* [V2] mtd: devices: docg3:- Handle return value of devm_ioremap.
@ 2016-12-12 3:00 Arvind Yadav
2016-12-12 4:10 ` Marek Vasut
2016-12-12 8:42 ` Boris Brezillon
0 siblings, 2 replies; 8+ messages in thread
From: Arvind Yadav @ 2016-12-12 3:00 UTC (permalink / raw)
To: robert.jarzmik, dwmw2, computersforpeace, boris.brezillon,
marek.vasut, richard, cyrille.pitchen
Cc: linux-mtd, linux-kernel
Here, If devm_ioremap will fail. It will return NULL.
Kernel can run into a NULL-pointer dereference.
Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
---
drivers/mtd/devices/docg3.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
index b833e6c..ffe3db0 100644
--- a/drivers/mtd/devices/docg3.c
+++ b/drivers/mtd/devices/docg3.c
@@ -2083,9 +2083,14 @@ static int __init docg3_probe(struct platform_device *pdev)
dev_err(dev, "No I/O memory resource defined\n");
return ret;
}
- base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
ret = -ENOMEM;
+ base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
+ if (!base) {
+ dev_err(dev, "failed to map I/O memory\n");
+ return ret;
+ }
+
cascade = devm_kzalloc(dev, sizeof(*cascade) * DOC_MAX_NBFLOORS,
GFP_KERNEL);
if (!cascade)
--
2.7.4
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [V2] mtd: devices: docg3:- Handle return value of devm_ioremap.
2016-12-12 3:00 [V2] mtd: devices: docg3:- Handle return value of devm_ioremap Arvind Yadav
@ 2016-12-12 4:10 ` Marek Vasut
2016-12-12 8:42 ` Boris Brezillon
1 sibling, 0 replies; 8+ messages in thread
From: Marek Vasut @ 2016-12-12 4:10 UTC (permalink / raw)
To: Arvind Yadav, robert.jarzmik, dwmw2, computersforpeace,
boris.brezillon, richard, cyrille.pitchen
Cc: linux-mtd, linux-kernel
On 12/12/2016 04:00 AM, Arvind Yadav wrote:
> Here, If devm_ioremap will fail. It will return NULL.
> Kernel can run into a NULL-pointer dereference.
>
> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
> ---
> drivers/mtd/devices/docg3.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
> index b833e6c..ffe3db0 100644
> --- a/drivers/mtd/devices/docg3.c
> +++ b/drivers/mtd/devices/docg3.c
> @@ -2083,9 +2083,14 @@ static int __init docg3_probe(struct platform_device *pdev)
> dev_err(dev, "No I/O memory resource defined\n");
> return ret;
> }
> - base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
>
> ret = -ENOMEM;
> + base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
> + if (!base) {
> + dev_err(dev, "failed to map I/O memory\n");
> + return ret;
Um, return -ENOMEM right away ?
Otherwise,
Acked-by: Marek Vasut <marek.vasut@gmail.com>
> + }
> +
> cascade = devm_kzalloc(dev, sizeof(*cascade) * DOC_MAX_NBFLOORS,
> GFP_KERNEL);
> if (!cascade)
>
--
Best regards,
Marek Vasut
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [V2] mtd: devices: docg3:- Handle return value of devm_ioremap.
2016-12-12 3:00 [V2] mtd: devices: docg3:- Handle return value of devm_ioremap Arvind Yadav
2016-12-12 4:10 ` Marek Vasut
@ 2016-12-12 8:42 ` Boris Brezillon
2016-12-12 16:03 ` arvind Yadav
1 sibling, 1 reply; 8+ messages in thread
From: Boris Brezillon @ 2016-12-12 8:42 UTC (permalink / raw)
To: Arvind Yadav
Cc: robert.jarzmik, dwmw2, computersforpeace, marek.vasut, richard,
cyrille.pitchen, linux-mtd, linux-kernel
On Mon, 12 Dec 2016 08:30:04 +0530
Arvind Yadav <arvind.yadav.cs@gmail.com> wrote:
> Here, If devm_ioremap will fail. It will return NULL.
> Kernel can run into a NULL-pointer dereference.
>
> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
> ---
> drivers/mtd/devices/docg3.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
> index b833e6c..ffe3db0 100644
> --- a/drivers/mtd/devices/docg3.c
> +++ b/drivers/mtd/devices/docg3.c
> @@ -2083,9 +2083,14 @@ static int __init docg3_probe(struct platform_device *pdev)
> dev_err(dev, "No I/O memory resource defined\n");
> return ret;
> }
> - base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
>
> ret = -ENOMEM;
> + base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
> + if (!base) {
> + dev_err(dev, "failed to map I/O memory\n");
> + return ret;
> + }
> +
> cascade = devm_kzalloc(dev, sizeof(*cascade) * DOC_MAX_NBFLOORS,
> GFP_KERNEL);
> if (!cascade)
How about going even further and doing the following?
This way you can drop the test on rres (it's done for you in
devm_ioremap_resource()), and you can directly return the error
returned by devm_ioremap_resource().
--->8---
diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
index b833e6cc684c..c59b91734344 100644
--- a/drivers/mtd/devices/docg3.c
+++ b/drivers/mtd/devices/docg3.c
@@ -2077,13 +2077,10 @@ static int __init docg3_probe(struct
platform_device *pdev) int ret, floor;
struct docg3_cascade *cascade;
- ret = -ENXIO;
ress = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (!ress) {
- dev_err(dev, "No I/O memory resource defined\n");
- return ret;
- }
- base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
+ base = devm_ioremap_resource(dev, ress);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
ret = -ENOMEM;
cascade = devm_kzalloc(dev, sizeof(*cascade) * DOC_MAX_NBFLOORS,
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [V2] mtd: devices: docg3:- Handle return value of devm_ioremap.
2016-12-12 8:42 ` Boris Brezillon
@ 2016-12-12 16:03 ` arvind Yadav
2016-12-12 16:32 ` Robert Jarzmik
2016-12-12 17:04 ` Boris Brezillon
0 siblings, 2 replies; 8+ messages in thread
From: arvind Yadav @ 2016-12-12 16:03 UTC (permalink / raw)
To: Boris Brezillon
Cc: robert.jarzmik, dwmw2, computersforpeace, marek.vasut, richard,
cyrille.pitchen, linux-mtd, linux-kernel
There is problem, if you will use devm_ioremap_resource instead of
devm_ioremap,
than devm_ioremap_resource will call request_mem_region().
request_mem_region() allows to tell the kernel that this driver is going
to use
this range of I/O addresses, which will prevent other drivers to make an
overlapping call to request_mem_region If other driver want to use same
address
space to access then it will not allow. Means we can not share same
address space
between two driver.
Thanks
-Arvind
On Monday 12 December 2016 02:12 PM, Boris Brezillon wrote:
> On Mon, 12 Dec 2016 08:30:04 +0530
> Arvind Yadav <arvind.yadav.cs@gmail.com> wrote:
>
>> Here, If devm_ioremap will fail. It will return NULL.
>> Kernel can run into a NULL-pointer dereference.
>>
>> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
>> ---
>> drivers/mtd/devices/docg3.c | 7 ++++++-
>> 1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
>> index b833e6c..ffe3db0 100644
>> --- a/drivers/mtd/devices/docg3.c
>> +++ b/drivers/mtd/devices/docg3.c
>> @@ -2083,9 +2083,14 @@ static int __init docg3_probe(struct platform_device *pdev)
>> dev_err(dev, "No I/O memory resource defined\n");
>> return ret;
>> }
>> - base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
>>
>> ret = -ENOMEM;
>> + base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
>> + if (!base) {
>> + dev_err(dev, "failed to map I/O memory\n");
>> + return ret;
>> + }
>> +
>> cascade = devm_kzalloc(dev, sizeof(*cascade) * DOC_MAX_NBFLOORS,
>> GFP_KERNEL);
>> if (!cascade)
> How about going even further and doing the following?
> This way you can drop the test on rres (it's done for you in
> devm_ioremap_resource()), and you can directly return the error
> returned by devm_ioremap_resource().
>
> --->8---
> diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
> index b833e6cc684c..c59b91734344 100644
> --- a/drivers/mtd/devices/docg3.c
> +++ b/drivers/mtd/devices/docg3.c
> @@ -2077,13 +2077,10 @@ static int __init docg3_probe(struct
> platform_device *pdev) int ret, floor;
> struct docg3_cascade *cascade;
>
> - ret = -ENXIO;
> ress = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> - if (!ress) {
> - dev_err(dev, "No I/O memory resource defined\n");
> - return ret;
> - }
> - base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
> + base = devm_ioremap_resource(dev, ress);
> + if (IS_ERR(base))
> + return PTR_ERR(base);
>
> ret = -ENOMEM;
> cascade = devm_kzalloc(dev, sizeof(*cascade) * DOC_MAX_NBFLOORS,
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [V2] mtd: devices: docg3:- Handle return value of devm_ioremap.
2016-12-12 16:03 ` arvind Yadav
@ 2016-12-12 16:32 ` Robert Jarzmik
2016-12-12 17:00 ` Boris Brezillon
2016-12-12 17:04 ` Boris Brezillon
1 sibling, 1 reply; 8+ messages in thread
From: Robert Jarzmik @ 2016-12-12 16:32 UTC (permalink / raw)
To: arvind Yadav
Cc: Boris Brezillon, dwmw2, computersforpeace, marek.vasut, richard,
cyrille.pitchen, linux-mtd, linux-kernel
arvind Yadav <arvind.yadav.cs@gmail.com> writes:
> There is problem, if you will use devm_ioremap_resource instead of devm_ioremap,
> than devm_ioremap_resource will call request_mem_region().
> request_mem_region() allows to tell the kernel that this driver is going to use
> this range of I/O addresses, which will prevent other drivers to make an
> overlapping call to request_mem_region If other driver want to use same address
> space to access then it will not allow. Means we can not share same address
> space
> between two driver.
Hi,
You're right Arvind, and still, it's worth noticing that the docg3 access
semantics imply a "reserved" resource path (see how doc_register_readb() does a
write and how this cannot be shared with another driver).
Therefore I'll be willing to ack a mix of your both patches, the
devm_ioremap_resource() from Boris and the error message from your patch.
Cheers.
--
Robert
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [V2] mtd: devices: docg3:- Handle return value of devm_ioremap.
2016-12-12 16:32 ` Robert Jarzmik
@ 2016-12-12 17:00 ` Boris Brezillon
0 siblings, 0 replies; 8+ messages in thread
From: Boris Brezillon @ 2016-12-12 17:00 UTC (permalink / raw)
To: Robert Jarzmik
Cc: arvind Yadav, dwmw2, computersforpeace, marek.vasut, richard,
cyrille.pitchen, linux-mtd, linux-kernel
On Mon, 12 Dec 2016 17:32:58 +0100
Robert Jarzmik <robert.jarzmik@free.fr> wrote:
> arvind Yadav <arvind.yadav.cs@gmail.com> writes:
>
> > There is problem, if you will use devm_ioremap_resource instead of devm_ioremap,
> > than devm_ioremap_resource will call request_mem_region().
> > request_mem_region() allows to tell the kernel that this driver is going to use
> > this range of I/O addresses, which will prevent other drivers to make an
> > overlapping call to request_mem_region If other driver want to use same address
> > space to access then it will not allow. Means we can not share same address
> > space
> > between two driver.
>
> Hi,
>
> You're right Arvind, and still, it's worth noticing that the docg3 access
> semantics imply a "reserved" resource path (see how doc_register_readb() does a
> write and how this cannot be shared with another driver).
>
> Therefore I'll be willing to ack a mix of your both patches, the
> devm_ioremap_resource() from Boris and the error message from your patch.
devm_ioremap_resource() already prints different error messages
depending on the error type [1], no need to duplicate it.
[1]http://lxr.free-electrons.com/source/lib/devres.c#L134
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [V2] mtd: devices: docg3:- Handle return value of devm_ioremap.
2016-12-12 16:03 ` arvind Yadav
2016-12-12 16:32 ` Robert Jarzmik
@ 2016-12-12 17:04 ` Boris Brezillon
2016-12-12 18:15 ` arvind Yadav
1 sibling, 1 reply; 8+ messages in thread
From: Boris Brezillon @ 2016-12-12 17:04 UTC (permalink / raw)
To: arvind Yadav
Cc: robert.jarzmik, dwmw2, computersforpeace, marek.vasut, richard,
cyrille.pitchen, linux-mtd, linux-kernel
Hi Arvind,
On Mon, 12 Dec 2016 21:33:05 +0530
arvind Yadav <arvind.yadav.cs@gmail.com> wrote:
> There is problem, if you will use devm_ioremap_resource instead of
> devm_ioremap,
> than devm_ioremap_resource will call request_mem_region().
> request_mem_region() allows to tell the kernel that this driver is going
> to use
> this range of I/O addresses, which will prevent other drivers to make an
> overlapping call to request_mem_region If other driver want to use same
> address
> space to access then it will not allow. Means we can not share same
> address space
> between two driver.
The question is, is it required here? In general, allowing 2 different
drivers from touching the same iomem region is a bad idea, so, if
there's a reason to allow that here, I'd like to know more about it.
Thanks,
Boris
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [V2] mtd: devices: docg3:- Handle return value of devm_ioremap.
2016-12-12 17:04 ` Boris Brezillon
@ 2016-12-12 18:15 ` arvind Yadav
0 siblings, 0 replies; 8+ messages in thread
From: arvind Yadav @ 2016-12-12 18:15 UTC (permalink / raw)
To: Boris Brezillon
Cc: robert.jarzmik, dwmw2, computersforpeace, marek.vasut, richard,
cyrille.pitchen, linux-mtd, linux-kernel
Hi Boris,
Yes, It's possible that two driver can use same iomem region.
For example you can check
commit id - : 33cf75656923ff11d67a937a4f8e9344f58cea77
Here, It's not required.
Thanks
-Arvind
On Monday 12 December 2016 10:34 PM, Boris Brezillon wrote:
> Hi Arvind,
>
> On Mon, 12 Dec 2016 21:33:05 +0530
> arvind Yadav <arvind.yadav.cs@gmail.com> wrote:
>
>> There is problem, if you will use devm_ioremap_resource instead of
>> devm_ioremap,
>> than devm_ioremap_resource will call request_mem_region().
>> request_mem_region() allows to tell the kernel that this driver is going
>> to use
>> this range of I/O addresses, which will prevent other drivers to make an
>> overlapping call to request_mem_region If other driver want to use same
>> address
>> space to access then it will not allow. Means we can not share same
>> address space
>> between two driver.
> The question is, is it required here? In general, allowing 2 different
> drivers from touching the same iomem region is a bad idea, so, if
> there's a reason to allow that here, I'd like to know more about it.
>
> Thanks,
>
> Boris
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2016-12-12 18:16 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-12-12 3:00 [V2] mtd: devices: docg3:- Handle return value of devm_ioremap Arvind Yadav
2016-12-12 4:10 ` Marek Vasut
2016-12-12 8:42 ` Boris Brezillon
2016-12-12 16:03 ` arvind Yadav
2016-12-12 16:32 ` Robert Jarzmik
2016-12-12 17:00 ` Boris Brezillon
2016-12-12 17:04 ` Boris Brezillon
2016-12-12 18:15 ` arvind Yadav
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