[PATCH] mmc: core: optimize mmc_calc_max_discard

[Sergio Valverde <vlvrdv@gmail.com>]

If the max_discard value is zero, the conditional branch that checks the
trim capabilities will never update this value with max_trim.

Change the condition statement to also check the max_discard value in order
to avoid an unnecessary call to mmc_do_calc_max_discard.

Signed-off-by: Sergio Valverde <vlvrdv@gmail.com>
---
 drivers/mmc/core/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 1f0f44f..97856b1 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2567,7 +2567,7 @@ unsigned int mmc_calc_max_discard(struct mmc_card *card)
 		return card->pref_erase;
 
 	max_discard = mmc_do_calc_max_discard(card, MMC_ERASE_ARG);
-	if (mmc_can_trim(card)) {
+	if (mmc_can_trim(card) && max_discard) {
 		max_trim = mmc_do_calc_max_discard(card, MMC_TRIM_ARG);
 		if (max_trim < max_discard)
 			max_discard = max_trim;
-- 
2.7.4