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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: Matthew Wilcox <matthew.r.wilcox@intel.com>
This commit is contained in:
Matthew Wilcox 2011-02-22 14:18:30 -05:00
parent c42705592b
commit 00df5cb4eb
1 changed files with 40 additions and 0 deletions
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40
drivers/block/nvme.c
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@ -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",