dm bufio: introduce a global queue

Rename param_spinlock to global_spinlock and introduce a global queue of
all used buffers.  The queue will be used in the following commits.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 12 insertions, 3 deletions

diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index 58df20fd5465..2451a4d68aed 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -132,6 +132,7 @@ 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_* */
@@ -192,7 +193,9 @@ 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);
 
 /*
  * Buffers are freed after this timeout
@@ -301,7 +304,7 @@ static void adjust_total_allocated(struct dm_buffer *b, bool unlink)
         if (unlink)
                 diff = -diff;
 
-        spin_lock(&param_spinlock);
+        spin_lock(&global_spinlock);
 
         *class_ptr[data_mode] += diff;
 
@@ -310,7 +313,13 @@ static void adjust_total_allocated(struct dm_buffer *b, bool unlink)
         if (dm_bufio_current_allocated > dm_bufio_peak_allocated)
                 dm_bufio_peak_allocated = dm_bufio_current_allocated;
 
-        spin_unlock(&param_spinlock);
+        if (!unlink) {
+                list_add(&b->global_list, &global_queue);
+        } else {
+                list_del(&b->global_list);
+        }
+
+        spin_unlock(&global_spinlock);
 }
 
 /*