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Commit ef96f639 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
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PM / hibernate: Clean up comments in snapshot.c 

Many comments in kernel/power/snapshot.c do not follow the general
comment formatting rules.  They look odd, some of them are outdated
too, some are hard to parse and generally difficult to understand.

Clean them up to make them easier to comprehend.

No functional changes.
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent efd5a852
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Showing with 330 additions and 306 deletions
kernel/power/snapshot.c
View file @ ef96f639
...@@ -67,7 +67,8 @@ void __init hibernate_image_size_init(void) ...@@ -67,7 +67,8 @@ void __init hibernate_image_size_init(void)
image_size = ((totalram_pages * 2) / 5) * PAGE_SIZE; image_size = ((totalram_pages * 2) / 5) * PAGE_SIZE;
} }
/* List of PBEs needed for restoring the pages that were allocated before /*
* List of PBEs needed for restoring the pages that were allocated before
* the suspend and included in the suspend image, but have also been * the suspend and included in the suspend image, but have also been
* allocated by the "resume" kernel, so their contents cannot be written * allocated by the "resume" kernel, so their contents cannot be written
* directly to their "original" page frames. * directly to their "original" page frames.
...@@ -93,16 +94,6 @@ static struct linked_page *safe_pages_list; ...@@ -93,16 +94,6 @@ static struct linked_page *safe_pages_list;
/* Pointer to an auxiliary buffer (1 page) */ /* Pointer to an auxiliary buffer (1 page) */
static void *buffer; static void *buffer;
/**
* @safe_needed - on resume, for storing the PBE list and the image,
* we can only use memory pages that do not conflict with the pages
* used before suspend. The unsafe pages have PageNosaveFree set
* and we count them using unsafe_pages.
*
* Each allocated image page is marked as PageNosave and PageNosaveFree
* so that swsusp_free() can release it.
*/
#define PG_ANY 0 #define PG_ANY 0
#define PG_SAFE 1 #define PG_SAFE 1
#define PG_UNSAFE_CLEAR 1 #define PG_UNSAFE_CLEAR 1
...@@ -110,6 +101,19 @@ static void *buffer; ...@@ -110,6 +101,19 @@ static void *buffer;
static unsigned int allocated_unsafe_pages; static unsigned int allocated_unsafe_pages;
/**
* get_image_page - Allocate a page for a hibernation image.
* @gfp_mask: GFP mask for the allocation.
* @safe_needed: Get pages that were not used before hibernation (restore only)
*
* During image restoration, for storing the PBE list and the image data, we can
* only use memory pages that do not conflict with the pages used before
* hibernation. The "unsafe" pages have PageNosaveFree set and we count them
* using allocated_unsafe_pages.
*
* Each allocated image page is marked as PageNosave and PageNosaveFree so that
* swsusp_free() can release it.
*/
static void *get_image_page(gfp_t gfp_mask, int safe_needed) static void *get_image_page(gfp_t gfp_mask, int safe_needed)
{ {
void *res; void *res;
...@@ -167,10 +171,13 @@ static void recycle_safe_page(void *page_address) ...@@ -167,10 +171,13 @@ static void recycle_safe_page(void *page_address)
} }
/** /**
* free_image_page - free page represented by @addr, allocated with * free_image_page - Free a page allocated for hibernation image.
* get_image_page (page flags set by it must be cleared) * @addr: Address of the page to free.
* @clear_nosave_free: If set, clear the PageNosaveFree bit for the page.
*
* The page to free should have been allocated by get_image_page() (page flags
* set by it are affected).
*/ */
static inline void free_image_page(void *addr, int clear_nosave_free) static inline void free_image_page(void *addr, int clear_nosave_free)
{ {
struct page *page; struct page *page;
...@@ -197,7 +204,7 @@ static inline void free_list_of_pages(struct linked_page *list, ...@@ -197,7 +204,7 @@ static inline void free_list_of_pages(struct linked_page *list,
} }
} }
/** /*
* struct chain_allocator is used for allocating small objects out of * struct chain_allocator is used for allocating small objects out of
* a linked list of pages called 'the chain'. * a linked list of pages called 'the chain'.
* *
...@@ -209,12 +216,10 @@ static inline void free_list_of_pages(struct linked_page *list, ...@@ -209,12 +216,10 @@ static inline void free_list_of_pages(struct linked_page *list,
* NOTE: The chain allocator may be inefficient if the allocated objects * NOTE: The chain allocator may be inefficient if the allocated objects
* are not much smaller than PAGE_SIZE. * are not much smaller than PAGE_SIZE.
*/ */
struct chain_allocator { struct chain_allocator {
struct linked_page *chain; /* the chain */ struct linked_page *chain; /* the chain */
unsigned int used_space; /* total size of objects allocated out unsigned int used_space; /* total size of objects allocated out
* of the current page of the current page */
*/
gfp_t gfp_mask; /* mask for allocating pages */ gfp_t gfp_mask; /* mask for allocating pages */
int safe_needed; /* if set, only "safe" pages are allocated */ int safe_needed; /* if set, only "safe" pages are allocated */
}; };
...@@ -271,7 +276,7 @@ static void *chain_alloc(struct chain_allocator *ca, unsigned int size) ...@@ -271,7 +276,7 @@ static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
* struct zone_bitmap contains a pointer to a list of bitmap block * struct zone_bitmap contains a pointer to a list of bitmap block
* objects and a pointer to the bitmap block object that has been * objects and a pointer to the bitmap block object that has been
* most recently used for setting bits. Additionally, it contains the * most recently used for setting bits. Additionally, it contains the
* pfns that correspond to the start and end of the represented zone. * PFNs that correspond to the start and end of the represented zone.
* *
* struct bm_block contains a pointer to the memory page in which * struct bm_block contains a pointer to the memory page in which
* information is stored (in the form of a block of bitmap) * information is stored (in the form of a block of bitmap)
...@@ -333,9 +338,8 @@ struct bm_position { ...@@ -333,9 +338,8 @@ struct bm_position {
struct memory_bitmap { struct memory_bitmap {
struct list_head zones; struct list_head zones;
struct linked_page *p_list; /* list of pages used to store zone struct linked_page *p_list; /* list of pages used to store zone
* bitmap objects and bitmap block bitmap objects and bitmap block
* objects objects */
*/
struct bm_position cur; /* most recently used bit position */ struct bm_position cur; /* most recently used bit position */
}; };
...@@ -349,7 +353,7 @@ struct memory_bitmap { ...@@ -349,7 +353,7 @@ struct memory_bitmap {
#endif #endif
#define BM_RTREE_LEVEL_MASK ((1UL << BM_RTREE_LEVEL_SHIFT) - 1) #define BM_RTREE_LEVEL_MASK ((1UL << BM_RTREE_LEVEL_SHIFT) - 1)
/* /**
* alloc_rtree_node - Allocate a new node and add it to the radix tree. * alloc_rtree_node - Allocate a new node and add it to the radix tree.
* *
* This function is used to allocate inner nodes as well as the * This function is used to allocate inner nodes as well as the
...@@ -375,8 +379,8 @@ static struct rtree_node *alloc_rtree_node(gfp_t gfp_mask, int safe_needed, ...@@ -375,8 +379,8 @@ static struct rtree_node *alloc_rtree_node(gfp_t gfp_mask, int safe_needed,
return node; return node;
} }
/* /**
* add_rtree_block - Add a new leave node to the radix tree * add_rtree_block - Add a new leave node to the radix tree.
* *
* The leave nodes need to be allocated in order to keep the leaves * The leave nodes need to be allocated in order to keep the leaves
* linked list in order. This is guaranteed by the zone->blocks * linked list in order. This is guaranteed by the zone->blocks
...@@ -445,8 +449,8 @@ static int add_rtree_block(struct mem_zone_bm_rtree *zone, gfp_t gfp_mask, ...@@ -445,8 +449,8 @@ static int add_rtree_block(struct mem_zone_bm_rtree *zone, gfp_t gfp_mask,
static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone, static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
int clear_nosave_free); int clear_nosave_free);
/* /**
* create_zone_bm_rtree - create a radix tree for one zone * create_zone_bm_rtree - Create a radix tree for one zone.
* *
* Allocated the mem_zone_bm_rtree structure and initializes it. * Allocated the mem_zone_bm_rtree structure and initializes it.
* This function also allocated and builds the radix tree for the * This function also allocated and builds the radix tree for the
...@@ -483,8 +487,8 @@ static struct mem_zone_bm_rtree *create_zone_bm_rtree(gfp_t gfp_mask, ...@@ -483,8 +487,8 @@ static struct mem_zone_bm_rtree *create_zone_bm_rtree(gfp_t gfp_mask,
return zone; return zone;
} }
/* /**
* free_zone_bm_rtree - Free the memory of the radix tree * free_zone_bm_rtree - Free the memory of the radix tree.
* *
* Free all node pages of the radix tree. The mem_zone_bm_rtree * Free all node pages of the radix tree. The mem_zone_bm_rtree
* structure itself is not freed here nor are the rtree_node * structure itself is not freed here nor are the rtree_node
...@@ -521,8 +525,8 @@ struct mem_extent { ...@@ -521,8 +525,8 @@ struct mem_extent {
}; };
/** /**
* free_mem_extents - free a list of memory extents * free_mem_extents - Free a list of memory extents.
* @list - list of extents to empty * @list: List of extents to free.
*/ */
static void free_mem_extents(struct list_head *list) static void free_mem_extents(struct list_head *list)
{ {
...@@ -535,10 +539,11 @@ static void free_mem_extents(struct list_head *list) ...@@ -535,10 +539,11 @@ static void free_mem_extents(struct list_head *list)
} }
/** /**
* create_mem_extents - create a list of memory extents representing * create_mem_extents - Create a list of memory extents.
* contiguous ranges of PFNs * @list: List to put the extents into.
* @list - list to put the extents into * @gfp_mask: Mask to use for memory allocations.
* @gfp_mask - mask to use for memory allocations *
* The extents represent contiguous ranges of PFNs.
*/ */
static int create_mem_extents(struct list_head *list, gfp_t gfp_mask) static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
{ {
...@@ -594,7 +599,7 @@ static int create_mem_extents(struct list_head *list, gfp_t gfp_mask) ...@@ -594,7 +599,7 @@ static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
} }
/** /**
* memory_bm_create - allocate memory for a memory bitmap * memory_bm_create - Allocate memory for a memory bitmap.
*/ */
static int memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, static int memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask,
int safe_needed) int safe_needed)
...@@ -636,7 +641,8 @@ static int memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, ...@@ -636,7 +641,8 @@ static int memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask,
} }
/** /**
* memory_bm_free - free memory occupied by the memory bitmap @bm * memory_bm_free - Free memory occupied by the memory bitmap.
* @bm: Memory bitmap.
*/ */
static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free) static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
{ {
...@@ -651,14 +657,13 @@ static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free) ...@@ -651,14 +657,13 @@ static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
} }
/** /**
* memory_bm_find_bit - Find the bit for pfn in the memory * memory_bm_find_bit - Find the bit for a given PFN in a memory bitmap.
* bitmap
* *
* Find the bit in the bitmap @bm that corresponds to given pfn. * Find the bit in memory bitmap @bm that corresponds to the given PFN.
* The cur.zone, cur.block and cur.node_pfn member of @bm are * The cur.zone, cur.block and cur.node_pfn members of @bm are updated.
* updated. *
* It walks the radix tree to find the page which contains the bit for * Walk the radix tree to find the page containing the bit that represents @pfn
* pfn and returns the bit position in **addr and *bit_nr. * and return the position of the bit in @addr and @bit_nr.
*/ */
static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn, static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
void **addr, unsigned int *bit_nr) void **addr, unsigned int *bit_nr)
...@@ -687,10 +692,9 @@ static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn, ...@@ -687,10 +692,9 @@ static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
zone_found: zone_found:
/* /*
* We have a zone. Now walk the radix tree to find the leave * We have found the zone. Now walk the radix tree to find the leaf node
* node for our pfn. * for our PFN.
*/ */
node = bm->cur.node; node = bm->cur.node;
if (((pfn - zone->start_pfn) & ~BM_BLOCK_MASK) == bm->cur.node_pfn) if (((pfn - zone->start_pfn) & ~BM_BLOCK_MASK) == bm->cur.node_pfn)
goto node_found; goto node_found;
...@@ -783,14 +787,14 @@ static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn) ...@@ -783,14 +787,14 @@ static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
} }
/* /*
* rtree_next_node - Jumps to the next leave node * rtree_next_node - Jump to the next leaf node.
* *
* Sets the position to the beginning of the next node in the * Set the position to the beginning of the next node in the
* memory bitmap. This is either the next node in the current * memory bitmap. This is either the next node in the current
* zone's radix tree or the first node in the radix tree of the * zone's radix tree or the first node in the radix tree of the
* next zone. * next zone.
* *
* Returns true if there is a next node, false otherwise. * Return true if there is a next node, false otherwise.
*/ */
static bool rtree_next_node(struct memory_bitmap *bm) static bool rtree_next_node(struct memory_bitmap *bm)
{ {
...@@ -819,14 +823,15 @@ static bool rtree_next_node(struct memory_bitmap *bm) ...@@ -819,14 +823,15 @@ static bool rtree_next_node(struct memory_bitmap *bm)
} }
/** /**
* memory_bm_rtree_next_pfn - Find the next set bit in the bitmap @bm * memory_bm_rtree_next_pfn - Find the next set bit in a memory bitmap.
* @bm: Memory bitmap.
* *
* Starting from the last returned position this function searches * Starting from the last returned position this function searches for the next
* for the next set bit in the memory bitmap and returns its * set bit in @bm and returns the PFN represented by it. If no more bits are
* number. If no more bit is set BM_END_OF_MAP is returned. * set, BM_END_OF_MAP is returned.
* *
* It is required to run memory_bm_position_reset() before the * It is required to run memory_bm_position_reset() before the first call to
* first call to this function. * this function for the given memory bitmap.
*/ */
static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm) static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
{ {
...@@ -848,11 +853,10 @@ static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm) ...@@ -848,11 +853,10 @@ static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
return BM_END_OF_MAP; return BM_END_OF_MAP;
} }
/** /*
* This structure represents a range of page frames the contents of which * This structure represents a range of page frames the contents of which
* should not be saved during the suspend. * should not be saved during hibernation.
*/ */
struct nosave_region { struct nosave_region {
struct list_head list; struct list_head list;
unsigned long start_pfn; unsigned long start_pfn;
...@@ -890,11 +894,11 @@ static void memory_bm_recycle(struct memory_bitmap *bm) ...@@ -890,11 +894,11 @@ static void memory_bm_recycle(struct memory_bitmap *bm)
} }
/** /**
* register_nosave_region - register a range of page frames the contents * register_nosave_region - Register a region of unsaveable memory.
* of which should not be saved during the suspend (to be used in the early *
* initialization code) * Register a range of page frames the contents of which should not be saved
* during hibernation (to be used in the early initialization code).
*/ */
void __init __register_nosave_region(unsigned long start_pfn, void __init __register_nosave_region(unsigned long start_pfn,
unsigned long end_pfn, int use_kmalloc) unsigned long end_pfn, int use_kmalloc)
{ {
...@@ -913,7 +917,7 @@ void __init __register_nosave_region(unsigned long start_pfn, ...@@ -913,7 +917,7 @@ void __init __register_nosave_region(unsigned long start_pfn,
} }
} }
if (use_kmalloc) { if (use_kmalloc) {
/* during init, this shouldn't fail */ /* During init, this shouldn't fail */
region = kmalloc(sizeof(struct nosave_region), GFP_KERNEL); region = kmalloc(sizeof(struct nosave_region), GFP_KERNEL);
BUG_ON(!region); BUG_ON(!region);
} else } else
...@@ -979,10 +983,12 @@ static void swsusp_unset_page_forbidden(struct page *page) ...@@ -979,10 +983,12 @@ static void swsusp_unset_page_forbidden(struct page *page)
} }
/** /**
* mark_nosave_pages - set bits corresponding to the page frames the * mark_nosave_pages - Mark pages that should not be saved.
* contents of which should not be saved in a given bitmap. * @bm: Memory bitmap.
*
* Set the bits in @bm that correspond to the page frames the contents of which
* should not be saved.
*/ */
static void mark_nosave_pages(struct memory_bitmap *bm) static void mark_nosave_pages(struct memory_bitmap *bm)
{ {
struct nosave_region *region; struct nosave_region *region;
...@@ -1012,13 +1018,13 @@ static void mark_nosave_pages(struct memory_bitmap *bm) ...@@ -1012,13 +1018,13 @@ static void mark_nosave_pages(struct memory_bitmap *bm)
} }
/** /**
* create_basic_memory_bitmaps - create bitmaps needed for marking page * create_basic_memory_bitmaps - Create bitmaps to hold basic page information.
* frames that should not be saved and free page frames. The pointers *
* forbidden_pages_map and free_pages_map are only modified if everything * Create bitmaps needed for marking page frames that should not be saved and
* goes well, because we don't want the bits to be used before both bitmaps * free page frames. The forbidden_pages_map and free_pages_map pointers are
* are set up. * only modified if everything goes well, because we don't want the bits to be
* touched before both bitmaps are set up.
*/ */
int create_basic_memory_bitmaps(void) int create_basic_memory_bitmaps(void)
{ {
struct memory_bitmap *bm1, *bm2; struct memory_bitmap *bm1, *bm2;
...@@ -1063,12 +1069,12 @@ int create_basic_memory_bitmaps(void) ...@@ -1063,12 +1069,12 @@ int create_basic_memory_bitmaps(void)
} }
/** /**
* free_basic_memory_bitmaps - free memory bitmaps allocated by * free_basic_memory_bitmaps - Free memory bitmaps holding basic information.
* create_basic_memory_bitmaps(). The auxiliary pointers are necessary *
* so that the bitmaps themselves are not referred to while they are being * Free memory bitmaps allocated by create_basic_memory_bitmaps(). The
* freed. * auxiliary pointers are necessary so that the bitmaps themselves are not
* referred to while they are being freed.
*/ */
void free_basic_memory_bitmaps(void) void free_basic_memory_bitmaps(void)
{ {
struct memory_bitmap *bm1, *bm2; struct memory_bitmap *bm1, *bm2;
...@@ -1089,11 +1095,13 @@ void free_basic_memory_bitmaps(void) ...@@ -1089,11 +1095,13 @@ void free_basic_memory_bitmaps(void)
} }
/** /**
* snapshot_additional_pages - estimate the number of additional pages * snapshot_additional_pages - Estimate the number of extra pages needed.
* be needed for setting up the suspend image data structures for given * @zone: Memory zone to carry out the computation for.
* zone (usually the returned value is greater than the exact number) *
* Estimate the number of additional pages needed for setting up a hibernation
* image data structures for @zone (usually, the returned value is greater than
* the exact number).
*/ */
unsigned int snapshot_additional_pages(struct zone *zone) unsigned int snapshot_additional_pages(struct zone *zone)
{ {
unsigned int rtree, nodes; unsigned int rtree, nodes;
...@@ -1111,10 +1119,10 @@ unsigned int snapshot_additional_pages(struct zone *zone) ...@@ -1111,10 +1119,10 @@ unsigned int snapshot_additional_pages(struct zone *zone)
#ifdef CONFIG_HIGHMEM #ifdef CONFIG_HIGHMEM
/** /**
* count_free_highmem_pages - compute the total number of free highmem * count_free_highmem_pages - Compute the total number of free highmem pages.
* pages, system-wide. *
* The returned number is system-wide.
*/ */
static unsigned int count_free_highmem_pages(void) static unsigned int count_free_highmem_pages(void)
{ {
struct zone *zone; struct zone *zone;
...@@ -1128,11 +1136,12 @@ static unsigned int count_free_highmem_pages(void) ...@@ -1128,11 +1136,12 @@ static unsigned int count_free_highmem_pages(void)
} }
/** /**
* saveable_highmem_page - Determine whether a highmem page should be * saveable_highmem_page - Check if a highmem page is saveable.
* included in the suspend image. *
* Determine whether a highmem page should be included in a hibernation image.
* *
* We should save the page if it isn't Nosave or NosaveFree, or Reserved, * We should save the page if it isn't Nosave or NosaveFree, or Reserved,
* and it isn't a part of a free chunk of pages. * and it isn't part of a free chunk of pages.
*/ */
static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn) static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
{ {
...@@ -1158,10 +1167,8 @@ static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn) ...@@ -1158,10 +1167,8 @@ static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
} }
/** /**
* count_highmem_pages - compute the total number of saveable highmem * count_highmem_pages - Compute the total number of saveable highmem pages.
* pages.
*/ */
static unsigned int count_highmem_pages(void) static unsigned int count_highmem_pages(void)
{ {
struct zone *zone; struct zone *zone;
...@@ -1189,11 +1196,13 @@ static inline void *saveable_highmem_page(struct zone *z, unsigned long p) ...@@ -1189,11 +1196,13 @@ static inline void *saveable_highmem_page(struct zone *z, unsigned long p)
#endif /* CONFIG_HIGHMEM */ #endif /* CONFIG_HIGHMEM */
/** /**
* saveable_page - Determine whether a non-highmem page should be included * saveable_page - Check if the given page is saveable.
* in the suspend image. *
* Determine whether a non-highmem page should be included in a hibernation
* image.
* *
* We should save the page if it isn't Nosave, and is not in the range * We should save the page if it isn't Nosave, and is not in the range
* of pages statically defined as 'unsaveable', and it isn't a part of * of pages statically defined as 'unsaveable', and it isn't part of
* a free chunk of pages. * a free chunk of pages.
*/ */
static struct page *saveable_page(struct zone *zone, unsigned long pfn) static struct page *saveable_page(struct zone *zone, unsigned long pfn)
...@@ -1223,10 +1232,8 @@ static struct page *saveable_page(struct zone *zone, unsigned long pfn) ...@@ -1223,10 +1232,8 @@ static struct page *saveable_page(struct zone *zone, unsigned long pfn)
} }
/** /**
* count_data_pages - compute the total number of saveable non-highmem * count_data_pages - Compute the total number of saveable non-highmem pages.
* pages.
*/ */
static unsigned int count_data_pages(void) static unsigned int count_data_pages(void)
{ {
struct zone *zone; struct zone *zone;
...@@ -1246,7 +1253,8 @@ static unsigned int count_data_pages(void) ...@@ -1246,7 +1253,8 @@ static unsigned int count_data_pages(void)
return n; return n;
} }
/* This is needed, because copy_page and memcpy are not usable for copying /*
* This is needed, because copy_page and memcpy are not usable for copying
* task structs. * task structs.
*/ */
static inline void do_copy_page(long *dst, long *src) static inline void do_copy_page(long *dst, long *src)
...@@ -1257,12 +1265,12 @@ static inline void do_copy_page(long *dst, long *src) ...@@ -1257,12 +1265,12 @@ static inline void do_copy_page(long *dst, long *src)
*dst++ = *src++; *dst++ = *src++;
} }
/** /**
* safe_copy_page - check if the page we are going to copy is marked as * safe_copy_page - Copy a page in a safe way.
* present in the kernel page tables (this always is the case if *
* CONFIG_DEBUG_PAGEALLOC is not set and in that case * Check if the page we are going to copy is marked as present in the kernel
* kernel_page_present() always returns 'true'). * page tables (this always is the case if CONFIG_DEBUG_PAGEALLOC is not set
* and in that case kernel_page_present() always returns 'true').
*/ */
static void safe_copy_page(void *dst, struct page *s_page) static void safe_copy_page(void *dst, struct page *s_page)
{ {
...@@ -1275,7 +1283,6 @@ static void safe_copy_page(void *dst, struct page *s_page) ...@@ -1275,7 +1283,6 @@ static void safe_copy_page(void *dst, struct page *s_page)
} }
} }
#ifdef CONFIG_HIGHMEM #ifdef CONFIG_HIGHMEM
static inline struct page *page_is_saveable(struct zone *zone, unsigned long pfn) static inline struct page *page_is_saveable(struct zone *zone, unsigned long pfn)
{ {
...@@ -1298,7 +1305,8 @@ static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn) ...@@ -1298,7 +1305,8 @@ static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
kunmap_atomic(src); kunmap_atomic(src);
} else { } else {
if (PageHighMem(d_page)) { if (PageHighMem(d_page)) {
/* Page pointed to by src may contain some kernel /*
* The page pointed to by src may contain some kernel
* data modified by kmap_atomic() * data modified by kmap_atomic()
*/ */
safe_copy_page(buffer, s_page); safe_copy_page(buffer, s_page);
...@@ -1370,12 +1378,11 @@ static struct memory_bitmap orig_bm; ...@@ -1370,12 +1378,11 @@ static struct memory_bitmap orig_bm;
static struct memory_bitmap copy_bm; static struct memory_bitmap copy_bm;
/** /**
* swsusp_free - free pages allocated for the suspend. * swsusp_free - Free pages allocated for hibernation image.
* *
* Suspend pages are alocated before the atomic copy is made, so we * Image pages are alocated before snapshot creation, so they need to be
* need to release them after the resume. * released after resume.
*/ */
void swsusp_free(void) void swsusp_free(void)
{ {
unsigned long fb_pfn, fr_pfn; unsigned long fb_pfn, fr_pfn;
...@@ -1424,7 +1431,7 @@ void swsusp_free(void) ...@@ -1424,7 +1431,7 @@ void swsusp_free(void)
#define GFP_IMAGE (GFP_KERNEL | __GFP_NOWARN) #define GFP_IMAGE (GFP_KERNEL | __GFP_NOWARN)
/** /**
* preallocate_image_pages - Allocate a number of pages for hibernation image * preallocate_image_pages - Allocate a number of pages for hibernation image.
* @nr_pages: Number of page frames to allocate. * @nr_pages: Number of page frames to allocate.
* @mask: GFP flags to use for the allocation. * @mask: GFP flags to use for the allocation.
* *
...@@ -1474,7 +1481,7 @@ static unsigned long preallocate_image_highmem(unsigned long nr_pages) ...@@ -1474,7 +1481,7 @@ static unsigned long preallocate_image_highmem(unsigned long nr_pages)
} }
/** /**
* __fraction - Compute (an approximation of) x * (multiplier / base) * __fraction - Compute (an approximation of) x * (multiplier / base).
*/ */
static unsigned long __fraction(u64 x, u64 multiplier, u64 base) static unsigned long __fraction(u64 x, u64 multiplier, u64 base)
{ {
...@@ -1506,7 +1513,7 @@ static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages, ...@@ -1506,7 +1513,7 @@ static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
#endif /* CONFIG_HIGHMEM */ #endif /* CONFIG_HIGHMEM */
/** /**
* free_unnecessary_pages - Release preallocated pages not needed for the image * free_unnecessary_pages - Release preallocated pages not needed for the image.
*/ */
static unsigned long free_unnecessary_pages(void) static unsigned long free_unnecessary_pages(void)
{ {
...@@ -1560,7 +1567,7 @@ static unsigned long free_unnecessary_pages(void) ...@@ -1560,7 +1567,7 @@ static unsigned long free_unnecessary_pages(void)
} }
/** /**
* minimum_image_size - Estimate the minimum acceptable size of an image * minimum_image_size - Estimate the minimum acceptable size of an image.
* @saveable: Number of saveable pages in the system. * @saveable: Number of saveable pages in the system.
* *
* We want to avoid attempting to free too much memory too hard, so estimate the * We want to avoid attempting to free too much memory too hard, so estimate the
...@@ -1590,7 +1597,7 @@ static unsigned long minimum_image_size(unsigned long saveable) ...@@ -1590,7 +1597,7 @@ static unsigned long minimum_image_size(unsigned long saveable)
} }
/** /**
* hibernate_preallocate_memory - Preallocate memory for hibernation image * hibernate_preallocate_memory - Preallocate memory for hibernation image.
* *
* To create a hibernation image it is necessary to make a copy of every page * To create a hibernation image it is necessary to make a copy of every page
* frame in use. We also need a number of page frames to be free during * frame in use. We also need a number of page frames to be free during
...@@ -1763,10 +1770,11 @@ int hibernate_preallocate_memory(void) ...@@ -1763,10 +1770,11 @@ int hibernate_preallocate_memory(void)
#ifdef CONFIG_HIGHMEM #ifdef CONFIG_HIGHMEM
/** /**
* count_pages_for_highmem - compute the number of non-highmem pages * count_pages_for_highmem - Count non-highmem pages needed for copying highmem.
* that will be necessary for creating copies of highmem pages. *
* Compute the number of non-highmem pages that will be necessary for creating
* copies of highmem pages.
*/ */
static unsigned int count_pages_for_highmem(unsigned int nr_highmem) static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
{ {
unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem; unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem;
...@@ -1783,10 +1791,8 @@ static unsigned int count_pages_for_highmem(unsigned int nr_highmem) { return 0; ...@@ -1783,10 +1791,8 @@ static unsigned int count_pages_for_highmem(unsigned int nr_highmem) { return 0;
#endif /* CONFIG_HIGHMEM */ #endif /* CONFIG_HIGHMEM */
/** /**
* enough_free_mem - Make sure we have enough free memory for the * enough_free_mem - Check if there is enough free memory for the image.
* snapshot image.
*/ */
static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem) static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
{ {
struct zone *zone; struct zone *zone;
...@@ -1805,10 +1811,11 @@ static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem) ...@@ -1805,10 +1811,11 @@ static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
#ifdef CONFIG_HIGHMEM #ifdef CONFIG_HIGHMEM
/** /**
* get_highmem_buffer - if there are some highmem pages in the suspend * get_highmem_buffer - Allocate a buffer for highmem pages.
* image, we may need the buffer to copy them and/or load their data. *
* If there are some highmem pages in the hibernation image, we may need a
* buffer to copy them and/or load their data.
*/ */
static inline int get_highmem_buffer(int safe_needed) static inline int get_highmem_buffer(int safe_needed)
{ {
buffer = get_image_page(GFP_ATOMIC | __GFP_COLD, safe_needed); buffer = get_image_page(GFP_ATOMIC | __GFP_COLD, safe_needed);
...@@ -1816,11 +1823,11 @@ static inline int get_highmem_buffer(int safe_needed) ...@@ -1816,11 +1823,11 @@ static inline int get_highmem_buffer(int safe_needed)
} }
/** /**
* alloc_highmem_image_pages - allocate some highmem pages for the image. * alloc_highmem_image_pages - Allocate some highmem pages for the image.
* Try to allocate as many pages as needed, but if the number of free *
* highmem pages is lesser than that, allocate them all. * Try to allocate as many pages as needed, but if the number of free highmem
* pages is less than that, allocate them all.
*/ */
static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm, static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm,
unsigned int nr_highmem) unsigned int nr_highmem)
{ {
...@@ -1846,7 +1853,7 @@ static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm, ...@@ -1846,7 +1853,7 @@ static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm,
#endif /* CONFIG_HIGHMEM */ #endif /* CONFIG_HIGHMEM */
/** /**
* swsusp_alloc - allocate memory for the suspend image * swsusp_alloc - Allocate memory for hibernation image.
* *
* We first try to allocate as many highmem pages as there are * We first try to allocate as many highmem pages as there are
* saveable highmem pages in the system. If that fails, we allocate * saveable highmem pages in the system. If that fails, we allocate
...@@ -1856,7 +1863,6 @@ static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm, ...@@ -1856,7 +1863,6 @@ static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm,
* also be located in the high memory, because of the way in which * also be located in the high memory, because of the way in which
* copy_data_pages() works. * copy_data_pages() works.
*/ */
static int swsusp_alloc(struct memory_bitmap *orig_bm, static int swsusp_alloc(struct memory_bitmap *orig_bm,
struct memory_bitmap *copy_bm, struct memory_bitmap *copy_bm,
unsigned int nr_pages, unsigned int nr_highmem) unsigned int nr_pages, unsigned int nr_highmem)
...@@ -1909,7 +1915,8 @@ asmlinkage __visible int swsusp_save(void) ...@@ -1909,7 +1915,8 @@ asmlinkage __visible int swsusp_save(void)
return -ENOMEM; return -ENOMEM;
} }
/* During allocating of suspend pagedir, new cold pages may appear. /*
* During allocating of suspend pagedir, new cold pages may appear.
* Kill them. * Kill them.
*/ */
drain_local_pages(NULL); drain_local_pages(NULL);
...@@ -1972,10 +1979,13 @@ static int init_header(struct swsusp_info *info) ...@@ -1972,10 +1979,13 @@ static int init_header(struct swsusp_info *info)
} }
/** /**
* pack_pfns - pfns corresponding to the set bits found in the bitmap @bm * pack_pfns - Prepare PFNs for saving.
* are stored in the array @buf[] (1 page at a time) * @bm: Memory bitmap.
* @buf: Memory buffer to store the PFNs in.
*
* PFNs corresponding to set bits in @bm are stored in the area of memory
* pointed to by @buf (1 page at a time).
*/ */
static inline void pack_pfns(unsigned long *buf, struct memory_bitmap *bm) static inline void pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
{ {
int j; int j;
...@@ -1990,22 +2000,21 @@ static inline void pack_pfns(unsigned long *buf, struct memory_bitmap *bm) ...@@ -1990,22 +2000,21 @@ static inline void pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
} }
/** /**
* snapshot_read_next - used for reading the system memory snapshot. * snapshot_read_next - Get the address to read the next image page from.
* @handle: Snapshot handle to be used for the reading.
* *
* On the first call to it @handle should point to a zeroed * On the first call, @handle should point to a zeroed snapshot_handle
* snapshot_handle structure. The structure gets updated and a pointer * structure. The structure gets populated then and a pointer to it should be
* to it should be passed to this function every next time. * passed to this function every next time.
* *
* On success the function returns a positive number. Then, the caller * On success, the function returns a positive number. Then, the caller
* is allowed to read up to the returned number of bytes from the memory * is allowed to read up to the returned number of bytes from the memory
* location computed by the data_of() macro. * location computed by the data_of() macro.
* *
* The function returns 0 to indicate the end of data stream condition, * The function returns 0 to indicate the end of the data stream condition,
* and a negative number is returned on error. In such cases the * and negative numbers are returned on errors. If that happens, the structure
* structure pointed to by @handle is not updated and should not be used * pointed to by @handle is not updated and should not be used any more.
* any more.
*/ */
int snapshot_read_next(struct snapshot_handle *handle) int snapshot_read_next(struct snapshot_handle *handle)
{ {
if (handle->cur > nr_meta_pages + nr_copy_pages) if (handle->cur > nr_meta_pages + nr_copy_pages)
...@@ -2034,7 +2043,8 @@ int snapshot_read_next(struct snapshot_handle *handle) ...@@ -2034,7 +2043,8 @@ int snapshot_read_next(struct snapshot_handle *handle)
page = pfn_to_page(memory_bm_next_pfn(&copy_bm)); page = pfn_to_page(memory_bm_next_pfn(&copy_bm));
if (PageHighMem(page)) { if (PageHighMem(page)) {
/* Highmem pages are copied to the buffer, /*
* Highmem pages are copied to the buffer,
* because we can't return with a kmapped * because we can't return with a kmapped
* highmem page (we may not be called again). * highmem page (we may not be called again).
*/ */
...@@ -2066,11 +2076,11 @@ static void duplicate_memory_bitmap(struct memory_bitmap *dst, ...@@ -2066,11 +2076,11 @@ static void duplicate_memory_bitmap(struct memory_bitmap *dst,
} }
/** /**
* mark_unsafe_pages - mark the pages that cannot be used for storing * mark_unsafe_pages - Mark pages that were used before hibernation.
* the image during resume, because they conflict with the pages that *
* had been used before suspend * Mark the pages that cannot be used for storing the image during restoration,
* because they conflict with the pages that had been used before hibernation.
*/ */
static void mark_unsafe_pages(struct memory_bitmap *bm) static void mark_unsafe_pages(struct memory_bitmap *bm)
{ {
unsigned long pfn; unsigned long pfn;
...@@ -2104,9 +2114,8 @@ static int check_header(struct swsusp_info *info) ...@@ -2104,9 +2114,8 @@ static int check_header(struct swsusp_info *info)
} }
/** /**
* load header - check the image header and copy data from it * load header - Check the image header and copy the data from it.
*/ */
static int load_header(struct swsusp_info *info) static int load_header(struct swsusp_info *info)
{ {
int error; int error;
...@@ -2121,8 +2130,12 @@ static int load_header(struct swsusp_info *info) ...@@ -2121,8 +2130,12 @@ static int load_header(struct swsusp_info *info)
} }
/** /**
* unpack_orig_pfns - for each element of @buf[] (1 page at a time) set * unpack_orig_pfns - Set bits corresponding to given PFNs in a memory bitmap.
* the corresponding bit in the memory bitmap @bm * @bm: Memory bitmap.
* @buf: Area of memory containing the PFNs.
*
* For each element of the array pointed to by @buf (1 page at a time), set the
* corresponding bit in @bm.
*/ */
static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm) static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
{ {
...@@ -2145,7 +2158,8 @@ static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm) ...@@ -2145,7 +2158,8 @@ static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
} }
#ifdef CONFIG_HIGHMEM #ifdef CONFIG_HIGHMEM
/* struct highmem_pbe is used for creating the list of highmem pages that /*
* struct highmem_pbe is used for creating the list of highmem pages that
* should be restored atomically during the resume from disk, because the page * should be restored atomically during the resume from disk, because the page
* frames they have occupied before the suspend are in use. * frames they have occupied before the suspend are in use.
*/ */
...@@ -2155,7 +2169,8 @@ struct highmem_pbe { ...@@ -2155,7 +2169,8 @@ struct highmem_pbe {
struct highmem_pbe *next; struct highmem_pbe *next;
}; };
/* List of highmem PBEs needed for restoring the highmem pages that were /*
* List of highmem PBEs needed for restoring the highmem pages that were
* allocated before the suspend and included in the suspend image, but have * allocated before the suspend and included in the suspend image, but have
* also been allocated by the "resume" kernel, so their contents cannot be * also been allocated by the "resume" kernel, so their contents cannot be
* written directly to their "original" page frames. * written directly to their "original" page frames.
...@@ -2163,11 +2178,11 @@ struct highmem_pbe { ...@@ -2163,11 +2178,11 @@ struct highmem_pbe {
static struct highmem_pbe *highmem_pblist; static struct highmem_pbe *highmem_pblist;
/** /**
* count_highmem_image_pages - compute the number of highmem pages in the * count_highmem_image_pages - Compute the number of highmem pages in the image.
* suspend image. The bits in the memory bitmap @bm that correspond to the * @bm: Memory bitmap.
* image pages are assumed to be set. *
* The bits in @bm that correspond to image pages are assumed to be set.
*/ */
static unsigned int count_highmem_image_pages(struct memory_bitmap *bm) static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
{ {
unsigned long pfn; unsigned long pfn;
...@@ -2184,22 +2199,23 @@ static unsigned int count_highmem_image_pages(struct memory_bitmap *bm) ...@@ -2184,22 +2199,23 @@ static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
return cnt; return cnt;
} }
/**
* prepare_highmem_image - try to allocate as many highmem pages as
* there are highmem image pages (@nr_highmem_p points to the variable
* containing the number of highmem image pages). The pages that are
* "safe" (ie. will not be overwritten when the suspend image is
* restored) have the corresponding bits set in @bm (it must be
* unitialized).
*
* NOTE: This function should not be called if there are no highmem
* image pages.
*/
static unsigned int safe_highmem_pages; static unsigned int safe_highmem_pages;
static struct memory_bitmap *safe_highmem_bm; static struct memory_bitmap *safe_highmem_bm;
/**
* prepare_highmem_image - Allocate memory for loading highmem data from image.
* @bm: Pointer to an uninitialized memory bitmap structure.
* @nr_highmem_p: Pointer to the number of highmem image pages.
*
* Try to allocate as many highmem pages as there are highmem image pages
* (@nr_highmem_p points to the variable containing the number of highmem image
* pages). The pages that are "safe" (ie. will not be overwritten when the
* hibernation image is restored entirely) have the corresponding bits set in
* @bm (it must be unitialized).
*
* NOTE: This function should not be called if there are no highmem image pages.
*/
static int prepare_highmem_image(struct memory_bitmap *bm, static int prepare_highmem_image(struct memory_bitmap *bm,
unsigned int *nr_highmem_p) unsigned int *nr_highmem_p)
{ {
...@@ -2236,9 +2252,13 @@ static int prepare_highmem_image(struct memory_bitmap *bm, ...@@ -2236,9 +2252,13 @@ static int prepare_highmem_image(struct memory_bitmap *bm,
return 0; return 0;
} }
static struct page *last_highmem_page;
/** /**
* get_highmem_page_buffer - for given highmem image page find the buffer * get_highmem_page_buffer - Prepare a buffer to store a highmem image page.
* that suspend_write_next() should set for its caller to write to. *
* For a given highmem image page get a buffer that suspend_write_next() should
* return to its caller to write to.
* *
* If the page is to be saved to its "original" page frame or a copy of * If the page is to be saved to its "original" page frame or a copy of
* the page is to be made in the highmem, @buffer is returned. Otherwise, * the page is to be made in the highmem, @buffer is returned. Otherwise,
...@@ -2249,12 +2269,9 @@ static int prepare_highmem_image(struct memory_bitmap *bm, ...@@ -2249,12 +2269,9 @@ static int prepare_highmem_image(struct memory_bitmap *bm,
* the page's contents to @buffer, so they will have to be copied to the * the page's contents to @buffer, so they will have to be copied to the
* right location on the next call to suspend_write_next() and it is done * right location on the next call to suspend_write_next() and it is done
* with the help of copy_last_highmem_page(). For this purpose, if * with the help of copy_last_highmem_page(). For this purpose, if
* @buffer is returned, @last_highmem page is set to the page to which * @buffer is returned, @last_highmem_page is set to the page to which
* the data will have to be copied from @buffer. * the data will have to be copied from @buffer.
*/ */
static struct page *last_highmem_page;
static void *get_highmem_page_buffer(struct page *page, static void *get_highmem_page_buffer(struct page *page,
struct chain_allocator *ca) struct chain_allocator *ca)
{ {
...@@ -2262,13 +2279,15 @@ static void *get_highmem_page_buffer(struct page *page, ...@@ -2262,13 +2279,15 @@ static void *get_highmem_page_buffer(struct page *page,
void *kaddr; void *kaddr;
if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) { if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {
/* We have allocated the "original" page frame and we can /*
* We have allocated the "original" page frame and we can
* use it directly to store the loaded page. * use it directly to store the loaded page.
*/ */
last_highmem_page = page; last_highmem_page = page;
return buffer; return buffer;
} }
/* The "original" page frame has not been allocated and we have to /*
* The "original" page frame has not been allocated and we have to
* use a "safe" page frame to store the loaded page. * use a "safe" page frame to store the loaded page.
*/ */
pbe = chain_alloc(ca, sizeof(struct highmem_pbe)); pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
...@@ -2298,11 +2317,12 @@ static void *get_highmem_page_buffer(struct page *page, ...@@ -2298,11 +2317,12 @@ static void *get_highmem_page_buffer(struct page *page,
} }
/** /**
* copy_last_highmem_page - copy the contents of a highmem image from * copy_last_highmem_page - Copy most the most recent highmem image page.
* @buffer, where the caller of snapshot_write_next() has place them, *
* to the right location represented by @last_highmem_page . * Copy the contents of a highmem image from @buffer, where the caller of
* snapshot_write_next() has stored them, to the right location represented by
* @last_highmem_page .
*/ */
static void copy_last_highmem_page(void) static void copy_last_highmem_page(void)
{ {
if (last_highmem_page) { if (last_highmem_page) {
...@@ -2345,22 +2365,23 @@ static inline int last_highmem_page_copied(void) { return 1; } ...@@ -2345,22 +2365,23 @@ static inline int last_highmem_page_copied(void) { return 1; }
static inline void free_highmem_data(void) {} static inline void free_highmem_data(void) {}
#endif /* CONFIG_HIGHMEM */ #endif /* CONFIG_HIGHMEM */
#define PBES_PER_LINKED_PAGE (LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
/** /**
* prepare_image - use the memory bitmap @bm to mark the pages that will * prepare_image - Make room for loading hibernation image.
* be overwritten in the process of restoring the system memory state * @new_bm: Unitialized memory bitmap structure.
* from the suspend image ("unsafe" pages) and allocate memory for the * @bm: Memory bitmap with unsafe pages marked.
* image. *
* Use @bm to mark the pages that will be overwritten in the process of
* restoring the system memory state from the suspend image ("unsafe" pages)
* and allocate memory for the image.
* *
* The idea is to allocate a new memory bitmap first and then allocate * The idea is to allocate a new memory bitmap first and then allocate
* as many pages as needed for the image data, but not to assign these * as many pages as needed for image data, but without specifying what those
* pages to specific tasks initially. Instead, we just mark them as * pages will be used for just yet. Instead, we mark them all as allocated and
* allocated and create a lists of "safe" pages that will be used * create a lists of "safe" pages to be used later. On systems with high
* later. On systems with high memory a list of "safe" highmem pages is * memory a list of "safe" highmem pages is created too.
* also created.
*/ */
#define PBES_PER_LINKED_PAGE (LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm) static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
{ {
unsigned int nr_pages, nr_highmem; unsigned int nr_pages, nr_highmem;
...@@ -2385,7 +2406,8 @@ static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm) ...@@ -2385,7 +2406,8 @@ static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
if (error) if (error)
goto Free; goto Free;
} }
/* Reserve some safe pages for potential later use. /*
* Reserve some safe pages for potential later use.
* *
* NOTE: This way we make sure there will be enough safe pages for the * NOTE: This way we make sure there will be enough safe pages for the
* chain_alloc() in get_buffer(). It is a bit wasteful, but * chain_alloc() in get_buffer(). It is a bit wasteful, but
...@@ -2431,10 +2453,11 @@ static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm) ...@@ -2431,10 +2453,11 @@ static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
} }
/** /**
* get_buffer - compute the address that snapshot_write_next() should * get_buffer - Get the address to store the next image data page.
* set for its caller to write to. *
* Get the address that snapshot_write_next() should return to its caller to
* write to.
*/ */
static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca) static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
{ {
struct pbe *pbe; struct pbe *pbe;
...@@ -2449,12 +2472,14 @@ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca) ...@@ -2449,12 +2472,14 @@ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
return get_highmem_page_buffer(page, ca); return get_highmem_page_buffer(page, ca);
if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page))
/* We have allocated the "original" page frame and we can /*
* We have allocated the "original" page frame and we can
* use it directly to store the loaded page. * use it directly to store the loaded page.
*/ */
return page_address(page); return page_address(page);
/* The "original" page frame has not been allocated and we have to /*
* The "original" page frame has not been allocated and we have to
* use a "safe" page frame to store the loaded page. * use a "safe" page frame to store the loaded page.
*/ */
pbe = chain_alloc(ca, sizeof(struct pbe)); pbe = chain_alloc(ca, sizeof(struct pbe));
...@@ -2471,22 +2496,21 @@ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca) ...@@ -2471,22 +2496,21 @@ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
} }
/** /**
* snapshot_write_next - used for writing the system memory snapshot. * snapshot_write_next - Get the address to store the next image page.
* @handle: Snapshot handle structure to guide the writing.
* *
* On the first call to it @handle should point to a zeroed * On the first call, @handle should point to a zeroed snapshot_handle
* snapshot_handle structure. The structure gets updated and a pointer * structure. The structure gets populated then and a pointer to it should be
* to it should be passed to this function every next time. * passed to this function every next time.
* *
* On success the function returns a positive number. Then, the caller * On success, the function returns a positive number. Then, the caller
* is allowed to write up to the returned number of bytes to the memory * is allowed to write up to the returned number of bytes to the memory
* location computed by the data_of() macro. * location computed by the data_of() macro.
* *
* The function returns 0 to indicate the "end of file" condition, * The function returns 0 to indicate the "end of file" condition. Negative
* and a negative number is returned on error. In such cases the * numbers are returned on errors, in which cases the structure pointed to by
* structure pointed to by @handle is not updated and should not be used * @handle is not updated and should not be used any more.
* any more.
*/ */
int snapshot_write_next(struct snapshot_handle *handle) int snapshot_write_next(struct snapshot_handle *handle)
{ {
static struct chain_allocator ca; static struct chain_allocator ca;
...@@ -2556,13 +2580,13 @@ int snapshot_write_next(struct snapshot_handle *handle) ...@@ -2556,13 +2580,13 @@ int snapshot_write_next(struct snapshot_handle *handle)
} }
/** /**
* snapshot_write_finalize - must be called after the last call to * snapshot_write_finalize - Complete the loading of a hibernation image.
* snapshot_write_next() in case the last page in the image happens *
* to be a highmem page and its contents should be stored in the * Must be called after the last call to snapshot_write_next() in case the last
* highmem. Additionally, it releases the memory that will not be * page in the image happens to be a highmem page and its contents should be
* used any more. * stored in highmem. Additionally, it recycles bitmap memory that's not
* necessary any more.
*/ */
void snapshot_write_finalize(struct snapshot_handle *handle) void snapshot_write_finalize(struct snapshot_handle *handle)
{ {
copy_last_highmem_page(); copy_last_highmem_page();
...@@ -2599,15 +2623,15 @@ static inline void swap_two_pages_data(struct page *p1, struct page *p2, ...@@ -2599,15 +2623,15 @@ static inline void swap_two_pages_data(struct page *p1, struct page *p2,
} }
/** /**
* restore_highmem - for each highmem page that was allocated before * restore_highmem - Put highmem image pages into their original locations.
* the suspend and included in the suspend image, and also has been *
* allocated by the "resume" kernel swap its current (ie. "before * For each highmem page that was in use before hibernation and is included in
* resume") contents with the previous (ie. "before suspend") one. * the image, and also has been allocated by the "restore" kernel, swap its
* current contents with the previous (ie. "before hibernation") ones.
* *
* If the resume eventually fails, we can call this function once * If the restore eventually fails, we can call this function once again and
* again and restore the "before resume" highmem state. * restore the highmem state as seen by the restore kernel.
*/ */
int restore_highmem(void) int restore_highmem(void)
{ {
struct highmem_pbe *pbe = highmem_pblist; struct highmem_pbe *pbe = highmem_pblist;
......
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