Support 'discard sectors' operation in translation layer support core
David Woodhouse [Tue, 5 Aug 2008 17:08:25 +0000 (18:08 +0100)]
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

drivers/mtd/mtd_blkdevs.c
include/linux/blkdev.h
include/linux/mtd/blktrans.h

index 9ff007c..681d5ac 100644 (file)
@@ -32,6 +32,14 @@ struct mtd_blkcore_priv {
        spinlock_t queue_lock;
 };
 
+static int blktrans_discard_request(struct request_queue *q,
+                                   struct request *req)
+{
+       req->cmd_type = REQ_TYPE_LINUX_BLOCK;
+       req->cmd[0] = REQ_LB_OP_DISCARD;
+       return 0;
+}
+
 static int do_blktrans_request(struct mtd_blktrans_ops *tr,
                               struct mtd_blktrans_dev *dev,
                               struct request *req)
@@ -44,6 +52,10 @@ static int do_blktrans_request(struct mtd_blktrans_ops *tr,
 
        buf = req->buffer;
 
+       if (req->cmd_type == REQ_TYPE_LINUX_BLOCK &&
+           req->cmd[0] == REQ_LB_OP_DISCARD)
+               return !tr->discard(dev, block, nsect);
+
        if (!blk_fs_request(req))
                return 0;
 
@@ -367,6 +379,10 @@ int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
 
        tr->blkcore_priv->rq->queuedata = tr;
        blk_queue_hardsect_size(tr->blkcore_priv->rq, tr->blksize);
+       if (tr->discard)
+               blk_queue_set_discard(tr->blkcore_priv->rq,
+                                     blktrans_discard_request);
+
        tr->blkshift = ffs(tr->blksize) - 1;
 
        tr->blkcore_priv->thread = kthread_run(mtd_blktrans_thread, tr,
index 26ececb..727886d 100644 (file)
@@ -81,6 +81,7 @@ enum {
         */
        REQ_LB_OP_EJECT = 0x40,         /* eject request */
        REQ_LB_OP_FLUSH = 0x41,         /* flush device */
+       REQ_LB_OP_DISCARD = 0x42,       /* discard sectors */
 };
 
 /*
index 310e616..8b4aa05 100644 (file)
@@ -41,6 +41,8 @@ struct mtd_blktrans_ops {
                    unsigned long block, char *buffer);
        int (*writesect)(struct mtd_blktrans_dev *dev,
                     unsigned long block, char *buffer);
+       int (*discard)(struct mtd_blktrans_dev *dev,
+                      unsigned long block, unsigned nr_blocks);
 
        /* Block layer ioctls */
        int (*getgeo)(struct mtd_blktrans_dev *dev, struct hd_geometry *geo);