Merge tag 'for-5.4/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - crypto and DM crypt advances that allow the crypto API to reclaim
   implementation details that do not belong in DM crypt. The wrapper
   template for ESSIV generation that was factored out will also be used
   by fscrypt in the future.

 - Add root hash pkcs#7 signature verification to the DM verity target.

 - Add a new "clone" DM target that allows for efficient remote
   replication of a device.

 - Enhance DM bufio's cache to be tailored to each client based on use.
   Clients that make heavy use of the cache get more of it, and those
   that use less have reduced cache usage.

 - Add a new DM_GET_TARGET_VERSION ioctl to allow userspace to query the
   version number of a DM target (even if the associated module isn't
   yet loaded).

 - Fix invalid memory access in DM zoned target.

 - Fix the max_discard_sectors limit advertised by the DM raid target;
   it was mistakenly storing the limit in bytes rather than sectors.

 - Small optimizations and cleanups in DM writecache target.

 - Various fixes and cleanups in DM core, DM raid1 and space map portion
   of DM persistent data library.

* tag 'for-5.4/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (22 commits)
  dm: introduce DM_GET_TARGET_VERSION
  dm bufio: introduce a global cache replacement
  dm bufio: remove old-style buffer cleanup
  dm bufio: introduce a global queue
  dm bufio: refactor adjust_total_allocated
  dm bufio: call adjust_total_allocated from __link_buffer and __unlink_buffer
  dm: add clone target
  dm raid: fix updating of max_discard_sectors limit
  dm writecache: skip writecache_wait for pmem mode
  dm stats: use struct_size() helper
  dm crypt: omit parsing of the encapsulated cipher
  dm crypt: switch to ESSIV crypto API template
  crypto: essiv - create wrapper template for ESSIV generation
  dm space map common: remove check for impossible sm_find_free() return value
  dm raid1: use struct_size() with kzalloc()
  dm writecache: optimize performance by sorting the blocks for writeback_all
  dm writecache: add unlikely for getting two block with same LBA
  dm writecache: remove unused member pointer in writeback_struct
  dm zoned: fix invalid memory access
  dm verity: add root hash pkcs#7 signature verification
  ...

1 files changed, 119 insertions, 73 deletions

diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index 2a48ea3f1b30..2d519c223562 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -33,7 +33,8 @@
 
 #define DM_BUFIO_MEMORY_PERCENT		2
 #define DM_BUFIO_VMALLOC_PERCENT	25
-#define DM_BUFIO_WRITEBACK_PERCENT	75
+#define DM_BUFIO_WRITEBACK_RATIO	3
+#define DM_BUFIO_LOW_WATERMARK_RATIO	16
 
 /*
  * Check buffer ages in this interval (seconds)
@@ -132,12 +133,14 @@ enum data_mode {
 struct dm_buffer {
 	struct rb_node node;
 	struct list_head lru_list;
+	struct list_head global_list;
 	sector_t block;
 	void *data;
 	unsigned char data_mode;		/* DATA_MODE_* */
 	unsigned char list_mode;		/* LIST_* */
 	blk_status_t read_error;
 	blk_status_t write_error;
+	unsigned accessed;
 	unsigned hold_count;
 	unsigned long state;
 	unsigned long last_accessed;
@@ -192,7 +195,11 @@ static unsigned long dm_bufio_cache_size;
  */
 static unsigned long dm_bufio_cache_size_latch;
 
-static DEFINE_SPINLOCK(param_spinlock);
+static DEFINE_SPINLOCK(global_spinlock);
+
+static LIST_HEAD(global_queue);
+
+static unsigned long global_num = 0;
 
 /*
  * Buffers are freed after this timeout
@@ -209,11 +216,6 @@ static unsigned long dm_bufio_current_allocated;
 /*----------------------------------------------------------------*/
 
 /*
- * Per-client cache: dm_bufio_cache_size / dm_bufio_client_count
- */
-static unsigned long dm_bufio_cache_size_per_client;
-
-/*
  * The current number of clients.
  */
 static int dm_bufio_client_count;
@@ -224,11 +226,15 @@ static int dm_bufio_client_count;
 static LIST_HEAD(dm_bufio_all_clients);
 
 /*
- * This mutex protects dm_bufio_cache_size_latch,
- * dm_bufio_cache_size_per_client and dm_bufio_client_count
+ * This mutex protects dm_bufio_cache_size_latch and dm_bufio_client_count
  */
 static DEFINE_MUTEX(dm_bufio_clients_lock);
 
+static struct workqueue_struct *dm_bufio_wq;
+static struct delayed_work dm_bufio_cleanup_old_work;
+static struct work_struct dm_bufio_replacement_work;
+
+
 #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
 static void buffer_record_stack(struct dm_buffer *b)
 {
@@ -285,15 +291,23 @@ static void __remove(struct dm_bufio_client *c, struct dm_buffer *b)
 
 /*----------------------------------------------------------------*/
 
-static void adjust_total_allocated(unsigned char data_mode, long diff)
+static void adjust_total_allocated(struct dm_buffer *b, bool unlink)
 {
+	unsigned char data_mode;
+	long diff;
+
 	static unsigned long * const class_ptr[DATA_MODE_LIMIT] = {
 		&dm_bufio_allocated_kmem_cache,
 		&dm_bufio_allocated_get_free_pages,
 		&dm_bufio_allocated_vmalloc,
 	};
 
-	spin_lock(&param_spinlock);
+	data_mode = b->data_mode;
+	diff = (long)b->c->block_size;
+	if (unlink)
+		diff = -diff;
+
+	spin_lock(&global_spinlock);
 
 	*class_ptr[data_mode] += diff;
 
@@ -302,7 +316,19 @@ static void adjust_total_allocated(unsigned char data_mode, long diff)
 	if (dm_bufio_current_allocated > dm_bufio_peak_allocated)
 		dm_bufio_peak_allocated = dm_bufio_current_allocated;
 
-	spin_unlock(&param_spinlock);
+	b->accessed = 1;
+
+	if (!unlink) {
+		list_add(&b->global_list, &global_queue);
+		global_num++;
+		if (dm_bufio_current_allocated > dm_bufio_cache_size)
+			queue_work(dm_bufio_wq, &dm_bufio_replacement_work);
+	} else {
+		list_del(&b->global_list);
+		global_num--;
+	}
+
+	spin_unlock(&global_spinlock);
 }
 
 /*
@@ -323,9 +349,6 @@ static void __cache_size_refresh(void)
 			      dm_bufio_default_cache_size);
 		dm_bufio_cache_size_latch = dm_bufio_default_cache_size;
 	}
-
-	dm_bufio_cache_size_per_client = dm_bufio_cache_size_latch /
-					 (dm_bufio_client_count ? : 1);
 }
 
 /*
@@ -431,8 +454,6 @@ static struct dm_buffer *alloc_buffer(struct dm_bufio_client *c, gfp_t gfp_mask)
 		return NULL;
 	}
 
-	adjust_total_allocated(b->data_mode, (long)c->block_size);
-
 #ifdef CONFIG_DM_DEBUG_BLOCK_STACK_TRACING
 	b->stack_len = 0;
 #endif
@@ -446,8 +467,6 @@ static void free_buffer(struct dm_buffer *b)
 {
 	struct dm_bufio_client *c = b->c;
 
-	adjust_total_allocated(b->data_mode, -(long)c->block_size);
-
 	free_buffer_data(c, b->data, b->data_mode);
 	kmem_cache_free(c->slab_buffer, b);
 }
@@ -465,6 +484,8 @@ static void __link_buffer(struct dm_buffer *b, sector_t block, int dirty)
 	list_add(&b->lru_list, &c->lru[dirty]);
 	__insert(b->c, b);
 	b->last_accessed = jiffies;
+
+	adjust_total_allocated(b, false);
 }
 
 /*
@@ -479,6 +500,8 @@ static void __unlink_buffer(struct dm_buffer *b)
 	c->n_buffers[b->list_mode]--;
 	__remove(b->c, b);
 	list_del(&b->lru_list);
+
+	adjust_total_allocated(b, true);
 }
 
 /*
@@ -488,6 +511,8 @@ static void __relink_lru(struct dm_buffer *b, int dirty)
 {
 	struct dm_bufio_client *c = b->c;
 
+	b->accessed = 1;
+
 	BUG_ON(!c->n_buffers[b->list_mode]);
 
 	c->n_buffers[b->list_mode]--;
@@ -907,36 +932,6 @@ static void __write_dirty_buffers_async(struct dm_bufio_client *c, int no_wait,
 }
 
 /*
- * Get writeback threshold and buffer limit for a given client.
- */
-static void __get_memory_limit(struct dm_bufio_client *c,
-			       unsigned long *threshold_buffers,
-			       unsigned long *limit_buffers)
-{
-	unsigned long buffers;
-
-	if (unlikely(READ_ONCE(dm_bufio_cache_size) != dm_bufio_cache_size_latch)) {
-		if (mutex_trylock(&dm_bufio_clients_lock)) {
-			__cache_size_refresh();
-			mutex_unlock(&dm_bufio_clients_lock);
-		}
-	}
-
-	buffers = dm_bufio_cache_size_per_client;
-	if (likely(c->sectors_per_block_bits >= 0))
-		buffers >>= c->sectors_per_block_bits + SECTOR_SHIFT;
-	else
-		buffers /= c->block_size;
-
-	if (buffers < c->minimum_buffers)
-		buffers = c->minimum_buffers;
-
-	*limit_buffers = buffers;
-	*threshold_buffers = mult_frac(buffers,
-				       DM_BUFIO_WRITEBACK_PERCENT, 100);
-}
-
-/*
  * Check if we're over watermark.
  * If we are over threshold_buffers, start freeing buffers.
  * If we're over "limit_buffers", block until we get under the limit.
@@ -944,23 +939,7 @@ static void __get_memory_limit(struct dm_bufio_client *c,
 static void __check_watermark(struct dm_bufio_client *c,
 			      struct list_head *write_list)
 {
-	unsigned long threshold_buffers, limit_buffers;
-
-	__get_memory_limit(c, &threshold_buffers, &limit_buffers);
-
-	while (c->n_buffers[LIST_CLEAN] + c->n_buffers[LIST_DIRTY] >
-	       limit_buffers) {
-
-		struct dm_buffer *b = __get_unclaimed_buffer(c);
-
-		if (!b)
-			return;
-
-		__free_buffer_wake(b);
-		cond_resched();
-	}
-
-	if (c->n_buffers[LIST_DIRTY] > threshold_buffers)
+	if (c->n_buffers[LIST_DIRTY] > c->n_buffers[LIST_CLEAN] * DM_BUFIO_WRITEBACK_RATIO)
 		__write_dirty_buffers_async(c, 1, write_list);
 }
 
@@ -1841,6 +1820,74 @@ static void __evict_old_buffers(struct dm_bufio_client *c, unsigned long age_hz)
 	dm_bufio_unlock(c);
 }
 
+static void do_global_cleanup(struct work_struct *w)
+{
+	struct dm_bufio_client *locked_client = NULL;
+	struct dm_bufio_client *current_client;
+	struct dm_buffer *b;
+	unsigned spinlock_hold_count;
+	unsigned long threshold = dm_bufio_cache_size -
+		dm_bufio_cache_size / DM_BUFIO_LOW_WATERMARK_RATIO;
+	unsigned long loops = global_num * 2;
+
+	mutex_lock(&dm_bufio_clients_lock);
+
+	while (1) {
+		cond_resched();
+
+		spin_lock(&global_spinlock);
+		if (unlikely(dm_bufio_current_allocated <= threshold))
+			break;
+
+		spinlock_hold_count = 0;
+get_next:
+		if (!loops--)
+			break;
+		if (unlikely(list_empty(&global_queue)))
+			break;
+		b = list_entry(global_queue.prev, struct dm_buffer, global_list);
+
+		if (b->accessed) {
+			b->accessed = 0;
+			list_move(&b->global_list, &global_queue);
+			if (likely(++spinlock_hold_count < 16))
+				goto get_next;
+			spin_unlock(&global_spinlock);
+			continue;
+		}
+
+		current_client = b->c;
+		if (unlikely(current_client != locked_client)) {
+			if (locked_client)
+				dm_bufio_unlock(locked_client);
+
+			if (!dm_bufio_trylock(current_client)) {
+				spin_unlock(&global_spinlock);
+				dm_bufio_lock(current_client);
+				locked_client = current_client;
+				continue;
+			}
+
+			locked_client = current_client;
+		}
+
+		spin_unlock(&global_spinlock);
+
+		if (unlikely(!__try_evict_buffer(b, GFP_KERNEL))) {
+			spin_lock(&global_spinlock);
+			list_move(&b->global_list, &global_queue);
+			spin_unlock(&global_spinlock);
+		}
+	}
+
+	spin_unlock(&global_spinlock);
+
+	if (locked_client)
+		dm_bufio_unlock(locked_client);
+
+	mutex_unlock(&dm_bufio_clients_lock);
+}
+
 static void cleanup_old_buffers(void)
 {
 	unsigned long max_age_hz = get_max_age_hz();
@@ -1856,14 +1903,11 @@ static void cleanup_old_buffers(void)
 	mutex_unlock(&dm_bufio_clients_lock);
 }
 
-static struct workqueue_struct *dm_bufio_wq;
-static struct delayed_work dm_bufio_work;
-
 static void work_fn(struct work_struct *w)
 {
 	cleanup_old_buffers();
 
-	queue_delayed_work(dm_bufio_wq, &dm_bufio_work,
+	queue_delayed_work(dm_bufio_wq, &dm_bufio_cleanup_old_work,
 			   DM_BUFIO_WORK_TIMER_SECS * HZ);
 }
 
@@ -1905,8 +1949,9 @@ static int __init dm_bufio_init(void)
 	if (!dm_bufio_wq)
 		return -ENOMEM;
 
-	INIT_DELAYED_WORK(&dm_bufio_work, work_fn);
-	queue_delayed_work(dm_bufio_wq, &dm_bufio_work,
+	INIT_DELAYED_WORK(&dm_bufio_cleanup_old_work, work_fn);
+	INIT_WORK(&dm_bufio_replacement_work, do_global_cleanup);
+	queue_delayed_work(dm_bufio_wq, &dm_bufio_cleanup_old_work,
 			   DM_BUFIO_WORK_TIMER_SECS * HZ);
 
 	return 0;
@@ -1919,7 +1964,8 @@ static void __exit dm_bufio_exit(void)
 {
 	int bug = 0;
 
-	cancel_delayed_work_sync(&dm_bufio_work);
+	cancel_delayed_work_sync(&dm_bufio_cleanup_old_work);
+	flush_workqueue(dm_bufio_wq);
 	destroy_workqueue(dm_bufio_wq);
 
 	if (dm_bufio_client_count) {