Subject: Suspend 2 merge: 47/51: GZIP support.
From: Nigel Cunningham <ncunningham@linuxmail.org>
Reply-To: ncunningham@linuxmail.org
To: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
In-Reply-To: <1101292194.5805.180.camel@desktop.cunninghams>
References: <1101292194.5805.180.camel@desktop.cunninghams>
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Message-Id: <1101300182.5805.383.camel@desktop.cunninghams>
Mime-Version: 1.0
Date: Thu, 25 Nov 2004 00:02:19 +1100
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The original compressor. Slow. I've tried to drop it, but for reasons I
simply don't understand, some users still want it.

diff -ruN 853-gzip-old/kernel/power/suspend_gzip.c 853-gzip-new/kernel/power/suspend_gzip.c
--- 853-gzip-old/kernel/power/suspend_gzip.c	1970-01-01 10:00:00.000000000 +1000
+++ 853-gzip-new/kernel/power/suspend_gzip.c	2004-11-11 08:46:25.000000000 +1100
@@ -0,0 +1,560 @@
+/*
+ * kernel/power/gzip_compression.c
+ *
+ * Copyright (C) 2003,2004 Nigel Cunningham <ncunningham@linuxmail.org>
+ *
+ * This file is released under the GPLv2.
+ *
+ * This file contains data compression routines for suspend.
+ * Compression is implemented using the zlib library.
+ *
+ */
+
+#include <linux/suspend.h>
+#include <linux/module.h>
+#include <linux/highmem.h>
+#include <linux/zlib.h>
+
+#include "plugins.h"
+#include "proc.h"
+#include "suspend.h"
+
+/* Forward declaration for the ops structure we export */
+struct suspend_plugin_ops gzip_compression_ops;
+
+/* The next driver in the pipeline */
+static struct suspend_plugin_ops * next_driver;
+
+/* Zlib routines we use to compress/decompress the data */
+extern int zlib_compress(unsigned char *data_in, unsigned char *cpage_out,
+		u32 *sourcelen, u32 *dstlen);
+extern void zlib_decompress(unsigned char *data_in, unsigned char *cpage_out,
+	       u32 srclen, u32 destlen);
+
+/* Buffers */
+static void *compression_workspace = NULL;
+static char *local_buffer = NULL;
+
+/* Configuration data we pass to zlib */
+static z_stream strm;
+
+/* Stats we save */
+static __nosavedata unsigned long bytes_in = 0, bytes_out = 0;
+
+/* Expected compression is used to reduce the amount of storage allocated */
+static int expected_gzip_compression = 0;
+
+/* ---- Zlib memory management ---- */
+
+/* allocate_zlib_compression_space
+ *
+ * Description:	Allocate space for zlib to use in compressing our data.
+ *		Each call must have a matching call to free_zlib_memory.
+ * Returns:	Int: Zero if successful, -ENONEM otherwise.
+ */
+static inline int allocate_zlib_compression_space(void)
+{
+	BUG_ON(compression_workspace);
+
+	compression_workspace = vmalloc_32(zlib_deflate_workspacesize());
+	if (!compression_workspace) {
+		printk(KERN_WARNING
+			"Failed to allocate %d bytes for deflate workspace\n",
+			zlib_deflate_workspacesize());
+		return -ENOMEM;
+	}
+	
+	return 0;
+}
+
+/* allocate_zlib_decompression_space
+ *
+ * Description:	Allocate space for zlib to use in decompressing our data.
+ *		Each call must have a matching call to free_zlib_memory.
+ * Returns:	Int: Zero if successful, -ENONEM otherwise.
+ */
+static inline int allocate_zlib_decompression_space(void)
+{
+	BUG_ON(compression_workspace);
+
+	compression_workspace = vmalloc_32(zlib_inflate_workspacesize());
+	if (!compression_workspace) {
+		printk(KERN_WARNING
+			"Failed to allocate %d bytes for inflate workspace\n",
+			zlib_inflate_workspacesize());
+		return -ENOMEM;
+	}
+	
+	return 0;
+}
+
+/* free_zlib_memory
+ *
+ * Description:	Frees memory allocated by either allocation routine (above).
+ */
+static inline void free_zlib_memory(void)
+{
+	if (!compression_workspace)
+		return;
+
+	vfree(compression_workspace);
+	compression_workspace = NULL;
+}
+
+/* ---- Local buffer management ---- */
+
+/* allocate_local_buffer
+ *
+ * Description:	Allocates a page of memory for buffering output.
+ * Returns:	Int: Zero if successful, -ENONEM otherwise.
+ */
+static int allocate_local_buffer(void)
+{
+	if (local_buffer)
+		return 0;
+
+	local_buffer = (char *) get_zeroed_page(GFP_ATOMIC);
+	
+	if (!local_buffer) {
+		printk(KERN_ERR
+			"Failed to allocate a page for compression "
+			"driver's buffer.\n");
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/* free_local_buffer
+ *
+ * Description:	Frees memory allocated for buffering output.
+ */
+static inline void free_local_buffer(void)
+{
+	if (local_buffer)
+		free_pages((unsigned long) local_buffer, 0);
+	local_buffer = NULL;
+}
+
+/* ---- Functions exported via operations struct ---- */
+
+/* gzip_write_init
+ *
+ * Description:	Allocate buffers and prepares zlib for deflating a new stream
+ * 		of data.
+ * Arguments:	Stream_number:	Ignored.
+ * Returns: 	Int. Zero if successful, otherwise an appropriate error number.
+ */
+
+static int gzip_write_init(int stream_number)
+{
+	int result;
+	
+	next_driver = get_next_filter(&gzip_compression_ops);
+
+	if (!next_driver) {
+		printk("GZip Compression Driver: Argh! No one wants my output!");
+		return -ECHILD;
+	}
+
+	if ((result = allocate_zlib_compression_space()))
+		return result;
+	
+	if ((result = allocate_local_buffer()))
+		return result;
+
+	strm.total_in = 0;
+	strm.total_out = 0;
+	strm.workspace = compression_workspace;
+	strm.next_out = (char *) local_buffer;
+	strm.avail_out = PAGE_SIZE;
+	result = zlib_deflateInit(&strm, Z_BEST_SPEED);
+		
+	if (Z_OK != result) {
+		printk(KERN_ERR name_suspend "Failed to initialise zlib.\n");
+		return -EPERM;
+	}
+
+	/* 
+	 * Reset the statistics iif we are about to write the first part of
+	 * the image
+	 */
+	if (stream_number == 2)
+		bytes_in = bytes_out = 0;
+
+	return 0;
+}
+
+/* gzip_write_chunk()
+ *
+ * Description:	Compress a page of data, buffering output and passing on
+ * 		filled pages to the next plugin in the pipeline.
+ * Arguments:	Buffer_start:	Pointer to a buffer of size PAGE_SIZE, 
+ * 				containing data to be compressed.
+ * Returns:	0 on success. Otherwise the error is that returned by later
+ * 		plugins, -ECHILD if we have a broken pipeline or -EPERM if
+ * 		zlib errs.
+ */
+
+static int gzip_write_chunk(struct page * buffer_page)
+{
+	int ret; 
+	char * buffer_start = kmap(buffer_page);
+	
+	/* Work to do */
+	strm.next_in = buffer_start;
+	strm.avail_in = PAGE_SIZE;
+	while (strm.avail_in) {
+		ret = zlib_deflate(&strm, Z_PARTIAL_FLUSH);
+		if (ret != Z_OK) {
+			printk("Zlib failed to compress our data. "
+				"Result code was %d.\n", ret);
+			kunmap(buffer_page);
+			return -EPERM;
+		}
+
+		if (!strm.avail_out) {
+
+			if ((ret = next_driver->ops.filter.write_chunk(
+					virt_to_page(local_buffer)))) {
+				kunmap(buffer_page);
+				return ret;
+			}
+			strm.next_out = local_buffer;
+			strm.avail_out = PAGE_SIZE;
+		}
+	}
+	kunmap(buffer_page);
+
+	return 0;
+}
+
+/* gzip_write_cleanup()
+ *
+ * Description:	Flush remaining data, update statistics and free allocated
+ * 		space.
+ * Returns:	Zero. Never fails. Okay. Zlib might fail... but it shouldn't.
+ */
+
+static int gzip_write_cleanup(void)
+{
+	int ret = 0, finished = 0;
+	
+	while (!finished) {
+		if (strm.avail_out) {
+			ret = zlib_deflate(&strm, Z_FINISH);
+
+			if (ret == Z_STREAM_END) {
+				ret = zlib_deflateEnd(&strm);
+				finished = 1;
+			}
+
+			if ((ret != Z_OK) && (ret != Z_STREAM_END)) {
+				zlib_deflateEnd(&strm);
+				printk("Failed to finish compressing data. "
+					"Result %d received.\n", ret);
+				return -EPERM;
+			}
+		}
+
+		if ((!strm.avail_out) || (finished)) {
+			if ((ret = next_driver->ops.filter.write_chunk(
+					virt_to_page(local_buffer))))
+				return ret;
+			strm.next_out = local_buffer;
+			strm.avail_out = PAGE_SIZE;
+		}
+	}
+
+	bytes_in+= strm.total_in;
+	bytes_out+= strm.total_out;
+
+	free_zlib_memory();
+	free_local_buffer();
+
+	return 0;
+}
+
+/* gzip_read_init
+ *
+ * Description:	Prepare to read a new stream of data.
+ * Arguments:	Stream_number:	Not used.
+ * Returns: 	Int. Zero if successful, otherwise an appropriate error number.
+ */
+
+static int gzip_read_init(int stream_number)
+{
+	int result;
+
+	next_driver = get_next_filter(&gzip_compression_ops);
+
+	if (!next_driver) {
+		printk("GZip Compression Driver: Argh! "
+			"No one wants to feed me data!");
+		return -ECHILD;
+	}
+	
+	if ((result = allocate_zlib_decompression_space()))
+		return result;
+	
+	if ((result = allocate_local_buffer()))
+		return result;
+
+	strm.total_in = 0;
+	strm.total_out = 0;
+	strm.workspace = compression_workspace;
+	strm.avail_in = 0;
+	if ((result = zlib_inflateInit(&strm)) != Z_OK) {
+		printk(KERN_ERR name_suspend "Failed to initialise zlib.\n");
+		return -EPERM;
+	}
+
+	return 0;
+}
+
+/* gzip_read_chunk()
+ *
+ * Description:	Retrieve data from later plugins and decompress it until the
+ * 		input buffer is filled.
+ * Arguments:	Buffer_start: 	Pointer to a buffer of size PAGE_SIZE.
+ * 		Sync:		Whether the previous plugin (or core) wants its
+ * 				data synchronously.
+ * Returns:	Zero if successful. Error condition from me or from downstream
+ * 		on failure.
+ */
+
+static int gzip_read_chunk(struct page * buffer_page, int sync)
+{
+	int ret; 
+	char * buffer_start = kmap(buffer_page);
+
+	/* 
+	 * All our reads must be synchronous - we can't decompress
+	 * data that hasn't been read yet.
+	 */
+
+	/* Work to do */
+	strm.next_out = buffer_start;
+	strm.avail_out = PAGE_SIZE;
+	while (strm.avail_out) {
+		if (!strm.avail_in) {
+			if ((ret = next_driver->ops.filter.read_chunk(
+					virt_to_page(local_buffer), 
+					SUSPEND_SYNC)) < 0) {
+				kunmap(buffer_page);
+				return ret;
+			}
+			strm.next_in = local_buffer;
+			strm.avail_in = PAGE_SIZE;
+		}
+			
+		ret = zlib_inflate(&strm, Z_PARTIAL_FLUSH);
+
+		if ((ret == Z_BUF_ERROR) && (!strm.avail_in)) {
+			continue;
+		}
+			
+		if ((ret != Z_OK) && (ret != Z_STREAM_END)) {
+			printk("Zlib failed to decompress our data. "
+					"Result code was %d.\n", ret);
+			kunmap(buffer_page);
+			return -EPERM;
+		}
+	}
+	kunmap(buffer_page);
+
+	return 0;
+}
+
+/* read_cleanup()
+ *
+ * Description:	Clean up after reading part or all of a stream of data.
+ * Returns:	int: Always zero. Never fails.
+ */
+
+static int gzip_read_cleanup(void)
+{
+	zlib_inflateEnd(&strm);
+	
+	free_zlib_memory();
+	free_local_buffer();
+	return 0;
+}
+
+/* gzip_print_debug_stats
+ *
+ * Description:	Print information to be recorded for debugging purposes into a
+ * 		buffer.
+ * Arguments:	buffer: Pointer to a buffer into which the debug info will be
+ * 			printed.
+ * 		size:	Size of the buffer.
+ * Returns:	Number of characters written to the buffer.
+ */
+
+static int gzip_print_debug_stats(char * buffer, int size)
+{
+	int pages_in = bytes_in >> PAGE_SHIFT;
+	int pages_out = bytes_out >> PAGE_SHIFT;
+	int len;
+	
+	//Output the compression ratio achieved.
+	len = suspend_snprintf(buffer, size, "- GZIP compressor enabled.\n");
+	if (pages_in)
+		len+= suspend_snprintf(buffer+len, size - len,
+		  "  Compressed %ld bytes into %ld.\n  "
+		  "Image compressed by %d percent.\n",
+		  bytes_in, bytes_out, (pages_in - pages_out) * 100 / pages_in);
+	return len;
+}
+
+/* compression_memory_needed
+ *
+ * Description:	Tell the caller how much memory we need to operate during
+ * 		suspend/resume.
+ * Returns:	Unsigned long. Maximum number of bytes of memory required for
+ * 		operation.
+ */
+
+static unsigned long gzip_memory_needed(void)
+{
+	return PAGE_SIZE + max( zlib_deflate_workspacesize(),
+				zlib_inflate_workspacesize());
+}
+
+static unsigned long gzip_storage_needed(void)
+{
+	return 2 * sizeof(unsigned long);
+}
+
+/* gzip_save_config_info
+ *
+ * Description:	Save information needed when reloading the image at resume time.
+ * Arguments:	Buffer:		Pointer to a buffer of size PAGE_SIZE.
+ * Returns:	Number of bytes used for saving our data.
+ */
+
+static int gzip_save_config_info(char * buffer)
+{
+	*((unsigned long *) buffer) = bytes_in;
+	*((unsigned long *) (buffer + sizeof(unsigned long))) = bytes_out;
+	*((int *) (buffer + 2 * sizeof(unsigned long))) = expected_gzip_compression;
+	return 2 * sizeof(unsigned long) + sizeof(int);
+}
+
+/* gzip_load_config_info
+ *
+ * Description:	Reload information needed for decompressing the image at 
+ * 		resume time.
+ * Arguments:	Buffer:		Pointer to the start of the data.
+ *		Size:		Number of bytes that were saved.
+ */
+
+static void gzip_load_config_info(char * buffer, int size)
+{
+	if(size == 2 * sizeof(unsigned long) + sizeof(int)) {
+		bytes_in = *((unsigned long *) buffer);
+		bytes_out = *((unsigned long *) (buffer + sizeof(unsigned long)));
+		expected_gzip_compression = *((int *) (buffer + 2 * sizeof(unsigned long)));
+	} else
+		printk("Suspend GZIP config info size mismatch: settings ignored.\n");
+	return;
+}
+
+/* gzip_get_expected_compression
+ * 
+ * Description:	Returns the expected ratio between data passed into this plugin
+ * 		and the amount of data output when writing.
+ * Returns:	The value set by the user via our proc entry.
+ */
+
+static int gzip_get_expected_compression(void)
+{
+	return 100 - expected_gzip_compression;
+}
+
+/*
+ * data for our proc entries.
+ */
+
+struct suspend_proc_data expected_compression_proc_data = {
+	.filename			= "expected_gzip_compression",
+	.permissions			= PROC_RW,
+	.type				= SUSPEND_PROC_DATA_INTEGER,
+	.data = {
+		.integer = {
+			.variable	= &expected_gzip_compression,
+			.minimum	= 0,
+			.maximum	= 99,
+		}
+	}
+};
+
+struct suspend_proc_data disable_compression_proc_data = {
+	.filename			= "disable_gzip_compression",
+	.permissions			= PROC_RW,
+	.type				= SUSPEND_PROC_DATA_INTEGER,
+	.data = {
+		.integer = {
+			.variable	= &gzip_compression_ops.disabled,
+			.minimum	= 0,
+			.maximum	= 1,
+		}
+	}
+};
+
+/*
+ * Ops structure.
+ */
+
+struct suspend_plugin_ops gzip_compression_ops = {
+	.type			= FILTER_PLUGIN,
+	.name			= "Zlib Page Compressor",
+	.memory_needed 		= gzip_memory_needed,
+	.print_debug_info	= gzip_print_debug_stats,
+	.save_config_info	= gzip_save_config_info,
+	.load_config_info	= gzip_load_config_info,
+	.storage_needed		= gzip_storage_needed,
+	.ops = {
+		.filter = {
+		 .write_init		= gzip_write_init,
+		 .write_chunk		= gzip_write_chunk,
+		 .write_cleanup		= gzip_write_cleanup,
+		 .read_init		= gzip_read_init,
+		 .read_chunk		= gzip_read_chunk,
+		 .read_cleanup		= gzip_read_cleanup,
+		 .expected_compression	= gzip_get_expected_compression,
+		}
+	}
+};
+
+/* ---- Registration ---- */
+
+static __init int gzip_load(void)
+{
+	int result;
+
+	if (!(result = suspend_register_plugin(&gzip_compression_ops))) {
+		printk("Software Suspend Gzip Compression Driver registered.\n");
+		suspend_register_procfile(&expected_compression_proc_data);
+		suspend_register_procfile(&disable_compression_proc_data);
+	}
+	return result;
+}
+
+#ifdef MODULE
+static __exit void gzip_unload(void)
+{
+	printk("Software Suspend Gzip Compression Driver unloading.\n");
+	suspend_unregister_procfile(&expected_compression_proc_data);
+	suspend_unregister_procfile(&disable_compression_proc_data);
+	suspend_unregister_plugin(&gzip_compression_ops);
+}
+
+module_init(gzip_load);
+module_exit(gzip_unload);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Nigel Cunningham");
+MODULE_DESCRIPTION("Gzip Compression support for Suspend2");
+#else
+late_initcall(gzip_load);
+#endif


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