Commit 00df5cb4 authored by Matthew Wilcox's avatar Matthew Wilcox
Browse files

NVMe: Implement Flush 



Linux implements Flush as a bit in the bio.  That means there may also be
data associated with the flush; if so the flush should be sent before the
data.  To avoid completing the bio twice, I add CMD_CTX_FLUSH to indicate
the completion routine should do nothing.

Signed-off-by: default avatarMatthew Wilcox <matthew.r.wilcox@intel.com>
parent c4270559

drivers/block/nvme.c

+40 −0
Original line number Diff line number Diff line
@@ -191,10 +191,12 @@ enum { 
	bio_completion_id,

};



/* Special values must be a multiple of 4, and less than 0x1000 */

#define CMD_CTX_BASE		(POISON_POINTER_DELTA + sync_completion_id)

#define CMD_CTX_CANCELLED	(0x30C + CMD_CTX_BASE)

#define CMD_CTX_COMPLETED	(0x310 + CMD_CTX_BASE)

#define CMD_CTX_INVALID		(0x314 + CMD_CTX_BASE)

#define CMD_CTX_FLUSH		(0x318 + CMD_CTX_BASE)



static unsigned long free_cmdid(struct nvme_queue *nvmeq, int cmdid)

{
@@ -416,6 +418,33 @@ static int nvme_map_bio(struct device *dev, struct nvme_bio *nbio, 
	return dma_map_sg(dev, nbio->sg, nbio->nents, dma_dir);

}



static int nvme_submit_flush(struct nvme_queue *nvmeq, struct nvme_ns *ns,

								int cmdid)

{

	struct nvme_command *cmnd = &nvmeq->sq_cmds[nvmeq->sq_tail];



	memset(cmnd, 0, sizeof(*cmnd));

	cmnd->common.opcode = nvme_cmd_flush;

	cmnd->common.command_id = cmdid;

	cmnd->common.nsid = cpu_to_le32(ns->ns_id);



	if (++nvmeq->sq_tail == nvmeq->q_depth)

		nvmeq->sq_tail = 0;

	writel(nvmeq->sq_tail, nvmeq->q_db);



	return 0;

}



static int nvme_submit_flush_data(struct nvme_queue *nvmeq, struct nvme_ns *ns)

{

	int cmdid = alloc_cmdid(nvmeq, (void *)CMD_CTX_FLUSH,

						sync_completion_id, IO_TIMEOUT);

	if (unlikely(cmdid < 0))

		return cmdid;



	return nvme_submit_flush(nvmeq, ns, cmdid);

}



static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,

								struct bio *bio)

{
@@ -427,6 +456,12 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns, 
	u32 dsmgmt;

	int psegs = bio_phys_segments(ns->queue, bio);



	if ((bio->bi_rw & REQ_FLUSH) && psegs) {

		result = nvme_submit_flush_data(nvmeq, ns);

		if (result)

			return result;

	}



	nbio = alloc_nbio(psegs, GFP_ATOMIC);

	if (!nbio)

		goto nomem;
@@ -437,6 +472,9 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns, 
	if (unlikely(cmdid < 0))

		goto free_nbio;



	if ((bio->bi_rw & REQ_FLUSH) && !psegs)

		return nvme_submit_flush(nvmeq, ns, cmdid);



	control = 0;

	if (bio->bi_rw & REQ_FUA)

		control |= NVME_RW_FUA;
@@ -520,6 +558,8 @@ static void sync_completion(struct nvme_queue *nvmeq, void *ctx, 
	struct sync_cmd_info *cmdinfo = ctx;

	if (unlikely((unsigned long)cmdinfo == CMD_CTX_CANCELLED))

		return;

	if ((unsigned long)cmdinfo == CMD_CTX_FLUSH)

		return;

	if (unlikely((unsigned long)cmdinfo == CMD_CTX_COMPLETED)) {

		dev_warn(nvmeq->q_dmadev,

				"completed id %d twice on queue %d\n",

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