125 lines
3.0 KiB
Diff
125 lines
3.0 KiB
Diff
From: Thomas Gleixner <tglx@linutronix.de>
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Date: Tue, 14 Jul 2015 14:26:34 +0200
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Subject: idr: Use local lock instead of preempt enable/disable
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.4/patches-4.4-rt2.tar.xz
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We need to protect the per cpu variable and prevent migration.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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include/linux/idr.h | 4 ++++
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lib/idr.c | 43 +++++++++++++++++++++++++++++++++++++------
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2 files changed, 41 insertions(+), 6 deletions(-)
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--- a/include/linux/idr.h
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+++ b/include/linux/idr.h
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@@ -95,10 +95,14 @@ bool idr_is_empty(struct idr *idp);
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* Each idr_preload() should be matched with an invocation of this
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* function. See idr_preload() for details.
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*/
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+#ifdef CONFIG_PREEMPT_RT_FULL
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+void idr_preload_end(void);
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+#else
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static inline void idr_preload_end(void)
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{
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preempt_enable();
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}
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+#endif
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/**
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* idr_find - return pointer for given id
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--- a/lib/idr.c
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+++ b/lib/idr.c
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@@ -30,6 +30,7 @@
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#include <linux/idr.h>
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#include <linux/spinlock.h>
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#include <linux/percpu.h>
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+#include <linux/locallock.h>
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#define MAX_IDR_SHIFT (sizeof(int) * 8 - 1)
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#define MAX_IDR_BIT (1U << MAX_IDR_SHIFT)
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@@ -45,6 +46,37 @@ static DEFINE_PER_CPU(struct idr_layer *
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static DEFINE_PER_CPU(int, idr_preload_cnt);
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static DEFINE_SPINLOCK(simple_ida_lock);
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+#ifdef CONFIG_PREEMPT_RT_FULL
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+static DEFINE_LOCAL_IRQ_LOCK(idr_lock);
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+
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+static inline void idr_preload_lock(void)
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+{
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+ local_lock(idr_lock);
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+}
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+
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+static inline void idr_preload_unlock(void)
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+{
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+ local_unlock(idr_lock);
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+}
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+
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+void idr_preload_end(void)
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+{
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+ idr_preload_unlock();
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+}
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+EXPORT_SYMBOL(idr_preload_end);
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+#else
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+static inline void idr_preload_lock(void)
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+{
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+ preempt_disable();
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+}
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+
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+static inline void idr_preload_unlock(void)
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+{
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+ preempt_enable();
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+}
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+#endif
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+
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+
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/* the maximum ID which can be allocated given idr->layers */
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static int idr_max(int layers)
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{
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@@ -115,14 +147,14 @@ static struct idr_layer *idr_layer_alloc
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* context. See idr_preload() for details.
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*/
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if (!in_interrupt()) {
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- preempt_disable();
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+ idr_preload_lock();
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new = __this_cpu_read(idr_preload_head);
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if (new) {
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__this_cpu_write(idr_preload_head, new->ary[0]);
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__this_cpu_dec(idr_preload_cnt);
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new->ary[0] = NULL;
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}
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- preempt_enable();
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+ idr_preload_unlock();
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if (new)
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return new;
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}
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@@ -366,7 +398,6 @@ static void idr_fill_slot(struct idr *id
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idr_mark_full(pa, id);
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}
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-
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/**
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* idr_preload - preload for idr_alloc()
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* @gfp_mask: allocation mask to use for preloading
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@@ -401,7 +432,7 @@ void idr_preload(gfp_t gfp_mask)
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WARN_ON_ONCE(in_interrupt());
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might_sleep_if(gfpflags_allow_blocking(gfp_mask));
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- preempt_disable();
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+ idr_preload_lock();
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/*
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* idr_alloc() is likely to succeed w/o full idr_layer buffer and
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@@ -413,9 +444,9 @@ void idr_preload(gfp_t gfp_mask)
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while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) {
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struct idr_layer *new;
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- preempt_enable();
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+ idr_preload_unlock();
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new = kmem_cache_zalloc(idr_layer_cache, gfp_mask);
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- preempt_disable();
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+ idr_preload_lock();
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if (!new)
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break;
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