[PATCH 158/241] mmc: sh-mmcif: avoid oops on spurious interrupts (second try)

[Herton Ronaldo Krzesinski]

3.5.7.2 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Guennadi Liakhovetski <g.liakhovetski at gmx.de>

commit 91ab252ac5a5c3461dd6910797611e9172626aed upstream.

On some systems, e.g., kzm9g, MMCIF interfaces can produce spurious
interrupts without any active request. To prevent the Oops, that results
in such cases, don't dereference the mmc request pointer until we make
sure, that we are indeed processing such a request.

Reported-by: Tetsuyuki Kobayashi <koba at kmckk.co.jp>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski at gmx.de>
Tested-by: Tetsuyuki Kobayashi <koba at kmckk.co.jp>
Signed-off-by: Chris Ball <cjb at laptop.org>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 drivers/mmc/host/sh_mmcif.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c
index 724b35e..a5786a8 100644
--- a/drivers/mmc/host/sh_mmcif.c
+++ b/drivers/mmc/host/sh_mmcif.c
@@ -1066,7 +1066,6 @@ static irqreturn_t sh_mmcif_irqt(int irq, void *dev_id)
 {
 	struct sh_mmcif_host *host = dev_id;
 	struct mmc_request *mrq = host->mrq;
-	struct mmc_data *data = mrq->data;
 
 	cancel_delayed_work_sync(&host->timeout_work);
 
@@ -1114,13 +1113,14 @@ static irqreturn_t sh_mmcif_irqt(int irq, void *dev_id)
 	case MMCIF_WAIT_FOR_READ_END:
 	case MMCIF_WAIT_FOR_WRITE_END:
 		if (host->sd_error)
-			data->error = sh_mmcif_error_manage(host);
+			mrq->data->error = sh_mmcif_error_manage(host);
 		break;
 	default:
 		BUG();
 	}
 
 	if (host->wait_for != MMCIF_WAIT_FOR_STOP) {
+		struct mmc_data *data = mrq->data;
 		if (!mrq->cmd->error && data && !data->error)
 			data->bytes_xfered =
 				data->blocks * data->blksz;
-- 
1.7.9.5