[ANNOUNCE] 3.6.11-rt26

From: Thomas Gleixner
Date: Mon Feb 04 2013 - 09:58:33 EST

Dear RT Folks,

I'm pleased to announce the 3.6.11-rt26 release.

Changes since 3.6.11-rt25:

1) Fix the RT highmem implementation on x86

2) Support highmem + RT on ARM

3) Fix an one off error in the generic highmem code (upstream fix
did not make it into 3.6.stable)

4) Upstream SLUB fixes (Christoph Lameter)

5) Fix a few RT issues in mmc and amba drivers

6) Initialize local locks in mm/swap.c early

7) Use simple wait queues for completions. This is a performance
improvement.

Completions do not have complex callbacks and the wakeup path is
disabling interrupts anyway. So using simple wait locks with the
raw spinlock is not a latency problem, but the "sleeping lock"
in the normal waitqueue is a source for lock bouncing:

T1 T2
lock(WQ)
wakeup(T2)
---> preemption
lock(WQ)
pi_boost(T1)
wait_for_lock(WQ)
unlock(WQ)
deboost(T1)
---> preemption
....

The simple waitqueue reduces this to:

T1 T2
raw_lock(WQ)
wakeup(T2)
raw_unlock(WQ)
---> preemption
raw_lock(WQ)
....

@Steven: Sorry, I forgot the stable tags on:
drivers-tty-pl011-irq-disable-madness.patch
mmci-remove-bogus-irq-save.patch
idle-state.patch
might-sleep-check-for-idle.patch
mm-swap-fix-initialization.patch

I'm still digging through my mail backlog, so I have not yet decided
whether this is the last RT release for 3.6.


The delta patch against 3.6.11-rt25 is appended below and can be found
here:

http://www.kernel.org/pub/linux/kernel/projects/rt/3.6/incr/patch-3.6.11-rt25-rt26.patch.xz

The RT patch against 3.6.11 can be found here:

http://www.kernel.org/pub/linux/kernel/projects/rt/3.6/patch-3.6.11-rt26.patch.xz

The split quilt queue is available at:

http://www.kernel.org/pub/linux/kernel/projects/rt/3.6/patches-3.6.11-rt26.tar.xz

Enjoy,

tglx

------------->
Index: linux-stable/arch/arm/Kconfig
===================================================================
--- linux-stable.orig/arch/arm/Kconfig
+++ linux-stable/arch/arm/Kconfig
@@ -1749,7 +1749,7 @@ config HAVE_ARCH_PFN_VALID

config HIGHMEM
bool "High Memory Support"
- depends on MMU && !PREEMPT_RT_FULL
+ depends on MMU
help
The address space of ARM processors is only 4 Gigabytes large
and it has to accommodate user address space, kernel address
Index: linux-stable/arch/x86/mm/highmem_32.c
===================================================================
--- linux-stable.orig/arch/x86/mm/highmem_32.c
+++ linux-stable/arch/x86/mm/highmem_32.c
@@ -21,6 +21,7 @@ void kunmap(struct page *page)
}
EXPORT_SYMBOL(kunmap);

+#ifndef CONFIG_PREEMPT_RT_FULL
/*
* kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
* no global lock is needed and because the kmap code must perform a global TLB
@@ -115,6 +116,7 @@ struct page *kmap_atomic_to_page(void *p
return pte_page(*pte);
}
EXPORT_SYMBOL(kmap_atomic_to_page);
+#endif

void __init set_highmem_pages_init(void)
{
Index: linux-stable/include/linux/wait-simple.h
===================================================================
--- linux-stable.orig/include/linux/wait-simple.h
+++ linux-stable/include/linux/wait-simple.h
@@ -22,12 +22,14 @@ struct swait_head {
struct list_head list;
};

-#define DEFINE_SWAIT_HEAD(name) \
- struct swait_head name = { \
+#define SWAIT_HEAD_INITIALIZER(name) { \
.lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \
.list = LIST_HEAD_INIT((name).list), \
}

+#define DEFINE_SWAIT_HEAD(name) \
+ struct swait_head name = SWAIT_HEAD_INITIALIZER(name)
+
extern void __init_swait_head(struct swait_head *h, struct lock_class_key *key);

#define init_swait_head(swh) \
@@ -40,59 +42,25 @@ extern void __init_swait_head(struct swa
/*
* Waiter functions
*/
-static inline bool swaiter_enqueued(struct swaiter *w)
-{
- return w->task != NULL;
-}
-
+extern void swait_prepare_locked(struct swait_head *head, struct swaiter *w);
extern void swait_prepare(struct swait_head *head, struct swaiter *w, int state);
+extern void swait_finish_locked(struct swait_head *head, struct swaiter *w);
extern void swait_finish(struct swait_head *head, struct swaiter *w);

/*
- * Adds w to head->list. Must be called with head->lock locked.
- */
-static inline void __swait_enqueue(struct swait_head *head, struct swaiter *w)
-{
- list_add(&w->node, &head->list);
-}
-
-/*
- * Removes w from head->list. Must be called with head->lock locked.
- */
-static inline void __swait_dequeue(struct swaiter *w)
-{
- list_del_init(&w->node);
-}
-
-/*
- * Check whether a head has waiters enqueued
- */
-static inline bool swait_head_has_waiters(struct swait_head *h)
-{
- return !list_empty(&h->list);
-}
-
-/*
* Wakeup functions
*/
-extern int __swait_wake(struct swait_head *head, unsigned int state);
+extern unsigned int __swait_wake(struct swait_head *head, unsigned int state, unsigned int num);
+extern unsigned int __swait_wake_locked(struct swait_head *head, unsigned int state, unsigned int num);

-static inline int swait_wake(struct swait_head *head)
-{
- return swait_head_has_waiters(head) ?
- __swait_wake(head, TASK_NORMAL) : 0;
-}
-
-static inline int swait_wake_interruptible(struct swait_head *head)
-{
- return swait_head_has_waiters(head) ?
- __swait_wake(head, TASK_INTERRUPTIBLE) : 0;
-}
+#define swait_wake(head) __swait_wake(head, TASK_NORMAL, 1)
+#define swait_wake_interruptible(head) __swait_wake(head, TASK_INTERRUPTIBLE, 1)
+#define swait_wake_all(head) __swait_wake(head, TASK_NORMAL, 0)
+#define swait_wake_all_interruptible(head) __swait_wake(head, TASK_INTERRUPTIBLE, 0)

/*
* Event API
*/
-
#define __swait_event(wq, condition) \
do { \
DEFINE_SWAITER(__wait); \
Index: linux-stable/kernel/sched/core.c
===================================================================
--- linux-stable.orig/kernel/sched/core.c
+++ linux-stable/kernel/sched/core.c
@@ -3959,10 +3959,10 @@ void complete(struct completion *x)
{
unsigned long flags;

- spin_lock_irqsave(&x->wait.lock, flags);
+ raw_spin_lock_irqsave(&x->wait.lock, flags);
x->done++;
- __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
- spin_unlock_irqrestore(&x->wait.lock, flags);
+ __swait_wake_locked(&x->wait, TASK_NORMAL, 1);
+ raw_spin_unlock_irqrestore(&x->wait.lock, flags);
}
EXPORT_SYMBOL(complete);

@@ -3979,10 +3979,10 @@ void complete_all(struct completion *x)
{
unsigned long flags;

- spin_lock_irqsave(&x->wait.lock, flags);
+ raw_spin_lock_irqsave(&x->wait.lock, flags);
x->done += UINT_MAX/2;
- __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
- spin_unlock_irqrestore(&x->wait.lock, flags);
+ __swait_wake_locked(&x->wait, TASK_NORMAL, 0);
+ raw_spin_unlock_irqrestore(&x->wait.lock, flags);
}
EXPORT_SYMBOL(complete_all);

@@ -3990,20 +3990,20 @@ static inline long __sched
do_wait_for_common(struct completion *x, long timeout, int state)
{
if (!x->done) {
- DECLARE_WAITQUEUE(wait, current);
+ DEFINE_SWAITER(wait);

- __add_wait_queue_tail_exclusive(&x->wait, &wait);
+ swait_prepare_locked(&x->wait, &wait);
do {
if (signal_pending_state(state, current)) {
timeout = -ERESTARTSYS;
break;
}
__set_current_state(state);
- spin_unlock_irq(&x->wait.lock);
+ raw_spin_unlock_irq(&x->wait.lock);
timeout = schedule_timeout(timeout);
- spin_lock_irq(&x->wait.lock);
+ raw_spin_lock_irq(&x->wait.lock);
} while (!x->done && timeout);
- __remove_wait_queue(&x->wait, &wait);
+ swait_finish_locked(&x->wait, &wait);
if (!x->done)
return timeout;
}
@@ -4016,9 +4016,9 @@ wait_for_common(struct completion *x, lo
{
might_sleep();

- spin_lock_irq(&x->wait.lock);
+ raw_spin_lock_irq(&x->wait.lock);
timeout = do_wait_for_common(x, timeout, state);
- spin_unlock_irq(&x->wait.lock);
+ raw_spin_unlock_irq(&x->wait.lock);
return timeout;
}

@@ -4149,12 +4149,12 @@ bool try_wait_for_completion(struct comp
unsigned long flags;
int ret = 1;

- spin_lock_irqsave(&x->wait.lock, flags);
+ raw_spin_lock_irqsave(&x->wait.lock, flags);
if (!x->done)
ret = 0;
else
x->done--;
- spin_unlock_irqrestore(&x->wait.lock, flags);
+ raw_spin_unlock_irqrestore(&x->wait.lock, flags);
return ret;
}
EXPORT_SYMBOL(try_wait_for_completion);
@@ -4172,10 +4172,10 @@ bool completion_done(struct completion *
unsigned long flags;
int ret = 1;

- spin_lock_irqsave(&x->wait.lock, flags);
+ raw_spin_lock_irqsave(&x->wait.lock, flags);
if (!x->done)
ret = 0;
- spin_unlock_irqrestore(&x->wait.lock, flags);
+ raw_spin_unlock_irqrestore(&x->wait.lock, flags);
return ret;
}
EXPORT_SYMBOL(completion_done);
@@ -5410,6 +5410,7 @@ void __cpuinit init_idle(struct task_str
rcu_read_unlock();

rq->curr = rq->idle = idle;
+ idle->on_rq = 1;
#if defined(CONFIG_SMP)
idle->on_cpu = 1;
#endif
@@ -7782,7 +7783,8 @@ void __might_sleep(const char *file, int
static unsigned long prev_jiffy; /* ratelimiting */

rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
- if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
+ if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
+ !is_idle_task(current)) ||
system_state != SYSTEM_RUNNING || oops_in_progress)
return;
if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
Index: linux-stable/kernel/wait-simple.c
===================================================================
--- linux-stable.orig/kernel/wait-simple.c
+++ linux-stable/kernel/wait-simple.c
@@ -12,6 +12,24 @@
#include <linux/sched.h>
#include <linux/wait-simple.h>

+/* Adds w to head->list. Must be called with head->lock locked. */
+static inline void __swait_enqueue(struct swait_head *head, struct swaiter *w)
+{
+ list_add(&w->node, &head->list);
+}
+
+/* Removes w from head->list. Must be called with head->lock locked. */
+static inline void __swait_dequeue(struct swaiter *w)
+{
+ list_del_init(&w->node);
+}
+
+/* Check whether a head has waiters enqueued */
+static inline bool swait_head_has_waiters(struct swait_head *h)
+{
+ return !list_empty(&h->list);
+}
+
void __init_swait_head(struct swait_head *head, struct lock_class_key *key)
{
raw_spin_lock_init(&head->lock);
@@ -20,19 +38,31 @@ void __init_swait_head(struct swait_head
}
EXPORT_SYMBOL_GPL(__init_swait_head);

+void swait_prepare_locked(struct swait_head *head, struct swaiter *w)
+{
+ w->task = current;
+ if (list_empty(&w->node))
+ __swait_enqueue(head, w);
+}
+
void swait_prepare(struct swait_head *head, struct swaiter *w, int state)
{
unsigned long flags;

raw_spin_lock_irqsave(&head->lock, flags);
- w->task = current;
- if (list_empty(&w->node))
- __swait_enqueue(head, w);
- set_current_state(state);
+ swait_prepare_locked(head, w);
+ __set_current_state(state);
raw_spin_unlock_irqrestore(&head->lock, flags);
}
EXPORT_SYMBOL_GPL(swait_prepare);

+void swait_finish_locked(struct swait_head *head, struct swaiter *w)
+{
+ __set_current_state(TASK_RUNNING);
+ if (w->task)
+ __swait_dequeue(w);
+}
+
void swait_finish(struct swait_head *head, struct swaiter *w)
{
unsigned long flags;
@@ -46,22 +76,43 @@ void swait_finish(struct swait_head *hea
}
EXPORT_SYMBOL_GPL(swait_finish);

-int __swait_wake(struct swait_head *head, unsigned int state)
+unsigned int
+__swait_wake_locked(struct swait_head *head, unsigned int state, unsigned int num)
{
struct swaiter *curr, *next;
- unsigned long flags;
int woken = 0;

- raw_spin_lock_irqsave(&head->lock, flags);
-
list_for_each_entry_safe(curr, next, &head->list, node) {
if (wake_up_state(curr->task, state)) {
__swait_dequeue(curr);
+ /*
+ * The waiting task can free the waiter as
+ * soon as curr->task = NULL is written,
+ * without taking any locks. A memory barrier
+ * is required here to prevent the following
+ * store to curr->task from getting ahead of
+ * the dequeue operation.
+ */
+ smp_wmb();
curr->task = NULL;
- woken++;
+ if (++woken == num)
+ break;
}
}
+ return woken;
+}
+
+unsigned int
+__swait_wake(struct swait_head *head, unsigned int state, unsigned int num)
+{
+ unsigned long flags;
+ int woken;

+ if (!swait_head_has_waiters(head))
+ return 0;
+
+ raw_spin_lock_irqsave(&head->lock, flags);
+ woken = __swait_wake_locked(head, state, num);
raw_spin_unlock_irqrestore(&head->lock, flags);
return woken;
}
Index: linux-stable/localversion-rt
===================================================================
--- linux-stable.orig/localversion-rt
+++ linux-stable/localversion-rt
@@ -1 +1 @@
--rt25
+-rt26
Index: linux-stable/mm/memory.c
===================================================================
--- linux-stable.orig/mm/memory.c
+++ linux-stable/mm/memory.c
@@ -3495,7 +3495,7 @@ void pagefault_disable(void)
*/
barrier();
}
-EXPORT_SYMBOL_GPL(pagefault_disable);
+EXPORT_SYMBOL(pagefault_disable);

void pagefault_enable(void)
{
@@ -3507,7 +3507,7 @@ void pagefault_enable(void)
current->pagefault_disabled--;
migrate_enable();
}
-EXPORT_SYMBOL_GPL(pagefault_enable);
+EXPORT_SYMBOL(pagefault_enable);
#endif

/*
Index: linux-stable/mm/slub.c
===================================================================
--- linux-stable.orig/mm/slub.c
+++ linux-stable/mm/slub.c
@@ -1280,14 +1280,15 @@ static struct page *allocate_slab(struct
struct page *page;
struct kmem_cache_order_objects oo = s->oo;
gfp_t alloc_gfp;
+ bool enableirqs;

flags &= gfp_allowed_mask;

+ enableirqs = (flags & __GFP_WAIT) != 0;
#ifdef CONFIG_PREEMPT_RT_FULL
- if (system_state == SYSTEM_RUNNING)
-#else
- if (flags & __GFP_WAIT)
+ enableirqs |= system_state == SYSTEM_RUNNING;
#endif
+ if (enableirqs)
local_irq_enable();

flags |= s->allocflags;
@@ -1327,11 +1328,7 @@ static struct page *allocate_slab(struct
kmemcheck_mark_unallocated_pages(page, pages);
}

-#ifdef CONFIG_PREEMPT_RT_FULL
- if (system_state == SYSTEM_RUNNING)
-#else
- if (flags & __GFP_WAIT)
-#endif
+ if (enableirqs)
local_irq_disable();
if (!page)
return NULL;
@@ -2085,7 +2082,7 @@ static void flush_all(struct kmem_cache
static inline int node_match(struct page *page, int node)
{
#ifdef CONFIG_NUMA
- if (node != NUMA_NO_NODE && page_to_nid(page) != node)
+ if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
return 0;
#endif
return 1;
@@ -2379,13 +2376,18 @@ static __always_inline void *slab_alloc(
return NULL;

redo:
-
/*
* Must read kmem_cache cpu data via this cpu ptr. Preemption is
* enabled. We may switch back and forth between cpus while
* reading from one cpu area. That does not matter as long
* as we end up on the original cpu again when doing the cmpxchg.
+ *
+ * Preemption is disabled for the retrieval of the tid because that
+ * must occur from the current processor. We cannot allow rescheduling
+ * on a different processor between the determination of the pointer
+ * and the retrieval of the tid.
*/
+ preempt_disable();
c = __this_cpu_ptr(s->cpu_slab);

/*
@@ -2395,7 +2397,7 @@ redo:
* linked list in between.
*/
tid = c->tid;
- barrier();
+ preempt_enable();

object = c->freelist;
page = c->page;
@@ -2641,10 +2643,11 @@ redo:
* data is retrieved via this pointer. If we are on the same cpu
* during the cmpxchg then the free will succedd.
*/
+ preempt_disable();
c = __this_cpu_ptr(s->cpu_slab);

tid = c->tid;
- barrier();
+ preempt_enable();

if (likely(page == c->page)) {
set_freepointer(s, object, c->freelist);
Index: linux-stable/mm/swap.c
===================================================================
--- linux-stable.orig/mm/swap.c
+++ linux-stable/mm/swap.c
@@ -846,6 +846,15 @@ unsigned pagevec_lookup_tag(struct pagev
}
EXPORT_SYMBOL(pagevec_lookup_tag);

+/* Early setup for the local locks */
+static int __init swap_init_locks(void)
+{
+ local_irq_lock_init(rotate_lock);
+ local_irq_lock_init(swap_lock);
+ return 1;
+}
+early_initcall(swap_init_locks);
+
/*
* Perform any setup for the swap system
*/
@@ -853,9 +862,6 @@ void __init swap_setup(void)
{
unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT);

- local_irq_lock_init(rotate_lock);
- local_irq_lock_init(swap_lock);
-
#ifdef CONFIG_SWAP
bdi_init(swapper_space.backing_dev_info);
#endif
Index: linux-stable/mm/highmem.c
===================================================================
--- linux-stable.orig/mm/highmem.c
+++ linux-stable/mm/highmem.c
@@ -98,7 +98,7 @@ struct page *kmap_to_page(void *vaddr)
{
unsigned long addr = (unsigned long)vaddr;

- if (addr >= PKMAP_ADDR(0) && addr <= PKMAP_ADDR(LAST_PKMAP)) {
+ if (addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP)) {
int i = (addr - PKMAP_ADDR(0)) >> PAGE_SHIFT;
return pte_page(pkmap_page_table[i]);
}
@@ -157,7 +157,7 @@ void kmap_flush_unused(void)
unlock_kmap();
}

-static inline unsigned long map_new_virtual(struct page *page)
+static inline unsigned long map_new_virtual(struct page *page, pgprot_t prot)
{
unsigned long vaddr;
int count;
@@ -199,7 +199,7 @@ start:
}
vaddr = PKMAP_ADDR(last_pkmap_nr);
set_pte_at(&init_mm, vaddr,
- &(pkmap_page_table[last_pkmap_nr]), mk_pte(page, kmap_prot));
+ &(pkmap_page_table[last_pkmap_nr]), mk_pte(page, prot));

pkmap_count[last_pkmap_nr] = 1;
set_page_address(page, (void *)vaddr);
@@ -215,7 +215,7 @@ start:
*
* We cannot call this from interrupts, as it may block.
*/
-void *kmap_high(struct page *page)
+void *kmap_high_prot(struct page *page, pgprot_t prot)
{
unsigned long vaddr;

@@ -226,13 +226,26 @@ void *kmap_high(struct page *page)
lock_kmap();
vaddr = (unsigned long)page_address(page);
if (!vaddr)
- vaddr = map_new_virtual(page);
+ vaddr = map_new_virtual(page, prot);
pkmap_count[PKMAP_NR(vaddr)]++;
BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 2);
unlock_kmap();
return (void*) vaddr;
}
+EXPORT_SYMBOL(kmap_high_prot);

+/**
+ * kmap_high - map a highmem page into memory
+ * @page: &struct page to map
+ *
+ * Returns the page's virtual memory address.
+ *
+ * We cannot call this from interrupts, as it may block.
+ */
+void *kmap_high(struct page *page)
+{
+ return kmap_high_prot(page, kmap_prot);
+}
EXPORT_SYMBOL(kmap_high);

#ifdef ARCH_NEEDS_KMAP_HIGH_GET
Index: linux-stable/drivers/tty/serial/amba-pl011.c
===================================================================
--- linux-stable.orig/drivers/tty/serial/amba-pl011.c
+++ linux-stable/drivers/tty/serial/amba-pl011.c
@@ -1737,13 +1737,19 @@ pl011_console_write(struct console *co,

clk_enable(uap->clk);

- local_irq_save(flags);
+ /*
+ * local_irq_save(flags);
+ *
+ * This local_irq_save() is nonsense. If we come in via sysrq
+ * handling then interrupts are already disabled. Aside of
+ * that the port.sysrq check is racy on SMP regardless.
+ */
if (uap->port.sysrq)
locked = 0;
else if (oops_in_progress)
- locked = spin_trylock(&uap->port.lock);
+ locked = spin_trylock_irqsave(&uap->port.lock, flags);
else
- spin_lock(&uap->port.lock);
+ spin_lock_irqsave(&uap->port.lock, flags);

/*
* First save the CR then disable the interrupts
@@ -1765,8 +1771,7 @@ pl011_console_write(struct console *co,
writew(old_cr, uap->port.membase + UART011_CR);

if (locked)
- spin_unlock(&uap->port.lock);
- local_irq_restore(flags);
+ spin_unlock_irqrestore(&uap->port.lock, flags);

clk_disable(uap->clk);
}
Index: linux-stable/mm/bounce.c
===================================================================
--- linux-stable.orig/mm/bounce.c
+++ linux-stable/mm/bounce.c
@@ -51,11 +51,11 @@ static void bounce_copy_vec(struct bio_v
unsigned long flags;
unsigned char *vto;

- local_irq_save(flags);
+ local_irq_save_nort(flags);
vto = kmap_atomic(to->bv_page);
memcpy(vto + to->bv_offset, vfrom, to->bv_len);
kunmap_atomic(vto);
- local_irq_restore(flags);
+ local_irq_restore_nort(flags);
}

#else /* CONFIG_HIGHMEM */
Index: linux-stable/drivers/mmc/host/mmci.c
===================================================================
--- linux-stable.orig/drivers/mmc/host/mmci.c
+++ linux-stable/drivers/mmc/host/mmci.c
@@ -923,15 +923,12 @@ static irqreturn_t mmci_pio_irq(int irq,
struct sg_mapping_iter *sg_miter = &host->sg_miter;
struct variant_data *variant = host->variant;
void __iomem *base = host->base;
- unsigned long flags;
u32 status;

status = readl(base + MMCISTATUS);

dev_dbg(mmc_dev(host->mmc), "irq1 (pio) %08x\n", status);

- local_irq_save(flags);
-
do {
unsigned int remain, len;
char *buffer;
@@ -971,8 +968,6 @@ static irqreturn_t mmci_pio_irq(int irq,

sg_miter_stop(sg_miter);

- local_irq_restore(flags);
-
/*
* If we have less than the fifo 'half-full' threshold to transfer,
* trigger a PIO interrupt as soon as any data is available.
Index: linux-stable/include/linux/completion.h
===================================================================
--- linux-stable.orig/include/linux/completion.h
+++ linux-stable/include/linux/completion.h
@@ -8,7 +8,7 @@
* See kernel/sched.c for details.
*/

-#include <linux/wait.h>
+#include <linux/wait-simple.h>

/*
* struct completion - structure used to maintain state for a "completion"
@@ -24,11 +24,11 @@
*/
struct completion {
unsigned int done;
- wait_queue_head_t wait;
+ struct swait_head wait;
};

#define COMPLETION_INITIALIZER(work) \
- { 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
+ { 0, SWAIT_HEAD_INITIALIZER((work).wait) }

#define COMPLETION_INITIALIZER_ONSTACK(work) \
({ init_completion(&work); work; })
@@ -73,7 +73,7 @@ struct completion {
static inline void init_completion(struct completion *x)
{
x->done = 0;
- init_waitqueue_head(&x->wait);
+ init_swait_head(&x->wait);
}

extern void wait_for_completion(struct completion *);
Index: linux-stable/arch/x86/include/asm/highmem.h
===================================================================
--- linux-stable.orig/arch/x86/include/asm/highmem.h
+++ linux-stable/arch/x86/include/asm/highmem.h
@@ -56,16 +56,39 @@ extern unsigned long highstart_pfn, high

extern void *kmap_high(struct page *page);
extern void kunmap_high(struct page *page);
+extern void *kmap_high_prot(struct page *page, pgprot_t prot);

void *kmap(struct page *page);
void kunmap(struct page *page);

+#ifndef CONFIG_PREEMPT_RT_FULL
void *kmap_atomic_prot(struct page *page, pgprot_t prot);
void *kmap_atomic(struct page *page);
void __kunmap_atomic(void *kvaddr);
void *kmap_atomic_pfn(unsigned long pfn);
void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot);
struct page *kmap_atomic_to_page(void *ptr);
+#else
+void *kmap_prot(struct page *page, pgprot_t prot);
+# define kmap_atomic(page) \
+ ({ pagefault_disable(); kmap(page); })
+
+# define kmap_atomic_pfn(pfn) \
+ ({ pagefault_disable(); kmap(pfn_to_page(pfn)) })
+
+# define __kunmap_atomic(kvaddr) \
+ do { kunmap(kmap_to_page(kvaddr)); pagefault_enable(); } while(0)
+
+# define kmap_atomic_prot(page, prot) \
+ ({ pagefault_disable(); kmap_prot(page, prot); })
+
+# define kmap_atomic_prot_pfn(pfn, prot) \
+ ({ pagefault_disable(); kmap_prot(pfn_to_page(pfn), prot); })
+
+# define kmap_atomic_to_page(kvaddr) \
+ kmap_to_page(kvaddr)
+
+#endif

#define flush_cache_kmaps() do { } while (0)

Index: linux-stable/include/linux/highmem.h
===================================================================
--- linux-stable.orig/include/linux/highmem.h
+++ linux-stable/include/linux/highmem.h
@@ -59,6 +59,8 @@ static inline void *kmap(struct page *pa
return page_address(page);
}

+#define kmap_prot(page, prot) kmap(page)
+
static inline void kunmap(struct page *page)
{
}
Index: linux-stable/arch/arm/include/asm/highmem.h
===================================================================
--- linux-stable.orig/arch/arm/include/asm/highmem.h
+++ linux-stable/arch/arm/include/asm/highmem.h
@@ -57,10 +57,25 @@ static inline void *kmap_high_get(struct
#ifdef CONFIG_HIGHMEM
extern void *kmap(struct page *page);
extern void kunmap(struct page *page);
+# ifndef CONFIG_PREEMPT_RT_FULL
extern void *kmap_atomic(struct page *page);
extern void __kunmap_atomic(void *kvaddr);
extern void *kmap_atomic_pfn(unsigned long pfn);
extern struct page *kmap_atomic_to_page(const void *ptr);
+# else
+# define kmap_atomic(page) \
+ ({ pagefault_disable(); kmap(page); })
+
+# define kmap_atomic_pfn(pfn) \
+ ({ pagefault_disable(); kmap(pfn_to_page(pfn)) })
+
+# define __kunmap_atomic(kvaddr) \
+ do { kunmap(kmap_to_page(kvaddr)); pagefault_enable(); } while(0)
+
+# define kmap_atomic_to_page(kvaddr) \
+ kmap_to_page(kvaddr)
+
+# endif
#endif

#endif
Index: linux-stable/arch/arm/mm/highmem.c
===================================================================
--- linux-stable.orig/arch/arm/mm/highmem.c
+++ linux-stable/arch/arm/mm/highmem.c
@@ -36,6 +36,7 @@ void kunmap(struct page *page)
}
EXPORT_SYMBOL(kunmap);

+#ifndef CONFIG_PREEMPT_RT_FULL
void *kmap_atomic(struct page *page)
{
unsigned int idx;
@@ -135,3 +136,4 @@ struct page *kmap_atomic_to_page(const v

return pte_page(get_top_pte(vaddr));
}
+#endif
--
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