Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
index 9f96fa7..4f6c6eb 100644
--- a/lib/percpu-refcount.c
+++ b/lib/percpu-refcount.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
#define pr_fmt(fmt) "%s: " fmt "\n", __func__
#include <linux/kernel.h>
@@ -69,11 +70,14 @@
return -ENOMEM;
ref->force_atomic = flags & PERCPU_REF_INIT_ATOMIC;
+ ref->allow_reinit = flags & PERCPU_REF_ALLOW_REINIT;
- if (flags & (PERCPU_REF_INIT_ATOMIC | PERCPU_REF_INIT_DEAD))
+ if (flags & (PERCPU_REF_INIT_ATOMIC | PERCPU_REF_INIT_DEAD)) {
ref->percpu_count_ptr |= __PERCPU_REF_ATOMIC;
- else
+ ref->allow_reinit = true;
+ } else {
start_count += PERCPU_COUNT_BIAS;
+ }
if (flags & PERCPU_REF_INIT_DEAD)
ref->percpu_count_ptr |= __PERCPU_REF_DEAD;
@@ -119,6 +123,9 @@
ref->confirm_switch = NULL;
wake_up_all(&percpu_ref_switch_waitq);
+ if (!ref->allow_reinit)
+ percpu_ref_exit(ref);
+
/* drop ref from percpu_ref_switch_to_atomic() */
percpu_ref_put(ref);
}
@@ -151,7 +158,7 @@
atomic_long_add((long)count - PERCPU_COUNT_BIAS, &ref->count);
WARN_ONCE(atomic_long_read(&ref->count) <= 0,
- "percpu ref (%pf) <= 0 (%ld) after switching to atomic",
+ "percpu ref (%ps) <= 0 (%ld) after switching to atomic",
ref->release, atomic_long_read(&ref->count));
/* @ref is viewed as dead on all CPUs, send out switch confirmation */
@@ -181,7 +188,7 @@
ref->confirm_switch = confirm_switch ?: percpu_ref_noop_confirm_switch;
percpu_ref_get(ref); /* put after confirmation */
- call_rcu_sched(&ref->rcu, percpu_ref_switch_to_atomic_rcu);
+ call_rcu(&ref->rcu, percpu_ref_switch_to_atomic_rcu);
}
static void __percpu_ref_switch_to_percpu(struct percpu_ref *ref)
@@ -194,6 +201,9 @@
if (!(ref->percpu_count_ptr & __PERCPU_REF_ATOMIC))
return;
+ if (WARN_ON_ONCE(!ref->allow_reinit))
+ return;
+
atomic_long_add(PERCPU_COUNT_BIAS, &ref->count);
/*
@@ -333,7 +343,7 @@
spin_lock_irqsave(&percpu_ref_switch_lock, flags);
WARN_ONCE(ref->percpu_count_ptr & __PERCPU_REF_DEAD,
- "%s called more than once on %pf!", __func__, ref->release);
+ "%s called more than once on %ps!", __func__, ref->release);
ref->percpu_count_ptr |= __PERCPU_REF_DEAD;
__percpu_ref_switch_mode(ref, confirm_kill);
@@ -356,11 +366,35 @@
*/
void percpu_ref_reinit(struct percpu_ref *ref)
{
+ WARN_ON_ONCE(!percpu_ref_is_zero(ref));
+
+ percpu_ref_resurrect(ref);
+}
+EXPORT_SYMBOL_GPL(percpu_ref_reinit);
+
+/**
+ * percpu_ref_resurrect - modify a percpu refcount from dead to live
+ * @ref: perpcu_ref to resurrect
+ *
+ * Modify @ref so that it's in the same state as before percpu_ref_kill() was
+ * called. @ref must be dead but must not yet have exited.
+ *
+ * If @ref->release() frees @ref then the caller is responsible for
+ * guaranteeing that @ref->release() does not get called while this
+ * function is in progress.
+ *
+ * Note that percpu_ref_tryget[_live]() are safe to perform on @ref while
+ * this function is in progress.
+ */
+void percpu_ref_resurrect(struct percpu_ref *ref)
+{
+ unsigned long __percpu *percpu_count;
unsigned long flags;
spin_lock_irqsave(&percpu_ref_switch_lock, flags);
- WARN_ON_ONCE(!percpu_ref_is_zero(ref));
+ WARN_ON_ONCE(!(ref->percpu_count_ptr & __PERCPU_REF_DEAD));
+ WARN_ON_ONCE(__ref_is_percpu(ref, &percpu_count));
ref->percpu_count_ptr &= ~__PERCPU_REF_DEAD;
percpu_ref_get(ref);
@@ -368,4 +402,4 @@
spin_unlock_irqrestore(&percpu_ref_switch_lock, flags);
}
-EXPORT_SYMBOL_GPL(percpu_ref_reinit);
+EXPORT_SYMBOL_GPL(percpu_ref_resurrect);