
{
int ret = -ENOMEM;
+ pr_info("%s:%d %s\n", __FILE__, __LINE__, __func__);

*pinst = padata_alloc(name);
+ pr_info("%s:%d %s\n", __FILE__, __LINE__, __func__);
+ pr_info("%s:%d %s *pinst=%p\n", __FILE__, __LINE__, __func__, *pinst);
+
if (!*pinst)
return ret;
-
- ret = pcrypt_sysfs_add(*pinst, name);
- if (ret)
- padata_free(*pinst);
-
- return ret;
+ return 0;
}

static struct crypto_template pcrypt_tmpl = {
@@ -344,15 +327,18 @@ static int __init pcrypt_init(void)
pcrypt_kset = kset_create_and_add("pcrypt", NULL, kernel_kobj);
if (!pcrypt_kset)
goto err;
+ pr_info("%s:%d %s\n", __FILE__, __LINE__, __func__);

err = pcrypt_init_padata(&pencrypt, "pencrypt");
if (err)
goto err_unreg_kset;

+ pr_info("%s:%d %s\n", __FILE__, __LINE__, __func__);
err = pcrypt_init_padata(&pdecrypt, "pdecrypt");
if (err)
goto err_deinit_pencrypt;

+ pr_info("%s:%d %s\n", __FILE__, __LINE__, __func__);
return crypto_register_template(&pcrypt_tmpl);

err_deinit_pencrypt:
diff --git a/include/linux/padata.h b/include/linux/padata.h
index 495b16b6b4d7..ed880ef155c2 100644
--- a/include/linux/padata.h
+++ b/include/linux/padata.h
@@ -19,107 +19,36 @@
#include <linux/list.h>
#include <linux/kobject.h>

-#define PADATA_CPU_SERIAL 0x01
-#define PADATA_CPU_PARALLEL 0x02

/**
* struct padata_priv - Represents one job
*
- * @list: List entry, to attach to the padata lists.
- * @pd: Pointer to the internal control structure.
- * @cb_cpu: Callback cpu for serializatioon.
- * @seq_nr: Sequence number of the parallelized data object.
* @info: Used to pass information from the parallel to the serial function.
+ * @parallel_done: completetion of parallel_work.
+ * @parallel_work: Parallel work.
+ * @serial_work: Serial work.
* @parallel: Parallel execution function.
* @serial: Serial complete function.
*/
struct padata_priv {
- struct list_head list;
- struct parallel_data *pd;
- int cb_cpu;
- unsigned int seq_nr;
int info;
+ struct completion parallel_done;
+ struct work_struct parallel_work;
+ struct work_struct serial_work;
void (*parallel)(struct padata_priv *padata);
void (*serial)(struct padata_priv *padata);
};

-/**
- * struct padata_list - one per work type per CPU
- *
- * @list: List head.
- * @lock: List lock.
- */
-struct padata_list {
- struct list_head list;
- spinlock_t lock;
-};
-
-/**
-* struct padata_serial_queue - The percpu padata serial queue
-*
-* @serial: List to wait for serialization after reordering.
-* @work: work struct for serialization.
-* @pd: Backpointer to the internal control structure.
-*/
-struct padata_serial_queue {
- struct padata_list serial;
- struct work_struct work;
- struct parallel_data *pd;
-};
-
-/**
- * struct padata_cpumask - The cpumasks for the parallel/serial workers
- *
- * @pcpu: cpumask for the parallel workers.
- * @cbcpu: cpumask for the serial (callback) workers.
- */
-struct padata_cpumask {
- cpumask_var_t pcpu;
- cpumask_var_t cbcpu;
-};
-
-/**
- * struct parallel_data - Internal control structure, covers everything
- * that depends on the cpumask in use.
- *
- * @ps: padata_shell object.
- * @reorder_list: percpu reorder lists
- * @squeue: percpu padata queues used for serialuzation.
- * @refcnt: Number of objects holding a reference on this parallel_data.
- * @seq_nr: Sequence number of the parallelized data object.
- * @processed: Number of already processed objects.
- * @cpu: Next CPU to be processed.
- * @cpumask: The cpumasks in use for parallel and serial workers.
- * @reorder_work: work struct for reordering.
- * @lock: Reorder lock.
- */
-struct parallel_data {
- struct padata_shell *ps;
- struct padata_list __percpu *reorder_list;
- struct padata_serial_queue __percpu *squeue;
- refcount_t refcnt;
- unsigned int seq_nr;
- unsigned int processed;
- int cpu;
- struct padata_cpumask cpumask;
- struct work_struct reorder_work;
- spinlock_t ____cacheline_aligned lock;
-};
-
/**
* struct padata_shell - Wrapper around struct parallel_data, its
* purpose is to allow the underlying control structure to be replaced
* on the fly using RCU.
*
* @pinst: padat instance.
- * @pd: Actual parallel_data structure which may be substituted on the fly.
- * @opd: Pointer to old pd to be freed by padata_replace.
* @list: List entry in padata_instance list.
*/
struct padata_shell {
struct padata_instance *pinst;
- struct parallel_data __rcu *pd;
- struct parallel_data *opd;
struct list_head list;
};

@@ -151,24 +80,17 @@ struct padata_mt_job {
/**
* struct padata_instance - The overall control structure.
*
- * @cpu_online_node: Linkage for CPU online callback.
- * @cpu_dead_node: Linkage for CPU offline callback.
* @parallel_wq: The workqueue used for parallel work.
* @serial_wq: The workqueue used for serial work.
* @pslist: List of padata_shell objects attached to this instance.
- * @cpumask: User supplied cpumasks for parallel and serial works.
* @kobj: padata instance kernel object.
* @lock: padata instance lock.
* @flags: padata flags.
*/
struct padata_instance {
- struct hlist_node cpu_online_node;
- struct hlist_node cpu_dead_node;
struct workqueue_struct *parallel_wq;
struct workqueue_struct *serial_wq;
struct list_head pslist;
- struct padata_cpumask cpumask;
- struct kobject kobj;
struct mutex lock;
u8 flags;
#define PADATA_INIT 1
@@ -187,9 +109,6 @@ extern void padata_free(struct padata_instance *pinst);
extern struct padata_shell *padata_alloc_shell(struct padata_instance *pinst);
extern void padata_free_shell(struct padata_shell *ps);
extern int padata_do_parallel(struct padata_shell *ps,
- struct padata_priv *padata, int *cb_cpu);
-extern void padata_do_serial(struct padata_priv *padata);
+ struct padata_priv *padata);
extern void __init padata_do_multithreaded(struct padata_mt_job *job);
-extern int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
- cpumask_var_t cpumask);
#endif
diff --git a/kernel/padata.c b/kernel/padata.c
index 222d60195de6..ec80e2b9556d 100644
--- a/kernel/padata.c
+++ b/kernel/padata.c
@@ -13,9 +13,7 @@

#include <linux/completion.h>
#include <linux/export.h>
-#include <linux/cpumask.h>
#include <linux/err.h>
-#include <linux/cpu.h>
#include <linux/padata.h>
#include <linux/mutex.h>
#include <linux/sched.h>
@@ -44,31 +42,8 @@ struct padata_mt_job_state {
unsigned long chunk_size;
};

-static void padata_free_pd(struct parallel_data *pd);
static void __init padata_mt_helper(struct work_struct *work);

-static int padata_index_to_cpu(struct parallel_data *pd, int cpu_index)
-{
- int cpu, target_cpu;
-
- target_cpu = cpumask_first(pd->cpumask.pcpu);
- for (cpu = 0; cpu < cpu_index; cpu++)
- target_cpu = cpumask_next(target_cpu, pd->cpumask.pcpu);
-
- return target_cpu;
-}
-
-static int padata_cpu_hash(struct parallel_data *pd, unsigned int seq_nr)
-{
- /*
- * Hash the sequence numbers to the cpus by taking
- * seq_nr mod. number of cpus in use.
- */
- int cpu_index = seq_nr % cpumask_weight(pd->cpumask.pcpu);
-
- return padata_index_to_cpu(pd, cpu_index);
-}
-
static struct padata_work *padata_work_alloc(void)
{
struct padata_work *pw;
@@ -144,27 +119,18 @@ static void __init padata_works_free(struct list_head *works)

static void padata_parallel_worker(struct work_struct *parallel_work)
{
- struct padata_work *pw = container_of(parallel_work, struct padata_work,
- pw_work);
- struct padata_priv *padata = pw->pw_data;
-
- local_bh_disable();
+ struct padata_priv *padata = container_of(parallel_work, struct padata_priv, parallel_work);
padata->parallel(padata);
- spin_lock(&padata_works_lock);
- padata_work_free(pw);
- spin_unlock(&padata_works_lock);
- local_bh_enable();
+ complete(&padata->parallel_done);
}

+static void padata_serial_worker(struct work_struct *serial_work);
+
/**
* padata_do_parallel - padata parallelization function
*
* @ps: padatashell
* @padata: object to be parallelized
- * @cb_cpu: pointer to the CPU that the serialization callback function should
- * run on. If it's not in the serial cpumask of @pinst
- * (i.e. cpumask.cbcpu), this function selects a fallback CPU and if
- * none found, returns -EINVAL.
*
* The parallelization callback function will run with BHs off.
* Note: Every object which is parallelized by padata_do_parallel
@@ -173,269 +139,36 @@ static void padata_parallel_worker(struct work_struct *parallel_work)
* Return: 0 on success or else negative error code.
*/
int padata_do_parallel(struct padata_shell *ps,
- struct padata_priv *padata, int *cb_cpu)
+ struct padata_priv *padata)
{
struct padata_instance *pinst = ps->pinst;
- int i, cpu, cpu_index, err;
- struct parallel_data *pd;
- struct padata_work *pw;
-
- rcu_read_lock_bh();
-
- pd = rcu_dereference_bh(ps->pd);
+ int err;

err = -EINVAL;
if (!(pinst->flags & PADATA_INIT) || pinst->flags & PADATA_INVALID)
goto out;

- if (!cpumask_test_cpu(*cb_cpu, pd->cpumask.cbcpu)) {
- if (cpumask_empty(pd->cpumask.cbcpu))
- goto out;
-
- /* Select an alternate fallback CPU and notify the caller. */
- cpu_index = *cb_cpu % cpumask_weight(pd->cpumask.cbcpu);
-
- cpu = cpumask_first(pd->cpumask.cbcpu);
- for (i = 0; i < cpu_index; i++)
- cpu = cpumask_next(cpu, pd->cpumask.cbcpu);
-
- *cb_cpu = cpu;
- }
-
err = -EBUSY;
if ((pinst->flags & PADATA_RESET))
goto out;

- refcount_inc(&pd->refcnt);
- padata->pd = pd;
- padata->cb_cpu = *cb_cpu;
-
- spin_lock(&padata_works_lock);
- padata->seq_nr = ++pd->seq_nr;
- pw = padata_work_alloc();
- spin_unlock(&padata_works_lock);
-
- if (!pw) {
- /* Maximum works limit exceeded, run in the current task. */
- padata->parallel(padata);
- }
-
- rcu_read_unlock_bh();
-
- if (pw) {
- padata_work_init(pw, padata_parallel_worker, padata, 0);
- queue_work(pinst->parallel_wq, &pw->pw_work);
- }
+ INIT_WORK(&padata->parallel_work, padata_parallel_worker);
+ INIT_WORK(&padata->serial_work, padata_serial_worker);
+ init_completion(&padata->parallel_done);
+ queue_work(pinst->serial_wq, &padata->serial_work);
+ queue_work(pinst->parallel_wq, &padata->parallel_work);

return 0;
out:
- rcu_read_unlock_bh();
-
return err;
}
EXPORT_SYMBOL(padata_do_parallel);

-/*
- * padata_find_next - Find the next object that needs serialization.
- *
- * Return:
- * * A pointer to the control struct of the next object that needs
- * serialization, if present in one of the percpu reorder queues.
- * * NULL, if the next object that needs serialization will
- * be parallel processed by another cpu and is not yet present in
- * the cpu's reorder queue.
- */
-static struct padata_priv *padata_find_next(struct parallel_data *pd,
- bool remove_object)
-{
- struct padata_priv *padata;
- struct padata_list *reorder;
- int cpu = pd->cpu;
-
- reorder = per_cpu_ptr(pd->reorder_list, cpu);
-
- spin_lock(&reorder->lock);
- if (list_empty(&reorder->list)) {
- spin_unlock(&reorder->lock);
- return NULL;
- }
-
- padata = list_entry(reorder->list.next, struct padata_priv, list);
-
- /*
- * Checks the rare case where two or more parallel jobs have hashed to
- * the same CPU and one of the later ones finishes first.
- */
- if (padata->seq_nr != pd->processed) {
- spin_unlock(&reorder->lock);
- return NULL;
- }
-
- if (remove_object) {
- list_del_init(&padata->list);
- ++pd->processed;
- pd->cpu = cpumask_next_wrap(cpu, pd->cpumask.pcpu, -1, false);
- }
-
- spin_unlock(&reorder->lock);
- return padata;
-}
-
-static void padata_reorder(struct parallel_data *pd)
-{
- struct padata_instance *pinst = pd->ps->pinst;
- int cb_cpu;
- struct padata_priv *padata;
- struct padata_serial_queue *squeue;
- struct padata_list *reorder;
-
- /*
- * We need to ensure that only one cpu can work on dequeueing of
- * the reorder queue the time. Calculating in which percpu reorder
- * queue the next object will arrive takes some time. A spinlock
- * would be highly contended. Also it is not clear in which order
- * the objects arrive to the reorder queues. So a cpu could wait to
- * get the lock just to notice that there is nothing to do at the
- * moment. Therefore we use a trylock and let the holder of the lock
- * care for all the objects enqueued during the holdtime of the lock.
- */
- if (!spin_trylock_bh(&pd->lock))
- return;
-
- while (1) {
- padata = padata_find_next(pd, true);
-
- /*
- * If the next object that needs serialization is parallel
- * processed by another cpu and is still on it's way to the
- * cpu's reorder queue, nothing to do for now.
- */
- if (!padata)
- break;
-
- cb_cpu = padata->cb_cpu;
- squeue = per_cpu_ptr(pd->squeue, cb_cpu);
-
- spin_lock(&squeue->serial.lock);
- list_add_tail(&padata->list, &squeue->serial.list);
- spin_unlock(&squeue->serial.lock);
-
- queue_work_on(cb_cpu, pinst->serial_wq, &squeue->work);
- }
-
- spin_unlock_bh(&pd->lock);
-
- /*
- * The next object that needs serialization might have arrived to
- * the reorder queues in the meantime.
- *
- * Ensure reorder queue is read after pd->lock is dropped so we see
- * new objects from another task in padata_do_serial. Pairs with
- * smp_mb in padata_do_serial.
- */
- smp_mb();
-
- reorder = per_cpu_ptr(pd->reorder_list, pd->cpu);
- if (!list_empty(&reorder->list) && padata_find_next(pd, false))
- queue_work(pinst->serial_wq, &pd->reorder_work);
-}
-
-static void invoke_padata_reorder(struct work_struct *work)
-{
- struct parallel_data *pd;
-
- local_bh_disable();
- pd = container_of(work, struct parallel_data, reorder_work);
- padata_reorder(pd);
- local_bh_enable();
-}
-
static void padata_serial_worker(struct work_struct *serial_work)
{
- struct padata_serial_queue *squeue;
- struct parallel_data *pd;
- LIST_HEAD(local_list);
- int cnt;
-
- local_bh_disable();
- squeue = container_of(serial_work, struct padata_serial_queue, work);
- pd = squeue->pd;
-
- spin_lock(&squeue->serial.lock);
- list_replace_init(&squeue->serial.list, &local_list);
- spin_unlock(&squeue->serial.lock);
-
- cnt = 0;
-
- while (!list_empty(&local_list)) {
- struct padata_priv *padata;
-
- padata = list_entry(local_list.next,
- struct padata_priv, list);
-
- list_del_init(&padata->list);
-
- padata->serial(padata);
- cnt++;
- }
- local_bh_enable();
-
- if (refcount_sub_and_test(cnt, &pd->refcnt))
- padata_free_pd(pd);
-}
-
-/**
- * padata_do_serial - padata serialization function
- *
- * @padata: object to be serialized.
- *
- * padata_do_serial must be called for every parallelized object.
- * The serialization callback function will run with BHs off.
- */
-void padata_do_serial(struct padata_priv *padata)
-{
- struct parallel_data *pd = padata->pd;
- int hashed_cpu = padata_cpu_hash(pd, padata->seq_nr);
- struct padata_list *reorder = per_cpu_ptr(pd->reorder_list, hashed_cpu);
- struct padata_priv *cur;
- struct list_head *pos;
-
- spin_lock(&reorder->lock);
- /* Sort in ascending order of sequence number. */
- list_for_each_prev(pos, &reorder->list) {
- cur = list_entry(pos, struct padata_priv, list);
- if (cur->seq_nr < padata->seq_nr)
- break;
- }
- list_add(&padata->list, pos);
- spin_unlock(&reorder->lock);
-
- /*
- * Ensure the addition to the reorder list is ordered correctly
- * with the trylock of pd->lock in padata_reorder. Pairs with smp_mb
- * in padata_reorder.
- */
- smp_mb();
-
- padata_reorder(pd);
-}
-EXPORT_SYMBOL(padata_do_serial);
-
-static int padata_setup_cpumasks(struct padata_instance *pinst)
-{
- struct workqueue_attrs *attrs;
- int err;
-
- attrs = alloc_workqueue_attrs();
- if (!attrs)
- return -ENOMEM;
-
- /* Restrict parallel_wq workers to pd->cpumask.pcpu. */
- cpumask_copy(attrs->cpumask, pinst->cpumask.pcpu);
- err = apply_workqueue_attrs(pinst->parallel_wq, attrs);
- free_workqueue_attrs(attrs);
-
- return err;
+ struct padata_priv *padata = container_of(serial_work, struct padata_priv, serial_work);
+ wait_for_completion(&padata->parallel_done);
+ padata->serial(padata);
}

static void __init padata_mt_helper(struct work_struct *w)
@@ -530,449 +263,11 @@ void __init padata_do_multithreaded(struct padata_mt_job *job)
padata_works_free(&works);
}

-static void __padata_list_init(struct padata_list *pd_list)
-{
- INIT_LIST_HEAD(&pd_list->list);
- spin_lock_init(&pd_list->lock);
-}
-
-/* Initialize all percpu queues used by serial workers */
-static void padata_init_squeues(struct parallel_data *pd)
-{
- int cpu;
- struct padata_serial_queue *squeue;
-
- for_each_cpu(cpu, pd->cpumask.cbcpu) {
- squeue = per_cpu_ptr(pd->squeue, cpu);
- squeue->pd = pd;
- __padata_list_init(&squeue->serial);
- INIT_WORK(&squeue->work, padata_serial_worker);
- }
-}
-
-/* Initialize per-CPU reorder lists */
-static void padata_init_reorder_list(struct parallel_data *pd)
-{
- int cpu;
- struct padata_list *list;
-
- for_each_cpu(cpu, pd->cpumask.pcpu) {
- list = per_cpu_ptr(pd->reorder_list, cpu);
- __padata_list_init(list);
- }
-}
-
-/* Allocate and initialize the internal cpumask dependend resources. */
-static struct parallel_data *padata_alloc_pd(struct padata_shell *ps)
-{
- struct padata_instance *pinst = ps->pinst;
- struct parallel_data *pd;
-
- pd = kzalloc(sizeof(struct parallel_data), GFP_KERNEL);
- if (!pd)
- goto err;
-
- pd->reorder_list = alloc_percpu(struct padata_list);
- if (!pd->reorder_list)
- goto err_free_pd;
-
- pd->squeue = alloc_percpu(struct padata_serial_queue);
- if (!pd->squeue)
- goto err_free_reorder_list;
-
- pd->ps = ps;
-
- if (!alloc_cpumask_var(&pd->cpumask.pcpu, GFP_KERNEL))
- goto err_free_squeue;
- if (!alloc_cpumask_var(&pd->cpumask.cbcpu, GFP_KERNEL))
- goto err_free_pcpu;
-
- cpumask_and(pd->cpumask.pcpu, pinst->cpumask.pcpu, cpu_online_mask);
- cpumask_and(pd->cpumask.cbcpu, pinst->cpumask.cbcpu, cpu_online_mask);
-
- padata_init_reorder_list(pd);
- padata_init_squeues(pd);
- pd->seq_nr = -1;
- refcount_set(&pd->refcnt, 1);
- spin_lock_init(&pd->lock);
- pd->cpu = cpumask_first(pd->cpumask.pcpu);
- INIT_WORK(&pd->reorder_work, invoke_padata_reorder);
-
- return pd;
-
-err_free_pcpu:
- free_cpumask_var(pd->cpumask.pcpu);
-err_free_squeue:
- free_percpu(pd->squeue);
-err_free_reorder_list:
- free_percpu(pd->reorder_list);
-err_free_pd:
- kfree(pd);
-err:
- return NULL;
-}
-
-static void padata_free_pd(struct parallel_data *pd)
-{
- free_cpumask_var(pd->cpumask.pcpu);
- free_cpumask_var(pd->cpumask.cbcpu);
- free_percpu(pd->reorder_list);
- free_percpu(pd->squeue);
- kfree(pd);
-}
-
static void __padata_start(struct padata_instance *pinst)
{
pinst->flags |= PADATA_INIT;
}

-static void __padata_stop(struct padata_instance *pinst)
-{
- if (!(pinst->flags & PADATA_INIT))
- return;
-
- pinst->flags &= ~PADATA_INIT;
-
- synchronize_rcu();
-}
-
-/* Replace the internal control structure with a new one. */
-static int padata_replace_one(struct padata_shell *ps)
-{
- struct parallel_data *pd_new;
-
- pd_new = padata_alloc_pd(ps);
- if (!pd_new)
- return -ENOMEM;
-
- ps->opd = rcu_dereference_protected(ps->pd, 1);
- rcu_assign_pointer(ps->pd, pd_new);
-
- return 0;
-}
-
-static int padata_replace(struct padata_instance *pinst)
-{
- struct padata_shell *ps;
- int err = 0;
-
- pinst->flags |= PADATA_RESET;
-
- list_for_each_entry(ps, &pinst->pslist, list) {
- err = padata_replace_one(ps);
- if (err)
- break;
- }
-
- synchronize_rcu();
-
- list_for_each_entry_continue_reverse(ps, &pinst->pslist, list)
- if (refcount_dec_and_test(&ps->opd->refcnt))
- padata_free_pd(ps->opd);
-
- pinst->flags &= ~PADATA_RESET;
-
- return err;
-}
-
-/* If cpumask contains no active cpu, we mark the instance as invalid. */
-static bool padata_validate_cpumask(struct padata_instance *pinst,
- const struct cpumask *cpumask)
-{
- if (!cpumask_intersects(cpumask, cpu_online_mask)) {
- pinst->flags |= PADATA_INVALID;
- return false;
- }
-
- pinst->flags &= ~PADATA_INVALID;
- return true;
-}
-
-static int __padata_set_cpumasks(struct padata_instance *pinst,
- cpumask_var_t pcpumask,
- cpumask_var_t cbcpumask)
-{
- int valid;
- int err;
-
- valid = padata_validate_cpumask(pinst, pcpumask);
- if (!valid) {
- __padata_stop(pinst);
- goto out_replace;
- }
-
- valid = padata_validate_cpumask(pinst, cbcpumask);
- if (!valid)
- __padata_stop(pinst);
-
-out_replace:
- cpumask_copy(pinst->cpumask.pcpu, pcpumask);
- cpumask_copy(pinst->cpumask.cbcpu, cbcpumask);
-
- err = padata_setup_cpumasks(pinst) ?: padata_replace(pinst);
-
- if (valid)
- __padata_start(pinst);
-
- return err;
-}
-
-/**
- * padata_set_cpumask - Sets specified by @cpumask_type cpumask to the value
- * equivalent to @cpumask.
- * @pinst: padata instance
- * @cpumask_type: PADATA_CPU_SERIAL or PADATA_CPU_PARALLEL corresponding
- * to parallel and serial cpumasks respectively.
- * @cpumask: the cpumask to use
- *
- * Return: 0 on success or negative error code
- */
-int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
- cpumask_var_t cpumask)
-{
- struct cpumask *serial_mask, *parallel_mask;
- int err = -EINVAL;
-
- cpus_read_lock();
- mutex_lock(&pinst->lock);
-
- switch (cpumask_type) {
- case PADATA_CPU_PARALLEL:
- serial_mask = pinst->cpumask.cbcpu;
- parallel_mask = cpumask;
- break;
- case PADATA_CPU_SERIAL:
- parallel_mask = pinst->cpumask.pcpu;
- serial_mask = cpumask;
- break;
- default:
- goto out;
- }
-
- err = __padata_set_cpumasks(pinst, parallel_mask, serial_mask);
-
-out:
- mutex_unlock(&pinst->lock);
- cpus_read_unlock();
-
- return err;
-}
-EXPORT_SYMBOL(padata_set_cpumask);
-
-#ifdef CONFIG_HOTPLUG_CPU
-
-static int __padata_add_cpu(struct padata_instance *pinst, int cpu)
-{
- int err = 0;
-
- if (cpumask_test_cpu(cpu, cpu_online_mask)) {
- err = padata_replace(pinst);
-
- if (padata_validate_cpumask(pinst, pinst->cpumask.pcpu) &&
- padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
- __padata_start(pinst);
- }
-
- return err;
-}
-
-static int __padata_remove_cpu(struct padata_instance *pinst, int cpu)
-{
- int err = 0;
-
- if (!cpumask_test_cpu(cpu, cpu_online_mask)) {
- if (!padata_validate_cpumask(pinst, pinst->cpumask.pcpu) ||
- !padata_validate_cpumask(pinst, pinst->cpumask.cbcpu))
- __padata_stop(pinst);
-
- err = padata_replace(pinst);
- }
-
- return err;
-}
-
-static inline int pinst_has_cpu(struct padata_instance *pinst, int cpu)
-{
- return cpumask_test_cpu(cpu, pinst->cpumask.pcpu) ||
- cpumask_test_cpu(cpu, pinst->cpumask.cbcpu);
-}
-
-static int padata_cpu_online(unsigned int cpu, struct hlist_node *node)
-{
- struct padata_instance *pinst;
- int ret;
-
- pinst = hlist_entry_safe(node, struct padata_instance, cpu_online_node);
- if (!pinst_has_cpu(pinst, cpu))
- return 0;
-
- mutex_lock(&pinst->lock);
- ret = __padata_add_cpu(pinst, cpu);
- mutex_unlock(&pinst->lock);
- return ret;
-}
-
-static int padata_cpu_dead(unsigned int cpu, struct hlist_node *node)
-{
- struct padata_instance *pinst;
- int ret;
-
- pinst = hlist_entry_safe(node, struct padata_instance, cpu_dead_node);
- if (!pinst_has_cpu(pinst, cpu))
- return 0;
-
- mutex_lock(&pinst->lock);
- ret = __padata_remove_cpu(pinst, cpu);
- mutex_unlock(&pinst->lock);
- return ret;
-}
-
-static enum cpuhp_state hp_online;
-#endif
-
-static void __padata_free(struct padata_instance *pinst)
-{
-#ifdef CONFIG_HOTPLUG_CPU
- cpuhp_state_remove_instance_nocalls(CPUHP_PADATA_DEAD,
- &pinst->cpu_dead_node);
- cpuhp_state_remove_instance_nocalls(hp_online, &pinst->cpu_online_node);
-#endif
-
- WARN_ON(!list_empty(&pinst->pslist));
-
- free_cpumask_var(pinst->cpumask.pcpu);
- free_cpumask_var(pinst->cpumask.cbcpu);
- destroy_workqueue(pinst->serial_wq);
- destroy_workqueue(pinst->parallel_wq);
- kfree(pinst);
-}
-
-#define kobj2pinst(_kobj) \
- container_of(_kobj, struct padata_instance, kobj)
-#define attr2pentry(_attr) \
- container_of(_attr, struct padata_sysfs_entry, attr)
-
-static void padata_sysfs_release(struct kobject *kobj)
-{
- struct padata_instance *pinst = kobj2pinst(kobj);
- __padata_free(pinst);
-}
-
-struct padata_sysfs_entry {
- struct attribute attr;
- ssize_t (*show)(struct padata_instance *, struct attribute *, char *);
- ssize_t (*store)(struct padata_instance *, struct attribute *,
- const char *, size_t);
-};
-
-static ssize_t show_cpumask(struct padata_instance *pinst,
- struct attribute *attr, char *buf)
-{
- struct cpumask *cpumask;
- ssize_t len;
-
- mutex_lock(&pinst->lock);
- if (!strcmp(attr->name, "serial_cpumask"))
- cpumask = pinst->cpumask.cbcpu;
- else
- cpumask = pinst->cpumask.pcpu;
-
- len = snprintf(buf, PAGE_SIZE, "%*pb\n",
- nr_cpu_ids, cpumask_bits(cpumask));
- mutex_unlock(&pinst->lock);
- return len < PAGE_SIZE ? len : -EINVAL;
-}
-
-static ssize_t store_cpumask(struct padata_instance *pinst,
- struct attribute *attr,
- const char *buf, size_t count)
-{
- cpumask_var_t new_cpumask;
- ssize_t ret;
- int mask_type;
-
- if (!alloc_cpumask_var(&new_cpumask, GFP_KERNEL))
- return -ENOMEM;
-
- ret = bitmap_parse(buf, count, cpumask_bits(new_cpumask),
- nr_cpumask_bits);
- if (ret < 0)
- goto out;
-
- mask_type = !strcmp(attr->name, "serial_cpumask") ?
- PADATA_CPU_SERIAL : PADATA_CPU_PARALLEL;
- ret = padata_set_cpumask(pinst, mask_type, new_cpumask);
- if (!ret)
- ret = count;
-
-out:
- free_cpumask_var(new_cpumask);
- return ret;
-}
-
-#define PADATA_ATTR_RW(_name, _show_name, _store_name) \
- static struct padata_sysfs_entry _name##_attr = \
- __ATTR(_name, 0644, _show_name, _store_name)
-#define PADATA_ATTR_RO(_name, _show_name) \
- static struct padata_sysfs_entry _name##_attr = \
- __ATTR(_name, 0400, _show_name, NULL)
-
-PADATA_ATTR_RW(serial_cpumask, show_cpumask, store_cpumask);
-PADATA_ATTR_RW(parallel_cpumask, show_cpumask, store_cpumask);
-
-/*
- * Padata sysfs provides the following objects:
- * serial_cpumask [RW] - cpumask for serial workers
- * parallel_cpumask [RW] - cpumask for parallel workers
- */
-static struct attribute *padata_default_attrs[] = {
- &serial_cpumask_attr.attr,
- &parallel_cpumask_attr.attr,
- NULL,
-};
-ATTRIBUTE_GROUPS(padata_default);
-
-static ssize_t padata_sysfs_show(struct kobject *kobj,
- struct attribute *attr, char *buf)
-{
- struct padata_instance *pinst;
- struct padata_sysfs_entry *pentry;
- ssize_t ret = -EIO;
-
- pinst = kobj2pinst(kobj);
- pentry = attr2pentry(attr);
- if (pentry->show)
- ret = pentry->show(pinst, attr, buf);
-
- return ret;
-}
-
-static ssize_t padata_sysfs_store(struct kobject *kobj, struct attribute *attr,
- const char *buf, size_t count)
-{
- struct padata_instance *pinst;
- struct padata_sysfs_entry *pentry;
- ssize_t ret = -EIO;
-
- pinst = kobj2pinst(kobj);
- pentry = attr2pentry(attr);
- if (pentry->show)
- ret = pentry->store(pinst, attr, buf, count);
-
- return ret;
-}
-
-static const struct sysfs_ops padata_sysfs_ops = {
- .show = padata_sysfs_show,
- .store = padata_sysfs_store,
-};
-
-static const struct kobj_type padata_attr_type = {
- .sysfs_ops = &padata_sysfs_ops,
- .default_groups = padata_default_groups,
- .release = padata_sysfs_release,
-};
-
/**
* padata_alloc - allocate and initialize a padata instance
* @name: used to identify the instance
@@ -986,57 +281,27 @@ struct padata_instance *padata_alloc(const char *name)
pinst = kzalloc(sizeof(struct padata_instance), GFP_KERNEL);
if (!pinst)
goto err;
-
- pinst->parallel_wq = alloc_workqueue("%s_parallel", WQ_UNBOUND, 0,
+ pr_info("%s:%d %s\n", __FILE__, __LINE__, __func__);
+ pinst->parallel_wq = alloc_workqueue("%s_parallel", WQ_CPU_INTENSIVE, 0,
name);
if (!pinst->parallel_wq)
goto err_free_inst;

- cpus_read_lock();
-
- pinst->serial_wq = alloc_workqueue("%s_serial", WQ_MEM_RECLAIM |
- WQ_CPU_INTENSIVE, 1, name);
+ pinst->serial_wq = alloc_ordered_workqueue ("%s_serial",
+ WQ_MEM_RECLAIM | WQ_FREEZABLE,
+ name);
if (!pinst->serial_wq)
- goto err_put_cpus;
-
- if (!alloc_cpumask_var(&pinst->cpumask.pcpu, GFP_KERNEL))
- goto err_free_serial_wq;
- if (!alloc_cpumask_var(&pinst->cpumask.cbcpu, GFP_KERNEL)) {
- free_cpumask_var(pinst->cpumask.pcpu);
- goto err_free_serial_wq;
- }
+ goto err_free_parallel_wq;

INIT_LIST_HEAD(&pinst->pslist);

- cpumask_copy(pinst->cpumask.pcpu, cpu_possible_mask);
- cpumask_copy(pinst->cpumask.cbcpu, cpu_possible_mask);
-
- if (padata_setup_cpumasks(pinst))
- goto err_free_masks;
-
__padata_start(pinst);

- kobject_init(&pinst->kobj, &padata_attr_type);
mutex_init(&pinst->lock);

-#ifdef CONFIG_HOTPLUG_CPU
- cpuhp_state_add_instance_nocalls_cpuslocked(hp_online,
- &pinst->cpu_online_node);
- cpuhp_state_add_instance_nocalls_cpuslocked(CPUHP_PADATA_DEAD,
- &pinst->cpu_dead_node);
-#endif
-
- cpus_read_unlock();
-
return pinst;

-err_free_masks:
- free_cpumask_var(pinst->cpumask.pcpu);
- free_cpumask_var(pinst->cpumask.cbcpu);
-err_free_serial_wq:
- destroy_workqueue(pinst->serial_wq);
-err_put_cpus:
- cpus_read_unlock();
+err_free_parallel_wq:
destroy_workqueue(pinst->parallel_wq);
err_free_inst:
kfree(pinst);
@@ -1052,7 +317,11 @@ EXPORT_SYMBOL(padata_alloc);
*/
void padata_free(struct padata_instance *pinst)
{
- kobject_put(&pinst->kobj);
+ WARN_ON(!list_empty(&pinst->pslist));
+
+ destroy_workqueue(pinst->serial_wq);
+ destroy_workqueue(pinst->parallel_wq);
+ kfree(pinst);
}
EXPORT_SYMBOL(padata_free);

@@ -1065,7 +334,6 @@ EXPORT_SYMBOL(padata_free);
*/
struct padata_shell *padata_alloc_shell(struct padata_instance *pinst)
{
- struct parallel_data *pd;
struct padata_shell *ps;

ps = kzalloc(sizeof(*ps), GFP_KERNEL);
@@ -1074,22 +342,12 @@ struct padata_shell *padata_alloc_shell(struct padata_instance *pinst)

ps->pinst = pinst;

- cpus_read_lock();
- pd = padata_alloc_pd(ps);
- cpus_read_unlock();
-
- if (!pd)
- goto out_free_ps;
-
mutex_lock(&pinst->lock);
- RCU_INIT_POINTER(ps->pd, pd);
list_add(&ps->list, &pinst->pslist);
mutex_unlock(&pinst->lock);

return ps;

-out_free_ps:
- kfree(ps);
out:
return NULL;
}
@@ -1107,7 +365,6 @@ void padata_free_shell(struct padata_shell *ps)

mutex_lock(&ps->pinst->lock);
list_del(&ps->list);
- padata_free_pd(rcu_dereference_protected(ps->pd, 1));
mutex_unlock(&ps->pinst->lock);

kfree(ps);
@@ -1117,20 +374,6 @@ EXPORT_SYMBOL(padata_free_shell);
void __init padata_init(void)
{
unsigned int i, possible_cpus;
-#ifdef CONFIG_HOTPLUG_CPU
- int ret;
-
- ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, "padata:online",
- padata_cpu_online, NULL);
- if (ret < 0)
- goto err;
- hp_online = ret;
-
- ret = cpuhp_setup_state_multi(CPUHP_PADATA_DEAD, "padata:dead",
- NULL, padata_cpu_dead);
- if (ret < 0)
- goto remove_online_state;
-#endif

possible_cpus = num_possible_cpus();
padata_works = kmalloc_array(possible_cpus, sizeof(struct padata_work),
@@ -1144,11 +387,5 @@ void __init padata_init(void)
return;

remove_dead_state:
-#ifdef CONFIG_HOTPLUG_CPU
- cpuhp_remove_multi_state(CPUHP_PADATA_DEAD);
-remove_online_state:
- cpuhp_remove_multi_state(hp_online);
-err:
-#endif
pr_warn("padata: initialization failed\n");
}
--
2.40.0