From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/block/blk-ioc.c | 97 +++++++++++++++++-------------------------------
1 files changed, 35 insertions(+), 62 deletions(-)
diff --git a/kernel/block/blk-ioc.c b/kernel/block/blk-ioc.c
index 48089f5..57299f8 100644
--- a/kernel/block/blk-ioc.c
+++ b/kernel/block/blk-ioc.c
@@ -9,7 +9,6 @@
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/sched/task.h>
-#include <linux/delay.h>
#include "blk.h"
@@ -29,7 +28,6 @@
BUG_ON(atomic_long_read(&ioc->refcount) <= 0);
atomic_long_inc(&ioc->refcount);
}
-EXPORT_SYMBOL(get_io_context);
static void icq_free_icq_rcu(struct rcu_head *head)
{
@@ -49,10 +47,8 @@
if (icq->flags & ICQ_EXITED)
return;
- if (et->uses_mq && et->ops.mq.exit_icq)
- et->ops.mq.exit_icq(icq);
- else if (!et->uses_mq && et->ops.sq.elevator_exit_icq_fn)
- et->ops.sq.elevator_exit_icq_fn(icq);
+ if (et->ops.exit_icq)
+ et->ops.exit_icq(icq);
icq->flags |= ICQ_EXITED;
}
@@ -100,32 +96,38 @@
{
struct io_context *ioc = container_of(work, struct io_context,
release_work);
- unsigned long flags;
-
- /*
- * Exiting icq may call into put_io_context() through elevator
- * which will trigger lockdep warning. The ioc's are guaranteed to
- * be different, use a different locking subclass here. Use
- * irqsave variant as there's no spin_lock_irq_nested().
- */
- spin_lock_irqsave_nested(&ioc->lock, flags, 1);
+ spin_lock_irq(&ioc->lock);
while (!hlist_empty(&ioc->icq_list)) {
struct io_cq *icq = hlist_entry(ioc->icq_list.first,
struct io_cq, ioc_node);
struct request_queue *q = icq->q;
- if (spin_trylock(q->queue_lock)) {
+ if (spin_trylock(&q->queue_lock)) {
ioc_destroy_icq(icq);
- spin_unlock(q->queue_lock);
+ spin_unlock(&q->queue_lock);
} else {
- spin_unlock_irqrestore(&ioc->lock, flags);
- cpu_chill();
- spin_lock_irqsave_nested(&ioc->lock, flags, 1);
+ /* Make sure q and icq cannot be freed. */
+ rcu_read_lock();
+
+ /* Re-acquire the locks in the correct order. */
+ spin_unlock(&ioc->lock);
+ spin_lock(&q->queue_lock);
+ spin_lock(&ioc->lock);
+
+ /*
+ * The icq may have been destroyed when the ioc lock
+ * was released.
+ */
+ if (!(icq->flags & ICQ_DESTROYED))
+ ioc_destroy_icq(icq);
+
+ spin_unlock(&q->queue_lock);
+ rcu_read_unlock();
}
}
- spin_unlock_irqrestore(&ioc->lock, flags);
+ spin_unlock_irq(&ioc->lock);
kmem_cache_free(iocontext_cachep, ioc);
}
@@ -164,7 +166,6 @@
if (free_ioc)
kmem_cache_free(iocontext_cachep, ioc);
}
-EXPORT_SYMBOL(put_io_context);
/**
* put_io_context_active - put active reference on ioc
@@ -175,8 +176,6 @@
*/
void put_io_context_active(struct io_context *ioc)
{
- struct elevator_type *et;
- unsigned long flags;
struct io_cq *icq;
if (!atomic_dec_and_test(&ioc->active_ref)) {
@@ -184,32 +183,14 @@
return;
}
- /*
- * Need ioc lock to walk icq_list and q lock to exit icq. Perform
- * reverse double locking. Read comment in ioc_release_fn() for
- * explanation on the nested locking annotation.
- */
-retry:
- spin_lock_irqsave_nested(&ioc->lock, flags, 1);
+ spin_lock_irq(&ioc->lock);
hlist_for_each_entry(icq, &ioc->icq_list, ioc_node) {
if (icq->flags & ICQ_EXITED)
continue;
- et = icq->q->elevator->type;
- if (et->uses_mq) {
- ioc_exit_icq(icq);
- } else {
- if (spin_trylock(icq->q->queue_lock)) {
- ioc_exit_icq(icq);
- spin_unlock(icq->q->queue_lock);
- } else {
- spin_unlock_irqrestore(&ioc->lock, flags);
- cpu_chill();
- goto retry;
- }
- }
+ ioc_exit_icq(icq);
}
- spin_unlock_irqrestore(&ioc->lock, flags);
+ spin_unlock_irq(&ioc->lock);
put_io_context(ioc);
}
@@ -235,7 +216,7 @@
rcu_read_lock();
while (!list_empty(icq_list)) {
struct io_cq *icq = list_entry(icq_list->next,
- struct io_cq, q_node);
+ struct io_cq, q_node);
struct io_context *ioc = icq->ioc;
spin_lock_irqsave(&ioc->lock, flags);
@@ -259,16 +240,11 @@
{
LIST_HEAD(icq_list);
- spin_lock_irq(q->queue_lock);
+ spin_lock_irq(&q->queue_lock);
list_splice_init(&q->icq_list, &icq_list);
+ spin_unlock_irq(&q->queue_lock);
- if (q->mq_ops) {
- spin_unlock_irq(q->queue_lock);
- __ioc_clear_queue(&icq_list);
- } else {
- __ioc_clear_queue(&icq_list);
- spin_unlock_irq(q->queue_lock);
- }
+ __ioc_clear_queue(&icq_list);
}
int create_task_io_context(struct task_struct *task, gfp_t gfp_flags, int node)
@@ -344,7 +320,6 @@
return NULL;
}
-EXPORT_SYMBOL(get_task_io_context);
/**
* ioc_lookup_icq - lookup io_cq from ioc
@@ -358,7 +333,7 @@
{
struct io_cq *icq;
- lockdep_assert_held(q->queue_lock);
+ lockdep_assert_held(&q->queue_lock);
/*
* icq's are indexed from @ioc using radix tree and hint pointer,
@@ -417,16 +392,14 @@
INIT_HLIST_NODE(&icq->ioc_node);
/* lock both q and ioc and try to link @icq */
- spin_lock_irq(q->queue_lock);
+ spin_lock_irq(&q->queue_lock);
spin_lock(&ioc->lock);
if (likely(!radix_tree_insert(&ioc->icq_tree, q->id, icq))) {
hlist_add_head(&icq->ioc_node, &ioc->icq_list);
list_add(&icq->q_node, &q->icq_list);
- if (et->uses_mq && et->ops.mq.init_icq)
- et->ops.mq.init_icq(icq);
- else if (!et->uses_mq && et->ops.sq.elevator_init_icq_fn)
- et->ops.sq.elevator_init_icq_fn(icq);
+ if (et->ops.init_icq)
+ et->ops.init_icq(icq);
} else {
kmem_cache_free(et->icq_cache, icq);
icq = ioc_lookup_icq(ioc, q);
@@ -435,7 +408,7 @@
}
spin_unlock(&ioc->lock);
- spin_unlock_irq(q->queue_lock);
+ spin_unlock_irq(&q->queue_lock);
radix_tree_preload_end();
return icq;
}
--
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