[PATCH 1/2] mmc: core: Drop superfluous validations in mmc_hw|sw_reset()

[PATCH 1/2] mmc: core: Drop superfluous validations in mmc_hw|sw_reset()

[Ulf Hansson]

The mmc_hw|sw_reset() APIs are designed to be called solely from upper
layers, which means drivers that operates on top of the struct mmc_card,
like the mmc block device driver and an SDIO functional driver.

Additionally, as long as the struct mmc_host has a valid pointer to a
struct mmc_card, the corresponding host->bus_ops pointer stays valid and
assigned.

For these reasons, let's drop the superfluous reference counting and the
redundant validations in mmc_hw|sw_reset().

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
---

Note, ideally mmc_hw|sw_reset() shall be converted to take a struct mmc_card*
as an in-parameter, rather than the current struct mmc_host*, but that is left
to a future/separate change.

---
 drivers/mmc/core/block.c |  2 +-
 drivers/mmc/core/core.c  | 21 +--------------------
 2 files changed, 2 insertions(+), 21 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index b877f62df366..b7d3f5a73388 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -947,7 +947,7 @@ static int mmc_blk_reset(struct mmc_blk_data *md, struct mmc_host *host,
 	md->reset_done |= type;
 	err = mmc_hw_reset(host);
 	/* Ensure we switch back to the correct partition */
-	if (err != -EOPNOTSUPP) {
+	if (err) {
 		struct mmc_blk_data *main_md =
 			dev_get_drvdata(&host->card->dev);
 		int part_err;
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 1136b859ddd8..2e41fa598bd6 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -2080,18 +2080,7 @@ int mmc_hw_reset(struct mmc_host *host)
 {
 	int ret;
 
-	if (!host->card)
-		return -EINVAL;
-
-	mmc_bus_get(host);
-	if (!host->bus_ops || host->bus_dead || !host->bus_ops->hw_reset) {
-		mmc_bus_put(host);
-		return -EOPNOTSUPP;
-	}
-
 	ret = host->bus_ops->hw_reset(host);
-	mmc_bus_put(host);
-
 	if (ret < 0)
 		pr_warn("%s: tried to HW reset card, got error %d\n",
 			mmc_hostname(host), ret);
@@ -2104,18 +2093,10 @@ int mmc_sw_reset(struct mmc_host *host)
 {
 	int ret;
 
-	if (!host->card)
-		return -EINVAL;
-
-	mmc_bus_get(host);
-	if (!host->bus_ops || host->bus_dead || !host->bus_ops->sw_reset) {
-		mmc_bus_put(host);
+	if (!host->bus_ops->sw_reset)
 		return -EOPNOTSUPP;
-	}
 
 	ret = host->bus_ops->sw_reset(host);
-	mmc_bus_put(host);
-
 	if (ret)
 		pr_warn("%s: tried to SW reset card, got error %d\n",
 			mmc_hostname(host), ret);
-- 
2.25.1

Re: [PATCH 1/2] mmc: core: Drop superfluous validations in mmc_hw|sw_reset()

[Adrian Hunter]

On 12/02/21 3:15 pm, Ulf Hansson wrote:
> The mmc_hw|sw_reset() APIs are designed to be called solely from upper
> layers, which means drivers that operates on top of the struct mmc_card,
> like the mmc block device driver and an SDIO functional driver.
> 
> Additionally, as long as the struct mmc_host has a valid pointer to a
> struct mmc_card, the corresponding host->bus_ops pointer stays valid and
> assigned.
> 
> For these reasons, let's drop the superfluous reference counting and the
> redundant validations in mmc_hw|sw_reset().
> 
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>

> ---
> 
> Note, ideally mmc_hw|sw_reset() shall be converted to take a struct mmc_card*
> as an in-parameter, rather than the current struct mmc_host*, but that is left
> to a future/separate change.
> 
> ---
>  drivers/mmc/core/block.c |  2 +-
>  drivers/mmc/core/core.c  | 21 +--------------------
>  2 files changed, 2 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
> index b877f62df366..b7d3f5a73388 100644
> --- a/drivers/mmc/core/block.c
> +++ b/drivers/mmc/core/block.c
> @@ -947,7 +947,7 @@ static int mmc_blk_reset(struct mmc_blk_data *md, struct mmc_host *host,
>  	md->reset_done |= type;
>  	err = mmc_hw_reset(host);
>  	/* Ensure we switch back to the correct partition */
> -	if (err != -EOPNOTSUPP) {
> +	if (err) {
>  		struct mmc_blk_data *main_md =
>  			dev_get_drvdata(&host->card->dev);
>  		int part_err;
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 1136b859ddd8..2e41fa598bd6 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -2080,18 +2080,7 @@ int mmc_hw_reset(struct mmc_host *host)
>  {
>  	int ret;
>  
> -	if (!host->card)
> -		return -EINVAL;
> -
> -	mmc_bus_get(host);
> -	if (!host->bus_ops || host->bus_dead || !host->bus_ops->hw_reset) {
> -		mmc_bus_put(host);
> -		return -EOPNOTSUPP;
> -	}
> -
>  	ret = host->bus_ops->hw_reset(host);
> -	mmc_bus_put(host);
> -
>  	if (ret < 0)
>  		pr_warn("%s: tried to HW reset card, got error %d\n",
>  			mmc_hostname(host), ret);
> @@ -2104,18 +2093,10 @@ int mmc_sw_reset(struct mmc_host *host)
>  {
>  	int ret;
>  
> -	if (!host->card)
> -		return -EINVAL;
> -
> -	mmc_bus_get(host);
> -	if (!host->bus_ops || host->bus_dead || !host->bus_ops->sw_reset) {
> -		mmc_bus_put(host);
> +	if (!host->bus_ops->sw_reset)
>  		return -EOPNOTSUPP;
> -	}
>  
>  	ret = host->bus_ops->sw_reset(host);
> -	mmc_bus_put(host);
> -
>  	if (ret)
>  		pr_warn("%s: tried to SW reset card, got error %d\n",
>  			mmc_hostname(host), ret);
>