From f662ae48ae67dfd42739e65750274fe8de46240a Mon Sep 17 00:00:00 2001 From: Ray Jui Date: Sat, 26 Oct 2013 11:03:44 -0700 Subject: [PATCH] mmc: fix host release issue after discard operation Under function mmc_blk_issue_rq, after an MMC discard operation, the MMC request data structure may be freed in memory. Later in the same function, the check of req->cmd_flags & MMC_REQ_SPECIAL_MASK is dangerous and invalid. It causes the MMC host not to be released when it should. This patch fixes the issue by marking the special request down before the discard/flush operation. Reported by: Harold (SoonYeal) Yang Signed-off-by: Ray Jui Reviewed-by: Seungwon Jeon Acked-by: Seungwon Jeon Cc: stable Signed-off-by: Chris Ball --- drivers/mmc/card/block.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c index 29d5d98..7b5424f 100644 --- a/drivers/mmc/card/block.c +++ b/drivers/mmc/card/block.c @@ -1959,6 +1959,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) struct mmc_card *card = md->queue.card; struct mmc_host *host = card->host; unsigned long flags; + unsigned int cmd_flags = req ? req->cmd_flags : 0; if (req && !mq->mqrq_prev->req) /* claim host only for the first request */ @@ -1974,7 +1975,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) } mq->flags &= ~MMC_QUEUE_NEW_REQUEST; - if (req && req->cmd_flags & REQ_DISCARD) { + if (cmd_flags & REQ_DISCARD) { /* complete ongoing async transfer before issuing discard */ if (card->host->areq) mmc_blk_issue_rw_rq(mq, NULL); @@ -1983,7 +1984,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) ret = mmc_blk_issue_secdiscard_rq(mq, req); else ret = mmc_blk_issue_discard_rq(mq, req); - } else if (req && req->cmd_flags & REQ_FLUSH) { + } else if (cmd_flags & REQ_FLUSH) { /* complete ongoing async transfer before issuing flush */ if (card->host->areq) mmc_blk_issue_rw_rq(mq, NULL); @@ -1999,7 +2000,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req) out: if ((!req && !(mq->flags & MMC_QUEUE_NEW_REQUEST)) || - (req && (req->cmd_flags & MMC_REQ_SPECIAL_MASK))) + (cmd_flags & MMC_REQ_SPECIAL_MASK)) /* * Release host when there are no more requests * and after special request(discard, flush) is done. -- 2.7.4