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mmc: block: Add CQE support

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Add CQE support to the block driver, including:
    - optionally using DCMD for flush requests
    - "manually" issuing discard requests
    - issuing read / write requests to the CQE
    - supporting block-layer timeouts
    - handling recovery
    - supporting re-tuning

CQE offers 25% - 50% better random multi-threaded I/O.  There is a slight
(e.g. 2%) drop in sequential read speed but no observable change to sequential
write.

CQE automatically sends the commands to complete requests.  However it only
supports reads / writes and so-called "direct commands" (DCMD).  Furthermore
DCMD is limited to one command at a time, but discards require 3 commands.
That makes issuing discards through CQE very awkward, but some CQE's don't
support DCMD anyway.  So for discards, the existing non-CQE approach is
taken, where the mmc core code issues the 3 commands one at a time i.e.
mmc_erase(). Where DCMD is used, is for issuing flushes.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Adrian Hunter 2017-11-29 15:41:04 +02:00 • committed by Ulf Hansson
parent 81196976ed
commit 1e8e55b670
4 changed files with 326 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

150
drivers/mmc/core/block.c
View file

@ -112,6 +112,7 @@ struct mmc_blk_data {
#define MMC_BLK_WRITE BIT(1)
#define MMC_BLK_DISCARD BIT(2)
#define MMC_BLK_SECDISCARD BIT(3)
#define MMC_BLK_CQE_RECOVERY BIT(4)
/*
* Only set in main mmc_blk_data associated
@ -1730,6 +1731,138 @@ static void mmc_blk_data_prep(struct mmc_queue *mq, struct mmc_queue_req *mqrq,
*do_data_tag_p = do_data_tag;
}
#define MMC_CQE_RETRIES 2
static void mmc_blk_cqe_complete_rq(struct mmc_queue *mq, struct request *req)
{
struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
struct mmc_request *mrq = &mqrq->brq.mrq;
struct request_queue *q = req->q;
struct mmc_host *host = mq->card->host;
unsigned long flags;
bool put_card;
int err;
mmc_cqe_post_req(host, mrq);
if (mrq->cmd && mrq->cmd->error)
err = mrq->cmd->error;
else if (mrq->data && mrq->data->error)
err = mrq->data->error;
else
err = 0;
if (err) {
if (mqrq->retries++ < MMC_CQE_RETRIES)
blk_mq_requeue_request(req, true);
else
blk_mq_end_request(req, BLK_STS_IOERR);
} else if (mrq->data) {
if (blk_update_request(req, BLK_STS_OK, mrq->data->bytes_xfered))
blk_mq_requeue_request(req, true);
else
__blk_mq_end_request(req, BLK_STS_OK);
} else {
blk_mq_end_request(req, BLK_STS_OK);
}
spin_lock_irqsave(q->queue_lock, flags);
mq->in_flight[mmc_issue_type(mq, req)] -= 1;
put_card = (mmc_tot_in_flight(mq) == 0);
mmc_cqe_check_busy(mq);
spin_unlock_irqrestore(q->queue_lock, flags);
if (!mq->cqe_busy)
blk_mq_run_hw_queues(q, true);
if (put_card)
mmc_put_card(mq->card, &mq->ctx);
}
void mmc_blk_cqe_recovery(struct mmc_queue *mq)
{
struct mmc_card *card = mq->card;
struct mmc_host *host = card->host;
int err;
pr_debug("%s: CQE recovery start\n", mmc_hostname(host));
err = mmc_cqe_recovery(host);
if (err)
mmc_blk_reset(mq->blkdata, host, MMC_BLK_CQE_RECOVERY);
else
mmc_blk_reset_success(mq->blkdata, MMC_BLK_CQE_RECOVERY);
pr_debug("%s: CQE recovery done\n", mmc_hostname(host));
}
static void mmc_blk_cqe_req_done(struct mmc_request *mrq)
{
struct mmc_queue_req *mqrq = container_of(mrq, struct mmc_queue_req,
brq.mrq);
struct request *req = mmc_queue_req_to_req(mqrq);
struct request_queue *q = req->q;
struct mmc_queue *mq = q->queuedata;
/*
* Block layer timeouts race with completions which means the normal
* completion path cannot be used during recovery.
*/
if (mq->in_recovery)
mmc_blk_cqe_complete_rq(mq, req);
else
blk_mq_complete_request(req);
}
static int mmc_blk_cqe_start_req(struct mmc_host *host, struct mmc_request *mrq)
{
mrq->done = mmc_blk_cqe_req_done;
mrq->recovery_notifier = mmc_cqe_recovery_notifier;
return mmc_cqe_start_req(host, mrq);
}
static struct mmc_request *mmc_blk_cqe_prep_dcmd(struct mmc_queue_req *mqrq,
struct request *req)
{
struct mmc_blk_request *brq = &mqrq->brq;
memset(brq, 0, sizeof(*brq));
brq->mrq.cmd = &brq->cmd;
brq->mrq.tag = req->tag;
return &brq->mrq;
}
static int mmc_blk_cqe_issue_flush(struct mmc_queue *mq, struct request *req)
{
struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
struct mmc_request *mrq = mmc_blk_cqe_prep_dcmd(mqrq, req);
mrq->cmd->opcode = MMC_SWITCH;
mrq->cmd->arg = (MMC_SWITCH_MODE_WRITE_BYTE << 24) |
(EXT_CSD_FLUSH_CACHE << 16) |
(1 << 8) |
EXT_CSD_CMD_SET_NORMAL;
mrq->cmd->flags = MMC_CMD_AC | MMC_RSP_R1B;
return mmc_blk_cqe_start_req(mq->card->host, mrq);
}
static int mmc_blk_cqe_issue_rw_rq(struct mmc_queue *mq, struct request *req)
{
struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
mmc_blk_data_prep(mq, mqrq, 0, NULL, NULL);
return mmc_blk_cqe_start_req(mq->card->host, &mqrq->brq.mrq);
}
static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
struct mmc_card *card,
int disable_multi,
@ -2038,7 +2171,10 @@ void mmc_blk_mq_complete(struct request *req)
{
struct mmc_queue *mq = req->q->queuedata;
mmc_blk_mq_complete_rq(mq, req);
if (mq->use_cqe)
mmc_blk_cqe_complete_rq(mq, req);
else
mmc_blk_mq_complete_rq(mq, req);
}
static void mmc_blk_mq_poll_completion(struct mmc_queue *mq,
@ -2212,6 +2348,9 @@ out_post_req:
static int mmc_blk_wait_for_idle(struct mmc_queue *mq, struct mmc_host *host)
{
if (mq->use_cqe)
return host->cqe_ops->cqe_wait_for_idle(host);
return mmc_blk_rw_wait(mq, NULL);
}
@ -2250,11 +2389,18 @@ enum mmc_issued mmc_blk_mq_issue_rq(struct mmc_queue *mq, struct request *req)
return MMC_REQ_FAILED_TO_START;
}
return MMC_REQ_FINISHED;
case MMC_ISSUE_DCMD:
case MMC_ISSUE_ASYNC:
switch (req_op(req)) {
case REQ_OP_FLUSH:
ret = mmc_blk_cqe_issue_flush(mq, req);
break;
case REQ_OP_READ:
case REQ_OP_WRITE:
ret = mmc_blk_mq_issue_rw_rq(mq, req);
if (mq->use_cqe)
ret = mmc_blk_cqe_issue_rw_rq(mq, req);
else
ret = mmc_blk_mq_issue_rw_rq(mq, req);
break;
default:
WARN_ON_ONCE(1);