PM / Hibernate: Compress hibernation image with LZO

Compress hibernation image with LZO in order to save on I/O and
therefore time to hibernate/thaw.

[rjw: Added hibernate=nocompress command line option instead of just
 nocompress which would be confusing, fixed a couple of compiler
 warnings, fixed kerneldoc comments, minor cleanups.]

Signed-off-by: Bojan Smojver <bojan@rexursive.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

4 files changed, 299 insertions, 7 deletions

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index ca6066a6952e..cb57eb99215f 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -137,6 +137,8 @@ config SUSPEND_FREEZER
 config HIBERNATION
         bool "Hibernation (aka 'suspend to disk')"
         depends on PM && SWAP && ARCH_HIBERNATION_POSSIBLE
+        select LZO_COMPRESS
+        select LZO_DECOMPRESS
         select SUSPEND_NVS if HAS_IOMEM
         ---help---
           Enable the suspend to disk (STD) functionality, which is usually
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 8dc31e02ae12..6c9c9dc48c75 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -29,6 +29,7 @@
 #include "power.h"
 
 
+static int nocompress = 0;
 static int noresume = 0;
 static char resume_file[256] = CONFIG_PM_STD_PARTITION;
 dev_t swsusp_resume_device;
@@ -638,6 +639,8 @@ int hibernate(void)
 
                 if (hibernation_mode == HIBERNATION_PLATFORM)
                         flags |= SF_PLATFORM_MODE;
+                if (nocompress)
+                        flags |= SF_NOCOMPRESS_MODE;
                 pr_debug("PM: writing image.\n");
                 error = swsusp_write(flags);
                 swsusp_free();
@@ -1004,6 +1007,15 @@ static int __init resume_offset_setup(char *str)
         return 1;
 }
 
+static int __init hibernate_setup(char *str)
+{
+        if (!strncmp(str, "noresume", 8))
+                noresume = 1;
+        else if (!strncmp(str, "nocompress", 10))
+                nocompress = 1;
+        return 1;
+}
+
 static int __init noresume_setup(char *str)
 {
         noresume = 1;
@@ -1013,3 +1025,4 @@ static int __init noresume_setup(char *str)
 __setup("noresume", noresume_setup);
 __setup("resume_offset=", resume_offset_setup);
 __setup("resume=", resume_setup);
+__setup("hibernate=", hibernate_setup);
diff --git a/kernel/power/power.h b/kernel/power/power.h
index 006270fe382d..c7e42e47eb0b 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -134,6 +134,7 @@ extern int swsusp_swap_in_use(void);
  * the image header.
  */
 #define SF_PLATFORM_MODE        1
+#define SF_NOCOMPRESS_MODE      2
 
 /* kernel/power/hibernate.c */
 extern int swsusp_check(void);
diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index e6a5bdf61a37..3dc0552cddfb 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -24,6 +24,8 @@
 #include <linux/swapops.h>
 #include <linux/pm.h>
 #include <linux/slab.h>
+#include <linux/lzo.h>
+#include <linux/vmalloc.h>
 
 #include "power.h"
 
@@ -357,6 +359,18 @@ static int swap_writer_finish(struct swap_map_handle *handle,
         return error;
 }
 
+/* We need to remember how much compressed data we need to read. */
+#define LZO_HEADER      sizeof(size_t)
+
+/* Number of pages/bytes we'll compress at one time. */
+#define LZO_UNC_PAGES   32
+#define LZO_UNC_SIZE    (LZO_UNC_PAGES * PAGE_SIZE)
+
+/* Number of pages/bytes we need for compressed data (worst case). */
+#define LZO_CMP_PAGES   DIV_ROUND_UP(lzo1x_worst_compress(LZO_UNC_SIZE) + \
+                                     LZO_HEADER, PAGE_SIZE)
+#define LZO_CMP_SIZE    (LZO_CMP_PAGES * PAGE_SIZE)
+
 /**
  *      save_image - save the suspend image data
  */
@@ -404,6 +418,137 @@ static int save_image(struct swap_map_handle *handle,
         return ret;
 }
 
+
+/**
+ * save_image_lzo - Save the suspend image data compressed with LZO.
+ * @handle: Swap mam handle to use for saving the image.
+ * @snapshot: Image to read data from.
+ * @nr_to_write: Number of pages to save.
+ */
+static int save_image_lzo(struct swap_map_handle *handle,
+                          struct snapshot_handle *snapshot,
+                          unsigned int nr_to_write)
+{
+        unsigned int m;
+        int ret = 0;
+        int nr_pages;
+        int err2;
+        struct bio *bio;
+        struct timeval start;
+        struct timeval stop;
+        size_t off, unc_len, cmp_len;
+        unsigned char *unc, *cmp, *wrk, *page;
+
+        page = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
+        if (!page) {
+                printk(KERN_ERR "PM: Failed to allocate LZO page\n");
+                return -ENOMEM;
+        }
+
+        wrk = vmalloc(LZO1X_1_MEM_COMPRESS);
+        if (!wrk) {
+                printk(KERN_ERR "PM: Failed to allocate LZO workspace\n");
+                free_page((unsigned long)page);
+                return -ENOMEM;
+        }
+
+        unc = vmalloc(LZO_UNC_SIZE);
+        if (!unc) {
+                printk(KERN_ERR "PM: Failed to allocate LZO uncompressed\n");
+                vfree(wrk);
+                free_page((unsigned long)page);
+                return -ENOMEM;
+        }
+
+        cmp = vmalloc(LZO_CMP_SIZE);
+        if (!cmp) {
+                printk(KERN_ERR "PM: Failed to allocate LZO compressed\n");
+                vfree(unc);
+                vfree(wrk);
+                free_page((unsigned long)page);
+                return -ENOMEM;
+        }
+
+        printk(KERN_INFO
+                "PM: Compressing and saving image data (%u pages) ...     ",
+                nr_to_write);
+        m = nr_to_write / 100;
+        if (!m)
+                m = 1;
+        nr_pages = 0;
+        bio = NULL;
+        do_gettimeofday(&start);
+        for (;;) {
+                for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
+                        ret = snapshot_read_next(snapshot);
+                        if (ret < 0)
+                                goto out_finish;
+
+                        if (!ret)
+                                break;
+
+                        memcpy(unc + off, data_of(*snapshot), PAGE_SIZE);
+
+                        if (!(nr_pages % m))
+                                printk(KERN_CONT "\b\b\b\b%3d%%", nr_pages / m);
+                        nr_pages++;
+                }
+
+                if (!off)
+                        break;
+
+                unc_len = off;
+                ret = lzo1x_1_compress(unc, unc_len,
+                                       cmp + LZO_HEADER, &cmp_len, wrk);
+                if (ret < 0) {
+                        printk(KERN_ERR "PM: LZO compression failed\n");
+                        break;
+                }
+
+                if (unlikely(!cmp_len ||
+                             cmp_len > lzo1x_worst_compress(unc_len))) {
+                        printk(KERN_ERR "PM: Invalid LZO compressed length\n");
+                        ret = -1;
+                        break;
+                }
+
+                *(size_t *)cmp = cmp_len;
+
+                /*
+                 * Given we are writing one page at a time to disk, we copy
+                 * that much from the buffer, although the last bit will likely
+                 * be smaller than full page. This is OK - we saved the length
+                 * of the compressed data, so any garbage at the end will be
+                 * discarded when we read it.
+                 */
+                for (off = 0; off < LZO_HEADER + cmp_len; off += PAGE_SIZE) {
+                        memcpy(page, cmp + off, PAGE_SIZE);
+
+                        ret = swap_write_page(handle, page, &bio);
+                        if (ret)
+                                goto out_finish;
+                }
+        }
+
+out_finish:
+        err2 = hib_wait_on_bio_chain(&bio);
+        do_gettimeofday(&stop);
+        if (!ret)
+                ret = err2;
+        if (!ret)
+                printk(KERN_CONT "\b\b\b\bdone\n");
+        else
+                printk(KERN_CONT "\n");
+        swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
+
+        vfree(cmp);
+        vfree(unc);
+        vfree(wrk);
+        free_page((unsigned long)page);
+
+        return ret;
+}
+
 /**
  *      enough_swap - Make sure we have enough swap to save the image.
  *
@@ -411,12 +556,16 @@ static int save_image(struct swap_map_handle *handle,
  *      space avaiable from the resume partition.
  */
 
-static int enough_swap(unsigned int nr_pages)
+static int enough_swap(unsigned int nr_pages, unsigned int flags)
 {
         unsigned int free_swap = count_swap_pages(root_swap, 1);
+        unsigned int required;
 
         pr_debug("PM: Free swap pages: %u\n", free_swap);
-        return free_swap > nr_pages + PAGES_FOR_IO;
+
+        required = PAGES_FOR_IO + ((flags & SF_NOCOMPRESS_MODE) ?
+                nr_pages : (nr_pages * LZO_CMP_PAGES) / LZO_UNC_PAGES + 1);
+        return free_swap > required;
 }
 
 /**
@@ -443,7 +592,7 @@ int swsusp_write(unsigned int flags)
                 printk(KERN_ERR "PM: Cannot get swap writer\n");
                 return error;
         }
-        if (!enough_swap(pages)) {
+        if (!enough_swap(pages, flags)) {
                 printk(KERN_ERR "PM: Not enough free swap\n");
                 error = -ENOSPC;
                 goto out_finish;
@@ -458,8 +607,11 @@ int swsusp_write(unsigned int flags)
         }
         header = (struct swsusp_info *)data_of(snapshot);
         error = swap_write_page(&handle, header, NULL);
-        if (!error)
-                error = save_image(&handle, &snapshot, pages - 1);
+        if (!error) {
+                error = (flags & SF_NOCOMPRESS_MODE) ?
+                        save_image(&handle, &snapshot, pages - 1) :
+                        save_image_lzo(&handle, &snapshot, pages - 1);
+        }
 out_finish:
         error = swap_writer_finish(&handle, flags, error);
         return error;
@@ -590,6 +742,127 @@ static int load_image(struct swap_map_handle *handle,
 }
 
 /**
+ * load_image_lzo - Load compressed image data and decompress them with LZO.
+ * @handle: Swap map handle to use for loading data.
+ * @snapshot: Image to copy uncompressed data into.
+ * @nr_to_read: Number of pages to load.
+ */
+static int load_image_lzo(struct swap_map_handle *handle,
+                          struct snapshot_handle *snapshot,
+                          unsigned int nr_to_read)
+{
+        unsigned int m;
+        int error = 0;
+        struct timeval start;
+        struct timeval stop;
+        unsigned nr_pages;
+        size_t off, unc_len, cmp_len;
+        unsigned char *unc, *cmp, *page;
+
+        page = (void *)__get_free_page(__GFP_WAIT | __GFP_HIGH);
+        if (!page) {
+                printk(KERN_ERR "PM: Failed to allocate LZO page\n");
+                return -ENOMEM;
+        }
+
+        unc = vmalloc(LZO_UNC_SIZE);
+        if (!unc) {
+                printk(KERN_ERR "PM: Failed to allocate LZO uncompressed\n");
+                free_page((unsigned long)page);
+                return -ENOMEM;
+        }
+
+        cmp = vmalloc(LZO_CMP_SIZE);
+        if (!cmp) {
+                printk(KERN_ERR "PM: Failed to allocate LZO compressed\n");
+                vfree(unc);
+                free_page((unsigned long)page);
+                return -ENOMEM;
+        }
+
+        printk(KERN_INFO
+                "PM: Loading and decompressing image data (%u pages) ...     ",
+                nr_to_read);
+        m = nr_to_read / 100;
+        if (!m)
+                m = 1;
+        nr_pages = 0;
+        do_gettimeofday(&start);
+
+        error = snapshot_write_next(snapshot);
+        if (error <= 0)
+                goto out_finish;
+
+        for (;;) {
+                error = swap_read_page(handle, page, NULL); /* sync */
+                if (error)
+                        break;
+
+                cmp_len = *(size_t *)page;
+                if (unlikely(!cmp_len ||
+                             cmp_len > lzo1x_worst_compress(LZO_UNC_SIZE))) {
+                        printk(KERN_ERR "PM: Invalid LZO compressed length\n");
+                        error = -1;
+                        break;
+                }
+
+                memcpy(cmp, page, PAGE_SIZE);
+                for (off = PAGE_SIZE; off < LZO_HEADER + cmp_len; off += PAGE_SIZE) {
+                        error = swap_read_page(handle, page, NULL); /* sync */
+                        if (error)
+                                goto out_finish;
+
+                        memcpy(cmp + off, page, PAGE_SIZE);
+                }
+
+                unc_len = LZO_UNC_SIZE;
+                error = lzo1x_decompress_safe(cmp + LZO_HEADER, cmp_len,
+                                              unc, &unc_len);
+                if (error < 0) {
+                        printk(KERN_ERR "PM: LZO decompression failed\n");
+                        break;
+                }
+
+                if (unlikely(!unc_len ||
+                             unc_len > LZO_UNC_SIZE ||
+                             unc_len & (PAGE_SIZE - 1))) {
+                        printk(KERN_ERR "PM: Invalid LZO uncompressed length\n");
+                        error = -1;
+                        break;
+                }
+
+                for (off = 0; off < unc_len; off += PAGE_SIZE) {
+                        memcpy(data_of(*snapshot), unc + off, PAGE_SIZE);
+
+                        if (!(nr_pages % m))
+                                printk("\b\b\b\b%3d%%", nr_pages / m);
+                        nr_pages++;
+
+                        error = snapshot_write_next(snapshot);
+                        if (error <= 0)
+                                goto out_finish;
+                }
+        }
+
+out_finish:
+        do_gettimeofday(&stop);
+        if (!error) {
+                printk("\b\b\b\bdone\n");
+                snapshot_write_finalize(snapshot);
+                if (!snapshot_image_loaded(snapshot))
+                        error = -ENODATA;
+        } else
+                printk("\n");
+        swsusp_show_speed(&start, &stop, nr_to_read, "Read");
+
+        vfree(cmp);
+        vfree(unc);
+        free_page((unsigned long)page);
+
+        return error;
+}
+
+/**
  *      swsusp_read - read the hibernation image.
  *      @flags_p: flags passed by the "frozen" kernel in the image header should
  *                be written into this memeory location
@@ -612,8 +885,11 @@ int swsusp_read(unsigned int *flags_p)
                 goto end;
         if (!error)
                 error = swap_read_page(&handle, header, NULL);
-        if (!error)
-                error = load_image(&handle, &snapshot, header->pages - 1);
+        if (!error) {
+                error = (*flags_p & SF_NOCOMPRESS_MODE) ?
+                        load_image(&handle, &snapshot, header->pages - 1) :
+                        load_image_lzo(&handle, &snapshot, header->pages - 1);
+        }
         swap_reader_finish(&handle);
 end:
         if (!error)