linux-kernel - [PATCH v2] mmc: core: optimize mmc_calc_max

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Message-Id: <1518111705-11122-1-git-send-email-vlvrdv@gmail.com>
Date:   Thu,  8 Feb 2018 11:41:43 -0600
From:   Sergio Valverde <vlvrdv@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Sergio Valverde <vlvrdv@...il.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Shawn Lin <shawn.lin@...k-chips.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] mmc: core: optimize mmc_calc_max_discard

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@...il.com>
---
Changes in v2:
- Evaluate max_discard to avoid unnecessary calls to mmc_can_trim.

 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..c32c0f4 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 (max_discard && mmc_can_trim(card)) {
 		max_trim = mmc_do_calc_max_discard(card, MMC_TRIM_ARG);
 		if (max_trim < max_discard)
 			max_discard = max_trim;
-- 
2.7.4