Patch "mmc: card: Fixup request missing in mmc_blk_issue_rw_rq" has been added to the 3.10-stable tree

This is a note to let you know that I've just added the patch titled

mmc: card: Fixup request missing in mmc_blk_issue_rw_rq

to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mmc-card-fixup-request-missing-in-mmc_blk_issue_rw_rq.patch
and it can be found in the queue-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Ding Wang <[email protected]>
Date: Mon, 18 May 2015 20:14:15 +0800
Subject: mmc: card: Fixup request missing in mmc_blk_issue_rw_rq

From: Ding Wang <[email protected]>

commit 29535f7b797df35cc9b6b3bca635591cdd3dd2a8 upstream.

The current handler of MMC_BLK_CMD_ERR in mmc_blk_issue_rw_rq function may cause new coming request permanent missing when the ongoing request (previoulsy started) complete end.

The problem scenario is as follows:
(1) Request A is ongoing;
(2) Request B arrived, and finally mmc_blk_issue_rw_rq() is called;
(3) Request A encounters the MMC_BLK_CMD_ERR error;
(4) In the error handling of MMC_BLK_CMD_ERR, suppose mmc_blk_cmd_err() end request A completed and return zero. Continue the error handling, suppose mmc_blk_reset() reset device success;
(5) Continue the execution, while loop completed because variable ret

    is zero now;

(6) Finally, mmc_blk_issue_rw_rq() return without processing request B.

The process related to the missing request may wait that IO request complete forever, possibly crashing the application or hanging the system.

Fix this issue by starting new request when reset success.

---
 drivers/mmc/card/block.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

@@ -1835,9 +1835,11 @@ static int mmc_blk_issue_rw_rq(struct mm
 			break;
 		case MMC_BLK_CMD_ERR:
 			ret = mmc_blk_cmd_err(md, card, brq, req, ret);
-			if (!mmc_blk_reset(md, card->host, type))
-				break;
-			goto cmd_abort;
+			if (mmc_blk_reset(md, card->host, type))
+				goto cmd_abort;
+			if (!ret)
+				goto start_new_req;
+			break;
 		case MMC_BLK_RETRY:
 			if (retry++ < 5)
 				break;

Patches currently in stable-queue which might be from [email protected] are

queue-3.10/mmc-card-fixup-request-missing-in-mmc_blk_issue_rw_rq.patch