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-rw-r--r--kernel/power/tuxonice_prune.c406
1 files changed, 406 insertions, 0 deletions
diff --git a/kernel/power/tuxonice_prune.c b/kernel/power/tuxonice_prune.c
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+/*
+ * kernel/power/tuxonice_prune.c
+ *
+ * Copyright (C) 2012 Nigel Cunningham (nigel at nigelcunningham com au)
+ *
+ * This file is released under the GPLv2.
+ *
+ * This file implements a TuxOnIce module that seeks to prune the
+ * amount of data written to disk. It builds a table of hashes
+ * of the uncompressed data, and writes the pfn of the previous page
+ * with the same contents instead of repeating the data when a match
+ * is found.
+ */
+
+#include <linux/suspend.h>
+#include <linux/highmem.h>
+#include <linux/vmalloc.h>
+#include <linux/crypto.h>
+#include <linux/scatterlist.h>
+#include <crypto/hash.h>
+
+#include "tuxonice_builtin.h"
+#include "tuxonice.h"
+#include "tuxonice_modules.h"
+#include "tuxonice_sysfs.h"
+#include "tuxonice_io.h"
+#include "tuxonice_ui.h"
+#include "tuxonice_alloc.h"
+
+/*
+ * We never write a page bigger than PAGE_SIZE, so use a large number
+ * to indicate that data is a PFN.
+ */
+#define PRUNE_DATA_IS_PFN (PAGE_SIZE + 100)
+
+static unsigned long toi_pruned_pages;
+
+static struct toi_module_ops toi_prune_ops;
+static struct toi_module_ops *next_driver;
+
+static char toi_prune_hash_algo_name[32] = "sha1";
+
+static DEFINE_MUTEX(stats_lock);
+
+struct cpu_context {
+ struct shash_desc desc;
+ char *digest;
+};
+
+#define OUT_BUF_SIZE (2 * PAGE_SIZE)
+
+static DEFINE_PER_CPU(struct cpu_context, contexts);
+
+/*
+ * toi_crypto_prepare
+ *
+ * Prepare to do some work by allocating buffers and transforms.
+ */
+static int toi_prune_crypto_prepare(void)
+{
+ int cpu, ret, digestsize;
+
+ if (!*toi_prune_hash_algo_name) {
+ printk(KERN_INFO "TuxOnIce: Pruning enabled but no "
+ "hash algorithm set.\n");
+ return 1;
+ }
+
+ for_each_online_cpu(cpu) {
+ struct cpu_context *this = &per_cpu(contexts, cpu);
+ this->desc.tfm = crypto_alloc_shash(toi_prune_hash_algo_name, 0, 0);
+ if (IS_ERR(this->desc.tfm)) {
+ printk(KERN_INFO "TuxOnIce: Failed to allocate the "
+ "%s prune hash algorithm.\n",
+ toi_prune_hash_algo_name);
+ this->desc.tfm = NULL;
+ return 1;
+ }
+
+ if (!digestsize)
+ digestsize = crypto_shash_digestsize(this->desc.tfm);
+
+ this->digest = kmalloc(digestsize, GFP_KERNEL);
+ if (!this->digest) {
+ printk(KERN_INFO "TuxOnIce: Failed to allocate space "
+ "for digest output.\n");
+ crypto_free_shash(this->desc.tfm);
+ this->desc.tfm = NULL;
+ }
+
+ this->desc.flags = 0;
+
+ ret = crypto_shash_init(&this->desc);
+ if (ret < 0) {
+ printk(KERN_INFO "TuxOnIce: Failed to initialise the "
+ "%s prune hash algorithm.\n",
+ toi_prune_hash_algo_name);
+ kfree(this->digest);
+ this->digest = NULL;
+ crypto_free_shash(this->desc.tfm);
+ this->desc.tfm = NULL;
+ return 1;
+ }
+ }
+
+ return 0;
+}
+
+static int toi_prune_rw_cleanup(int writing)
+{
+ int cpu;
+
+ for_each_online_cpu(cpu) {
+ struct cpu_context *this = &per_cpu(contexts, cpu);
+ if (this->desc.tfm) {
+ crypto_free_shash(this->desc.tfm);
+ this->desc.tfm = NULL;
+ }
+
+ if (this->digest) {
+ kfree(this->digest);
+ this->digest = NULL;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * toi_prune_init
+ */
+
+static int toi_prune_init(int toi_or_resume)
+{
+ if (!toi_or_resume)
+ return 0;
+
+ toi_pruned_pages = 0;
+
+ next_driver = toi_get_next_filter(&toi_prune_ops);
+
+ return next_driver ? 0 : -ECHILD;
+}
+
+/*
+ * toi_prune_rw_init()
+ */
+
+static int toi_prune_rw_init(int rw, int stream_number)
+{
+ if (toi_prune_crypto_prepare()) {
+ printk(KERN_ERR "Failed to initialise prune "
+ "algorithm.\n");
+ if (rw == READ) {
+ printk(KERN_INFO "Unable to read the image.\n");
+ return -ENODEV;
+ } else {
+ printk(KERN_INFO "Continuing without "
+ "pruning the image.\n");
+ toi_prune_ops.enabled = 0;
+ }
+ }
+
+ return 0;
+}
+
+/*
+ * toi_prune_write_page()
+ *
+ * Compress a page of data, buffering output and passing on filled
+ * pages to the next module in the pipeline.
+ *
+ * Buffer_page: Pointer to a buffer of size PAGE_SIZE, containing
+ * data to be checked.
+ *
+ * Returns: 0 on success. Otherwise the error is that returned by later
+ * modules, -ECHILD if we have a broken pipeline or -EIO if
+ * zlib errs.
+ */
+static int toi_prune_write_page(unsigned long index, int buf_type,
+ void *buffer_page, unsigned int buf_size)
+{
+ int ret = 0, cpu = smp_processor_id(), write_data = 1;
+ struct cpu_context *ctx = &per_cpu(contexts, cpu);
+ u8* output_buffer = buffer_page;
+ int output_len = buf_size;
+ int out_buf_type = buf_type;
+ void *buffer_start;
+ u32 buf[4];
+
+ if (ctx->desc.tfm) {
+
+ buffer_start = TOI_MAP(buf_type, buffer_page);
+ ctx->len = OUT_BUF_SIZE;
+
+ ret = crypto_shash_digest(&ctx->desc, buffer_start, buf_size, &ctx->digest);
+ if (ret) {
+ printk(KERN_INFO "TuxOnIce: Failed to calculate digest (%d).\n", ret);
+ } else {
+ mutex_lock(&stats_lock);
+
+ toi_pruned_pages++;
+
+ mutex_unlock(&stats_lock);
+
+ }
+
+ TOI_UNMAP(buf_type, buffer_page);
+ }
+
+ if (write_data)
+ ret = next_driver->write_page(index, out_buf_type,
+ output_buffer, output_len);
+ else
+ ret = next_driver->write_page(index, out_buf_type,
+ output_buffer, output_len);
+
+ return ret;
+}
+
+/*
+ * toi_prune_read_page()
+ * @buffer_page: struct page *. Pointer to a buffer of size PAGE_SIZE.
+ *
+ * Retrieve data from later modules or from a previously loaded page and
+ * fill the input buffer.
+ * Zero if successful. Error condition from me or from downstream on failure.
+ */
+static int toi_prune_read_page(unsigned long *index, int buf_type,
+ void *buffer_page, unsigned int *buf_size)
+{
+ int ret, cpu = smp_processor_id();
+ unsigned int len;
+ char *buffer_start;
+ struct cpu_context *ctx = &per_cpu(contexts, cpu);
+
+ if (!ctx->desc.tfm)
+ return next_driver->read_page(index, TOI_PAGE, buffer_page,
+ buf_size);
+
+ /*
+ * All our reads must be synchronous - we can't handle
+ * data that hasn't been read yet.
+ */
+
+ ret = next_driver->read_page(index, buf_type, buffer_page, &len);
+
+ if (len == PRUNE_DATA_IS_PFN) {
+ buffer_start = kmap(buffer_page);
+ }
+
+ return ret;
+}
+
+/*
+ * toi_prune_print_debug_stats
+ * @buffer: Pointer to a buffer into which the debug info will be printed.
+ * @size: Size of the buffer.
+ *
+ * Print information to be recorded for debugging purposes into a buffer.
+ * Returns: Number of characters written to the buffer.
+ */
+
+static int toi_prune_print_debug_stats(char *buffer, int size)
+{
+ int len;
+
+ /* Output the number of pages pruned. */
+ if (*toi_prune_hash_algo_name)
+ len = scnprintf(buffer, size, "- Compressor is '%s'.\n",
+ toi_prune_hash_algo_name);
+ else
+ len = scnprintf(buffer, size, "- Compressor is not set.\n");
+
+ if (toi_pruned_pages)
+ len += scnprintf(buffer+len, size - len, " Pruned "
+ "%lu pages).\n",
+ toi_pruned_pages);
+ return len;
+}
+
+/*
+ * toi_prune_memory_needed
+ *
+ * Tell the caller how much memory we need to operate during hibernate/resume.
+ * Returns: Unsigned long. Maximum number of bytes of memory required for
+ * operation.
+ */
+static int toi_prune_memory_needed(void)
+{
+ return 2 * PAGE_SIZE;
+}
+
+static int toi_prune_storage_needed(void)
+{
+ return 2 * sizeof(unsigned long) + 2 * sizeof(int) +
+ strlen(toi_prune_hash_algo_name) + 1;
+}
+
+/*
+ * toi_prune_save_config_info
+ * @buffer: Pointer to a buffer of size PAGE_SIZE.
+ *
+ * Save informaton needed when reloading the image at resume time.
+ * Returns: Number of bytes used for saving our data.
+ */
+static int toi_prune_save_config_info(char *buffer)
+{
+ int len = strlen(toi_prune_hash_algo_name) + 1, offset = 0;
+
+ *((unsigned long *) buffer) = toi_pruned_pages;
+ offset += sizeof(unsigned long);
+ *((int *) (buffer + offset)) = len;
+ offset += sizeof(int);
+ strncpy(buffer + offset, toi_prune_hash_algo_name, len);
+ return offset + len;
+}
+
+/* toi_prune_load_config_info
+ * @buffer: Pointer to the start of the data.
+ * @size: Number of bytes that were saved.
+ *
+ * Description: Reload information needed for passing back to the
+ * resumed kernel.
+ */
+static void toi_prune_load_config_info(char *buffer, int size)
+{
+ int len, offset = 0;
+
+ toi_pruned_pages = *((unsigned long *) buffer);
+ offset += sizeof(unsigned long);
+ len = *((int *) (buffer + offset));
+ offset += sizeof(int);
+ strncpy(toi_prune_hash_algo_name, buffer + offset, len);
+}
+
+static void toi_prune_pre_atomic_restore(struct toi_boot_kernel_data *bkd)
+{
+ bkd->pruned_pages = toi_pruned_pages;
+}
+
+static void toi_prune_post_atomic_restore(struct toi_boot_kernel_data *bkd)
+{
+ toi_pruned_pages = bkd->pruned_pages;
+}
+
+/*
+ * toi_expected_ratio
+ *
+ * Description: Returns the expected ratio between data passed into this module
+ * and the amount of data output when writing.
+ * Returns: 100 - we have no idea how many pages will be pruned.
+ */
+
+static int toi_prune_expected_ratio(void)
+{
+ return 100;
+}
+
+/*
+ * data for our sysfs entries.
+ */
+static struct toi_sysfs_data sysfs_params[] = {
+ SYSFS_INT("enabled", SYSFS_RW, &toi_prune_ops.enabled, 0, 1, 0,
+ NULL),
+ SYSFS_STRING("algorithm", SYSFS_RW, toi_prune_hash_algo_name, 31, 0, NULL),
+};
+
+/*
+ * Ops structure.
+ */
+static struct toi_module_ops toi_prune_ops = {
+ .type = FILTER_MODULE,
+ .name = "prune",
+ .directory = "prune",
+ .module = THIS_MODULE,
+ .initialise = toi_prune_init,
+ .memory_needed = toi_prune_memory_needed,
+ .print_debug_info = toi_prune_print_debug_stats,
+ .save_config_info = toi_prune_save_config_info,
+ .load_config_info = toi_prune_load_config_info,
+ .storage_needed = toi_prune_storage_needed,
+ .expected_compression = toi_prune_expected_ratio,
+
+ .pre_atomic_restore = toi_prune_pre_atomic_restore,
+ .post_atomic_restore = toi_prune_post_atomic_restore,
+
+ .rw_init = toi_prune_rw_init,
+ .rw_cleanup = toi_prune_rw_cleanup,
+
+ .write_page = toi_prune_write_page,
+ .read_page = toi_prune_read_page,
+
+ .sysfs_data = sysfs_params,
+ .num_sysfs_entries = sizeof(sysfs_params) /
+ sizeof(struct toi_sysfs_data),
+};
+
+/* ---- Registration ---- */
+
+static __init int toi_prune_load(void)
+{
+ return toi_register_module(&toi_prune_ops);
+}
+
+late_initcall(toi_prune_load);