Re: [PATCH v3] mmc: core: Optimize the mmc erase size alignment

From: Shawn Lin
Date: Fri Sep 02 2016 - 04:35:51 EST


Hi Baolin,

On 2016/8/31 17:32, Baolin Wang wrote:
Before issuing mmc_erase() function, users always have checked if it can
erase with mmc_can_erase/trim/discard() function, thus remove the redundant
erase checking in mmc_erase() function.

This patch also optimizes the erase start/end sector alignment with

It implies you could split this patch into two for dealing with diff
things. :) Otherwise, you could add my test tag,

Tested-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>

round_up()/round_down() function, when erase command is MMC_ERASE_ARG.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
---
Changes since v2:
- Add nr checking and other optimization in mmc_erase() function.

Changes since v1:
- Add the alignment if card->erase_size is not power of 2.
---
drivers/mmc/core/core.c | 82 ++++++++++++++++++++++++++++++-----------------
1 file changed, 53 insertions(+), 29 deletions(-)

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index e55cde6..52156d4 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2202,6 +2202,51 @@ 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;
+
+ if (is_power_of_2(card->erase_size)) {
+ unsigned int temp = from_new;
+
+ from_new = round_up(temp, card->erase_size);
+ rem = from_new - temp;
+
+ if (nr_new > rem)
+ nr_new -= rem;
+ else
+ return 0;
+
+ nr_new = round_down(nr_new, card->erase_size);
+ } else {
+ 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
@@ -2217,13 +2262,6 @@ int mmc_erase(struct mmc_card *card, unsigned int from, unsigned int nr,
unsigned int rem, to = from + nr;
int err;

- if (!(card->host->caps & MMC_CAP_ERASE) ||
- !(card->csd.cmdclass & CCC_ERASE))
- return -EOPNOTSUPP;
-
- if (!card->erase_size)
- return -EOPNOTSUPP;
-
if (mmc_card_sd(card) && arg != MMC_ERASE_ARG)
return -EOPNOTSUPP;

@@ -2240,31 +2278,17 @@ int mmc_erase(struct mmc_card *card, unsigned int from, unsigned int nr,
return -EINVAL;
}

- 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;
- }
-
if (nr == 0)
return 0;

- to = from + nr;
-
- if (to <= from)
- return -EINVAL;
-
- /* 'from' and 'to' are inclusive */
- to -= 1;
+ if (arg == MMC_ERASE_ARG) {
+ nr = mmc_align_erase_size(card, &from, &to, nr);
+ if (nr == 0)
+ return 0;
+ } else {
+ /* 'from' and 'to' are inclusive */
+ to -= 1;
+ }

/*
* Special case where only one erase-group fits in the timeout budget:



--
Best Regards
Shawn Lin