[PATCH AUTOSEL 5.10 10/47] mmc: mediatek: fix race condition between msdc_request_timeout and irq

Sasha Levin
2021-03-02T19:49:12Z

From: Chaotian Jing <chaotian.jing@mediatek.com>

[ Upstream commit 0354ca6edd464a2cf332f390581977b8699ed081 ]

when get request SW timeout, if CMD/DAT xfer done irq coming right now,
then there is race between the msdc_request_timeout work and irq handler,
and the host->cmd and host->data may set to NULL in irq handler. also,
current flow ensure that only one path can go to msdc_request_done(), so
no need check the return value of cancel_delayed_work().

Signed-off-by: Chaotian Jing <chaotian.jing@mediatek.com>
Link: https://lore.kernel.org/r/20201218071611.12276-1-chaotian.jing@mediatek.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/mmc/host/mtk-sd.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
index 004fbfc23672..dc84e2dff408 100644
--- a/drivers/mmc/host/mtk-sd.c
+++ b/drivers/mmc/host/mtk-sd.c
@@ -1101,13 +1101,13 @@ static void msdc_track_cmd_data(struct msdc_host *host,
static void msdc_request_done(struct msdc_host *host, struct mmc_request *mrq)
{
unsigned long flags;
- bool ret;

- ret = cancel_delayed_work(&host->req_timeout);
- if (!ret) {
- /* delay work already running */
- return;
- }
+ /*
+ * No need check the return value of cancel_delayed_work, as only ONE
+ * path will go here!
+ */
+ cancel_delayed_work(&host->req_timeout);
+
spin_lock_irqsave(&host->lock, flags);
host->mrq = NULL;
spin_unlock_irqrestore(&host->lock, flags);
@@ -1129,7 +1129,7 @@ static bool msdc_cmd_done(struct msdc_host *host, int events,
bool done = false;
bool sbc_error;
unsigned long flags;
- u32 *rsp = cmd->resp;
+ u32 *rsp;

if (mrq->sbc && cmd == mrq->cmd &&
(events & (MSDC_INT_ACMDRDY | MSDC_INT_ACMDCRCERR
@@ -1150,6 +1150,7 @@ static bool msdc_cmd_done(struct msdc_host *host, int events,

if (done)
return true;
+ rsp = cmd->resp;

sdr_clr_bits(host->base + MSDC_INTEN, cmd_ints_mask);

@@ -1337,7 +1338,7 @@ static void msdc_data_xfer_next(struct msdc_host *host,
static bool msdc_data_xfer_done(struct msdc_host *host, u32 events,
struct mmc_request *mrq, struct mmc_data *data)
{
- struct mmc_command *stop = data->stop;
+ struct mmc_command *stop;
unsigned long flags;
bool done;
unsigned int check_data = events &
@@ -1353,6 +1354,7 @@ static bool msdc_data_xfer_done(struct msdc_host *host, u32 events,

if (done)
return true;
+ stop = data->stop;

if (check_data || (stop && stop->error)) {
dev_dbg(host->dev, "DMA status: 0x%8X\n",
--
2.30.1