Merge "percpu: fix synchronization between synchronous map extension and chunk destruction" (343967f2) · Commits · e / devices / android_kernel_xiaomi_markw

mm/percpu.c

+8 −8

Original line number	Diff line number	Diff line
		@@ -160,7 +160,7 @@ static struct pcpu_chunk *pcpu_reserved_chunk;
		static int pcpu_reserved_chunk_limit;

		static DEFINE_SPINLOCK(pcpu_lock); /* all internal data structures */
		static DEFINE_MUTEX(pcpu_alloc_mutex); /* chunk create/destroy, [de]pop */
		static DEFINE_MUTEX(pcpu_alloc_mutex); /* chunk create/destroy, [de]pop, map ext */

		static struct list_head pcpu_slot __read_mostly; / chunk list slots */

		@@ -437,6 +437,8 @@ 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;

		lockdep_assert_held(&pcpu_alloc_mutex);

		new = pcpu_mem_zalloc(new_size);
		if (!new)
		return -ENOMEM;
		@@ -897,6 +899,9 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved,
		return NULL;
		}

		if (!is_atomic)
		mutex_lock(&pcpu_alloc_mutex);

		spin_lock_irqsave(&pcpu_lock, flags);

		/* serve reserved allocations from the reserved chunk if available */
		@@ -969,12 +974,9 @@ restart:
		if (is_atomic)
		goto fail;

		mutex_lock(&pcpu_alloc_mutex);

		if (list_empty(&pcpu_slot[pcpu_nr_slots - 1])) {
		chunk = pcpu_create_chunk();
		if (!chunk) {
		mutex_unlock(&pcpu_alloc_mutex);
		err = "failed to allocate new chunk";
		goto fail;
		}
		@@ -985,7 +987,6 @@ restart:
		spin_lock_irqsave(&pcpu_lock, flags);
		}

		mutex_unlock(&pcpu_alloc_mutex);
		goto restart;

		area_found:
		@@ -995,8 +996,6 @@ area_found:
		if (!is_atomic) {
		int page_start, page_end, rs, re;

		mutex_lock(&pcpu_alloc_mutex);

		page_start = PFN_DOWN(off);
		page_end = PFN_UP(off + size);

		@@ -1007,7 +1006,6 @@ area_found:

		spin_lock_irqsave(&pcpu_lock, flags);
		if (ret) {
		mutex_unlock(&pcpu_alloc_mutex);
		pcpu_free_area(chunk, off, &occ_pages);
		err = "failed to populate";
		goto fail_unlock;
		@@ -1047,6 +1045,8 @@ fail:
		/* see the flag handling in pcpu_blance_workfn() */
		pcpu_atomic_alloc_failed = true;
		pcpu_schedule_balance_work();
		} else {
		mutex_unlock(&pcpu_alloc_mutex);
		}
		return NULL;
		}