[PATCH] mmc/core:fix mmc_sd_hw_reset oops mmc_sd_hw_reset function may be oops if the ejection of sd and the reset of sd simultaneously occur

[yanxiaoyong5]

Signed-off-by: yanxiaoyong5 <yanxiaoyong5@xxxxxxxxx>
---
 drivers/mmc/core/sd.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index fe914ff..73a1e68 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -1247,8 +1247,13 @@ static int mmc_sd_runtime_resume(struct mmc_host *host)
 
 static int mmc_sd_hw_reset(struct mmc_host *host)
 {
-	mmc_power_cycle(host, host->card->ocr);
-	return mmc_sd_init_card(host, host->card->ocr, host->card);
+	struct mmc_card *card;
+
+	card = host->card;
+	if (!card)
+		return -EINVAL;
+	mmc_power_cycle(host, card->ocr);
+	return mmc_sd_init_card(host, card->ocr, host->card);
 }
 
 static const struct mmc_bus_ops mmc_sd_ops = {
-- 
2.7.4