Merge branch 'slab/urgent' into slab/for-linus

14 files changed, 120 insertions, 92 deletions

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index a0860640378d..71034f41a2ba 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -724,6 +724,14 @@ void bdi_destroy(struct backing_dev_info *bdi)
 
 	bdi_unregister(bdi);
 
+	/*
+	 * If bdi_unregister() had already been called earlier, the
+	 * wakeup_timer could still be armed because bdi_prune_sb()
+	 * can race with the bdi_wakeup_thread_delayed() calls from
+	 * __mark_inode_dirty().
+	 */
+	del_timer_sync(&bdi->wb.wakeup_timer);
+
 	for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
 		percpu_counter_destroy(&bdi->bdi_stat[i]);
 
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 4298abaae153..36b3d988b4ef 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2259,12 +2259,8 @@ static void khugepaged_do_scan(struct page **hpage)
 
 static void khugepaged_alloc_sleep(void)
 {
-	DEFINE_WAIT(wait);
-	add_wait_queue(&khugepaged_wait, &wait);
-	schedule_timeout_interruptible(
-		msecs_to_jiffies(
-			khugepaged_alloc_sleep_millisecs));
-	remove_wait_queue(&khugepaged_wait, &wait);
+	wait_event_freezable_timeout(khugepaged_wait, false,
+			msecs_to_jiffies(khugepaged_alloc_sleep_millisecs));
 }
 
 #ifndef CONFIG_NUMA
@@ -2313,14 +2309,10 @@ static void khugepaged_loop(void)
 		if (unlikely(kthread_should_stop()))
 			break;
 		if (khugepaged_has_work()) {
-			DEFINE_WAIT(wait);
 			if (!khugepaged_scan_sleep_millisecs)
 				continue;
-			add_wait_queue(&khugepaged_wait, &wait);
-			schedule_timeout_interruptible(
-				msecs_to_jiffies(
-					khugepaged_scan_sleep_millisecs));
-			remove_wait_queue(&khugepaged_wait, &wait);
+			wait_event_freezable_timeout(khugepaged_wait, false,
+			    msecs_to_jiffies(khugepaged_scan_sleep_millisecs));
 		} else if (khugepaged_enabled())
 			wait_event_freezable(khugepaged_wait,
 					     khugepaged_wait_event());
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index dae27ba3be2c..73f17c0293c0 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -576,6 +576,7 @@ static void prep_compound_gigantic_page(struct page *page, unsigned long order)
 	__SetPageHead(page);
 	for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
 		__SetPageTail(p);
+		set_page_count(p, 0);
 		p->first_page = page;
 	}
 }
@@ -2422,6 +2423,8 @@ retry_avoidcopy:
 	 * anon_vma prepared.
 	 */
 	if (unlikely(anon_vma_prepare(vma))) {
+		page_cache_release(new_page);
+		page_cache_release(old_page);
 		/* Caller expects lock to be held */
 		spin_lock(&mm->page_table_lock);
 		return VM_FAULT_OOM;
diff --git a/mm/migrate.c b/mm/migrate.c
index 578e29174fa6..177aca424a06 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -871,9 +871,9 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
 
 	if (anon_vma)
 		put_anon_vma(anon_vma);
-out:
 	unlock_page(hpage);
 
+out:
 	if (rc != -EAGAIN) {
 		list_del(&hpage->lru);
 		put_page(hpage);
diff --git a/mm/nommu.c b/mm/nommu.c
index 73419c55eda6..b982290fd962 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -454,7 +454,7 @@ void  __attribute__((weak)) vmalloc_sync_all(void)
  *	between processes, it syncs the pagetable across all
  *	processes.
  */
-struct vm_struct *alloc_vm_area(size_t size)
+struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
 {
 	BUG();
 	return NULL;
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 471dedb463ab..76f2c5ae908e 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -185,6 +185,11 @@ unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem,
 	if (!p)
 		return 0;
 
+	if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) {
+		task_unlock(p);
+		return 0;
+	}
+
 	/*
 	 * The memory controller may have a limit of 0 bytes, so avoid a divide
 	 * by zero, if necessary.
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index a3278f005230..71252486bc6f 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -128,7 +128,6 @@ unsigned long global_dirty_limit;
  *
  */
 static struct prop_descriptor vm_completions;
-static struct prop_descriptor vm_dirties;
 
 /*
  * couple the period to the dirty_ratio:
@@ -154,7 +153,6 @@ static void update_completion_period(void)
 {
 	int shift = calc_period_shift();
 	prop_change_shift(&vm_completions, shift);
-	prop_change_shift(&vm_dirties, shift);
 
 	writeback_set_ratelimit();
 }
@@ -235,11 +233,6 @@ void bdi_writeout_inc(struct backing_dev_info *bdi)
 }
 EXPORT_SYMBOL_GPL(bdi_writeout_inc);
 
-void task_dirty_inc(struct task_struct *tsk)
-{
-	prop_inc_single(&vm_dirties, &tsk->dirties);
-}
-
 /*
  * Obtain an accurate fraction of the BDI's portion.
  */
@@ -1133,17 +1126,17 @@ pause:
 					  pages_dirtied,
 					  pause,
 					  start_time);
-		__set_current_state(TASK_UNINTERRUPTIBLE);
+		__set_current_state(TASK_KILLABLE);
 		io_schedule_timeout(pause);
 
-		dirty_thresh = hard_dirty_limit(dirty_thresh);
 		/*
-		 * max-pause area. If dirty exceeded but still within this
-		 * area, no need to sleep for more than 200ms: (a) 8 pages per
-		 * 200ms is typically more than enough to curb heavy dirtiers;
-		 * (b) the pause time limit makes the dirtiers more responsive.
+		 * This is typically equal to (nr_dirty < dirty_thresh) and can
+		 * also keep "1000+ dd on a slow USB stick" under control.
 		 */
-		if (nr_dirty < dirty_thresh)
+		if (task_ratelimit)
+			break;
+
+		if (fatal_signal_pending(current))
 			break;
 	}
 
@@ -1395,7 +1388,6 @@ void __init page_writeback_init(void)
 
 	shift = calc_period_shift();
 	prop_descriptor_init(&vm_completions, shift);
-	prop_descriptor_init(&vm_dirties, shift);
 }
 
 /**
@@ -1724,7 +1716,6 @@ void account_page_dirtied(struct page *page, struct address_space *mapping)
 		__inc_zone_page_state(page, NR_DIRTIED);
 		__inc_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE);
 		__inc_bdi_stat(mapping->backing_dev_info, BDI_DIRTIED);
-		task_dirty_inc(current);
 		task_io_account_write(PAGE_CACHE_SIZE);
 	}
 }
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9dd443d89d8b..2b8ba3aebf6e 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -356,8 +356,8 @@ void prep_compound_page(struct page *page, unsigned long order)
 	__SetPageHead(page);
 	for (i = 1; i < nr_pages; i++) {
 		struct page *p = page + i;
-
 		__SetPageTail(p);
+		set_page_count(p, 0);
 		p->first_page = page;
 	}
 }
@@ -3377,9 +3377,15 @@ static void setup_zone_migrate_reserve(struct zone *zone)
 	unsigned long block_migratetype;
 	int reserve;
 
-	/* Get the start pfn, end pfn and the number of blocks to reserve */
+	/*
+	 * Get the start pfn, end pfn and the number of blocks to reserve
+	 * We have to be careful to be aligned to pageblock_nr_pages to
+	 * make sure that we always check pfn_valid for the first page in
+	 * the block.
+	 */
 	start_pfn = zone->zone_start_pfn;
 	end_pfn = start_pfn + zone->spanned_pages;
+	start_pfn = roundup(start_pfn, pageblock_nr_pages);
 	reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >>
 							pageblock_order;
 
diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c
index ea534960a04b..12a48a88c0d8 100644
--- a/mm/percpu-vm.c
+++ b/mm/percpu-vm.c
@@ -50,14 +50,13 @@ static struct page **pcpu_get_pages_and_bitmap(struct pcpu_chunk *chunk,
 
 	if (!pages || !bitmap) {
 		if (may_alloc && !pages)
-			pages = pcpu_mem_alloc(pages_size);
+			pages = pcpu_mem_zalloc(pages_size);
 		if (may_alloc && !bitmap)
-			bitmap = pcpu_mem_alloc(bitmap_size);
+			bitmap = pcpu_mem_zalloc(bitmap_size);
 		if (!pages || !bitmap)
 			return NULL;
 	}
 
-	memset(pages, 0, pages_size);
 	bitmap_copy(bitmap, chunk->populated, pcpu_unit_pages);
 
 	*bitmapp = bitmap;
@@ -143,8 +142,8 @@ static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
 				 int page_start, int page_end)
 {
 	flush_cache_vunmap(
-		pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
-		pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
+		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
+		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
 }
 
 static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
@@ -206,8 +205,8 @@ static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
 				      int page_start, int page_end)
 {
 	flush_tlb_kernel_range(
-		pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
-		pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
+		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
+		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
 }
 
 static int __pcpu_map_pages(unsigned long addr, struct page **pages,
@@ -284,8 +283,8 @@ static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
 				int page_start, int page_end)
 {
 	flush_cache_vmap(
-		pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
-		pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
+		pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
+		pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
 }
 
 /**
diff --git a/mm/percpu.c b/mm/percpu.c
index bf80e55dbed7..3bb810a72006 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -116,9 +116,9 @@ static int pcpu_atom_size __read_mostly;
 static int pcpu_nr_slots __read_mostly;
 static size_t pcpu_chunk_struct_size __read_mostly;
 
-/* cpus with the lowest and highest unit numbers */
-static unsigned int pcpu_first_unit_cpu __read_mostly;
-static unsigned int pcpu_last_unit_cpu __read_mostly;
+/* cpus with the lowest and highest unit addresses */
+static unsigned int pcpu_low_unit_cpu __read_mostly;
+static unsigned int pcpu_high_unit_cpu __read_mostly;
 
 /* the address of the first chunk which starts with the kernel static area */
 void *pcpu_base_addr __read_mostly;
@@ -273,11 +273,11 @@ static void __maybe_unused pcpu_next_pop(struct pcpu_chunk *chunk,
 	     (rs) = (re) + 1, pcpu_next_pop((chunk), &(rs), &(re), (end)))
 
 /**
- * pcpu_mem_alloc - allocate memory
+ * pcpu_mem_zalloc - allocate memory
  * @size: bytes to allocate
  *
  * Allocate @size bytes.  If @size is smaller than PAGE_SIZE,
- * kzalloc() is used; otherwise, vmalloc() is used.  The returned
+ * kzalloc() is used; otherwise, vzalloc() is used.  The returned
  * memory is always zeroed.
  *
  * CONTEXT:
@@ -286,7 +286,7 @@ static void __maybe_unused pcpu_next_pop(struct pcpu_chunk *chunk,
  * RETURNS:
  * Pointer to the allocated area on success, NULL on failure.
  */
-static void *pcpu_mem_alloc(size_t size)
+static void *pcpu_mem_zalloc(size_t size)
 {
 	if (WARN_ON_ONCE(!slab_is_available()))
 		return NULL;
@@ -302,7 +302,7 @@ static void *pcpu_mem_alloc(size_t size)
  * @ptr: memory to free
  * @size: size of the area
  *
- * Free @ptr.  @ptr should have been allocated using pcpu_mem_alloc().
+ * Free @ptr.  @ptr should have been allocated using pcpu_mem_zalloc().
  */
 static void pcpu_mem_free(void *ptr, size_t size)
 {
@@ -384,7 +384,7 @@ static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc)
 	size_t old_size = 0, new_size = new_alloc * sizeof(new[0]);
 	unsigned long flags;
 
-	new = pcpu_mem_alloc(new_size);
+	new = pcpu_mem_zalloc(new_size);
 	if (!new)
 		return -ENOMEM;
 
@@ -604,11 +604,12 @@ static struct pcpu_chunk *pcpu_alloc_chunk(void)
 {
 	struct pcpu_chunk *chunk;
 
-	chunk = pcpu_mem_alloc(pcpu_chunk_struct_size);
+	chunk = pcpu_mem_zalloc(pcpu_chunk_struct_size);
 	if (!chunk)
 		return NULL;
 
-	chunk->map = pcpu_mem_alloc(PCPU_DFL_MAP_ALLOC * sizeof(chunk->map[0]));
+	chunk->map = pcpu_mem_zalloc(PCPU_DFL_MAP_ALLOC *
+						sizeof(chunk->map[0]));
 	if (!chunk->map) {
 		kfree(chunk);
 		return NULL;
@@ -977,6 +978,17 @@ bool is_kernel_percpu_address(unsigned long addr)
  * address.  The caller is responsible for ensuring @addr stays valid
  * until this function finishes.
  *
+ * percpu allocator has special setup for the first chunk, which currently
+ * supports either embedding in linear address space or vmalloc mapping,
+ * and, from the second one, the backing allocator (currently either vm or
+ * km) provides translation.
+ *
+ * The addr can be tranlated simply without checking if it falls into the
+ * first chunk. But the current code reflects better how percpu allocator
+ * actually works, and the verification can discover both bugs in percpu
+ * allocator itself and per_cpu_ptr_to_phys() callers. So we keep current
+ * code.
+ *
  * RETURNS:
  * The physical address for @addr.
  */
@@ -984,19 +996,19 @@ phys_addr_t per_cpu_ptr_to_phys(void *addr)
 {
 	void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
 	bool in_first_chunk = false;
-	unsigned long first_start, first_end;
+	unsigned long first_low, first_high;
 	unsigned int cpu;
 
 	/*
-	 * The following test on first_start/end isn't strictly
+	 * The following test on unit_low/high isn't strictly
 	 * necessary but will speed up lookups of addresses which
 	 * aren't in the first chunk.
 	 */
-	first_start = pcpu_chunk_addr(pcpu_first_chunk, pcpu_first_unit_cpu, 0);
-	first_end = pcpu_chunk_addr(pcpu_first_chunk, pcpu_last_unit_cpu,
-				    pcpu_unit_pages);
-	if ((unsigned long)addr >= first_start &&
-	    (unsigned long)addr < first_end) {
+	first_low = pcpu_chunk_addr(pcpu_first_chunk, pcpu_low_unit_cpu, 0);
+	first_high = pcpu_chunk_addr(pcpu_first_chunk, pcpu_high_unit_cpu,
+				     pcpu_unit_pages);
+	if ((unsigned long)addr >= first_low &&
+	    (unsigned long)addr < first_high) {
 		for_each_possible_cpu(cpu) {
 			void *start = per_cpu_ptr(base, cpu);
 
@@ -1233,7 +1245,9 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
 
 	for (cpu = 0; cpu < nr_cpu_ids; cpu++)
 		unit_map[cpu] = UINT_MAX;
-	pcpu_first_unit_cpu = NR_CPUS;
+
+	pcpu_low_unit_cpu = NR_CPUS;
+	pcpu_high_unit_cpu = NR_CPUS;
 
 	for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
 		const struct pcpu_group_info *gi = &ai->groups[group];
@@ -1253,9 +1267,13 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
 			unit_map[cpu] = unit + i;
 			unit_off[cpu] = gi->base_offset + i * ai->unit_size;
 
-			if (pcpu_first_unit_cpu == NR_CPUS)
-				pcpu_first_unit_cpu = cpu;
-			pcpu_last_unit_cpu = cpu;
+			/* determine low/high unit_cpu */
+			if (pcpu_low_unit_cpu == NR_CPUS ||
+			    unit_off[cpu] < unit_off[pcpu_low_unit_cpu])
+				pcpu_low_unit_cpu = cpu;
+			if (pcpu_high_unit_cpu == NR_CPUS ||
+			    unit_off[cpu] > unit_off[pcpu_high_unit_cpu])
+				pcpu_high_unit_cpu = cpu;
 		}
 	}
 	pcpu_nr_units = unit;
@@ -1889,7 +1907,7 @@ void __init percpu_init_late(void)
 
 		BUILD_BUG_ON(size > PAGE_SIZE);
 
-		map = pcpu_mem_alloc(size);
+		map = pcpu_mem_zalloc(size);
 		BUG_ON(!map);
 
 		spin_lock_irqsave(&pcpu_lock, flags);
diff --git a/mm/slab.c b/mm/slab.c
index a7f9c244aac6..4ef42baf66f0 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -597,6 +597,7 @@ static enum {
 	PARTIAL_AC,
 	PARTIAL_L3,
 	EARLY,
+	LATE,
 	FULL
 } g_cpucache_up;
 
@@ -673,7 +674,7 @@ static void init_node_lock_keys(int q)
 {
 	struct cache_sizes *s = malloc_sizes;
 
-	if (g_cpucache_up != FULL)
+	if (g_cpucache_up < LATE)
 		return;
 
 	for (s = malloc_sizes; s->cs_size != ULONG_MAX; s++) {
@@ -1680,6 +1681,8 @@ void __init kmem_cache_init_late(void)
 {
 	struct kmem_cache *cachep;
 
+	g_cpucache_up = LATE;
+
 	/* Annotate slab for lockdep -- annotate the malloc caches */
 	init_lock_keys();
 
diff --git a/mm/slub.c b/mm/slub.c
index a47df0aa5d36..19436f538760 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3043,7 +3043,9 @@ static int kmem_cache_open(struct kmem_cache *s,
 	 *    per node list when we run out of per cpu objects. We only fetch 50%
 	 *    to keep some capacity around for frees.
 	 */
-	if (s->size >= PAGE_SIZE)
+	if (kmem_cache_debug(s))
+		s->cpu_partial = 0;
+	else if (s->size >= PAGE_SIZE)
 		s->cpu_partial = 2;
 	else if (s->size >= 1024)
 		s->cpu_partial = 6;
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index b669aa6f6caf..1d8b32f07139 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1633,6 +1633,8 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
 		goto fail;
 
 	addr = __vmalloc_area_node(area, gfp_mask, prot, node, caller);
+	if (!addr)
+		return NULL;
 
 	/*
 	 * In this function, newly allocated vm_struct is not added
@@ -2141,23 +2143,30 @@ void  __attribute__((weak)) vmalloc_sync_all(void)
 
 static int f(pte_t *pte, pgtable_t table, unsigned long addr, void *data)
 {
-	/* apply_to_page_range() does all the hard work. */
+	pte_t ***p = data;
+
+	if (p) {
+		*(*p) = pte;
+		(*p)++;
+	}
 	return 0;
 }
 
 /**
  *	alloc_vm_area - allocate a range of kernel address space
  *	@size:		size of the area
+ *	@ptes:		returns the PTEs for the address space
  *
  *	Returns:	NULL on failure, vm_struct on success
  *
  *	This function reserves a range of kernel address space, and
  *	allocates pagetables to map that range.  No actual mappings
- *	are created.  If the kernel address space is not shared
- *	between processes, it syncs the pagetable across all
- *	processes.
+ *	are created.
+ *
+ *	If @ptes is non-NULL, pointers to the PTEs (in init_mm)
+ *	allocated for the VM area are returned.
  */
-struct vm_struct *alloc_vm_area(size_t size)
+struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
 {
 	struct vm_struct *area;
 
@@ -2171,19 +2180,11 @@ struct vm_struct *alloc_vm_area(size_t size)
 	 * of kernel virtual address space and mapped into init_mm.
 	 */
 	if (apply_to_page_range(&init_mm, (unsigned long)area->addr,
-				area->size, f, NULL)) {
+				size, f, ptes ? &ptes : NULL)) {
 		free_vm_area(area);
 		return NULL;
 	}
 
-	/*
-	 * If the allocated address space is passed to a hypercall
-	 * before being used then we cannot rely on a page fault to
-	 * trigger an update of the page tables.  So sync all the page
-	 * tables here.
-	 */
-	vmalloc_sync_all();
-
 	return area;
 }
 EXPORT_SYMBOL_GPL(alloc_vm_area);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index a1893c050795..f54a05b7a61d 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -183,7 +183,7 @@ static unsigned long zone_nr_lru_pages(struct zone *zone,
  */
 void register_shrinker(struct shrinker *shrinker)
 {
-	shrinker->nr = 0;
+	atomic_long_set(&shrinker->nr_in_batch, 0);
 	down_write(&shrinker_rwsem);
 	list_add_tail(&shrinker->list, &shrinker_list);
 	up_write(&shrinker_rwsem);
@@ -247,25 +247,26 @@ unsigned long shrink_slab(struct shrink_control *shrink,
 
 	list_for_each_entry(shrinker, &shrinker_list, list) {
 		unsigned long long delta;
-		unsigned long total_scan;
-		unsigned long max_pass;
+		long total_scan;
+		long max_pass;
 		int shrink_ret = 0;
 		long nr;
 		long new_nr;
 		long batch_size = shrinker->batch ? shrinker->batch
 						  : SHRINK_BATCH;
 
+		max_pass = do_shrinker_shrink(shrinker, shrink, 0);
+		if (max_pass <= 0)
+			continue;
+
 		/*
 		 * copy the current shrinker scan count into a local variable
 		 * and zero it so that other concurrent shrinker invocations
 		 * don't also do this scanning work.
 		 */
-		do {
-			nr = shrinker->nr;
-		} while (cmpxchg(&shrinker->nr, nr, 0) != nr);
+		nr = atomic_long_xchg(&shrinker->nr_in_batch, 0);
 
 		total_scan = nr;
-		max_pass = do_shrinker_shrink(shrinker, shrink, 0);
 		delta = (4 * nr_pages_scanned) / shrinker->seeks;
 		delta *= max_pass;
 		do_div(delta, lru_pages + 1);
@@ -325,12 +326,11 @@ unsigned long shrink_slab(struct shrink_control *shrink,
 		 * manner that handles concurrent updates. If we exhausted the
 		 * scan, there is no need to do an update.
 		 */
-		do {
-			nr = shrinker->nr;
-			new_nr = total_scan + nr;
-			if (total_scan <= 0)
-				break;
-		} while (cmpxchg(&shrinker->nr, nr, new_nr) != nr);
+		if (total_scan > 0)
+			new_nr = atomic_long_add_return(total_scan,
+					&shrinker->nr_in_batch);
+		else
+			new_nr = atomic_long_read(&shrinker->nr_in_batch);
 
 		trace_mm_shrink_slab_end(shrinker, shrink_ret, nr, new_nr);
 	}