Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1300855 > unrolled thread

[PATCH v2 2/2] memory-hotplug: keep the request_resource() error code

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  [PATCH v2 2/2] memory-hotplug: keep the request_resource() error code Vitaly Kuznetsov <vkuznets@redhat.com> - 2016-01-04 17:20 +0100
    Re: [PATCH v2 2/2] memory-hotplug: keep the request_resource() error code "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-01-04 23:00 +0100
    Re: [PATCH v2 2/2] memory-hotplug: keep the request_resource() error  code David Rientjes <rientjes@google.com> - 2016-01-13 00:30 +0100
      Re: [PATCH v2 2/2] memory-hotplug: keep the request_resource() error code Vitaly Kuznetsov <vkuznets@redhat.com> - 2016-01-13 11:30 +0100

#1300855 — [PATCH v2 2/2] memory-hotplug: keep the request_resource() error code

Don't overwrite the request_resource() return value with -EEXIST in
register_memory_resource(), just propagate the return value. As we return
-EBUSY instead of -EEXIST when the desired resource is already occupied
now we need to adapt acpi_memory_enable_device(). -EBUSY is currently the
only possible error returned by request_resource() so this is just a
cleanup, no functional changes intended.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 drivers/acpi/acpi_memhotplug.c | 4 ++--
 mm/memory_hotplug.c            | 6 ++++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 6b0d3ef..e367e4b 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -232,10 +232,10 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 
 		/*
 		 * If the memory block has been used by the kernel, add_memory()
-		 * returns -EEXIST. If add_memory() returns the other error, it
+		 * returns -EBUSY. If add_memory() returns the other error, it
 		 * means that this memory block is not used by the kernel.
 		 */
-		if (result && result != -EEXIST)
+		if (result && result != -EBUSY)
 			continue;
 
 		result = acpi_bind_memory_blocks(info, mem_device->device);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 92f9595..07eab2c 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -130,6 +130,7 @@ void mem_hotplug_done(void)
 static struct resource *register_memory_resource(u64 start, u64 size)
 {
 	struct resource *res;
+	int ret;
 	res = kzalloc(sizeof(struct resource), GFP_KERNEL);
 	if (!res)
 		return ERR_PTR(-ENOMEM);
@@ -138,10 +139,11 @@ static struct resource *register_memory_resource(u64 start, u64 size)
 	res->start = start;
 	res->end = start + size - 1;
 	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
-	if (request_resource(&iomem_resource, res) < 0) {
+	ret = request_resource(&iomem_resource, res);
+	if (ret < 0) {
 		pr_debug("System RAM resource %pR cannot be added\n", res);
 		kfree(res);
-		return ERR_PTR(-EEXIST);
+		return ERR_PTR(ret);
 	}
 	return res;
 }
-- 
2.4.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [next] | [standalone]

#1301135

On Monday, January 04, 2016 05:17:31 PM Vitaly Kuznetsov wrote:
> Don't overwrite the request_resource() return value with -EEXIST in
> register_memory_resource(), just propagate the return value. As we return
> -EBUSY instead of -EEXIST when the desired resource is already occupied
> now we need to adapt acpi_memory_enable_device(). -EBUSY is currently the
> only possible error returned by request_resource() so this is just a
> cleanup, no functional changes intended.
> 
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Tang Chen <tangchen@cn.fujitsu.com>
> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: David Vrabel <david.vrabel@citrix.com>
> Cc: Igor Mammedov <imammedo@redhat.com>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: Len Brown <lenb@kernel.org>
> Suggested-by: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

for the ACPI part and I'm assumig that this will go in through the mm tree.

> ---
>  drivers/acpi/acpi_memhotplug.c | 4 ++--
>  mm/memory_hotplug.c            | 6 ++++--
>  2 files changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index 6b0d3ef..e367e4b 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -232,10 +232,10 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
>  
>  		/*
>  		 * If the memory block has been used by the kernel, add_memory()
> -		 * returns -EEXIST. If add_memory() returns the other error, it
> +		 * returns -EBUSY. If add_memory() returns the other error, it
>  		 * means that this memory block is not used by the kernel.
>  		 */
> -		if (result && result != -EEXIST)
> +		if (result && result != -EBUSY)
>  			continue;
>  
>  		result = acpi_bind_memory_blocks(info, mem_device->device);
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 92f9595..07eab2c 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -130,6 +130,7 @@ void mem_hotplug_done(void)
>  static struct resource *register_memory_resource(u64 start, u64 size)
>  {
>  	struct resource *res;
> +	int ret;
>  	res = kzalloc(sizeof(struct resource), GFP_KERNEL);
>  	if (!res)
>  		return ERR_PTR(-ENOMEM);
> @@ -138,10 +139,11 @@ static struct resource *register_memory_resource(u64 start, u64 size)
>  	res->start = start;
>  	res->end = start + size - 1;
>  	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> -	if (request_resource(&iomem_resource, res) < 0) {
> +	ret = request_resource(&iomem_resource, res);
> +	if (ret < 0) {
>  		pr_debug("System RAM resource %pR cannot be added\n", res);
>  		kfree(res);
> -		return ERR_PTR(-EEXIST);
> +		return ERR_PTR(ret);
>  	}
>  	return res;
>  }
> 

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [next] | [standalone]

#1307910 — Re: [PATCH v2 2/2] memory-hotplug: keep the request_resource() error code

On Mon, 4 Jan 2016, Vitaly Kuznetsov wrote:

> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index 6b0d3ef..e367e4b 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -232,10 +232,10 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
>  
>  		/*
>  		 * If the memory block has been used by the kernel, add_memory()
> -		 * returns -EEXIST. If add_memory() returns the other error, it
> +		 * returns -EBUSY. If add_memory() returns the other error, it
>  		 * means that this memory block is not used by the kernel.
>  		 */
> -		if (result && result != -EEXIST)
> +		if (result && result != -EBUSY)
>  			continue;
>  
>  		result = acpi_bind_memory_blocks(info, mem_device->device);
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 92f9595..07eab2c 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -130,6 +130,7 @@ void mem_hotplug_done(void)
>  static struct resource *register_memory_resource(u64 start, u64 size)
>  {
>  	struct resource *res;
> +	int ret;
>  	res = kzalloc(sizeof(struct resource), GFP_KERNEL);
>  	if (!res)
>  		return ERR_PTR(-ENOMEM);
> @@ -138,10 +139,11 @@ static struct resource *register_memory_resource(u64 start, u64 size)
>  	res->start = start;
>  	res->end = start + size - 1;
>  	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> -	if (request_resource(&iomem_resource, res) < 0) {
> +	ret = request_resource(&iomem_resource, res);
> +	if (ret < 0) {
>  		pr_debug("System RAM resource %pR cannot be added\n", res);
>  		kfree(res);
> -		return ERR_PTR(-EEXIST);
> +		return ERR_PTR(ret);
>  	}
>  	return res;
>  }

The result of this change is that add_memory() returns -EBUSY instead of 
-EEXIST for overlapping ranges.  This patch breaks hv_mem_hot_add() since 
it strictly uses a return value of -EEXIST to indicate a non-transient 
failure, so NACK.  It also changes the return value of both the "probe" 
and "dlpar" (on ppc) userspace triggers, which I could imagine is tested 
from existing userspace scripts.

[toc] | [prev] | [next] | [standalone]

#1308258

David Rientjes <rientjes@google.com> writes:

> On Mon, 4 Jan 2016, Vitaly Kuznetsov wrote:
>
>> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
>> index 6b0d3ef..e367e4b 100644
>> --- a/drivers/acpi/acpi_memhotplug.c
>> +++ b/drivers/acpi/acpi_memhotplug.c
>> @@ -232,10 +232,10 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
>>  
>>  		/*
>>  		 * If the memory block has been used by the kernel, add_memory()
>> -		 * returns -EEXIST. If add_memory() returns the other error, it
>> +		 * returns -EBUSY. If add_memory() returns the other error, it
>>  		 * means that this memory block is not used by the kernel.
>>  		 */
>> -		if (result && result != -EEXIST)
>> +		if (result && result != -EBUSY)
>>  			continue;
>>  
>>  		result = acpi_bind_memory_blocks(info, mem_device->device);
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index 92f9595..07eab2c 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>> @@ -130,6 +130,7 @@ void mem_hotplug_done(void)
>>  static struct resource *register_memory_resource(u64 start, u64 size)
>>  {
>>  	struct resource *res;
>> +	int ret;
>>  	res = kzalloc(sizeof(struct resource), GFP_KERNEL);
>>  	if (!res)
>>  		return ERR_PTR(-ENOMEM);
>> @@ -138,10 +139,11 @@ static struct resource *register_memory_resource(u64 start, u64 size)
>>  	res->start = start;
>>  	res->end = start + size - 1;
>>  	res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
>> -	if (request_resource(&iomem_resource, res) < 0) {
>> +	ret = request_resource(&iomem_resource, res);
>> +	if (ret < 0) {
>>  		pr_debug("System RAM resource %pR cannot be added\n", res);
>>  		kfree(res);
>> -		return ERR_PTR(-EEXIST);
>> +		return ERR_PTR(ret);
>>  	}
>>  	return res;
>>  }
>
> The result of this change is that add_memory() returns -EBUSY instead of 
> -EEXIST for overlapping ranges.  This patch breaks hv_mem_hot_add() since 
> it strictly uses a return value of -EEXIST to indicate a non-transient 
> failure, so NACK.

While this is shameful but fixable ...

> It also changes the return value of both the "probe" 
> and "dlpar" (on ppc) userspace triggers, which I could imagine is tested 
> from existing userspace scripts.

this is probably a show-stopper as we're bound by "we don't break
userspace" rule (and it's not worth it anyway). Thanks for pointing this
out!

Andrew, please drop this patch from your queue permanently. The patch 1
of the series is worthwhile (and is acked by David).

Thanks,

-- 
  Vitaly

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web