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* [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-03 13:59 ` Colin King
  0 siblings, 0 replies; 30+ messages in thread
From: Colin King @ 2021-02-03 13:59 UTC (permalink / raw)
  To: Joerg Roedel, Will Deacon, Matthias Brugger, Anan sun, Yong Wu,
	Chao Hao, Tomasz Figa, iommu, linux-arm-kernel, linux-mediatek
  Cc: kernel-janitors, linux-kernel

From: Colin Ian King <colin.king@canonical.com>

Currently the check for domid < 0 is always false because domid
is unsigned.  Fix this by making it signed.

Addresses-CoverityL ("Unsigned comparison against 0")
Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/iommu/mtk_iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 0ad14a7604b1..823d719945b2 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
 				       struct list_head *head)
 {
 	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
-	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
+	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
 	const struct mtk_iommu_iova_region *resv, *curdom;
 	struct iommu_resv_region *region;
 	int prot = IOMMU_WRITE | IOMMU_READ;
-- 
2.29.2


^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-03 13:59 ` Colin King
  0 siblings, 0 replies; 30+ messages in thread
From: Colin King @ 2021-02-03 13:59 UTC (permalink / raw)
  To: Joerg Roedel, Will Deacon, Matthias Brugger, Anan sun, Yong Wu,
	Chao Hao, Tomasz Figa, iommu, linux-arm-kernel, linux-mediatek
  Cc: kernel-janitors, linux-kernel

From: Colin Ian King <colin.king@canonical.com>

Currently the check for domid < 0 is always false because domid
is unsigned.  Fix this by making it signed.

Addresses-CoverityL ("Unsigned comparison against 0")
Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/iommu/mtk_iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 0ad14a7604b1..823d719945b2 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
 				       struct list_head *head)
 {
 	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
-	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
+	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
 	const struct mtk_iommu_iova_region *resv, *curdom;
 	struct iommu_resv_region *region;
 	int prot = IOMMU_WRITE | IOMMU_READ;
-- 
2.29.2

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-03 13:59 ` Colin King
  0 siblings, 0 replies; 30+ messages in thread
From: Colin King @ 2021-02-03 13:59 UTC (permalink / raw)
  To: Joerg Roedel, Will Deacon, Matthias Brugger, Anan sun, Yong Wu,
	Chao Hao, Tomasz Figa, iommu, linux-arm-kernel, linux-mediatek
  Cc: kernel-janitors, linux-kernel

From: Colin Ian King <colin.king@canonical.com>

Currently the check for domid < 0 is always false because domid
is unsigned.  Fix this by making it signed.

Addresses-CoverityL ("Unsigned comparison against 0")
Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/iommu/mtk_iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 0ad14a7604b1..823d719945b2 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
 				       struct list_head *head)
 {
 	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
-	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
+	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
 	const struct mtk_iommu_iova_region *resv, *curdom;
 	struct iommu_resv_region *region;
 	int prot = IOMMU_WRITE | IOMMU_READ;
-- 
2.29.2

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-03 13:59 ` Colin King
  0 siblings, 0 replies; 30+ messages in thread
From: Colin King @ 2021-02-03 13:59 UTC (permalink / raw)
  To: Joerg Roedel, Will Deacon, Matthias Brugger, Anan sun, Yong Wu,
	Chao Hao, Tomasz Figa, iommu, linux-arm-kernel, linux-mediatek
  Cc: kernel-janitors, linux-kernel

From: Colin Ian King <colin.king@canonical.com>

Currently the check for domid < 0 is always false because domid
is unsigned.  Fix this by making it signed.

Addresses-CoverityL ("Unsigned comparison against 0")
Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/iommu/mtk_iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 0ad14a7604b1..823d719945b2 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
 				       struct list_head *head)
 {
 	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
-	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
+	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
 	const struct mtk_iommu_iova_region *resv, *curdom;
 	struct iommu_resv_region *region;
 	int prot = IOMMU_WRITE | IOMMU_READ;
-- 
2.29.2


_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-03 13:59 ` Colin King
  0 siblings, 0 replies; 30+ messages in thread
From: Colin King @ 2021-02-03 13:59 UTC (permalink / raw)
  To: Joerg Roedel, Will Deacon, Matthias Brugger, Anan sun, Yong Wu,
	Chao Hao, Tomasz Figa, iommu, linux-arm-kernel, linux-mediatek
  Cc: kernel-janitors, linux-kernel

From: Colin Ian King <colin.king@canonical.com>

Currently the check for domid < 0 is always false because domid
is unsigned.  Fix this by making it signed.

Addresses-CoverityL ("Unsigned comparison against 0")
Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/iommu/mtk_iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 0ad14a7604b1..823d719945b2 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
 				       struct list_head *head)
 {
 	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
-	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
+	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
 	const struct mtk_iommu_iova_region *resv, *curdom;
 	struct iommu_resv_region *region;
 	int prot = IOMMU_WRITE | IOMMU_READ;
-- 
2.29.2


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
  2021-02-03 13:59 ` Colin King
                     ` (2 preceding siblings ...)
  (?)
@ 2021-02-04  1:11   ` Yong Wu
  -1 siblings, 0 replies; 30+ messages in thread
From: Yong Wu @ 2021-02-04  1:11 UTC (permalink / raw)
  To: Colin King
  Cc: Joerg Roedel, Will Deacon, Matthias Brugger, Anan sun, Chao Hao,
	Tomasz Figa, iommu, linux-arm-kernel, linux-mediatek,
	kernel-janitors, linux-kernel

On Wed, 2021-02-03 at 13:59 +0000, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently the check for domid < 0 is always false because domid
> is unsigned.  Fix this by making it signed.
> 
> Addresses-CoverityL ("Unsigned comparison against 0")
> Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

Thanks for the fix.

Reviewed-by: Yong Wu <yong.wu@mediatek.com>

> ---
>  drivers/iommu/mtk_iommu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 0ad14a7604b1..823d719945b2 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
>  				       struct list_head *head)
>  {
>  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
>  	const struct mtk_iommu_iova_region *resv, *curdom;
>  	struct iommu_resv_region *region;
>  	int prot = IOMMU_WRITE | IOMMU_READ;


^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-04  1:11   ` Yong Wu
  0 siblings, 0 replies; 30+ messages in thread
From: Yong Wu @ 2021-02-04  1:11 UTC (permalink / raw)
  To: Colin King
  Cc: Anan sun, Joerg Roedel, kernel-janitors, linux-kernel,
	Tomasz Figa, Chao Hao, iommu, linux-mediatek, Matthias Brugger,
	Will Deacon, linux-arm-kernel

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cm9tOiBDb2xpbiBJYW4gS2luZyA8Y29saW4ua2luZ0BjYW5vbmljYWwuY29tPg0KPiANCj4gQ3Vy
cmVudGx5IHRoZSBjaGVjayBmb3IgZG9taWQgPCAwIGlzIGFsd2F5cyBmYWxzZSBiZWNhdXNlIGRv
bWlkDQo+IGlzIHVuc2lnbmVkLiAgRml4IHRoaXMgYnkgbWFraW5nIGl0IHNpZ25lZC4NCj4gDQo+
IEFkZHJlc3Nlcy1Db3Zlcml0eUwgKCJVbnNpZ25lZCBjb21wYXJpc29uIGFnYWluc3QgMCIpDQo+
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IFd1IDx5b25nLnd1QG1lZGlhdGVrLmNvbT4NCg0KPiAtLS0NCj4gIGRyaXZlcnMvaW9tbXUvbXRr
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ZXRpb24oLSkNCj4gDQo+IGRpZmYgLS1naXQgYS9kcml2ZXJzL2lvbW11L210a19pb21tdS5jIGIv
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aTsNCj4gKwlpbnQgZG9taWQgPSBtdGtfaW9tbXVfZ2V0X2RvbWFpbl9pZChkZXYsIGRhdGEtPnBs
YXRfZGF0YSksIGk7DQo+ICAJY29uc3Qgc3RydWN0IG10a19pb21tdV9pb3ZhX3JlZ2lvbiAqcmVz
diwgKmN1cmRvbTsNCj4gIAlzdHJ1Y3QgaW9tbXVfcmVzdl9yZWdpb24gKnJlZ2lvbjsNCj4gIAlp
bnQgcHJvdCA9IElPTU1VX1dSSVRFIHwgSU9NTVVfUkVBRDsNCg0K

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-04  1:11   ` Yong Wu
  0 siblings, 0 replies; 30+ messages in thread
From: Yong Wu @ 2021-02-04  1:11 UTC (permalink / raw)
  To: Colin King
  Cc: Anan sun, kernel-janitors, linux-kernel, Chao Hao, iommu,
	linux-mediatek, Matthias Brugger, Will Deacon, linux-arm-kernel

On Wed, 2021-02-03 at 13:59 +0000, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently the check for domid < 0 is always false because domid
> is unsigned.  Fix this by making it signed.
> 
> Addresses-CoverityL ("Unsigned comparison against 0")
> Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

Thanks for the fix.

Reviewed-by: Yong Wu <yong.wu@mediatek.com>

> ---
>  drivers/iommu/mtk_iommu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 0ad14a7604b1..823d719945b2 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
>  				       struct list_head *head)
>  {
>  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
>  	const struct mtk_iommu_iova_region *resv, *curdom;
>  	struct iommu_resv_region *region;
>  	int prot = IOMMU_WRITE | IOMMU_READ;

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-04  1:11   ` Yong Wu
  0 siblings, 0 replies; 30+ messages in thread
From: Yong Wu @ 2021-02-04  1:11 UTC (permalink / raw)
  To: Colin King
  Cc: Anan sun, Joerg Roedel, kernel-janitors, linux-kernel,
	Tomasz Figa, Chao Hao, iommu, linux-mediatek, Matthias Brugger,
	Will Deacon, linux-arm-kernel

On Wed, 2021-02-03 at 13:59 +0000, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently the check for domid < 0 is always false because domid
> is unsigned.  Fix this by making it signed.
> 
> Addresses-CoverityL ("Unsigned comparison against 0")
> Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

Thanks for the fix.

Reviewed-by: Yong Wu <yong.wu@mediatek.com>

> ---
>  drivers/iommu/mtk_iommu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 0ad14a7604b1..823d719945b2 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
>  				       struct list_head *head)
>  {
>  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
>  	const struct mtk_iommu_iova_region *resv, *curdom;
>  	struct iommu_resv_region *region;
>  	int prot = IOMMU_WRITE | IOMMU_READ;

_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-04  1:11   ` Yong Wu
  0 siblings, 0 replies; 30+ messages in thread
From: Yong Wu @ 2021-02-04  1:11 UTC (permalink / raw)
  To: Colin King
  Cc: Anan sun, Joerg Roedel, kernel-janitors, linux-kernel,
	Tomasz Figa, Chao Hao, iommu, linux-mediatek, Matthias Brugger,
	Will Deacon, linux-arm-kernel

On Wed, 2021-02-03 at 13:59 +0000, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently the check for domid < 0 is always false because domid
> is unsigned.  Fix this by making it signed.
> 
> Addresses-CoverityL ("Unsigned comparison against 0")
> Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

Thanks for the fix.

Reviewed-by: Yong Wu <yong.wu@mediatek.com>

> ---
>  drivers/iommu/mtk_iommu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 0ad14a7604b1..823d719945b2 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
>  				       struct list_head *head)
>  {
>  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
>  	const struct mtk_iommu_iova_region *resv, *curdom;
>  	struct iommu_resv_region *region;
>  	int prot = IOMMU_WRITE | IOMMU_READ;

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
  2021-02-03 13:59 ` Colin King
                     ` (2 preceding siblings ...)
  (?)
@ 2021-02-04  9:25   ` Will Deacon
  -1 siblings, 0 replies; 30+ messages in thread
From: Will Deacon @ 2021-02-04  9:25 UTC (permalink / raw)
  To: Colin King
  Cc: Joerg Roedel, Matthias Brugger, Anan sun, Yong Wu, Chao Hao,
	Tomasz Figa, iommu, linux-arm-kernel, linux-mediatek,
	kernel-janitors, linux-kernel

On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently the check for domid < 0 is always false because domid
> is unsigned.  Fix this by making it signed.
> 
> Addresses-CoverityL ("Unsigned comparison against 0")

Typo here ('L' instead of ':')

> Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/iommu/mtk_iommu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 0ad14a7604b1..823d719945b2 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
>  				       struct list_head *head)
>  {
>  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;

Not sure if it's intentional, but this also makes 'i' signed. It probably
should remain 'unsigned' to match 'iova_region_nr' in
'struct mtk_iommu_plat_data'.

Will

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-04  9:25   ` Will Deacon
  0 siblings, 0 replies; 30+ messages in thread
From: Will Deacon @ 2021-02-04  9:25 UTC (permalink / raw)
  To: Colin King
  Cc: Anan sun, Joerg Roedel, kernel-janitors, linux-kernel,
	Tomasz Figa, Chao Hao, iommu, linux-mediatek, linux-arm-kernel,
	Matthias Brugger, Yong Wu

On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently the check for domid < 0 is always false because domid
> is unsigned.  Fix this by making it signed.
> 
> Addresses-CoverityL ("Unsigned comparison against 0")

Typo here ('L' instead of ':')

> Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/iommu/mtk_iommu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 0ad14a7604b1..823d719945b2 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
>  				       struct list_head *head)
>  {
>  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;

Not sure if it's intentional, but this also makes 'i' signed. It probably
should remain 'unsigned' to match 'iova_region_nr' in
'struct mtk_iommu_plat_data'.

Will

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-04  9:25   ` Will Deacon
  0 siblings, 0 replies; 30+ messages in thread
From: Will Deacon @ 2021-02-04  9:25 UTC (permalink / raw)
  To: Colin King
  Cc: Anan sun, kernel-janitors, linux-kernel, Chao Hao, iommu,
	linux-mediatek, linux-arm-kernel, Matthias Brugger

On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently the check for domid < 0 is always false because domid
> is unsigned.  Fix this by making it signed.
> 
> Addresses-CoverityL ("Unsigned comparison against 0")

Typo here ('L' instead of ':')

> Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/iommu/mtk_iommu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 0ad14a7604b1..823d719945b2 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
>  				       struct list_head *head)
>  {
>  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;

Not sure if it's intentional, but this also makes 'i' signed. It probably
should remain 'unsigned' to match 'iova_region_nr' in
'struct mtk_iommu_plat_data'.

Will
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-04  9:25   ` Will Deacon
  0 siblings, 0 replies; 30+ messages in thread
From: Will Deacon @ 2021-02-04  9:25 UTC (permalink / raw)
  To: Colin King
  Cc: Anan sun, Joerg Roedel, kernel-janitors, linux-kernel,
	Tomasz Figa, Chao Hao, iommu, linux-mediatek, linux-arm-kernel,
	Matthias Brugger, Yong Wu

On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently the check for domid < 0 is always false because domid
> is unsigned.  Fix this by making it signed.
> 
> Addresses-CoverityL ("Unsigned comparison against 0")

Typo here ('L' instead of ':')

> Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/iommu/mtk_iommu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 0ad14a7604b1..823d719945b2 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
>  				       struct list_head *head)
>  {
>  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;

Not sure if it's intentional, but this also makes 'i' signed. It probably
should remain 'unsigned' to match 'iova_region_nr' in
'struct mtk_iommu_plat_data'.

Will

_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-04  9:25   ` Will Deacon
  0 siblings, 0 replies; 30+ messages in thread
From: Will Deacon @ 2021-02-04  9:25 UTC (permalink / raw)
  To: Colin King
  Cc: Anan sun, Joerg Roedel, kernel-janitors, linux-kernel,
	Tomasz Figa, Chao Hao, iommu, linux-mediatek, linux-arm-kernel,
	Matthias Brugger, Yong Wu

On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> Currently the check for domid < 0 is always false because domid
> is unsigned.  Fix this by making it signed.
> 
> Addresses-CoverityL ("Unsigned comparison against 0")

Typo here ('L' instead of ':')

> Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/iommu/mtk_iommu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index 0ad14a7604b1..823d719945b2 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
>  				       struct list_head *head)
>  {
>  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;

Not sure if it's intentional, but this also makes 'i' signed. It probably
should remain 'unsigned' to match 'iova_region_nr' in
'struct mtk_iommu_plat_data'.

Will

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
  2021-02-04  9:25   ` Will Deacon
                       ` (2 preceding siblings ...)
  (?)
@ 2021-02-04 13:31     ` Joerg Roedel
  -1 siblings, 0 replies; 30+ messages in thread
From: Joerg Roedel @ 2021-02-04 13:31 UTC (permalink / raw)
  To: Will Deacon
  Cc: Colin King, Matthias Brugger, Anan sun, Yong Wu, Chao Hao,
	Tomasz Figa, iommu, linux-arm-kernel, linux-mediatek,
	kernel-janitors, linux-kernel

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> > 
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> > 
> > Addresses-CoverityL ("Unsigned comparison against 0")
> 
> Typo here ('L' instead of ':')
> 
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >  				       struct list_head *head)
> >  {
> >  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> 
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.

Yes, 'i' should stay unsigned. Colin, can you please fix that up and
re-send?

Thanks,

	Joerg

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-04 13:31     ` Joerg Roedel
  0 siblings, 0 replies; 30+ messages in thread
From: Joerg Roedel @ 2021-02-04 13:31 UTC (permalink / raw)
  To: Will Deacon
  Cc: Anan sun, kernel-janitors, linux-kernel, Tomasz Figa, Chao Hao,
	iommu, linux-mediatek, linux-arm-kernel, Matthias Brugger,
	Colin King, Yong Wu

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> > 
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> > 
> > Addresses-CoverityL ("Unsigned comparison against 0")
> 
> Typo here ('L' instead of ':')
> 
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >  				       struct list_head *head)
> >  {
> >  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> 
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.

Yes, 'i' should stay unsigned. Colin, can you please fix that up and
re-send?

Thanks,

	Joerg

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-04 13:31     ` Joerg Roedel
  0 siblings, 0 replies; 30+ messages in thread
From: Joerg Roedel @ 2021-02-04 13:31 UTC (permalink / raw)
  To: Will Deacon
  Cc: Anan sun, kernel-janitors, linux-kernel, Chao Hao, iommu,
	linux-mediatek, linux-arm-kernel, Matthias Brugger, Colin King

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> > 
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> > 
> > Addresses-CoverityL ("Unsigned comparison against 0")
> 
> Typo here ('L' instead of ':')
> 
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >  				       struct list_head *head)
> >  {
> >  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> 
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.

Yes, 'i' should stay unsigned. Colin, can you please fix that up and
re-send?

Thanks,

	Joerg
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-04 13:31     ` Joerg Roedel
  0 siblings, 0 replies; 30+ messages in thread
From: Joerg Roedel @ 2021-02-04 13:31 UTC (permalink / raw)
  To: Will Deacon
  Cc: Anan sun, kernel-janitors, linux-kernel, Tomasz Figa, Chao Hao,
	iommu, linux-mediatek, linux-arm-kernel, Matthias Brugger,
	Colin King, Yong Wu

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> > 
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> > 
> > Addresses-CoverityL ("Unsigned comparison against 0")
> 
> Typo here ('L' instead of ':')
> 
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >  				       struct list_head *head)
> >  {
> >  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> 
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.

Yes, 'i' should stay unsigned. Colin, can you please fix that up and
re-send?

Thanks,

	Joerg

_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-04 13:31     ` Joerg Roedel
  0 siblings, 0 replies; 30+ messages in thread
From: Joerg Roedel @ 2021-02-04 13:31 UTC (permalink / raw)
  To: Will Deacon
  Cc: Anan sun, kernel-janitors, linux-kernel, Tomasz Figa, Chao Hao,
	iommu, linux-mediatek, linux-arm-kernel, Matthias Brugger,
	Colin King, Yong Wu

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> > 
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> > 
> > Addresses-CoverityL ("Unsigned comparison against 0")
> 
> Typo here ('L' instead of ':')
> 
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >  				       struct list_head *head)
> >  {
> >  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> 
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.

Yes, 'i' should stay unsigned. Colin, can you please fix that up and
re-send?

Thanks,

	Joerg

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
  2021-02-04  9:25   ` Will Deacon
                       ` (2 preceding siblings ...)
  (?)
@ 2021-02-09  9:19     ` Dan Carpenter
  -1 siblings, 0 replies; 30+ messages in thread
From: Dan Carpenter @ 2021-02-09  9:19 UTC (permalink / raw)
  To: Will Deacon
  Cc: Colin King, Joerg Roedel, Matthias Brugger, Anan sun, Yong Wu,
	Chao Hao, Tomasz Figa, iommu, linux-arm-kernel, linux-mediatek,
	kernel-janitors, linux-kernel

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> > 
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> > 
> > Addresses-CoverityL ("Unsigned comparison against 0")
> 
> Typo here ('L' instead of ':')
> 
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >  				       struct list_head *head)
> >  {
> >  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> 
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.


iova_region_nr is either 1 or 5 so unsigned doesn't matter.

I once almost introduced a bug where the iterator was supposed to be
size_t.  I fixed a bug by making it signed but I ended up introducing a
new bug.  But generally that's pretty rare.  The more common case is
that making iterators unsigned introduces bugs.

It's better to default to "int i;" and if more complicated types are
required that should stand out.  "size_t pg_idx;" or whatever.

regards,
dan carpenter

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-09  9:19     ` Dan Carpenter
  0 siblings, 0 replies; 30+ messages in thread
From: Dan Carpenter @ 2021-02-09  9:19 UTC (permalink / raw)
  To: Will Deacon
  Cc: Anan sun, Joerg Roedel, kernel-janitors, linux-kernel,
	Tomasz Figa, Chao Hao, iommu, linux-mediatek, linux-arm-kernel,
	Matthias Brugger, Colin King, Yong Wu

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> > 
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> > 
> > Addresses-CoverityL ("Unsigned comparison against 0")
> 
> Typo here ('L' instead of ':')
> 
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >  				       struct list_head *head)
> >  {
> >  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> 
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.


iova_region_nr is either 1 or 5 so unsigned doesn't matter.

I once almost introduced a bug where the iterator was supposed to be
size_t.  I fixed a bug by making it signed but I ended up introducing a
new bug.  But generally that's pretty rare.  The more common case is
that making iterators unsigned introduces bugs.

It's better to default to "int i;" and if more complicated types are
required that should stand out.  "size_t pg_idx;" or whatever.

regards,
dan carpenter

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-09  9:19     ` Dan Carpenter
  0 siblings, 0 replies; 30+ messages in thread
From: Dan Carpenter @ 2021-02-09  9:19 UTC (permalink / raw)
  To: Will Deacon
  Cc: Anan sun, kernel-janitors, linux-kernel, Chao Hao, iommu,
	linux-mediatek, linux-arm-kernel, Matthias Brugger, Colin King

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> > 
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> > 
> > Addresses-CoverityL ("Unsigned comparison against 0")
> 
> Typo here ('L' instead of ':')
> 
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >  				       struct list_head *head)
> >  {
> >  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> 
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.


iova_region_nr is either 1 or 5 so unsigned doesn't matter.

I once almost introduced a bug where the iterator was supposed to be
size_t.  I fixed a bug by making it signed but I ended up introducing a
new bug.  But generally that's pretty rare.  The more common case is
that making iterators unsigned introduces bugs.

It's better to default to "int i;" and if more complicated types are
required that should stand out.  "size_t pg_idx;" or whatever.

regards,
dan carpenter
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-09  9:19     ` Dan Carpenter
  0 siblings, 0 replies; 30+ messages in thread
From: Dan Carpenter @ 2021-02-09  9:19 UTC (permalink / raw)
  To: Will Deacon
  Cc: Anan sun, Joerg Roedel, kernel-janitors, linux-kernel,
	Tomasz Figa, Chao Hao, iommu, linux-mediatek, linux-arm-kernel,
	Matthias Brugger, Colin King, Yong Wu

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> > 
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> > 
> > Addresses-CoverityL ("Unsigned comparison against 0")
> 
> Typo here ('L' instead of ':')
> 
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >  				       struct list_head *head)
> >  {
> >  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> 
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.


iova_region_nr is either 1 or 5 so unsigned doesn't matter.

I once almost introduced a bug where the iterator was supposed to be
size_t.  I fixed a bug by making it signed but I ended up introducing a
new bug.  But generally that's pretty rare.  The more common case is
that making iterators unsigned introduces bugs.

It's better to default to "int i;" and if more complicated types are
required that should stand out.  "size_t pg_idx;" or whatever.

regards,
dan carpenter

_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

^ permalink raw reply	[flat|nested] 30+ messages in thread

* Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-09  9:19     ` Dan Carpenter
  0 siblings, 0 replies; 30+ messages in thread
From: Dan Carpenter @ 2021-02-09  9:19 UTC (permalink / raw)
  To: Will Deacon
  Cc: Anan sun, Joerg Roedel, kernel-janitors, linux-kernel,
	Tomasz Figa, Chao Hao, iommu, linux-mediatek, linux-arm-kernel,
	Matthias Brugger, Colin King, Yong Wu

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> > 
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> > 
> > Addresses-CoverityL ("Unsigned comparison against 0")
> 
> Typo here ('L' instead of ':')
> 
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >  				       struct list_head *head)
> >  {
> >  	struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -	unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +	int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> 
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.


iova_region_nr is either 1 or 5 so unsigned doesn't matter.

I once almost introduced a bug where the iterator was supposed to be
size_t.  I fixed a bug by making it signed but I ended up introducing a
new bug.  But generally that's pretty rare.  The more common case is
that making iterators unsigned introduces bugs.

It's better to default to "int i;" and if more complicated types are
required that should stand out.  "size_t pg_idx;" or whatever.

regards,
dan carpenter

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 30+ messages in thread

* AW: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
  2021-02-09  9:19     ` Dan Carpenter
                         ` (2 preceding siblings ...)
  (?)
@ 2021-02-09 10:57       ` Walter Harms
  -1 siblings, 0 replies; 30+ messages in thread
From: Walter Harms @ 2021-02-09 10:57 UTC (permalink / raw)
  To: Dan Carpenter, Will Deacon
  Cc: Colin King, Joerg Roedel, Matthias Brugger, Anan sun, Yong Wu,
	Chao Hao, Tomasz Figa, iommu, linux-arm-kernel, linux-mediatek,
	kernel-janitors, linux-kernel

I second that ...

Having i unsigned violates the rule of "least surprise".
If you need it unsigned make it clearly visible, also adding
a simple comment may help.

jm2c,
 wh
________________________________________
Von: Dan Carpenter <dan.carpenter@oracle.com>
Gesendet: Dienstag, 9. Februar 2021 10:19:23
An: Will Deacon
Cc: Colin King; Joerg Roedel; Matthias Brugger; Anan sun; Yong Wu; Chao Hao; Tomasz Figa; iommu@lists.linux-foundation.org; linux-arm-kernel@lists.infradead.org; linux-mediatek@lists.infradead.org; kernel-janitors@vger.kernel.org; linux-kernel@vger.kernel.org
Betreff: Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> >
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> >
> > Addresses-CoverityL ("Unsigned comparison against 0")
>
> Typo here ('L' instead of ':')
>
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >                                    struct list_head *head)
> >  {
> >     struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -   unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +   int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
>
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.


iova_region_nr is either 1 or 5 so unsigned doesn't matter.

I once almost introduced a bug where the iterator was supposed to be
size_t.  I fixed a bug by making it signed but I ended up introducing a
new bug.  But generally that's pretty rare.  The more common case is
that making iterators unsigned introduces bugs.

It's better to default to "int i;" and if more complicated types are
required that should stand out.  "size_t pg_idx;" or whatever.

regards,
dan carpenter

^ permalink raw reply	[flat|nested] 30+ messages in thread

* AW: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-09 10:57       ` Walter Harms
  0 siblings, 0 replies; 30+ messages in thread
From: Walter Harms @ 2021-02-09 10:57 UTC (permalink / raw)
  To: Dan Carpenter, Will Deacon
  Cc: Anan sun, Joerg Roedel, kernel-janitors, linux-kernel,
	Tomasz Figa, Chao Hao, iommu, linux-mediatek, linux-arm-kernel,
	Matthias Brugger, Colin King, Yong Wu

I second that ...

Having i unsigned violates the rule of "least surprise".
If you need it unsigned make it clearly visible, also adding
a simple comment may help.

jm2c,
 wh
________________________________________
Von: Dan Carpenter <dan.carpenter@oracle.com>
Gesendet: Dienstag, 9. Februar 2021 10:19:23
An: Will Deacon
Cc: Colin King; Joerg Roedel; Matthias Brugger; Anan sun; Yong Wu; Chao Hao; Tomasz Figa; iommu@lists.linux-foundation.org; linux-arm-kernel@lists.infradead.org; linux-mediatek@lists.infradead.org; kernel-janitors@vger.kernel.org; linux-kernel@vger.kernel.org
Betreff: Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> >
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> >
> > Addresses-CoverityL ("Unsigned comparison against 0")
>
> Typo here ('L' instead of ':')
>
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >                                    struct list_head *head)
> >  {
> >     struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -   unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +   int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
>
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.


iova_region_nr is either 1 or 5 so unsigned doesn't matter.

I once almost introduced a bug where the iterator was supposed to be
size_t.  I fixed a bug by making it signed but I ended up introducing a
new bug.  But generally that's pretty rare.  The more common case is
that making iterators unsigned introduces bugs.

It's better to default to "int i;" and if more complicated types are
required that should stand out.  "size_t pg_idx;" or whatever.

regards,
dan carpenter

^ permalink raw reply	[flat|nested] 30+ messages in thread

* AW: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-09 10:57       ` Walter Harms
  0 siblings, 0 replies; 30+ messages in thread
From: Walter Harms @ 2021-02-09 10:57 UTC (permalink / raw)
  To: Dan Carpenter, Will Deacon
  Cc: Anan sun, kernel-janitors, linux-kernel, Chao Hao, iommu,
	linux-mediatek, linux-arm-kernel, Matthias Brugger, Colin King

I second that ...

Having i unsigned violates the rule of "least surprise".
If you need it unsigned make it clearly visible, also adding
a simple comment may help.

jm2c,
 wh
________________________________________
Von: Dan Carpenter <dan.carpenter@oracle.com>
Gesendet: Dienstag, 9. Februar 2021 10:19:23
An: Will Deacon
Cc: Colin King; Joerg Roedel; Matthias Brugger; Anan sun; Yong Wu; Chao Hao; Tomasz Figa; iommu@lists.linux-foundation.org; linux-arm-kernel@lists.infradead.org; linux-mediatek@lists.infradead.org; kernel-janitors@vger.kernel.org; linux-kernel@vger.kernel.org
Betreff: Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> >
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> >
> > Addresses-CoverityL ("Unsigned comparison against 0")
>
> Typo here ('L' instead of ':')
>
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >                                    struct list_head *head)
> >  {
> >     struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -   unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +   int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
>
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.


iova_region_nr is either 1 or 5 so unsigned doesn't matter.

I once almost introduced a bug where the iterator was supposed to be
size_t.  I fixed a bug by making it signed but I ended up introducing a
new bug.  But generally that's pretty rare.  The more common case is
that making iterators unsigned introduces bugs.

It's better to default to "int i;" and if more complicated types are
required that should stand out.  "size_t pg_idx;" or whatever.

regards,
dan carpenter
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

^ permalink raw reply	[flat|nested] 30+ messages in thread

* AW: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-09 10:57       ` Walter Harms
  0 siblings, 0 replies; 30+ messages in thread
From: Walter Harms @ 2021-02-09 10:57 UTC (permalink / raw)
  To: Dan Carpenter, Will Deacon
  Cc: Anan sun, Joerg Roedel, kernel-janitors, linux-kernel,
	Tomasz Figa, Chao Hao, iommu, linux-mediatek, linux-arm-kernel,
	Matthias Brugger, Colin King, Yong Wu

I second that ...

Having i unsigned violates the rule of "least surprise".
If you need it unsigned make it clearly visible, also adding
a simple comment may help.

jm2c,
 wh
________________________________________
Von: Dan Carpenter <dan.carpenter@oracle.com>
Gesendet: Dienstag, 9. Februar 2021 10:19:23
An: Will Deacon
Cc: Colin King; Joerg Roedel; Matthias Brugger; Anan sun; Yong Wu; Chao Hao; Tomasz Figa; iommu@lists.linux-foundation.org; linux-arm-kernel@lists.infradead.org; linux-mediatek@lists.infradead.org; kernel-janitors@vger.kernel.org; linux-kernel@vger.kernel.org
Betreff: Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> >
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> >
> > Addresses-CoverityL ("Unsigned comparison against 0")
>
> Typo here ('L' instead of ':')
>
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >                                    struct list_head *head)
> >  {
> >     struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -   unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +   int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
>
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.


iova_region_nr is either 1 or 5 so unsigned doesn't matter.

I once almost introduced a bug where the iterator was supposed to be
size_t.  I fixed a bug by making it signed but I ended up introducing a
new bug.  But generally that's pretty rare.  The more common case is
that making iterators unsigned introduces bugs.

It's better to default to "int i;" and if more complicated types are
required that should stand out.  "size_t pg_idx;" or whatever.

regards,
dan carpenter

_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

^ permalink raw reply	[flat|nested] 30+ messages in thread

* AW: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero
@ 2021-02-09 10:57       ` Walter Harms
  0 siblings, 0 replies; 30+ messages in thread
From: Walter Harms @ 2021-02-09 10:57 UTC (permalink / raw)
  To: Dan Carpenter, Will Deacon
  Cc: Anan sun, Joerg Roedel, kernel-janitors, linux-kernel,
	Tomasz Figa, Chao Hao, iommu, linux-mediatek, linux-arm-kernel,
	Matthias Brugger, Colin King, Yong Wu

I second that ...

Having i unsigned violates the rule of "least surprise".
If you need it unsigned make it clearly visible, also adding
a simple comment may help.

jm2c,
 wh
________________________________________
Von: Dan Carpenter <dan.carpenter@oracle.com>
Gesendet: Dienstag, 9. Februar 2021 10:19:23
An: Will Deacon
Cc: Colin King; Joerg Roedel; Matthias Brugger; Anan sun; Yong Wu; Chao Hao; Tomasz Figa; iommu@lists.linux-foundation.org; linux-arm-kernel@lists.infradead.org; linux-mediatek@lists.infradead.org; kernel-janitors@vger.kernel.org; linux-kernel@vger.kernel.org
Betreff: Re: [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero

On Thu, Feb 04, 2021 at 09:25:58AM +0000, Will Deacon wrote:
> On Wed, Feb 03, 2021 at 01:59:36PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> >
> > Currently the check for domid < 0 is always false because domid
> > is unsigned.  Fix this by making it signed.
> >
> > Addresses-CoverityL ("Unsigned comparison against 0")
>
> Typo here ('L' instead of ':')
>
> > Fixes: ab1d5281a62b ("iommu/mediatek: Add iova reserved function")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> >  drivers/iommu/mtk_iommu.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index 0ad14a7604b1..823d719945b2 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -640,7 +640,7 @@ static void mtk_iommu_get_resv_regions(struct device *dev,
> >                                    struct list_head *head)
> >  {
> >     struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
> > -   unsigned int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
> > +   int domid = mtk_iommu_get_domain_id(dev, data->plat_data), i;
>
> Not sure if it's intentional, but this also makes 'i' signed. It probably
> should remain 'unsigned' to match 'iova_region_nr' in
> 'struct mtk_iommu_plat_data'.


iova_region_nr is either 1 or 5 so unsigned doesn't matter.

I once almost introduced a bug where the iterator was supposed to be
size_t.  I fixed a bug by making it signed but I ended up introducing a
new bug.  But generally that's pretty rare.  The more common case is
that making iterators unsigned introduces bugs.

It's better to default to "int i;" and if more complicated types are
required that should stand out.  "size_t pg_idx;" or whatever.

regards,
dan carpenter

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^ permalink raw reply	[flat|nested] 30+ messages in thread

end of thread, other threads:[~2021-02-09 11:05 UTC | newest]

Thread overview: 30+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-03 13:59 [PATCH][next] iommu/mediatek: Fix unsigned domid comparison with less than zero Colin King
2021-02-03 13:59 ` Colin King
2021-02-03 13:59 ` Colin King
2021-02-03 13:59 ` Colin King
2021-02-03 13:59 ` Colin King
2021-02-04  1:11 ` Yong Wu
2021-02-04  1:11   ` Yong Wu
2021-02-04  1:11   ` Yong Wu
2021-02-04  1:11   ` Yong Wu
2021-02-04  1:11   ` Yong Wu
2021-02-04  9:25 ` Will Deacon
2021-02-04  9:25   ` Will Deacon
2021-02-04  9:25   ` Will Deacon
2021-02-04  9:25   ` Will Deacon
2021-02-04  9:25   ` Will Deacon
2021-02-04 13:31   ` Joerg Roedel
2021-02-04 13:31     ` Joerg Roedel
2021-02-04 13:31     ` Joerg Roedel
2021-02-04 13:31     ` Joerg Roedel
2021-02-04 13:31     ` Joerg Roedel
2021-02-09  9:19   ` Dan Carpenter
2021-02-09  9:19     ` Dan Carpenter
2021-02-09  9:19     ` Dan Carpenter
2021-02-09  9:19     ` Dan Carpenter
2021-02-09  9:19     ` Dan Carpenter
2021-02-09 10:57     ` AW: " Walter Harms
2021-02-09 10:57       ` Walter Harms
2021-02-09 10:57       ` Walter Harms
2021-02-09 10:57       ` Walter Harms
2021-02-09 10:57       ` Walter Harms

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