1 files changed, 402 insertions, 156 deletions

diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index bd3097c583bf..b09bd7c0998d 100644
--- a/kernel/power/swsusp.c
+++ b/kernel/power/swsusp.c
@@ -30,6 +30,9 @@
  * Alex Badea <vampire@go.ro>:
  * Fixed runaway init
  *
+ * Rafael J. Wysocki <rjw@sisk.pl>
+ * Added the swap map data structure and reworked the handling of swap
+ *
  * More state savers are welcome. Especially for the scsi layer...
  *
  * For TODOs,FIXMEs also look in Documentation/power/swsusp.txt
@@ -76,18 +79,6 @@ static int restore_highmem(void) { return 0; }
 
 extern char resume_file[];
 
-/* Local variables that should not be affected by save */
-unsigned int nr_copy_pages __nosavedata = 0;
-
-/* Suspend pagedir is allocated before final copy, therefore it
-   must be freed after resume
-
-   Warning: this is even more evil than it seems. Pagedirs this file
-   talks about are completely different from page directories used by
-   MMU hardware.
- */
-suspend_pagedir_t *pagedir_nosave __nosavedata = NULL;
-
 #define SWSUSP_SIG      "S1SUSPEND"
 
 static struct swsusp_header {
@@ -238,48 +229,205 @@ static int write_page(unsigned long addr, swp_entry_t *loc)
 }
 
 /**
- *      data_free - Free the swap entries used by the saved image.
+ *      Swap map-handling functions
+ *
+ *      The swap map is a data structure used for keeping track of each page
+ *      written to the swap.  It consists of many swap_map_page structures
+ *      that contain each an array of MAP_PAGE_SIZE swap entries.
+ *      These structures are linked together with the help of either the
+ *      .next (in memory) or the .next_swap (in swap) member.
  *
- *      Walk the list of used swap entries and free each one.
- *      This is only used for cleanup when suspend fails.
+ *      The swap map is created during suspend.  At that time we need to keep
+ *      it in memory, because we have to free all of the allocated swap
+ *      entries if an error occurs.  The memory needed is preallocated
+ *      so that we know in advance if there's enough of it.
+ *
+ *      The first swap_map_page structure is filled with the swap entries that
+ *      correspond to the first MAP_PAGE_SIZE data pages written to swap and
+ *      so on.  After the all of the data pages have been written, the order
+ *      of the swap_map_page structures in the map is reversed so that they
+ *      can be read from swap in the original order.  This causes the data
+ *      pages to be loaded in exactly the same order in which they have been
+ *      saved.
+ *
+ *      During resume we only need to use one swap_map_page structure
+ *      at a time, which means that we only need to use two memory pages for
+ *      reading the image - one for reading the swap_map_page structures
+ *      and the second for reading the data pages from swap.
  */
-static void data_free(void)
+
+#define MAP_PAGE_SIZE   ((PAGE_SIZE - sizeof(swp_entry_t) - sizeof(void *)) \
+                        / sizeof(swp_entry_t))
+
+struct swap_map_page {
+        swp_entry_t             entries[MAP_PAGE_SIZE];
+        swp_entry_t             next_swap;
+        struct swap_map_page    *next;
+};
+
+static inline void free_swap_map(struct swap_map_page *swap_map)
 {
-        swp_entry_t entry;
-        struct pbe *p;
+        struct swap_map_page *swp;
 
-        for_each_pbe (p, pagedir_nosave) {
-                entry = p->swap_address;
-                if (entry.val)
-                        swap_free(entry);
-                else
-                        break;
+        while (swap_map) {
+                swp = swap_map->next;
+                free_page((unsigned long)swap_map);
+                swap_map = swp;
+        }
+}
+
+static struct swap_map_page *alloc_swap_map(unsigned int nr_pages)
+{
+        struct swap_map_page *swap_map, *swp;
+        unsigned n = 0;
+
+        if (!nr_pages)
+                return NULL;
+
+        pr_debug("alloc_swap_map(): nr_pages = %d\n", nr_pages);
+        swap_map = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
+        swp = swap_map;
+        for (n = MAP_PAGE_SIZE; n < nr_pages; n += MAP_PAGE_SIZE) {
+                swp->next = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
+                swp = swp->next;
+                if (!swp) {
+                        free_swap_map(swap_map);
+                        return NULL;
+                }
         }
+        return swap_map;
 }
 
 /**
- *      data_write - Write saved image to swap.
- *
- *      Walk the list of pages in the image and sync each one to swap.
+ *      reverse_swap_map - reverse the order of pages in the swap map
+ *      @swap_map
  */
-static int data_write(void)
+
+static inline struct swap_map_page *reverse_swap_map(struct swap_map_page *swap_map)
 {
-        int error = 0, i = 0;
-        unsigned int mod = nr_copy_pages / 100;
-        struct pbe *p;
+        struct swap_map_page *prev, *next;
+
+        prev = NULL;
+        while (swap_map) {
+                next = swap_map->next;
+                swap_map->next = prev;
+                prev = swap_map;
+                swap_map = next;
+        }
+        return prev;
+}
 
-        if (!mod)
-                mod = 1;
+/**
+ *      free_swap_map_entries - free the swap entries allocated to store
+ *      the swap map @swap_map (this is only called in case of an error)
+ */
+static inline void free_swap_map_entries(struct swap_map_page *swap_map)
+{
+        while (swap_map) {
+                if (swap_map->next_swap.val)
+                        swap_free(swap_map->next_swap);
+                swap_map = swap_map->next;
+        }
+}
 
-        printk( "Writing data to swap (%d pages)...     ", nr_copy_pages );
-        for_each_pbe (p, pagedir_nosave) {
-                if (!(i%mod))
-                        printk( "\b\b\b\b%3d%%", i / mod );
-                if ((error = write_page(p->address, &p->swap_address)))
+/**
+ *      save_swap_map - save the swap map used for tracing the data pages
+ *      stored in the swap
+ */
+
+static int save_swap_map(struct swap_map_page *swap_map, swp_entry_t *start)
+{
+        swp_entry_t entry = (swp_entry_t){0};
+        int error;
+
+        while (swap_map) {
+                swap_map->next_swap = entry;
+                if ((error = write_page((unsigned long)swap_map, &entry)))
                         return error;
-                i++;
+                swap_map = swap_map->next;
         }
-        printk("\b\b\b\bdone\n");
+        *start = entry;
+        return 0;
+}
+
+/**
+ *      free_image_entries - free the swap entries allocated to store
+ *      the image data pages (this is only called in case of an error)
+ */
+
+static inline void free_image_entries(struct swap_map_page *swp)
+{
+        unsigned k;
+
+        while (swp) {
+                for (k = 0; k < MAP_PAGE_SIZE; k++)
+                        if (swp->entries[k].val)
+                                swap_free(swp->entries[k]);
+                swp = swp->next;
+        }
+}
+
+/**
+ *      The swap_map_handle structure is used for handling the swap map in
+ *      a file-alike way
+ */
+
+struct swap_map_handle {
+        struct swap_map_page *cur;
+        unsigned int k;
+};
+
+static inline void init_swap_map_handle(struct swap_map_handle *handle,
+                                        struct swap_map_page *map)
+{
+        handle->cur = map;
+        handle->k = 0;
+}
+
+static inline int swap_map_write_page(struct swap_map_handle *handle,
+                                      unsigned long addr)
+{
+        int error;
+
+        error = write_page(addr, handle->cur->entries + handle->k);
+        if (error)
+                return error;
+        if (++handle->k >= MAP_PAGE_SIZE) {
+                handle->cur = handle->cur->next;
+                handle->k = 0;
+        }
+        return 0;
+}
+
+/**
+ *      save_image_data - save the data pages pointed to by the PBEs
+ *      from the list @pblist using the swap map handle @handle
+ *      (assume there are @nr_pages data pages to save)
+ */
+
+static int save_image_data(struct pbe *pblist,
+                           struct swap_map_handle *handle,
+                           unsigned int nr_pages)
+{
+        unsigned int m;
+        struct pbe *p;
+        int error = 0;
+
+        printk("Saving image data pages (%u pages) ...     ", nr_pages);
+        m = nr_pages / 100;
+        if (!m)
+                m = 1;
+        nr_pages = 0;
+        for_each_pbe (p, pblist) {
+                error = swap_map_write_page(handle, p->address);
+                if (error)
+                        break;
+                if (!(nr_pages % m))
+                        printk("\b\b\b\b%3d%%", nr_pages / m);
+                nr_pages++;
+        }
+        if (!error)
+                printk("\b\b\b\bdone\n");
         return error;
 }
 
@@ -295,19 +443,20 @@ static void dump_info(void)
         pr_debug(" swsusp: UTS Domain: %s\n",swsusp_info.uts.domainname);
         pr_debug(" swsusp: CPUs: %d\n",swsusp_info.cpus);
         pr_debug(" swsusp: Image: %ld Pages\n",swsusp_info.image_pages);
-        pr_debug(" swsusp: Pagedir: %ld Pages\n",swsusp_info.pagedir_pages);
+        pr_debug(" swsusp: Total: %ld Pages\n", swsusp_info.pages);
 }
 
-static void init_header(void)
+static void init_header(unsigned int nr_pages)
 {
         memset(&swsusp_info, 0, sizeof(swsusp_info));
         swsusp_info.version_code = LINUX_VERSION_CODE;
         swsusp_info.num_physpages = num_physpages;
         memcpy(&swsusp_info.uts, &system_utsname, sizeof(system_utsname));
 
-        swsusp_info.suspend_pagedir = pagedir_nosave;
         swsusp_info.cpus = num_online_cpus();
-        swsusp_info.image_pages = nr_copy_pages;
+        swsusp_info.image_pages = nr_pages;
+        swsusp_info.pages = nr_pages +
+                ((nr_pages * sizeof(long) + PAGE_SIZE - 1) >> PAGE_SHIFT);
 }
 
 static int close_swap(void)
@@ -326,39 +475,53 @@ static int close_swap(void)
 }
 
 /**
- *      free_pagedir_entries - Free pages used by the page directory.
- *
- *      This is used during suspend for error recovery.
+ *      pack_orig_addresses - the .orig_address fields of the PBEs from the
+ *      list starting at @pbe are stored in the array @buf[] (1 page)
  */
 
-static void free_pagedir_entries(void)
+static inline struct pbe *pack_orig_addresses(unsigned long *buf,
+                                              struct pbe *pbe)
 {
-        int i;
+        int j;
 
-        for (i = 0; i < swsusp_info.pagedir_pages; i++)
-                swap_free(swsusp_info.pagedir[i]);
+        for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
+                buf[j] = pbe->orig_address;
+                pbe = pbe->next;
+        }
+        if (!pbe)
+                for (; j < PAGE_SIZE / sizeof(long); j++)
+                        buf[j] = 0;
+        return pbe;
 }
 
-
 /**
- *      write_pagedir - Write the array of pages holding the page directory.
- *      @last:  Last swap entry we write (needed for header).
+ *      save_image_metadata - save the .orig_address fields of the PBEs
+ *      from the list @pblist using the swap map handle @handle
  */
 
-static int write_pagedir(void)
+static int save_image_metadata(struct pbe *pblist,
+                               struct swap_map_handle *handle)
 {
-        int error = 0;
+        unsigned long *buf;
         unsigned int n = 0;
-        struct pbe *pbe;
+        struct pbe *p;
+        int error = 0;
 
-        printk( "Writing pagedir...");
-        for_each_pb_page (pbe, pagedir_nosave) {
-                if ((error = write_page((unsigned long)pbe, &swsusp_info.pagedir[n++])))
-                        return error;
+        printk("Saving image metadata ... ");
+        buf = (unsigned long *)get_zeroed_page(GFP_ATOMIC);
+        if (!buf)
+                return -ENOMEM;
+        p = pblist;
+        while (p) {
+                p = pack_orig_addresses(buf, p);
+                error = swap_map_write_page(handle, (unsigned long)buf);
+                if (error)
+                        break;
+                n++;
         }
-
-        swsusp_info.pagedir_pages = n;
-        printk("done (%u pages)\n", n);
+        free_page((unsigned long)buf);
+        if (!error)
+                printk("done (%u pages saved)\n", n);
         return error;
 }
 
@@ -384,33 +547,48 @@ static int enough_swap(unsigned int nr_pages)
 
 /**
  *      write_suspend_image - Write entire image and metadata.
- *
  */
-static int write_suspend_image(void)
+static int write_suspend_image(struct pbe *pblist, unsigned int nr_pages)
 {
+        struct swap_map_page *swap_map;
+        struct swap_map_handle handle;
         int error;
 
-        if (!enough_swap(nr_copy_pages)) {
+        if (!enough_swap(nr_pages)) {
                 printk(KERN_ERR "swsusp: Not enough free swap\n");
                 return -ENOSPC;
         }
 
-        init_header();
-        if ((error = data_write()))
-                goto FreeData;
+        init_header(nr_pages);
+        swap_map = alloc_swap_map(swsusp_info.pages);
+        if (!swap_map)
+                return -ENOMEM;
+        init_swap_map_handle(&handle, swap_map);
 
-        if ((error = write_pagedir()))
-                goto FreePagedir;
+        error = save_image_metadata(pblist, &handle);
+        if (!error)
+                error = save_image_data(pblist, &handle, nr_pages);
+        if (error)
+                goto Free_image_entries;
 
-        if ((error = close_swap()))
-                goto FreePagedir;
- Done:
+        swap_map = reverse_swap_map(swap_map);
+        error = save_swap_map(swap_map, &swsusp_info.start);
+        if (error)
+                goto Free_map_entries;
+
+        error = close_swap();
+        if (error)
+                goto Free_map_entries;
+
+Free_swap_map:
+        free_swap_map(swap_map);
         return error;
- FreePagedir:
-        free_pagedir_entries();
- FreeData:
-        data_free();
-        goto Done;
+
+Free_map_entries:
+        free_swap_map_entries(swap_map);
+Free_image_entries:
+        free_image_entries(swap_map);
+        goto Free_swap_map;
 }
 
 /* It is important _NOT_ to umount filesystems at this point. We want
@@ -418,7 +596,7 @@ static int write_suspend_image(void)
  * filesystem clean: it is not. (And it does not matter, if we resume
  * correctly, we'll mark system clean, anyway.)
  */
-int swsusp_write(void)
+int swsusp_write(struct pbe *pblist, unsigned int nr_pages)
 {
         int error;
 
@@ -427,14 +605,12 @@ int swsusp_write(void)
                 return error;
         }
         lock_swapdevices();
-        error = write_suspend_image();
+        error = write_suspend_image(pblist, nr_pages);
         /* This will unlock ignored swap devices since writing is finished */
         lock_swapdevices();
         return error;
 }
 
-
-
 int swsusp_suspend(void)
 {
         int error;
@@ -531,7 +707,6 @@ static void copy_page_backup_list(struct pbe *dst, struct pbe *src)
         /* We assume both lists contain the same number of elements */
         while (src) {
                 dst->orig_address = src->orig_address;
-                dst->swap_address = src->swap_address;
                 dst = dst->next;
                 src = src->next;
         }
@@ -611,6 +786,61 @@ static int bio_write_page(pgoff_t page_off, void *page)
         return submit(WRITE, page_off, page);
 }
 
+/**
+ *      The following functions allow us to read data using a swap map
+ *      in a file-alike way
+ */
+
+static inline void release_swap_map_reader(struct swap_map_handle *handle)
+{
+        if (handle->cur)
+                free_page((unsigned long)handle->cur);
+        handle->cur = NULL;
+}
+
+static inline int get_swap_map_reader(struct swap_map_handle *handle,
+                                      swp_entry_t start)
+{
+        int error;
+
+        if (!swp_offset(start))
+                return -EINVAL;
+        handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC);
+        if (!handle->cur)
+                return -ENOMEM;
+        error = bio_read_page(swp_offset(start), handle->cur);
+        if (error) {
+                release_swap_map_reader(handle);
+                return error;
+        }
+        handle->k = 0;
+        return 0;
+}
+
+static inline int swap_map_read_page(struct swap_map_handle *handle, void *buf)
+{
+        unsigned long offset;
+        int error;
+
+        if (!handle->cur)
+                return -EINVAL;
+        offset = swp_offset(handle->cur->entries[handle->k]);
+        if (!offset)
+                return -EINVAL;
+        error = bio_read_page(offset, buf);
+        if (error)
+                return error;
+        if (++handle->k >= MAP_PAGE_SIZE) {
+                handle->k = 0;
+                offset = swp_offset(handle->cur->next_swap);
+                if (!offset)
+                        release_swap_map_reader(handle);
+                else
+                        error = bio_read_page(offset, handle->cur);
+        }
+        return error;
+}
+
 /*
  * Sanity check if this image makes sense with this kernel/swap context
  * I really don't think that it's foolproof but more than nothing..
@@ -639,7 +869,6 @@ static const char *sanity_check(void)
         return NULL;
 }
 
-
 static int check_header(void)
 {
         const char *reason = NULL;
@@ -653,7 +882,6 @@ static int check_header(void)
                 printk(KERN_ERR "swsusp: Resume mismatch: %s\n",reason);
                 return -EPERM;
         }
-        nr_copy_pages = swsusp_info.image_pages;
         return error;
 }
 
@@ -680,75 +908,88 @@ static int check_sig(void)
 }
 
 /**
- *      data_read - Read image pages from swap.
- *
- *      You do not need to check for overlaps, check_pagedir()
- *      already did that.
+ *      load_image_data - load the image data using the swap map handle
+ *      @handle and store them using the page backup list @pblist
+ *      (assume there are @nr_pages pages to load)
  */
 
-static int data_read(struct pbe *pblist)
+static int load_image_data(struct pbe *pblist,
+                           struct swap_map_handle *handle,
+                           unsigned int nr_pages)
 {
+        int error;
+        unsigned int m;
         struct pbe *p;
-        int error = 0;
-        int i = 0;
-        int mod = swsusp_info.image_pages / 100;
-
-        if (!mod)
-                mod = 1;
-
-        printk("swsusp: Reading image data (%lu pages):     ",
-                        swsusp_info.image_pages);
-
-        for_each_pbe (p, pblist) {
-                if (!(i % mod))
-                        printk("\b\b\b\b%3d%%", i / mod);
 
-                if ((error = bio_read_page(swp_offset(p->swap_address),
-                                                (void *)p->address)))
-                        return error;
-
-                i++;
+        if (!pblist)
+                return -EINVAL;
+        printk("Loading image data pages (%u pages) ...     ", nr_pages);
+        m = nr_pages / 100;
+        if (!m)
+                m = 1;
+        nr_pages = 0;
+        p = pblist;
+        while (p) {
+                error = swap_map_read_page(handle, (void *)p->address);
+                if (error)
+                        break;
+                p = p->next;
+                if (!(nr_pages % m))
+                        printk("\b\b\b\b%3d%%", nr_pages / m);
+                nr_pages++;
         }
-        printk("\b\b\b\bdone\n");
+        if (!error)
+                printk("\b\b\b\bdone\n");
         return error;
 }
 
 /**
- *      read_pagedir - Read page backup list pages from swap
+ *      unpack_orig_addresses - copy the elements of @buf[] (1 page) to
+ *      the PBEs in the list starting at @pbe
  */
 
-static int read_pagedir(struct pbe *pblist)
+static inline struct pbe *unpack_orig_addresses(unsigned long *buf,
+                                                struct pbe *pbe)
 {
-        struct pbe *pbpage, *p;
-        unsigned int i = 0;
-        int error;
+        int j;
 
-        if (!pblist)
-                return -EFAULT;
+        for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
+                pbe->orig_address = buf[j];
+                pbe = pbe->next;
+        }
+        return pbe;
+}
 
-        printk("swsusp: Reading pagedir (%lu pages)\n",
-                        swsusp_info.pagedir_pages);
+/**
+ *      load_image_metadata - load the image metadata using the swap map
+ *      handle @handle and put them into the PBEs in the list @pblist
+ */
 
-        for_each_pb_page (pbpage, pblist) {
-                unsigned long offset = swp_offset(swsusp_info.pagedir[i++]);
+static int load_image_metadata(struct pbe *pblist, struct swap_map_handle *handle)
+{
+        struct pbe *p;
+        unsigned long *buf;
+        unsigned int n = 0;
+        int error = 0;
 
-                error = -EFAULT;
-                if (offset) {
-                        p = (pbpage + PB_PAGE_SKIP)->next;
-                        error = bio_read_page(offset, (void *)pbpage);
-                        (pbpage + PB_PAGE_SKIP)->next = p;
-                }
+        printk("Loading image metadata ... ");
+        buf = (unsigned long *)get_zeroed_page(GFP_ATOMIC);
+        if (!buf)
+                return -ENOMEM;
+        p = pblist;
+        while (p) {
+                error = swap_map_read_page(handle, buf);
                 if (error)
                         break;
+                p = unpack_orig_addresses(buf, p);
+                n++;
         }
-
+        free_page((unsigned long)buf);
         if (!error)
-                BUG_ON(i != swsusp_info.pagedir_pages);
-
+                printk("done (%u pages loaded)\n", n);
         return error;
 }
 
-
 static int check_suspend_image(void)
 {
         int error = 0;
@@ -762,34 +1003,39 @@ static int check_suspend_image(void)
         return 0;
 }
 
-static int read_suspend_image(void)
+static int read_suspend_image(struct pbe **pblist_ptr)
 {
         int error = 0;
-        struct pbe *p;
+        struct pbe *p, *pblist;
+        struct swap_map_handle handle;
+        unsigned int nr_pages = swsusp_info.image_pages;
 
-        if (!(p = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 0)))
+        p = alloc_pagedir(nr_pages, GFP_ATOMIC, 0);
+        if (!p)
                 return -ENOMEM;
-
-        if ((error = read_pagedir(p)))
+        error = get_swap_map_reader(&handle, swsusp_info.start);
+        if (error)
+                /* The PBE list at p will be released by swsusp_free() */
                 return error;
-        create_pbe_list(p, nr_copy_pages);
-        mark_unsafe_pages(p);
-        pagedir_nosave = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 1);
-        if (pagedir_nosave) {
-                create_pbe_list(pagedir_nosave, nr_copy_pages);
-                copy_page_backup_list(pagedir_nosave, p);
+        error = load_image_metadata(p, &handle);
+        if (!error) {
+                mark_unsafe_pages(p);
+                pblist = alloc_pagedir(nr_pages, GFP_ATOMIC, 1);
+                if (pblist)
+                        copy_page_backup_list(pblist, p);
+                free_pagedir(p);
+                if (!pblist)
+                        error = -ENOMEM;
+
+                /* Allocate memory for the image and read the data from swap */
+                if (!error)
+                        error = alloc_data_pages(pblist, GFP_ATOMIC, 1);
+                if (!error)
+                        error = load_image_data(pblist, &handle, nr_pages);
+                if (!error)
+                        *pblist_ptr = pblist;
         }
-        free_pagedir(p);
-        if (!pagedir_nosave)
-                return -ENOMEM;
-
-        /* Allocate memory for the image and read the data from swap */
-
-        error = alloc_data_pages(pagedir_nosave, GFP_ATOMIC, 1);
-
-        if (!error)
-                error = data_read(pagedir_nosave);
-
+        release_swap_map_reader(&handle);
         return error;
 }
 
@@ -821,7 +1067,7 @@ int swsusp_check(void)
  *      swsusp_read - Read saved image from swap.
  */
 
-int swsusp_read(void)
+int swsusp_read(struct pbe **pblist_ptr)
 {
         int error;
 
@@ -830,7 +1076,7 @@ int swsusp_read(void)
                 return PTR_ERR(resume_bdev);
         }
 
-        error = read_suspend_image();
+        error = read_suspend_image(pblist_ptr);
         blkdev_put(resume_bdev);
 
         if (!error)