[PATCH 0/1] swsusp: fix breakage with swap on LVM

[PATCH 0/1] swsusp: fix breakage with swap on LVM

[Rafael J. Wysocki]

Hi,

In the following two replies to this message there are two versions of
the same fix, one of which applies to 2.6.16-rc3 and the second to the recent
-mm.

The fix is needed to restore the compatibility with the older code that
allowed to suspend even if the kernel command line didn't contain the
"resume=" argument.  This feature is necessary so that swsusp can work
in the default Fedora setup where the swap partition is on an LVM.

I consider the first patch, against 2.6.16-rc3, as an urgent fix that should
go in 2.6.16, if possible.  It has been tested by Dave and evidently fixes the
Fedora issue.  Unfortunately it doesn't apply to the recent -mm, because
in -mm the code in question is split between mm/swapfile.c and
kernel/power/swap.c, so the other patch is needed.

Please apply.

Greetings,
Rafael

[PATCH 1/1] swsusp: fix breakage with swap on LVM

[Rafael J. Wysocki]

Restore the compatibility with the older code and make it possible to
suspend if the kernel command line doesn't contain the "resume="
argument


Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 kernel/power/swsusp.c |    4 +---
 1 files changed, 1 insertion(+), 3 deletions(-)

Index: linux-2.6.16-rc3/kernel/power/swsusp.c
===================================================================
--- linux-2.6.16-rc3.orig/kernel/power/swsusp.c
+++ linux-2.6.16-rc3/kernel/power/swsusp.c
@@ -153,13 +153,11 @@ static int swsusp_swap_check(void) /* Th
 {
 	int i;
 
-	if (!swsusp_resume_device)
-		return -ENODEV;
 	spin_lock(&swap_lock);
 	for (i = 0; i < MAX_SWAPFILES; i++) {
 		if (!(swap_info[i].flags & SWP_WRITEOK))
 			continue;
-		if (is_resume_device(swap_info + i)) {
+		if (!swsusp_resume_device || is_resume_device(swap_info + i)) {
 			spin_unlock(&swap_lock);
 			root_swap = i;
 			return 0;

[PATCH -mm 1/1] swsusp: fix breakage with swap on LVM

[Rafael J. Wysocki]

Restore the compatibility with the older code and make it possible to
suspend if the kernel command line doesn't contain the "resume="
argument.


Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 include/linux/swap.h |    1 +
 kernel/power/swap.c  |    3 ++-
 mm/swapfile.c        |   17 +++++++++++++++++
 3 files changed, 20 insertions(+), 1 deletion(-)

Index: linux-2.6.16-rc3-mm1/include/linux/swap.h
===================================================================
--- linux-2.6.16-rc3-mm1.orig/include/linux/swap.h
+++ linux-2.6.16-rc3-mm1/include/linux/swap.h
@@ -246,6 +246,7 @@ extern int valid_swaphandles(swp_entry_t
 extern void swap_free(swp_entry_t);
 extern void free_swap_and_cache(swp_entry_t);
 extern int swap_type_of(dev_t);
+extern int find_swap(void);
 extern unsigned int count_swap_pages(int, int);
 extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
 extern struct swap_info_struct *get_swap_info_struct(unsigned);
Index: linux-2.6.16-rc3-mm1/kernel/power/swap.c
===================================================================
--- linux-2.6.16-rc3-mm1.orig/kernel/power/swap.c
+++ linux-2.6.16-rc3-mm1/kernel/power/swap.c
@@ -75,8 +75,9 @@ static int mark_swapfiles(swp_entry_t st
 
 static int swsusp_swap_check(void) /* This is called before saving image */
 {
-	int res = swap_type_of(swsusp_resume_device);
+	int res;
 
+	res = swsusp_resume_device ? swap_type_of(swsusp_resume_device) : find_swap();
 	if (res >= 0) {
 		root_swap = res;
 		return 0;
Index: linux-2.6.16-rc3-mm1/mm/swapfile.c
===================================================================
--- linux-2.6.16-rc3-mm1.orig/mm/swapfile.c
+++ linux-2.6.16-rc3-mm1/mm/swapfile.c
@@ -448,6 +448,23 @@ int swap_type_of(dev_t device)
 }
 
 /*
+ * Find first writeable swap.
+ *
+ * This is needed for software suspend in case the resume device is not
+ * specified in the kernel command line
+ */
+int find_swap(void)
+{
+	int i = 0;
+
+	spin_lock(&swap_lock);
+	while (i < nr_swapfiles && !(swap_info[i].flags & SWP_WRITEOK))
+		i++;
+	spin_unlock(&swap_lock);
+	return i < nr_swapfiles ? i : -ENODEV;
+}
+
+/*
  * Return either the total number of swap pages of given type, or the number
  * of free pages of that type (depending on @free)
  *