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

Message ID 9de99671750430d7d80a8f351c0ec7a7088c9b00.1472635587.git.baolin.wang@linaro.org
State New
Headers show

Commit Message

(Exiting) Baolin Wang Aug. 31, 2016, 9:32 a.m.
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
round_up()/round_down() function, when erase command is MMC_ERASE_ARG.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

---
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(-)

-- 
1.7.9.5

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Comments

(Exiting) Baolin Wang Sept. 5, 2016, 8:17 a.m. | #1
Hi Shawn,

On 2 September 2016 at 16:34, Shawn Lin <shawn.lin@rock-chips.com> wrote:
> 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,


Yes, I will split it into two separate patches and thanks for your testing.

>

> Tested-by: Shawn Lin <shawn.lin@rock-chips.com>

>

>

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

>>

>> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

>> ---

>> 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

>




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(Exiting) Baolin Wang Sept. 5, 2016, 8:27 a.m. | #2
Hi Ulf,


On 2 September 2016 at 17:43, Ulf Hansson <ulf.hansson@linaro.org> wrote:
> On 31 August 2016 at 11:32, Baolin Wang <baolin.wang@linaro.org> 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

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

>>

>> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>

>> ---

>> 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)

>> +{

>

> How about make one patch that starts by moving the existing code into

> a separate function, then on top as a new change, start playing with

> the optimizations!?

> That would be more easy to review.


Make sense. I'll do what you suggested in next version.

>

>> +       unsigned int from_new = *from, nr_new = nr, rem;

>> +

>> +       if (is_power_of_2(card->erase_size)) {

>

> I would like some comment in the code, to understand what/why we do this.


I think the erase_size is power of 2 in most cases, then the
round_up/down() is more efficient than '%' operation. I'll add some
comments to explain that.

>

>> +               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 {

>

> Ditto.

>

>> +               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;

>> -

>

> I agree with Shawn here, please try to have one patch taking care of

> one thing. If we find out that things goes wrong later, then it's

> easier to drop/revert a change which causes the regression.


OK.

>

> Moreover, for the above particular change, I don't think you should

> remove these validations, as this is an API being exported. You may

> convert to use mmc_can_erase() though.


These validations are redundant, since we always have checked if it
can erase with mmc_can_erase/trim/discard() function before issuing
mmc_erase(). Another hand these validations should be moved into
mmc_can_erase() not in mmc_erase() function.

>

> Regarding all the mmc erase related exported APIs, there are certainly

> a need for some clean-ups. For example, I think too many APIs are

> being exported and we could probably also restructure the code a bit

> so it becomes more readable. Although, of course this deserves a

> standalone clean-up series. :-)


OK. I would like to do some clean up for erase function after this
optimization. Thanks for your comments.

>

>>         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:

>> --

>> 1.7.9.5

>>

>

> Kind regards

> Uffe




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Patch

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: