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Subject[PATCH v5 12/12] mmc: add handling for two parallel block requests in issue_rw_rq
Date
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@linaro.org>
---
drivers/mmc/card/block.c | 121 +++++++++++++++++++++++++++++++++-------------
drivers/mmc/card/queue.c | 17 +++++--
drivers/mmc/card/queue.h | 1 +
3 files changed, 101 insertions(+), 38 deletions(-)
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index 6a84a75..66db77a 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -108,6 +108,7 @@ static DEFINE_MUTEX(open_lock);

enum mmc_blk_status {
MMC_BLK_SUCCESS = 0,
+ MMC_BLK_PARTIAL,
MMC_BLK_RETRY,
MMC_BLK_DATA_ERR,
MMC_BLK_CMD_ERR,
@@ -668,14 +669,16 @@ static inline void mmc_apply_rel_rw(struct mmc_blk_request *brq,
}
}

-static enum mmc_blk_status 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)
{
struct mmc_command cmd;
u32 status = 0;
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;

/*
* Check for errors here, but don't jump to cmd_err
@@ -770,7 +773,11 @@ static enum mmc_blk_status mmc_blk_err_check(struct mmc_blk_request *brq,
else
ret = MMC_BLK_DATA_ERR;
}
-out:
+
+ if (ret == MMC_BLK_SUCCESS &&
+ blk_rq_bytes(req) != brq->data.bytes_xfered)
+ ret = MMC_BLK_PARTIAL;
+ out:
return ret;
}

@@ -901,27 +908,59 @@ 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;
+ struct mmc_blk_request *brq;
+ int ret = 1;
+ int disable_multi = 0;
enum mmc_blk_status status;
+ struct mmc_queue_req *mq_rq;
+ struct request *req;
+ struct mmc_async_req *areq;
+
+ if (!rqc && !mq->mqrq_prev->req)
+ goto out;

do {
- mmc_blk_rw_rq_prep(mq->mqrq_cur, card, disable_multi, mq);
- mmc_wait_for_req(card->host, &brq->mrq);
+ 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)
+ goto out;

- mmc_queue_bounce_post(mq->mqrq_cur);
- status = mmc_blk_err_check(brq, req, card, md);
+ 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);

switch (status) {
- case MMC_BLK_CMD_ERR:
- goto cmd_err;
+ case MMC_BLK_SUCCESS:
+ case MMC_BLK_PARTIAL:
+ /*
+ * A block was successfully transferred.
+ */
+ spin_lock_irq(&md->lock);
+ 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_err;
+ }
break;
case MMC_BLK_RETRY:
disable_multi = 1;
@@ -934,36 +973,41 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req)
* read a single sector.
*/
spin_lock_irq(&md->lock);
- ret = __blk_end_request(req, -EIO,
- brq->data.blksz);
+ ret = __blk_end_request(req, -EIO, brq->data.blksz);
spin_unlock_irq(&md->lock);
-
+ if (!ret)
+ goto start_new_req;
break;
- case MMC_BLK_SUCCESS:
+ case MMC_BLK_CMD_ERR:
+ ret = 1;
+ goto cmd_err;
+ break;
+ }
+
+ if (ret) {
/*
- * A block was successfully transferred.
+ * In case of a none complete request
+ * prepare it again and resend.
*/
- spin_lock_irq(&md->lock);
- ret = __blk_end_request(req, 0, brq->data.bytes_xfered);
- spin_unlock_irq(&md->lock);
- break;
+ 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;
-
+ out:
+ return 0;
cmd_err:
- /*
- * If this is an SD card and we're writing, we can first
- * mark the known good sectors as ok.
- *
+ /*
+ * If this is an SD card and we're writing, we can first
+ * mark the known good sectors as ok.
+ *
* If the card is not SD, we can still ok written sectors
* as reported by the controller (which might be less than
* the real number of written sectors, but never more).
*/
if (mmc_card_sd(card)) {
u32 blocks;
-
blocks = mmc_sd_num_wr_blocks(card);
if (blocks != (u32)-1) {
spin_lock_irq(&md->lock);
@@ -981,6 +1025,12 @@ 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;
}

@@ -990,26 +1040,31 @@ 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) {
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 0757a39..2d6696a 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 c8fb2dc..f937538 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


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