From 81d981629c93026be48ffc126d36078216cc05ee Mon Sep 17 00:00:00 2001
From: SecureCRT <securecrt2008@gmail.com>
Date: Thu, 23 Aug 2012 00:10:19 +0800
Subject: [PATCH] mmc: msm_sdcc: Fix possible circular locking dependency
 warning In the context of request processing thread, data mover lock is
 acquired after the host lock.  In another context, in the completion handler
 of data mover the locks are acquired in the reverse order, resulting in
 possible circular lock dependency warning. Hence, schedule a tasklet to
 process the dma completion so as to avoid nested locks.

---
 drivers/mmc/host/msm_sdcc.c | 46 +++++++++++++++++++++++++------------
 drivers/mmc/host/msm_sdcc.h |  2 +-
 2 files changed, 32 insertions(+), 16 deletions(-)

diff --git a/drivers/mmc/host/msm_sdcc.c b/drivers/mmc/host/msm_sdcc.c
index 1f8cd0ee..c3193db6 100755
--- a/drivers/mmc/host/msm_sdcc.c
+++ b/drivers/mmc/host/msm_sdcc.c
@@ -308,42 +308,40 @@ msmsdcc_dma_exec_func(struct msm_dmov_cmd *cmd)
 }
 
 static void
-msmsdcc_dma_complete_func(struct msm_dmov_cmd *cmd,
-			  unsigned int result,
-			  struct msm_dmov_errdata *err)
+msmsdcc_dma_complete_tlet(unsigned long data)
 {
-	struct msmsdcc_dma_data	*dma_data =
-		container_of(cmd, struct msmsdcc_dma_data, hdr);
-	struct msmsdcc_host	*host = dma_data->host;
+	struct msmsdcc_host *host = (struct msmsdcc_host *)data;
 	unsigned long		flags;
 	struct mmc_request	*mrq;
+	struct msm_dmov_errdata err;
 
 	spin_lock_irqsave(&host->lock, flags);
 	host->dma.active = 0;
 
+	err = host->dma.err;
 	mrq = host->curr.mrq;
 	BUG_ON(!mrq);
 	WARN_ON(!mrq->data);
 
-	if (!(result & DMOV_RSLT_VALID)) {
+	if (!(host->dma.result & DMOV_RSLT_VALID)) {
 		pr_err("msmsdcc: Invalid DataMover result\n");
 		goto out;
 	}
 
-	if (result & DMOV_RSLT_DONE) {
+	if (host->dma.result & DMOV_RSLT_DONE) {
 		host->curr.data_xfered = host->curr.xfer_size;
 	} else {
 		/* Error or flush  */
-		if (result & DMOV_RSLT_ERROR)
+		if (host->dma.result & DMOV_RSLT_ERROR)
 			pr_err("%s: DMA error (0x%.8x)\n",
-			       mmc_hostname(host->mmc), result);
-		if (result & DMOV_RSLT_FLUSH)
+			       mmc_hostname(host->mmc), host->dma.result);
+		if (host->dma.result & DMOV_RSLT_FLUSH)
 			pr_err("%s: DMA channel flushed (0x%.8x)\n",
-			       mmc_hostname(host->mmc), result);
-		if (err)
+			       mmc_hostname(host->mmc), host->dma.result);
+
 			pr_err("Flush data: %.8x %.8x %.8x %.8x %.8x %.8x\n",
-			       err->flush[0], err->flush[1], err->flush[2],
-			       err->flush[3], err->flush[4], err->flush[5]);
+		       err.flush[0], err.flush[1], err.flush[2],
+		       err.flush[3], err.flush[4], err.flush[5]);
 		if (!mrq->data->error)
 			mrq->data->error = -EIO;
 	}
@@ -391,6 +389,22 @@ out:
 	return;
 }
 
+static void
+msmsdcc_dma_complete_func(struct msm_dmov_cmd *cmd,
+			  unsigned int result,
+			  struct msm_dmov_errdata *err)
+{
+	struct msmsdcc_dma_data	*dma_data =
+		container_of(cmd, struct msmsdcc_dma_data, hdr);
+	struct msmsdcc_host *host = dma_data->host;
+
+	dma_data->result = result;
+	if (err)
+		memcpy(&dma_data->err, err, sizeof(struct msm_dmov_errdata));
+
+	tasklet_schedule(&host->dma_tlet);
+}
+
 static int validate_dma(struct msmsdcc_host *host, struct mmc_data *data)
 {
 	if (host->dma.channel == -1)
@@ -1364,6 +1378,8 @@ msmsdcc_probe(struct platform_device *pdev)
 	host->dmares = dmares;
 	spin_lock_init(&host->lock);
 
+	tasklet_init(&host->dma_tlet, msmsdcc_dma_complete_tlet,
+			(unsigned long)host);
 
 	/*
 	 * Setup DMA
diff --git a/drivers/mmc/host/msm_sdcc.h b/drivers/mmc/host/msm_sdcc.h
index 65c4a3e5..16504610 100755
--- a/drivers/mmc/host/msm_sdcc.h
+++ b/drivers/mmc/host/msm_sdcc.h
@@ -190,7 +190,7 @@ struct msmsdcc_dma_data {
 	int				busy; /* Set if DM is busy */
 	int				active;
 	unsigned int 			result;
-	struct msm_dmov_errdata 	*err;
+	struct msm_dmov_errdata		err;
 };
 
 struct msmsdcc_pio_data {