[PATCH] mtd: maps: add missing iounmap() in error path

[PATCH] mtd: maps: add missing iounmap() in error path

[Luis Henriques]

This patch was triggered by the following Coccinelle error:

./drivers/mtd/maps/sc520cdp.c:246:3-9: \
	ERROR: missing iounmap; ioremap on line 242 \
	and execution via conditional on line 244

Signed-off-by: Luis Henriques <henrix@camandro.org>
---
 drivers/mtd/maps/sc520cdp.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/mtd/maps/sc520cdp.c b/drivers/mtd/maps/sc520cdp.c
index 093edd51bdc7..7a27ed345d0d 100644
--- a/drivers/mtd/maps/sc520cdp.c
+++ b/drivers/mtd/maps/sc520cdp.c
@@ -243,6 +243,10 @@ static int __init init_sc520cdp(void)
 
 		if (!sc520cdp_map[i].virt) {
 			printk("Failed to ioremap_nocache\n");
+			if (i) {
+				while (--i)
+					iounmap(sc520cdp_map[i].virt);
+			}
 			return -EIO;
 		}
 

Re: [PATCH] mtd: maps: add missing iounmap() in error path

[Marek Vasut]

On 11/16/2016 11:50 PM, Luis Henriques wrote:
> This patch was triggered by the following Coccinelle error:
> 
> ./drivers/mtd/maps/sc520cdp.c:246:3-9: \
> 	ERROR: missing iounmap; ioremap on line 242 \
> 	and execution via conditional on line 244
> 
> Signed-off-by: Luis Henriques <henrix@camandro.org>

Reviewed-by: Marek Vasut <marek.vasut@gmail.com>

> ---
>  drivers/mtd/maps/sc520cdp.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/mtd/maps/sc520cdp.c b/drivers/mtd/maps/sc520cdp.c
> index 093edd51bdc7..7a27ed345d0d 100644
> --- a/drivers/mtd/maps/sc520cdp.c
> +++ b/drivers/mtd/maps/sc520cdp.c
> @@ -243,6 +243,10 @@ static int __init init_sc520cdp(void)
>  
>  		if (!sc520cdp_map[i].virt) {
>  			printk("Failed to ioremap_nocache\n");
> +			if (i) {
> +				while (--i)
> +					iounmap(sc520cdp_map[i].virt);
> +			}
>  			return -EIO;
>  		}
>  
> 


-- 
Best regards,
Marek Vasut

Re: [PATCH] mtd: maps: add missing iounmap() in error path

[Brian Norris]

On Wed, Nov 16, 2016 at 10:50:16PM +0000, Luis Henriques wrote:
> This patch was triggered by the following Coccinelle error:
> 
> ./drivers/mtd/maps/sc520cdp.c:246:3-9: \
> 	ERROR: missing iounmap; ioremap on line 242 \
> 	and execution via conditional on line 244
> 
> Signed-off-by: Luis Henriques <henrix@camandro.org>
> ---
>  drivers/mtd/maps/sc520cdp.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/mtd/maps/sc520cdp.c b/drivers/mtd/maps/sc520cdp.c
> index 093edd51bdc7..7a27ed345d0d 100644
> --- a/drivers/mtd/maps/sc520cdp.c
> +++ b/drivers/mtd/maps/sc520cdp.c
> @@ -243,6 +243,10 @@ static int __init init_sc520cdp(void)
>  
>  		if (!sc520cdp_map[i].virt) {
>  			printk("Failed to ioremap_nocache\n");
> +			if (i) {
> +				while (--i)

Umm, so you never unmap from sc520cdp_map[0].virt? How about:

				while (--i >= 0)

?

You can also skip the 'if (i)' part in that case. Or maybe make it a for
loop, to be even clearer.

> +					iounmap(sc520cdp_map[i].virt);

This may often be a double-iounmap. If you take a look later in the
loop, many instances of the loop may not find a device, and so they'll
unmap this memory and move on. You're just doing it a second time for
them.

> +			}
>  			return -EIO;
>  		}
>  

Please put some more care into your patch, since I very much expect that
you did not test it.

Brian

Re: [PATCH] mtd: maps: add missing iounmap() in error path

[Luis Henriques]

Brian Norris <computersforpeace@gmail.com> writes:

> On Wed, Nov 16, 2016 at 10:50:16PM +0000, Luis Henriques wrote:
>> This patch was triggered by the following Coccinelle error:
>> 
>> ./drivers/mtd/maps/sc520cdp.c:246:3-9: \
>> 	ERROR: missing iounmap; ioremap on line 242 \
>> 	and execution via conditional on line 244
>> 
>> Signed-off-by: Luis Henriques <henrix@camandro.org>
>> ---
>>  drivers/mtd/maps/sc520cdp.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>> 
>> diff --git a/drivers/mtd/maps/sc520cdp.c b/drivers/mtd/maps/sc520cdp.c
>> index 093edd51bdc7..7a27ed345d0d 100644
>> --- a/drivers/mtd/maps/sc520cdp.c
>> +++ b/drivers/mtd/maps/sc520cdp.c
>> @@ -243,6 +243,10 @@ static int __init init_sc520cdp(void)
>>  
>>  		if (!sc520cdp_map[i].virt) {
>>  			printk("Failed to ioremap_nocache\n");
>> +			if (i) {
>> +				while (--i)
>
> Umm, so you never unmap from sc520cdp_map[0].virt? How about:
>
> 				while (--i >= 0)
>
> ?
>
> You can also skip the 'if (i)' part in that case. Or maybe make it a for
> loop, to be even clearer.
>
>> +					iounmap(sc520cdp_map[i].virt);
>
> This may often be a double-iounmap. If you take a look later in the
> loop, many instances of the loop may not find a device, and so they'll
> unmap this memory and move on. You're just doing it a second time for
> them.
>
>> +			}
>>  			return -EIO;
>>  		}
>>  
>
> Please put some more care into your patch, since I very much expect that
> you did not test it.
>
> Brian

Thank you very much for your review.  All very good points indeed!
I'll try to send v2 soon to cover all the issues you've found.

Cheers,
-- 
Luís

[PATCH v2] mtd: maps: add missing iounmap() in error path

[Luis Henriques]

This patch was triggered by the following Coccinelle error:

./drivers/mtd/maps/sc520cdp.c:246:3-9: \
	ERROR: missing iounmap; ioremap on line 242 \
	and execution via conditional on line 244

Since do_map_probe() is also invoked in this loop, it is also necessary to
map_destroy() any initialised struct mtd_info.

Signed-off-by: Luis Henriques <henrix@camandro.org>
---
Changes since v1:
* Changes according to Brian Norris review:
  - Ensure sc520cdp_map[0].virt is unmaped when needed
  - Use a for loop instead of an 'if (i)'
  - Prevent double-iounmap
* Added map_destroy() in the cleanup

drivers/mtd/maps/sc520cdp.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/maps/sc520cdp.c b/drivers/mtd/maps/sc520cdp.c
index 093edd51bdc7..9b1c13aa9f20 100644
--- a/drivers/mtd/maps/sc520cdp.c
+++ b/drivers/mtd/maps/sc520cdp.c
@@ -227,7 +227,7 @@ static void sc520cdp_setup_par(void)
 
 static int __init init_sc520cdp(void)
 {
-	int i, devices_found = 0;
+	int i, j, devices_found = 0;
 
 #ifdef REPROGRAM_PAR
 	/* reprogram PAR registers so flash appears at the desired addresses */
@@ -243,6 +243,12 @@ static int __init init_sc520cdp(void)
 
 		if (!sc520cdp_map[i].virt) {
 			printk("Failed to ioremap_nocache\n");
+			for (j = 0; j < i; j++) {
+				if (mymtd[j]) {
+					map_destroy(mymtd[j]);
+					iounmap(sc520cdp_map[j].virt);
+				}
+			}
 			return -EIO;
 		}
 

Re: [PATCH v2] mtd: maps: add missing iounmap() in error path

[Marek Vasut]

On 11/24/2016 12:40 AM, Luis Henriques wrote:
> This patch was triggered by the following Coccinelle error:
> 
> ./drivers/mtd/maps/sc520cdp.c:246:3-9: \
> 	ERROR: missing iounmap; ioremap on line 242 \
> 	and execution via conditional on line 244
> 
> Since do_map_probe() is also invoked in this loop, it is also necessary to
> map_destroy() any initialised struct mtd_info.
> 
> Signed-off-by: Luis Henriques <henrix@camandro.org>
> ---
> Changes since v1:
> * Changes according to Brian Norris review:
>   - Ensure sc520cdp_map[0].virt is unmaped when needed
>   - Use a for loop instead of an 'if (i)'
>   - Prevent double-iounmap
> * Added map_destroy() in the cleanup
> 
> drivers/mtd/maps/sc520cdp.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/maps/sc520cdp.c b/drivers/mtd/maps/sc520cdp.c
> index 093edd51bdc7..9b1c13aa9f20 100644
> --- a/drivers/mtd/maps/sc520cdp.c
> +++ b/drivers/mtd/maps/sc520cdp.c
> @@ -227,7 +227,7 @@ static void sc520cdp_setup_par(void)
>  
>  static int __init init_sc520cdp(void)
>  {
> -	int i, devices_found = 0;
> +	int i, j, devices_found = 0;
>  
>  #ifdef REPROGRAM_PAR
>  	/* reprogram PAR registers so flash appears at the desired addresses */
> @@ -243,6 +243,12 @@ static int __init init_sc520cdp(void)
>  
>  		if (!sc520cdp_map[i].virt) {
>  			printk("Failed to ioremap_nocache\n");
> +			for (j = 0; j < i; j++) {
> +				if (mymtd[j]) {
> +					map_destroy(mymtd[j]);
> +					iounmap(sc520cdp_map[j].virt);
> +				}
> +			}

Reviewed-by: Marek Vasut <marek.vasut@gmail.com>

>  			return -EIO;
>  		}
>  
> 


-- 
Best regards,
Marek Vasut

Re: [PATCH v2] mtd: maps: add missing iounmap() in error path

[Brian Norris]

On Fri, Nov 25, 2016 at 03:18:09PM +0100, Marek Vasut wrote:
> On 11/24/2016 12:40 AM, Luis Henriques wrote:
> > This patch was triggered by the following Coccinelle error:
> > 
> > ./drivers/mtd/maps/sc520cdp.c:246:3-9: \
> > 	ERROR: missing iounmap; ioremap on line 242 \
> > 	and execution via conditional on line 244
> > 
> > Since do_map_probe() is also invoked in this loop, it is also necessary to
> > map_destroy() any initialised struct mtd_info.
> > 
> > Signed-off-by: Luis Henriques <henrix@camandro.org>
> > ---
> > Changes since v1:
> > * Changes according to Brian Norris review:
> >   - Ensure sc520cdp_map[0].virt is unmaped when needed
> >   - Use a for loop instead of an 'if (i)'
> >   - Prevent double-iounmap
> > * Added map_destroy() in the cleanup
> > 
> > drivers/mtd/maps/sc520cdp.c | 8 +++++++-
> >  1 file changed, 7 insertions(+), 1 deletion(-)

...

> Reviewed-by: Marek Vasut <marek.vasut@gmail.com>

Applied to l2-mtd.git