On 20 June 2011 17:17, Kishore Kadiyala [off-list ref] wrote:

On Mon, Jun 20, 2011 at 2:47 AM, Per Forlin [off-list ref] wrote:

quoted

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 <redacted>
---
?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);

I think 'status' is used uninitialized.
With this struct mmc_async_req *mmc_start_req in your first patch
if (error)
? ? ? ?*error = err;
return data;
condition which always passes.

It's valid to pass in NULL as status.
Do you suggest to make the status pointer mandatory?

You can have
enum mmc_blk_status status = MMC_BLK_SUCCESS;

status will be set to MMC_BLK_SUCCESS for the first iteration of the
do-while loop.
It may look like:
MMC_BLK_RETRY
MMC_BLK_PARTIAL
MMC_BLK_PARTIAL
MMC_BLK_PARTIAL
MMC_BLK_SUCCESS

This means mmc_start_req needs to return MMC_BLK_SUCCESS.

Regards,
Per