Commit 62612cf9 authored by Sahitya Tummala's avatar Sahitya Tummala Committed by David Brown
Browse files

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.

Signed-off-by: default avatarSahitya Tummala <stummala@codeaurora.org>
Signed-off-by: default avatarDavid Brown <davidb@codeaurora.org>
parent 50bc0ef4

drivers/mmc/host/msm_sdcc.c

+33 −16
Original line number Diff line number Diff line
@@ -189,42 +189,40 @@ 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;

	}
@@ -273,6 +271,22 @@ 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)
@@ -1118,6 +1132,9 @@ 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

	 */

drivers/mmc/host/msm_sdcc.h

+3 −0
Original line number Diff line number Diff line
@@ -172,6 +172,8 @@ struct msmsdcc_dma_data { 
	struct msmsdcc_host		*host;

	int				busy; /* Set if DM is busy */

	int				active;

	unsigned int			result;

	struct msm_dmov_errdata		err;

};



struct msmsdcc_pio_data {
@@ -235,6 +237,7 @@ struct msmsdcc_host { 
	int			cmdpoll;

	struct msmsdcc_stats	stats;



	struct tasklet_struct	dma_tlet;

	/* Command parameters */

	unsigned int		cmd_timeout;

	unsigned int		cmd_pio_irqmask;

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