[PATCH v8 12/12] mmc: block: add handling for two parallel block requests in issue_rw_rq

Per Forlin
2011-06-28T08:11:57Z

Change mmc_blk_issue_rw_rq() to become asynchronous.
The execution flow looks like this:
The mmc-queue calls issue_rw_rq(), which sends the request
to the host and returns back to the mmc-queue. The mmc-queue calls
issue_rw_rq() again with a new request. This new request is prepared,
in isuue_rw_rq(), then it waits for the active request to complete before
pushing it to the host. When to mmc-queue is empty it will call
isuue_rw_rq() with req=NULL to finish off the active request
without starting a new request.

Signed-off-by: Per Forlin <per.forlin-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
drivers/mmc/card/block.c | 80 +++++++++++++++++++++++++++++++++++++--------
drivers/mmc/card/queue.c | 17 +++++++---
drivers/mmc/card/queue.h | 1 +
3 files changed, 78 insertions(+), 20 deletions(-)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 7ed2c68..825741e 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -822,12 +822,14 @@ static inline void mmc_apply_rel_rw(struct mmc_blk_request *brq,
R1_CC_ERROR | /* Card controller error */ \
R1_ERROR) /* General/unknown error */

-int mmc_blk_err_check(struct mmc_blk_request *brq,
- struct request *req,
- struct mmc_card *card,
- struct mmc_blk_data *md)
+static int mmc_blk_err_check(struct mmc_card *card,
+ struct mmc_async_req *areq)
{
- int ret = MMC_BLK_SUCCESS;
+ enum mmc_blk_status ret = MMC_BLK_SUCCESS;
+ struct mmc_queue_req *mq_mrq = container_of(areq, struct mmc_queue_req,
+ mmc_active);
+ struct mmc_blk_request *brq = &mq_mrq->brq;
+ struct request *req = mq_mrq->req;

/*
* sbc.error indicates a problem with the set block count
@@ -1038,24 +1040,41 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
brq->data.sg_len = i;
}

+ mqrq->mmc_active.mrq = &brq->mrq;
+ mqrq->mmc_active.err_check = mmc_blk_err_check;
+
mmc_queue_bounce_pre(mqrq);
}

-static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req)
+static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
{
struct mmc_blk_data *md = mq->data;
struct mmc_card *card = md->queue.card;
struct mmc_blk_request *brq = &mq->mqrq_cur->brq;
int ret = 1, disable_multi = 0, retry = 0;
enum mmc_blk_status status;
+ struct mmc_queue_req *mq_rq;
+ struct request *req;
+ struct mmc_async_req *areq;

- do {
- mmc_blk_rw_rq_prep(mq->mqrq_cur, card, disable_multi, mq);
- mmc_wait_for_req(card->host, &brq->mrq);
+ if (!rqc && !mq->mqrq_prev->req)
+ return 0;

- mmc_queue_bounce_post(mq->mqrq_cur);
+ do {
+ if (rqc) {
+ mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
+ areq = &mq->mqrq_cur->mmc_active;
+ } else
+ areq = NULL;
+ areq = mmc_start_req(card->host, areq, (int *) &status);
+ if (!areq)
+ return 0;
+
+ mq_rq = container_of(areq, struct mmc_queue_req, mmc_active);
+ brq = &mq_rq->brq;
+ req = mq_rq->req;
+ mmc_queue_bounce_post(mq_rq);

- status = mmc_blk_err_check(brq, req, card, md);
switch (status) {
case MMC_BLK_SUCCESS:
case MMC_BLK_PARTIAL:
@@ -1066,6 +1085,13 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req)
ret = __blk_end_request(req, 0,
brq->data.bytes_xfered);
spin_unlock_irq(&md->lock);
+ if (status == MMC_BLK_SUCCESS && ret) {
+ /* If this happen it is a bug */
+ printk(KERN_ERR "%s BUG rq_tot %d d_xfer %d\n",
+ __func__, blk_rq_bytes(req),
+ brq->data.bytes_xfered);
+ goto cmd_abort;
+ }
break;
case MMC_BLK_CMD_ERR:
goto cmd_err;
@@ -1087,9 +1113,19 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req)
ret = __blk_end_request(req, -EIO,
brq->data.blksz);
spin_unlock_irq(&md->lock);
+ if (!ret)
+ goto start_new_req;
break;
}

+ if (ret) {
+ /*
+ * In case of a none complete request
+ * prepare it again and resend.
+ */
+ mmc_blk_rw_rq_prep(mq_rq, card, disable_multi, mq);
+ mmc_start_req(card->host, &mq_rq->mmc_active, NULL);
+ }
} while (ret);

return 1;
@@ -1124,6 +1160,12 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req)
ret = __blk_end_request(req, -EIO, blk_rq_cur_bytes(req));
spin_unlock_irq(&md->lock);

+ start_new_req:
+ if (rqc) {
+ mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
+ mmc_start_req(card->host, &mq->mqrq_cur->mmc_active, NULL);
+ }
+
return 0;
}

@@ -1133,26 +1175,34 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
struct mmc_blk_data *md = mq->data;
struct mmc_card *card = md->queue.card;

- mmc_claim_host(card->host);
+ if (req && !mq->mqrq_prev->req)
+ /* claim host only for the first request */
+ mmc_claim_host(card->host);
+
ret = mmc_blk_part_switch(card, md);
if (ret) {
ret = 0;
goto out;
}

- if (req->cmd_flags & REQ_DISCARD) {
+ if (req && req->cmd_flags & REQ_DISCARD) {
+ /* complete ongoing async transfer before issuing discard */
+ if (card->host->areq)
+ mmc_blk_issue_rw_rq(mq, NULL);
if (req->cmd_flags & REQ_SECURE)
ret = mmc_blk_issue_secdiscard_rq(mq, req);
else
ret = mmc_blk_issue_discard_rq(mq, req);
- } else if (req->cmd_flags & REQ_FLUSH) {
+ } else if (req && req->cmd_flags & REQ_FLUSH) {
ret = mmc_blk_issue_flush(mq, req);
} else {
ret = mmc_blk_issue_rw_rq(mq, req);
}

out:
- mmc_release_host(card->host);
+ if (!req)
+ /* release host only when there are no more requests */
+ mmc_release_host(card->host);
return ret;
}

diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
index d69d954..8c51a54 100644
--- a/drivers/mmc/card/queue.c
+++ b/drivers/mmc/card/queue.c
@@ -52,6 +52,7 @@ static int mmc_queue_thread(void *d)
down(&mq->thread_sem);
do {
struct request *req = NULL;
+ struct mmc_queue_req *tmp;

spin_lock_irq(q->queue_lock);
set_current_state(TASK_INTERRUPTIBLE);
@@ -59,7 +60,10 @@ static int mmc_queue_thread(void *d)
mq->mqrq_cur->req = req;
spin_unlock_irq(q->queue_lock);

- if (!req) {
+ if (req || mq->mqrq_prev->req) {
+ set_current_state(TASK_RUNNING);
+ mq->issue_fn(mq, req);
+ } else {
if (kthread_should_stop()) {
set_current_state(TASK_RUNNING);
break;
@@ -67,11 +71,14 @@ static int mmc_queue_thread(void *d)
up(&mq->thread_sem);
schedule();
down(&mq->thread_sem);
- continue;
}
- set_current_state(TASK_RUNNING);

- mq->issue_fn(mq, req);
+ /* Current request becomes previous request and vice versa. */
+ mq->mqrq_prev->brq.mrq.data = NULL;
+ mq->mqrq_prev->req = NULL;
+ tmp = mq->mqrq_prev;
+ mq->mqrq_prev = mq->mqrq_cur;
+ mq->mqrq_cur = tmp;
} while (1);
up(&mq->thread_sem);

@@ -97,7 +104,7 @@ static void mmc_request(struct request_queue *q)
return;
}

- if (!mq->mqrq_cur->req)
+ if (!mq->mqrq_cur->req && !mq->mqrq_prev->req)
wake_up_process(mq->thread);
}

diff --git a/drivers/mmc/card/queue.h b/drivers/mmc/card/queue.h
index 1a637d2..d2a1eb4 100644
--- a/drivers/mmc/card/queue.h
+++ b/drivers/mmc/card/queue.h
@@ -19,6 +19,7 @@ struct mmc_queue_req {
char *bounce_buf;
struct scatterlist *bounce_sg;
unsigned int bounce_sg_len;
+ struct mmc_async_req mmc_active;
};

struct mmc_queue {
--
1.7.4.1