From c15227de132f1295f3db6b7df9079956b1020fd8 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 30 Sep 2009 13:52:12 +0200 Subject: block: use normal I/O path for discard requests prepare_discard_fn() was being called in a place where memory allocation was effectively impossible. This makes it inappropriate for all but the most trivial translations of Linux's DISCARD operation to the block command set. Additionally adding a payload there makes the ownership of the bio backing unclear as it's now allocated by the device driver and not the submitter as usual. It is replaced with QUEUE_FLAG_DISCARD which is used to indicate whether the queue supports discard operations or not. blkdev_issue_discard now allocates a one-page, sector-length payload which is the right thing for the common ATA and SCSI implementations. The mtd implementation of prepare_discard_fn() is replaced with simply checking for the request being a discard. Largely based on a previous patch from Matthew Wilcox which did the prepare_discard_fn but not the different payload allocation yet. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- drivers/mtd/mtd_blkdevs.c | 19 +++++-------------- 1 file changed, 5 insertions(+), 14 deletions(-) (limited to 'drivers/mtd') diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c index 0acbf4f5be5..8ca17a3e96e 100644 --- a/drivers/mtd/mtd_blkdevs.c +++ b/drivers/mtd/mtd_blkdevs.c @@ -32,14 +32,6 @@ 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) @@ -52,10 +44,6 @@ 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 -EIO; @@ -63,6 +51,9 @@ static int do_blktrans_request(struct mtd_blktrans_ops *tr, get_capacity(req->rq_disk)) return -EIO; + if (blk_discard_rq(req)) + return tr->discard(dev, block, nsect); + switch(rq_data_dir(req)) { case READ: for (; nsect > 0; nsect--, block++, buf += tr->blksize) @@ -380,8 +371,8 @@ int register_mtd_blktrans(struct mtd_blktrans_ops *tr) tr->blkcore_priv->rq->queuedata = tr; blk_queue_logical_block_size(tr->blkcore_priv->rq, tr->blksize); if (tr->discard) - blk_queue_set_discard(tr->blkcore_priv->rq, - blktrans_discard_request); + queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, + tr->blkcore_priv->rq); tr->blkshift = ffs(tr->blksize) - 1; -- cgit v1.2.3