[PATCH V14 17/24] mmc: block: blk-mq: Add support for direct completion

Adrian Hunter
2017-11-21T13:42:43Z

For blk-mq, add support for completing requests directly in the ->done
callback. That means that error handling and urgent background operations
must be handled by recovery_work in that case.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
drivers/mmc/core/block.c | 102 +++++++++++++++++++++++++++++++++++++++++------
drivers/mmc/core/block.h | 1 +
drivers/mmc/core/queue.c | 5 ++-
drivers/mmc/core/queue.h | 6 +++
include/linux/mmc/host.h | 1 +
5 files changed, 101 insertions(+), 14 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 2aacd3fa0d1a..b1857eee46fd 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -2154,6 +2154,22 @@ static void mmc_blk_mq_rw_recovery(struct mmc_queue *mq, struct request *req)
}
}

+static inline bool mmc_blk_rq_error(struct mmc_blk_request *brq)
+{
+ mmc_blk_eval_resp_error(brq);
+
+ return brq->sbc.error || brq->cmd.error || brq->stop.error ||
+ brq->data.error || brq->cmd.resp[0] & CMD_ERRORS;
+}
+
+static inline void mmc_blk_rw_reset_success(struct mmc_queue *mq,
+ struct request *req)
+{
+ int type = rq_data_dir(req) == READ ? MMC_BLK_READ : MMC_BLK_WRITE;
+
+ mmc_blk_reset_success(mq->blkdata, type);
+}
+
static void mmc_blk_mq_complete_rq(struct mmc_queue *mq, struct request *req)
{
struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
@@ -2234,14 +2250,43 @@ static void mmc_blk_mq_post_req(struct mmc_queue *mq, struct request *req)

mmc_post_req(host, mrq, 0);

- blk_mq_complete_request(req);
+ /*
+ * Block layer timeouts race with completions which means the normal
+ * completion path cannot be used during recovery.
+ */
+ if (mq->in_recovery)
+ mmc_blk_mq_complete_rq(mq, req);
+ else
+ blk_mq_complete_request(req);

mmc_blk_mq_acct_req_done(mq, req);
}

+void mmc_blk_mq_recovery(struct mmc_queue *mq)
+{
+ struct request *req = mq->recovery_req;
+ struct mmc_host *host = mq->card->host;
+ struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
+
+ mq->recovery_req = NULL;
+ mq->rw_wait = false;
+
+ if (mmc_blk_rq_error(&mqrq->brq)) {
+ mmc_retune_hold_now(host);
+ mmc_blk_mq_rw_recovery(mq, req);
+ }
+
+ mmc_blk_urgent_bkops(mq, mqrq);
+
+ mmc_blk_mq_post_req(mq, req);
+}
+
static void mmc_blk_mq_complete_prev_req(struct mmc_queue *mq,
struct request **prev_req)
{
+ if (mmc_queue_direct_complete(mq->card->host))
+ return;
+
mutex_lock(&mq->complete_lock);

if (!mq->complete_req)
@@ -2275,19 +2320,43 @@ static void mmc_blk_mq_req_done(struct mmc_request *mrq)
struct request *req = mmc_queue_req_to_req(mqrq);
struct request_queue *q = req->q;
struct mmc_queue *mq = q->queuedata;
+ struct mmc_host *host = mq->card->host;
unsigned long flags;
- bool waiting;

- spin_lock_irqsave(q->queue_lock, flags);
- mq->complete_req = req;
- mq->rw_wait = false;
- waiting = mq->waiting;
- spin_unlock_irqrestore(q->queue_lock, flags);
+ if (!mmc_queue_direct_complete(host)) {
+ bool waiting;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ mq->complete_req = req;
+ mq->rw_wait = false;
+ waiting = mq->waiting;
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ if (waiting)
+ wake_up(&mq->wait);
+ else
+ kblockd_schedule_work(&mq->complete_work);
+
+ return;
+ }

- if (waiting)
+ if (mmc_blk_rq_error(&mqrq->brq) ||
+ mmc_blk_urgent_bkops_needed(mq, mqrq)) {
+ spin_lock_irqsave(q->queue_lock, flags);
+ mq->recovery_needed = true;
+ mq->recovery_req = req;
+ spin_unlock_irqrestore(q->queue_lock, flags);
wake_up(&mq->wait);
- else
- kblockd_schedule_work(&mq->complete_work);
+ schedule_work(&mq->recovery_work);
+ return;
+ }
+
+ mmc_blk_rw_reset_success(mq, req);
+
+ mq->rw_wait = false;
+ wake_up(&mq->wait);
+
+ mmc_blk_mq_post_req(mq, req);
}

static bool mmc_blk_rw_wait_cond(struct mmc_queue *mq, int *err)
@@ -2297,7 +2366,12 @@ static bool mmc_blk_rw_wait_cond(struct mmc_queue *mq, int *err)
bool done;

spin_lock_irqsave(q->queue_lock, flags);
- done = !mq->rw_wait;
+ if (mq->recovery_needed) {
+ *err = -EBUSY;
+ done = true;
+ } else {
+ done = !mq->rw_wait;
+ }
mq->waiting = !done;
spin_unlock_irqrestore(q->queue_lock, flags);

@@ -2340,10 +2414,12 @@ static int mmc_blk_mq_issue_rw_rq(struct mmc_queue *mq,
if (prev_req)
mmc_blk_mq_post_req(mq, prev_req);

- if (err) {
+ if (err)
mq->rw_wait = false;
+
+ /* Release re-tuning here where there is no synchronization required */
+ if (err || mmc_queue_direct_complete(host))
mmc_retune_release(host);
- }

out_post_req:
if (err)
diff --git a/drivers/mmc/core/block.h b/drivers/mmc/core/block.h
index f472ce5d5647..b126418fd163 100644
--- a/drivers/mmc/core/block.h
+++ b/drivers/mmc/core/block.h
@@ -13,6 +13,7 @@

enum mmc_issued mmc_blk_mq_issue_rq(struct mmc_queue *mq, struct request *req);
void mmc_blk_mq_complete(struct request *req);
+void mmc_blk_mq_recovery(struct mmc_queue *mq);

struct work_struct;

diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index d0eae15261d7..148a13d9adf0 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -165,7 +165,10 @@ static void mmc_mq_recovery_handler(struct work_struct *work)

mq->in_recovery = true;

- mmc_blk_cqe_recovery(mq);
+ if (mq->use_cqe)
+ mmc_blk_cqe_recovery(mq);
+ else
+ mmc_blk_mq_recovery(mq);

mq->in_recovery = false;

diff --git a/drivers/mmc/core/queue.h b/drivers/mmc/core/queue.h
index 1d7d3b0afff8..c4271fa54f1a 100644
--- a/drivers/mmc/core/queue.h
+++ b/drivers/mmc/core/queue.h
@@ -103,6 +103,7 @@ struct mmc_queue {
bool waiting;
struct work_struct recovery_work;
wait_queue_head_t wait;
+ struct request *recovery_req;
struct request *complete_req;
struct mutex complete_lock;
struct work_struct complete_work;
@@ -134,4 +135,9 @@ static inline int mmc_cqe_qcnt(struct mmc_queue *mq)
mq->in_flight[MMC_ISSUE_ASYNC];
}

+static inline bool mmc_queue_direct_complete(struct mmc_host *host)
+{
+ return host->caps & MMC_CAP_DIRECT_COMPLETE;
+}
+
#endif
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index ce2075d6f429..4b68a95a8818 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -324,6 +324,7 @@ struct mmc_host {
#define MMC_CAP_DRIVER_TYPE_A (1 << 23) /* Host supports Driver Type A */
#define MMC_CAP_DRIVER_TYPE_C (1 << 24) /* Host supports Driver Type C */
#define MMC_CAP_DRIVER_TYPE_D (1 << 25) /* Host supports Driver Type D */
+#define MMC_CAP_DIRECT_COMPLETE (1 << 27) /* RW reqs can be completed within mmc_request_done() */
#define MMC_CAP_CD_WAKE (1 << 28) /* Enable card detect wake */
#define MMC_CAP_CMD_DURING_TFR (1 << 29) /* Commands during data transfer */
#define MMC_CAP_CMD23 (1 << 30) /* CMD23 supported. */
--
1.9.1