]> nv-tegra.nvidia Code Review - linux-2.6.git/blobdiff - drivers/block/ll_rw_blk.c
[PATCH] blk: fix tag shrinking (revive real_max_size)
[linux-2.6.git] / drivers / block / ll_rw_blk.c
index 692a5fced76e448819f4e649cd5576a066deae4f..3c818544475ea857d249f1afc8f259028c163a2b 100644 (file)
@@ -719,7 +719,7 @@ struct request *blk_queue_find_tag(request_queue_t *q, int tag)
 {
        struct blk_queue_tag *bqt = q->queue_tags;
 
-       if (unlikely(bqt == NULL || tag >= bqt->max_depth))
+       if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
                return NULL;
 
        return bqt->tag_index[tag];
@@ -798,6 +798,7 @@ init_tag_map(request_queue_t *q, struct blk_queue_tag *tags, int depth)
 
        memset(tag_index, 0, depth * sizeof(struct request *));
        memset(tag_map, 0, nr_ulongs * sizeof(unsigned long));
+       tags->real_max_depth = depth;
        tags->max_depth = depth;
        tags->tag_index = tag_index;
        tags->tag_map = tag_map;
@@ -871,12 +872,23 @@ int blk_queue_resize_tags(request_queue_t *q, int new_depth)
        if (!bqt)
                return -ENXIO;
 
+       /*
+        * if we already have large enough real_max_depth.  just
+        * adjust max_depth.  *NOTE* as requests with tag value
+        * between new_depth and real_max_depth can be in-flight, tag
+        * map can not be shrunk blindly here.
+        */
+       if (new_depth <= bqt->real_max_depth) {
+               bqt->max_depth = new_depth;
+               return 0;
+       }
+
        /*
         * save the old state info, so we can copy it back
         */
        tag_index = bqt->tag_index;
        tag_map = bqt->tag_map;
-       max_depth = bqt->max_depth;
+       max_depth = bqt->real_max_depth;
 
        if (init_tag_map(q, bqt, new_depth))
                return -ENOMEM;
@@ -913,7 +925,7 @@ void blk_queue_end_tag(request_queue_t *q, struct request *rq)
 
        BUG_ON(tag == -1);
 
-       if (unlikely(tag >= bqt->max_depth))
+       if (unlikely(tag >= bqt->real_max_depth))
                /*
                 * This can happen after tag depth has been reduced.
                 * FIXME: how about a warning or info message here?