[RFC][PATCH] PM / Hibernate: Modify signature used to mark swap

[RFC][PATCH] PM / Hibernate: Modify signature used to mark swap

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>
Subject: PM / Hibernate: Modify signature used to mark swap

Since we are adding compression to the kernel's hibernate code,
change signature used by it to mark swap spaces, so that earlier
kernels don't attempt to restore compressed images they cannot
handle.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 kernel/power/swap.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Index: linux-2.6/kernel/power/swap.c
===================================================================
--- linux-2.6.orig/kernel/power/swap.c
+++ linux-2.6/kernel/power/swap.c
@@ -29,7 +29,7 @@
 
 #include "power.h"
 
-#define SWSUSP_SIG	"S1SUSPEND"
+#define HIBERNATE_SIG	"LINHIB0001"
 
 /*
  *	The swap map is a data structure used for keeping track of each page
@@ -195,7 +195,7 @@ static int mark_swapfiles(struct swap_ma
 	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
 	    !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
 		memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
-		memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
+		memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
 		swsusp_header->image = handle->first_sector;
 		swsusp_header->flags = flags;
 		error = hib_bio_write_page(swsusp_resume_block,
@@ -916,7 +916,7 @@ int swsusp_check(void)
 		if (error)
 			goto put;
 
-		if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
+		if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
 			memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
 			/* Reset swap signature now */
 			error = hib_bio_write_page(swsusp_resume_block,

Re: [RFC][PATCH] PM / Hibernate: Modify signature used to mark swap

[Nigel Cunningham]

Hi.

On 30/09/10 07:13, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki<rjw@sisk.pl>
> Subject: PM / Hibernate: Modify signature used to mark swap
>
> Since we are adding compression to the kernel's hibernate code,
> change signature used by it to mark swap spaces, so that earlier
> kernels don't attempt to restore compressed images they cannot
> handle.
>
> Signed-off-by: Rafael J. Wysocki<rjw@sisk.pl>
> ---
>   kernel/power/swap.c |    6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> Index: linux-2.6/kernel/power/swap.c
> ===================================================================
> --- linux-2.6.orig/kernel/power/swap.c
> +++ linux-2.6/kernel/power/swap.c
> @@ -29,7 +29,7 @@
>
>   #include "power.h"
>
> -#define SWSUSP_SIG	"S1SUSPEND"
> +#define HIBERNATE_SIG	"LINHIB0001"
>
>   /*
>    *	The swap map is a data structure used for keeping track of each page
> @@ -195,7 +195,7 @@ static int mark_swapfiles(struct swap_ma
>   	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
>   	    !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
>   		memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);

if no compression

> -		memcpy(swsusp_header->sig,SWSUSP_SIG, 10);

else

> +		memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);

??

>   		swsusp_header->image = handle->first_sector;
>   		swsusp_header->flags = flags;
>   		error = hib_bio_write_page(swsusp_resume_block,
> @@ -916,7 +916,7 @@ int swsusp_check(void)
>   		if (error)
>   			goto put;
>
> -		if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
> +		if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {

Reset the signature in either case?

>   			memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
>   			/* Reset swap signature now */
>   			error = hib_bio_write_page(swsusp_resume_block,
>

Regards,

Nigel

Re: [RFC][PATCH] PM / Hibernate: Modify signature used to mark swap

[Rafael J. Wysocki]

On Wednesday, September 29, 2010, Nigel Cunningham wrote:
> Hi.
> 
> On 30/09/10 07:13, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki<rjw@sisk.pl>
> > Subject: PM / Hibernate: Modify signature used to mark swap
> >
> > Since we are adding compression to the kernel's hibernate code,
> > change signature used by it to mark swap spaces, so that earlier
> > kernels don't attempt to restore compressed images they cannot
> > handle.
> >
> > Signed-off-by: Rafael J. Wysocki<rjw@sisk.pl>
> > ---
> >   kernel/power/swap.c |    6 +++---
> >   1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > Index: linux-2.6/kernel/power/swap.c
> > ===================================================================
> > --- linux-2.6.orig/kernel/power/swap.c
> > +++ linux-2.6/kernel/power/swap.c
> > @@ -29,7 +29,7 @@
> >
> >   #include "power.h"
> >
> > -#define SWSUSP_SIG	"S1SUSPEND"
> > +#define HIBERNATE_SIG	"LINHIB0001"
> >
> >   /*
> >    *	The swap map is a data structure used for keeping track of each page
> > @@ -195,7 +195,7 @@ static int mark_swapfiles(struct swap_ma
> >   	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
> >   	    !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
> >   		memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
> 
> if no compression
> 
> > -		memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
> 
> else
> 
> > +		memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
> 
> ??

I thought about that, but we'll need to drop the old signature when the image
format changes (I think it will after your patch series) anyway.  And the
benefit is not really worth it IMO (it only affects people using the in-kernel
hibernation on x86-64).

Thanks,
Rafael

Re: [RFC][PATCH] PM / Hibernate: Modify signature used to mark swap

[Nigel Cunningham]

Hi.

On 30/09/10 08:02, Rafael J. Wysocki wrote:
> On Wednesday, September 29, 2010, Nigel Cunningham wrote:
>> Hi.
>>
>> On 30/09/10 07:13, Rafael J. Wysocki wrote:
>>> From: Rafael J. Wysocki<rjw@sisk.pl>
>>> Subject: PM / Hibernate: Modify signature used to mark swap
>>>
>>> Since we are adding compression to the kernel's hibernate code,
>>> change signature used by it to mark swap spaces, so that earlier
>>> kernels don't attempt to restore compressed images they cannot
>>> handle.
>>>
>>> Signed-off-by: Rafael J. Wysocki<rjw@sisk.pl>
>>> ---
>>>    kernel/power/swap.c |    6 +++---
>>>    1 file changed, 3 insertions(+), 3 deletions(-)
>>>
>>> Index: linux-2.6/kernel/power/swap.c
>>> ===================================================================
>>> --- linux-2.6.orig/kernel/power/swap.c
>>> +++ linux-2.6/kernel/power/swap.c
>>> @@ -29,7 +29,7 @@
>>>
>>>    #include "power.h"
>>>
>>> -#define SWSUSP_SIG	"S1SUSPEND"
>>> +#define HIBERNATE_SIG	"LINHIB0001"
>>>
>>>    /*
>>>     *	The swap map is a data structure used for keeping track of each page
>>> @@ -195,7 +195,7 @@ static int mark_swapfiles(struct swap_ma
>>>    	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
>>>    	    !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
>>>    		memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
>>
>> if no compression
>>
>>> -		memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
>>
>> else
>>
>>> +		memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
>>
>> ??
>
> I thought about that, but we'll need to drop the old signature when the image
> format changes (I think it will after your patch series) anyway.  And the
> benefit is not really worth it IMO (it only affects people using the in-kernel
> hibernation on x86-64).

Okay. I'm just a little weary because if everything I want to get in 
gets in, we're going to then be changing this signature multiple times. 
I want to eventually reach a situation where we have a 'proper' header 
section to the image that stores (among other things) whether 
compression is enabled and which cryptoapi algorithm is used, allowing a 
person to en/disable compression at runtime without recompiling or 
rebooting. I suppose if I seek to put that stuff in earlier rather than 
later, that will simplify things.

Oh, while I'm writing to you: let's not worry about getting my patches 
in for 2.6.37. I won't be working on them much today, and want to put 
the time into making sure they're right before they get merged. As you 
said - let's seek to get things right first time.

Regards,

Nigel

Re: [RFC][PATCH] PM / Hibernate: Modify signature used to mark swap

[Rafael J. Wysocki]

On Saturday, October 02, 2010, Nigel Cunningham wrote:
> Hi.
> 
> On 30/09/10 08:02, Rafael J. Wysocki wrote:
> > On Wednesday, September 29, 2010, Nigel Cunningham wrote:
> >> Hi.
> >>
> >> On 30/09/10 07:13, Rafael J. Wysocki wrote:
> >>> From: Rafael J. Wysocki<rjw@sisk.pl>
> >>> Subject: PM / Hibernate: Modify signature used to mark swap
> >>>
> >>> Since we are adding compression to the kernel's hibernate code,
> >>> change signature used by it to mark swap spaces, so that earlier
> >>> kernels don't attempt to restore compressed images they cannot
> >>> handle.
> >>>
> >>> Signed-off-by: Rafael J. Wysocki<rjw@sisk.pl>
> >>> ---
> >>>    kernel/power/swap.c |    6 +++---
> >>>    1 file changed, 3 insertions(+), 3 deletions(-)
> >>>
> >>> Index: linux-2.6/kernel/power/swap.c
> >>> ===================================================================
> >>> --- linux-2.6.orig/kernel/power/swap.c
> >>> +++ linux-2.6/kernel/power/swap.c
> >>> @@ -29,7 +29,7 @@
> >>>
> >>>    #include "power.h"
> >>>
> >>> -#define SWSUSP_SIG	"S1SUSPEND"
> >>> +#define HIBERNATE_SIG	"LINHIB0001"
> >>>
> >>>    /*
> >>>     *	The swap map is a data structure used for keeping track of each page
> >>> @@ -195,7 +195,7 @@ static int mark_swapfiles(struct swap_ma
> >>>    	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
> >>>    	    !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
> >>>    		memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
> >>
> >> if no compression
> >>
> >>> -		memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
> >>
> >> else
> >>
> >>> +		memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
> >>
> >> ??
> >
> > I thought about that, but we'll need to drop the old signature when the image
> > format changes (I think it will after your patch series) anyway.  And the
> > benefit is not really worth it IMO (it only affects people using the in-kernel
> > hibernation on x86-64).
> 
> Okay. I'm just a little weary because if everything I want to get in 
> gets in, we're going to then be changing this signature multiple times. 

That most likely is correct.

> I want to eventually reach a situation where we have a 'proper' header 
> section to the image that stores (among other things) whether 
> compression is enabled and which cryptoapi algorithm is used, allowing a 
> person to en/disable compression at runtime without recompiling or 
> rebooting. I suppose if I seek to put that stuff in earlier rather than 
> later, that will simplify things.

I don't have a problem with changing the signature.  If the image format
changes, it's probably the best we can do.

> Oh, while I'm writing to you: let's not worry about getting my patches 
> in for 2.6.37. I won't be working on them much today, and want to put 
> the time into making sure they're right before they get merged. As you 
> said - let's seek to get things right first time.

OK

Thanks,
Rafael

Re: [RFC][PATCH] PM / Hibernate: Modify signature used to mark swap

[Rafael J. Wysocki]

On Saturday, October 02, 2010, Nigel Cunningham wrote:
> Hi.
> 
> On 30/09/10 08:02, Rafael J. Wysocki wrote:
> > On Wednesday, September 29, 2010, Nigel Cunningham wrote:
> >> Hi.
> >>
> >> On 30/09/10 07:13, Rafael J. Wysocki wrote:
> >>> From: Rafael J. Wysocki<rjw@sisk.pl>
> >>> Subject: PM / Hibernate: Modify signature used to mark swap
> >>>
> >>> Since we are adding compression to the kernel's hibernate code,
> >>> change signature used by it to mark swap spaces, so that earlier
> >>> kernels don't attempt to restore compressed images they cannot
> >>> handle.
> >>>
> >>> Signed-off-by: Rafael J. Wysocki<rjw@sisk.pl>
> >>> ---
> >>>    kernel/power/swap.c |    6 +++---
> >>>    1 file changed, 3 insertions(+), 3 deletions(-)
> >>>
> >>> Index: linux-2.6/kernel/power/swap.c
> >>> ===================================================================
> >>> --- linux-2.6.orig/kernel/power/swap.c
> >>> +++ linux-2.6/kernel/power/swap.c
> >>> @@ -29,7 +29,7 @@
> >>>
> >>>    #include "power.h"
> >>>
> >>> -#define SWSUSP_SIG	"S1SUSPEND"
> >>> +#define HIBERNATE_SIG	"LINHIB0001"
> >>>
> >>>    /*
> >>>     *	The swap map is a data structure used for keeping track of each page
> >>> @@ -195,7 +195,7 @@ static int mark_swapfiles(struct swap_ma
> >>>    	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
> >>>    	    !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
> >>>    		memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
> >>
> >> if no compression
> >>
> >>> -		memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
> >>
> >> else
> >>
> >>> +		memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
> >>
> >> ??
> >
> > I thought about that, but we'll need to drop the old signature when the image
> > format changes (I think it will after your patch series) anyway.  And the
> > benefit is not really worth it IMO (it only affects people using the in-kernel
> > hibernation on x86-64).
> 
> Okay. I'm just a little weary because if everything I want to get in 
> gets in, we're going to then be changing this signature multiple times. 

That most likely is correct.

> I want to eventually reach a situation where we have a 'proper' header 
> section to the image that stores (among other things) whether 
> compression is enabled and which cryptoapi algorithm is used, allowing a 
> person to en/disable compression at runtime without recompiling or 
> rebooting. I suppose if I seek to put that stuff in earlier rather than 
> later, that will simplify things.

I don't have a problem with changing the signature.  If the image format
changes, it's probably the best we can do.

> Oh, while I'm writing to you: let's not worry about getting my patches 
> in for 2.6.37. I won't be working on them much today, and want to put 
> the time into making sure they're right before they get merged. As you 
> said - let's seek to get things right first time.

OK

Thanks,
Rafael

Re: [RFC][PATCH] PM / Hibernate: Modify signature used to mark swap

[Pavel Machek]

> > > Index: linux-2.6/kernel/power/swap.c
> > > ===================================================================
> > > --- linux-2.6.orig/kernel/power/swap.c
> > > +++ linux-2.6/kernel/power/swap.c
> > > @@ -29,7 +29,7 @@
> > >
> > >   #include "power.h"
> > >
> > > -#define SWSUSP_SIG	"S1SUSPEND"
> > > +#define HIBERNATE_SIG	"LINHIB0001"
> > >
> > >   /*
> > >    *	The swap map is a data structure used for keeping track of each page
> > > @@ -195,7 +195,7 @@ static int mark_swapfiles(struct swap_ma
> > >   	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
> > >   	    !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
> > >   		memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
> > 
> > if no compression
> > 
> > > -		memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
> > 
> > else
> > 
> > > +		memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
> > 
> > ??
> 
> I thought about that, but we'll need to drop the old signature when the image
> format changes (I think it will after your patch series) anyway.  And the
> benefit is not really worth it IMO (it only affects people using the in-kernel
> hibernation on x86-64).
> 

ACK. Lets keep this simple.

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: [RFC][PATCH] PM / Hibernate: Modify signature used to mark swap

[Pavel Machek]

> > > Index: linux-2.6/kernel/power/swap.c
> > > ===================================================================
> > > --- linux-2.6.orig/kernel/power/swap.c
> > > +++ linux-2.6/kernel/power/swap.c
> > > @@ -29,7 +29,7 @@
> > >
> > >   #include "power.h"
> > >
> > > -#define SWSUSP_SIG	"S1SUSPEND"
> > > +#define HIBERNATE_SIG	"LINHIB0001"
> > >
> > >   /*
> > >    *	The swap map is a data structure used for keeping track of each page
> > > @@ -195,7 +195,7 @@ static int mark_swapfiles(struct swap_ma
> > >   	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
> > >   	    !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
> > >   		memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
> > 
> > if no compression
> > 
> > > -		memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
> > 
> > else
> > 
> > > +		memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
> > 
> > ??
> 
> I thought about that, but we'll need to drop the old signature when the image
> format changes (I think it will after your patch series) anyway.  And the
> benefit is not really worth it IMO (it only affects people using the in-kernel
> hibernation on x86-64).
> 

ACK. Lets keep this simple.

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: [RFC][PATCH] PM / Hibernate: Modify signature used to mark swap

[Nigel Cunningham]

Hi.

On 30/09/10 07:13, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki<rjw@sisk.pl>
> Subject: PM / Hibernate: Modify signature used to mark swap
>
> Since we are adding compression to the kernel's hibernate code,
> change signature used by it to mark swap spaces, so that earlier
> kernels don't attempt to restore compressed images they cannot
> handle.
>
> Signed-off-by: Rafael J. Wysocki<rjw@sisk.pl>
> ---
>   kernel/power/swap.c |    6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> Index: linux-2.6/kernel/power/swap.c
> ===================================================================
> --- linux-2.6.orig/kernel/power/swap.c
> +++ linux-2.6/kernel/power/swap.c
> @@ -29,7 +29,7 @@
>
>   #include "power.h"
>
> -#define SWSUSP_SIG	"S1SUSPEND"
> +#define HIBERNATE_SIG	"LINHIB0001"
>
>   /*
>    *	The swap map is a data structure used for keeping track of each page
> @@ -195,7 +195,7 @@ static int mark_swapfiles(struct swap_ma
>   	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
>   	    !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
>   		memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);

if no compression

> -		memcpy(swsusp_header->sig,SWSUSP_SIG, 10);

else

> +		memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);

??

>   		swsusp_header->image = handle->first_sector;
>   		swsusp_header->flags = flags;
>   		error = hib_bio_write_page(swsusp_resume_block,
> @@ -916,7 +916,7 @@ int swsusp_check(void)
>   		if (error)
>   			goto put;
>
> -		if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
> +		if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {

Reset the signature in either case?

>   			memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
>   			/* Reset swap signature now */
>   			error = hib_bio_write_page(swsusp_resume_block,
>

Regards,

Nigel

[RFC][PATCH] PM / Hibernate: Modify signature used to mark swap

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>
Subject: PM / Hibernate: Modify signature used to mark swap

Since we are adding compression to the kernel's hibernate code,
change signature used by it to mark swap spaces, so that earlier
kernels don't attempt to restore compressed images they cannot
handle.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 kernel/power/swap.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Index: linux-2.6/kernel/power/swap.c
===================================================================
--- linux-2.6.orig/kernel/power/swap.c
+++ linux-2.6/kernel/power/swap.c
@@ -29,7 +29,7 @@
 
 #include "power.h"
 
-#define SWSUSP_SIG	"S1SUSPEND"
+#define HIBERNATE_SIG	"LINHIB0001"
 
 /*
  *	The swap map is a data structure used for keeping track of each page
@@ -195,7 +195,7 @@ static int mark_swapfiles(struct swap_ma
 	if (!memcmp("SWAP-SPACE",swsusp_header->sig, 10) ||
 	    !memcmp("SWAPSPACE2",swsusp_header->sig, 10)) {
 		memcpy(swsusp_header->orig_sig,swsusp_header->sig, 10);
-		memcpy(swsusp_header->sig,SWSUSP_SIG, 10);
+		memcpy(swsusp_header->sig, HIBERNATE_SIG, 10);
 		swsusp_header->image = handle->first_sector;
 		swsusp_header->flags = flags;
 		error = hib_bio_write_page(swsusp_resume_block,
@@ -916,7 +916,7 @@ int swsusp_check(void)
 		if (error)
 			goto put;
 
-		if (!memcmp(SWSUSP_SIG, swsusp_header->sig, 10)) {
+		if (!memcmp(HIBERNATE_SIG, swsusp_header->sig, 10)) {
 			memcpy(swsusp_header->sig, swsusp_header->orig_sig, 10);
 			/* Reset swap signature now */
 			error = hib_bio_write_page(swsusp_resume_block,