linux-kernel - [PATCH v4 2/3] mmc: core: Factor out the alignment of erase size

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Date:   Tue,  6 Sep 2016 10:55:11 +0800
From:   Baolin Wang <baolin.wang@...aro.org>
To:     ulf.hansson@...aro.org
Cc:     adrian.hunter@...el.com, rmk+kernel@....linux.org.uk,
        shawn.lin@...k-chips.com, dianders@...omium.org, heiko@...ech.de,
        david@...tonic.nl, hdegoede@...hat.com, linux-mmc@...r.kernel.org,
        linux-kernel@...r.kernel.org, broonie@...nel.org,
        linus.walleij@...aro.org, baolin.wang@...aro.org
Subject: [PATCH v4 2/3] mmc: core: Factor out the alignment of erase size

In order to clean up the mmc_erase() function and do some optimization
for erase size alignment, factor out the guts of erase size alignment
into mmc_align_erase_size() function.

Signed-off-by: Baolin Wang <baolin.wang@...aro.org>
Tested-by: Shawn Lin <shawn.lin@...k-chips.com>
---
 drivers/mmc/core/core.c |   60 +++++++++++++++++++++++++++++------------------
 1 file changed, 37 insertions(+), 23 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 7d7209d..5f93eef 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2202,6 +2202,37 @@ out:
 	return err;
 }
 
+static unsigned int mmc_align_erase_size(struct mmc_card *card,
+					 unsigned int *from,
+					 unsigned int *to,
+					 unsigned int nr)
+{
+	unsigned int from_new = *from, nr_new = nr, rem;
+
+	rem = from_new % card->erase_size;
+	if (rem) {
+		rem = card->erase_size - rem;
+		from_new += rem;
+		if (nr_new > rem)
+			nr_new -= rem;
+		else
+			return 0;
+	}
+
+	rem = nr_new % card->erase_size;
+	if (rem)
+		nr_new -= rem;
+
+	if (nr_new == 0)
+		return 0;
+
+	/* 'from' and 'to' are inclusive */
+	*to = from_new + nr_new - 1;
+	*from = from_new;
+
+	return nr_new;
+}
+
 /**
  * mmc_erase - erase sectors.
  * @card: card to erase
@@ -2234,31 +2265,14 @@ int mmc_erase(struct mmc_card *card, unsigned int from, unsigned int nr,
 	}
 
 	if (arg == MMC_ERASE_ARG) {
-		rem = from % card->erase_size;
-		if (rem) {
-			rem = card->erase_size - rem;
-			from += rem;
-			if (nr > rem)
-				nr -= rem;
-			else
-				return 0;
-		}
-		rem = nr % card->erase_size;
-		if (rem)
-			nr -= rem;
+		nr = mmc_align_erase_size(card, &from, &to, nr);
+		if (nr == 0)
+			return 0;
+	} else {
+		/* 'from' and 'to' are inclusive */
+		to -= 1;
 	}
 
-	if (nr == 0)
-		return 0;
-
-	to = from + nr;
-
-	if (to <= from)
-		return -EINVAL;
-
-	/* 'from' and 'to' are inclusive */
-	to -= 1;
-
 	/*
 	 * Special case where only one erase-group fits in the timeout budget:
 	 * If the region crosses an erase-group boundary on this particular
-- 
1.7.9.5