[PATCH] s390: debug feature changes

This patch changes the memory allocation method for the s390 debug feature.
Trace buffers had been allocated using the get_free_pages() function before.
Therefore it was not possible to get big memory areas in a running system due
to memory fragmentation.  Now the trace buffers are subdivided into several
subbuffers with pagesize.  Therefore it is now possible to allocate more
memory for the trace buffers and more trace records can be written.

In addition to that, dynamic specification of the size of the trace buffers is
implemented.  It is now possible to change the size of a trace buffer using a
new debugfs file instance.  When writing a number into this file, the trace
buffer size is changed to 'number * pagesize'.

In the past all the traces could be obtained from userspace by accessing files
in the "proc" filesystem.  Now with debugfs we have a new filesystem which
should be used for debugging purposes.  This patch moves the debug feature
from procfs to debugfs.

Since the interface of debug_register() changed, all device drivers, which use
the debug feature had to be adjusted.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

20 files changed, 678 insertions, 403 deletions

diff --git a/Documentation/s390/s390dbf.txt b/Documentation/s390/s390dbf.txt
index 2d1cd939b4df..e24fdeada970 100644
--- a/Documentation/s390/s390dbf.txt
+++ b/Documentation/s390/s390dbf.txt
@@ -12,8 +12,8 @@ where log records can be stored efficiently in memory, where each component
 One purpose of this is to inspect the debug logs after a production system crash
 in order to analyze the reason for the crash.
 If the system still runs but only a subcomponent which uses dbf failes,
-it is possible to look at the debug logs on a live system via the Linux proc
-filesystem.
+it is possible to look at the debug logs on a live system via the Linux
+debugfs filesystem.
 The debug feature may also very useful for kernel and driver development.
 
 Design:
@@ -52,16 +52,18 @@ Each debug entry contains the following data:
 - Flag, if entry is an exception or not
 
 The debug logs can be inspected in a live system through entries in
-the proc-filesystem. Under the path /proc/s390dbf there is 
+the debugfs-filesystem. Under the toplevel directory "s390dbf" there is
 a directory for each registered component, which is named like the
-corresponding component.
+corresponding component. The debugfs normally should be mounted to
+/sys/kernel/debug therefore the debug feature can be accessed unter
+/sys/kernel/debug/s390dbf.
 
 The content of the directories are files which represent different views
 to the debug log. Each component can decide which views should be
 used through registering them with the function debug_register_view().
 Predefined views for hex/ascii, sprintf and raw binary data are provided.
 It is also possible to define other views. The content of
-a view can be inspected simply by reading the corresponding proc file.
+a view can be inspected simply by reading the corresponding debugfs file.
 
 All debug logs have an an actual debug level (range from 0 to 6).
 The default level is 3. Event and Exception functions have a 'level'
@@ -69,14 +71,14 @@ parameter. Only debug entries with a level that is lower or equal
 than the actual level are written to the log. This means, when
 writing events, high priority log entries should have a low level
 value whereas low priority entries should have a high one.
-The actual debug level can be changed with the help of the proc-filesystem 
-through writing a number string "x" to the 'level' proc file which is
+The actual debug level can be changed with the help of the debugfs-filesystem
+through writing a number string "x" to the 'level' debugfs file which is
 provided for every debug log. Debugging can be switched off completely
-by using "-" on the 'level' proc file.
+by using "-" on the 'level' debugfs file.
 
 Example:
 
-> echo "-" > /proc/s390dbf/dasd/level
+> echo "-" > /sys/kernel/debug/s390dbf/dasd/level
 
 It is also possible to deactivate the debug feature globally for every
 debug log. You can change the behavior using  2 sysctl parameters in
@@ -99,11 +101,11 @@ Kernel Interfaces:
 ------------------
 
 ----------------------------------------------------------------------------
-debug_info_t *debug_register(char *name, int pages_index, int nr_areas,
+debug_info_t *debug_register(char *name, int pages, int nr_areas,
                              int buf_size);
 
-Parameter:    name:        Name of debug log (e.g. used for proc entry) 
-              pages_index: 2^pages_index pages will be allocated per area
+Parameter:    name:        Name of debug log (e.g. used for debugfs entry)
+              pages:       number of pages, which will be allocated per area
               nr_areas:    number of debug areas
               buf_size:    size of data area in each debug entry
 
@@ -134,7 +136,7 @@ Return Value:  none
 Description:   Sets new actual debug level if new_level is valid. 
 
 ---------------------------------------------------------------------------
-+void debug_stop_all(void);
+void debug_stop_all(void);
 
 Parameter:     none
 
@@ -270,7 +272,7 @@ Parameter:     id:    handle for debug log
 Return Value:  0  : ok 
                < 0: Error 
 
-Description:   registers new debug view and creates proc dir entry 
+Description:   registers new debug view and creates debugfs dir entry
 
 ---------------------------------------------------------------------------
 int debug_unregister_view (debug_info_t * id, struct debug_view *view); 
@@ -281,7 +283,7 @@ Parameter:     id:    handle for debug log
 Return Value:  0  : ok 
                < 0: Error 
 
-Description:   unregisters debug view and removes proc dir entry 
+Description:   unregisters debug view and removes debugfs dir entry
 
 
 
@@ -308,7 +310,7 @@ static int init(void)
 {
     /* register 4 debug areas with one page each and 4 byte data field */
 
-    debug_info = debug_register ("test", 0, 4, 4 );
+    debug_info = debug_register ("test", 1, 4, 4 );
     debug_register_view(debug_info,&debug_hex_ascii_view);
     debug_register_view(debug_info,&debug_raw_view);
 
@@ -343,7 +345,7 @@ static int init(void)
     /* register 4 debug areas with one page each and data field for */
     /* format string pointer + 2 varargs (= 3 * sizeof(long))       */
 
-    debug_info = debug_register ("test", 0, 4, sizeof(long) * 3);
+    debug_info = debug_register ("test", 1, 4, sizeof(long) * 3);
     debug_register_view(debug_info,&debug_sprintf_view);
 
     debug_sprintf_event(debug_info, 2 , "first event in %s:%i\n",__FILE__,__LINE__);
@@ -362,16 +364,16 @@ module_exit(cleanup);
 
 
 
-ProcFS Interface
+Debugfs Interface
 ----------------
 Views to the debug logs can be investigated through reading the corresponding 
-proc-files:
+debugfs-files:
 
 Example:
 
-> ls /proc/s390dbf/dasd
-flush  hex_ascii  level      raw 
-> cat /proc/s390dbf/dasd/hex_ascii | sort +1
+> ls /sys/kernel/debug/s390dbf/dasd
+flush  hex_ascii  level pages raw
+> cat /sys/kernel/debug/s390dbf/dasd/hex_ascii | sort +1
 00 00974733272:680099 2 - 02 0006ad7e  07 ea 4a 90 | ....
 00 00974733272:682210 2 - 02 0006ade6  46 52 45 45 | FREE
 00 00974733272:682213 2 - 02 0006adf6  07 ea 4a 90 | ....
@@ -391,25 +393,36 @@ Changing the debug level
 Example:
 
 
-> cat /proc/s390dbf/dasd/level
+> cat /sys/kernel/debug/s390dbf/dasd/level
 3
-> echo "5" > /proc/s390dbf/dasd/level
-> cat /proc/s390dbf/dasd/level
+> echo "5" > /sys/kernel/debug/s390dbf/dasd/level
+> cat /sys/kernel/debug/s390dbf/dasd/level
 5
 
 Flushing debug areas
 --------------------
 Debug areas can be flushed with piping the number of the desired
-area (0...n) to the proc file "flush". When using "-" all debug areas
+area (0...n) to the debugfs file "flush". When using "-" all debug areas
 are flushed.
 
 Examples:
 
 1. Flush debug area 0:
-> echo "0" > /proc/s390dbf/dasd/flush  
+> echo "0" > /sys/kernel/debug/s390dbf/dasd/flush
 
 2. Flush all debug areas:
-> echo "-" > /proc/s390dbf/dasd/flush
+> echo "-" > /sys/kernel/debug/s390dbf/dasd/flush
+
+Changing the size of debug areas
+------------------------------------
+It is possible the change the size of debug areas through piping
+the number of pages to the debugfs file "pages". The resize request will
+also flush the debug areas.
+
+Example:
+
+Define 4 pages for the debug areas of debug feature "dasd":
+> echo "4" > /sys/kernel/debug/s390dbf/dasd/pages
 
 Stooping the debug feature
 --------------------------
@@ -491,7 +504,7 @@ Defining views
 --------------
 
 Views are specified with the 'debug_view' structure. There are defined
-callback functions which are used for reading and writing the proc files:
+callback functions which are used for reading and writing the debugfs files:
 
 struct debug_view {
         char name[DEBUG_MAX_PROCF_LEN];  
@@ -525,7 +538,7 @@ typedef int (debug_input_proc_t) (debug_info_t* id,
 The "private_data" member can be used as pointer to view specific data.
 It is not used by the debug feature itself.
 
-The output when reading a debug-proc file is structured like this:
+The output when reading a debugfs file is structured like this:
 
 "prolog_proc output"
 
@@ -534,13 +547,13 @@ The output when reading a debug-proc file is structured like this:
 "header_proc output 3"  "format_proc output 3"
 ...
 
-When a view is read from the proc fs, the Debug Feature calls the 
+When a view is read from the debugfs, the Debug Feature calls the
 'prolog_proc' once for writing the prolog.
 Then 'header_proc' and 'format_proc' are called for each 
 existing debug entry.
 
 The input_proc can be used to implement functionality when it is written to 
-the view (e.g. like with 'echo "0" > /proc/s390dbf/dasd/level).
+the view (e.g. like with 'echo "0" > /sys/kernel/debug/s390dbf/dasd/level).
 
 For header_proc there can be used the default function
 debug_dflt_header_fn() which is defined in in debug.h.
@@ -602,7 +615,7 @@ debug_info = debug_register ("test", 0, 4, 4 ));
 debug_register_view(debug_info, &debug_test_view);
 for(i = 0; i < 10; i ++) debug_int_event(debug_info, 1, i);
 
-> cat /proc/s390dbf/test/myview
+> cat /sys/kernel/debug/s390dbf/test/myview
 00 00964419734:611402 1 - 00 88042ca   This error...........
 00 00964419734:611405 1 - 00 88042ca   That error...........
 00 00964419734:611408 1 - 00 88042ca   Problem..............
diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c
index 91f8ce5543d3..960ba6029c3a 100644
--- a/arch/s390/kernel/debug.c
+++ b/arch/s390/kernel/debug.c
@@ -19,22 +19,27 @@
 #include <linux/sysctl.h>
 #include <asm/uaccess.h>
 #include <asm/semaphore.h>
-
 #include <linux/module.h>
 #include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/debugfs.h>
 
 #include <asm/debug.h>
 
 #define DEBUG_PROLOG_ENTRY -1
 
+#define ALL_AREAS 0 /* copy all debug areas */
+#define NO_AREAS  1 /* copy no debug areas */
+
 /* typedefs */
 
 typedef struct file_private_info {
 	loff_t offset;			/* offset of last read in file */
 	int    act_area;                /* number of last formated area */
+	int    act_page;                /* act page in given area */
 	int    act_entry;               /* last formated entry (offset */
                                         /* relative to beginning of last */
-                                        /* formated area) */ 
+                                        /* formated page) */
 	size_t act_entry_offset;        /* up to this offset we copied */
 					/* in last read the last formated */
 					/* entry to userland */
@@ -51,8 +56,8 @@ typedef struct
 	 * This assumes that all args are converted into longs 
 	 * on L/390 this is the case for all types of parameter 
 	 * except of floats, and long long (32 bit) 
-         *
-         */
+	 *
+	 */
 	long args[0];
 } debug_sprintf_entry_t;
 
@@ -63,32 +68,38 @@ extern void tod_to_timeval(uint64_t todval, struct timeval *xtime);
 
 static int debug_init(void);
 static ssize_t debug_output(struct file *file, char __user *user_buf,
-			    size_t user_len, loff_t * offset);
+			size_t user_len, loff_t * offset);
 static ssize_t debug_input(struct file *file, const char __user *user_buf,
-			   size_t user_len, loff_t * offset);
+			size_t user_len, loff_t * offset);
 static int debug_open(struct inode *inode, struct file *file);
 static int debug_close(struct inode *inode, struct file *file);
-static debug_info_t*  debug_info_create(char *name, int page_order, int nr_areas, int buf_size);
+static debug_info_t*  debug_info_create(char *name, int pages_per_area,
+			int nr_areas, int buf_size);
 static void debug_info_get(debug_info_t *);
 static void debug_info_put(debug_info_t *);
 static int debug_prolog_level_fn(debug_info_t * id,
-				 struct debug_view *view, char *out_buf);
+			struct debug_view *view, char *out_buf);
 static int debug_input_level_fn(debug_info_t * id, struct debug_view *view,
-				struct file *file, const char __user *user_buf,
-				size_t user_buf_size, loff_t * offset);
+			struct file *file, const char __user *user_buf,
+			size_t user_buf_size, loff_t * offset);
+static int debug_prolog_pages_fn(debug_info_t * id,
+			struct debug_view *view, char *out_buf);
+static int debug_input_pages_fn(debug_info_t * id, struct debug_view *view,
+			struct file *file, const char __user *user_buf,
+			size_t user_buf_size, loff_t * offset);
 static int debug_input_flush_fn(debug_info_t * id, struct debug_view *view,
-                                struct file *file, const char __user *user_buf,
-                                size_t user_buf_size, loff_t * offset);
+			struct file *file, const char __user *user_buf,
+			size_t user_buf_size, loff_t * offset);
 static int debug_hex_ascii_format_fn(debug_info_t * id, struct debug_view *view,
-                                char *out_buf, const char *in_buf);
+			char *out_buf, const char *in_buf);
 static int debug_raw_format_fn(debug_info_t * id,
-				 struct debug_view *view, char *out_buf,
-				 const char *in_buf);
+			struct debug_view *view, char *out_buf,
+			const char *in_buf);
 static int debug_raw_header_fn(debug_info_t * id, struct debug_view *view,
-                         int area, debug_entry_t * entry, char *out_buf);
+			int area, debug_entry_t * entry, char *out_buf);
 
 static int debug_sprintf_format_fn(debug_info_t * id, struct debug_view *view,
-				   char *out_buf, debug_sprintf_entry_t *curr_event);
+			char *out_buf, debug_sprintf_entry_t *curr_event);
 
 /* globals */
 
@@ -119,6 +130,15 @@ struct debug_view debug_level_view = {
 	NULL
 };
 
+struct debug_view debug_pages_view = {
+	"pages",
+	&debug_prolog_pages_fn,
+	NULL,
+	NULL,
+	&debug_input_pages_fn,
+	NULL
+};
+
 struct debug_view debug_flush_view = {
         "flush",
         NULL,
@@ -149,98 +169,161 @@ DECLARE_MUTEX(debug_lock);
 static int initialized;
 
 static struct file_operations debug_file_ops = {
-	.owner	 = THIS_MODULE,
+	.owner   = THIS_MODULE,
 	.read    = debug_output,
-	.write   = debug_input,	
+	.write   = debug_input,
 	.open    = debug_open,
 	.release = debug_close,
 };
 
-static struct proc_dir_entry *debug_proc_root_entry;
+static struct dentry *debug_debugfs_root_entry;
 
 /* functions */
 
 /*
+ * debug_areas_alloc
+ * - Debug areas are implemented as a threedimensonal array:
+ *   areas[areanumber][pagenumber][pageoffset]
+ */
+
+static debug_entry_t***
+debug_areas_alloc(int pages_per_area, int nr_areas)
+{
+	debug_entry_t*** areas;
+	int i,j;
+
+	areas = (debug_entry_t ***) kmalloc(nr_areas *
+					sizeof(debug_entry_t**),
+					GFP_KERNEL);
+	if (!areas)
+		goto fail_malloc_areas;
+	for (i = 0; i < nr_areas; i++) {
+		areas[i] = (debug_entry_t**) kmalloc(pages_per_area *
+				sizeof(debug_entry_t*),GFP_KERNEL);
+		if (!areas[i]) {
+			goto fail_malloc_areas2;
+		}
+		for(j = 0; j < pages_per_area; j++) {
+			areas[i][j] = (debug_entry_t*)kmalloc(PAGE_SIZE,
+						GFP_KERNEL);
+			if(!areas[i][j]) {
+				for(j--; j >=0 ; j--) {
+					kfree(areas[i][j]);
+				}
+				kfree(areas[i]);
+				goto fail_malloc_areas2;
+			} else {
+				memset(areas[i][j],0,PAGE_SIZE);
+			}
+		}
+	}
+	return areas;
+
+fail_malloc_areas2:
+	for(i--; i >= 0; i--){
+		for(j=0; j < pages_per_area;j++){
+			kfree(areas[i][j]);
+		}
+		kfree(areas[i]);
+	}
+	kfree(areas);
+fail_malloc_areas:
+	return NULL;
+
+}
+
+
+/*
  * debug_info_alloc
  * - alloc new debug-info
  */
 
-static debug_info_t*  debug_info_alloc(char *name, int page_order,
-                                        int nr_areas, int buf_size)
+static debug_info_t*
+debug_info_alloc(char *name, int pages_per_area, int nr_areas, int buf_size,
+		int level, int mode)
 {
 	debug_info_t* rc;
-	int i;
 
 	/* alloc everything */
 
-	rc = (debug_info_t*) kmalloc(sizeof(debug_info_t), GFP_ATOMIC);
+	rc = (debug_info_t*) kmalloc(sizeof(debug_info_t), GFP_KERNEL);
 	if(!rc)
 		goto fail_malloc_rc;
-	rc->active_entry = (int*)kmalloc(nr_areas * sizeof(int), GFP_ATOMIC);
-	if(!rc->active_entry)
-		goto fail_malloc_active_entry;
-	memset(rc->active_entry, 0, nr_areas * sizeof(int));
-	rc->areas = (debug_entry_t **) kmalloc(nr_areas *
-						sizeof(debug_entry_t *),
-						GFP_ATOMIC);
-	if (!rc->areas)
-		goto fail_malloc_areas;
-	for (i = 0; i < nr_areas; i++) {
-		rc->areas[i] = (debug_entry_t *) __get_free_pages(GFP_ATOMIC,
-								page_order);
-		if (!rc->areas[i]) {
-			for (i--; i >= 0; i--) {
-				free_pages((unsigned long) rc->areas[i],
-						page_order);
-			}
-			goto fail_malloc_areas2;
-		} else {
-			memset(rc->areas[i], 0, PAGE_SIZE << page_order);
-		}
+	rc->active_entries = (int*)kmalloc(nr_areas * sizeof(int), GFP_KERNEL);
+	if(!rc->active_entries)
+		goto fail_malloc_active_entries;
+	memset(rc->active_entries, 0, nr_areas * sizeof(int));
+	rc->active_pages = (int*)kmalloc(nr_areas * sizeof(int), GFP_KERNEL);
+	if(!rc->active_pages)
+		goto fail_malloc_active_pages;
+	memset(rc->active_pages, 0, nr_areas * sizeof(int));
+	if((mode == ALL_AREAS) && (pages_per_area != 0)){
+		rc->areas = debug_areas_alloc(pages_per_area, nr_areas);
+		if(!rc->areas)
+			goto fail_malloc_areas;
+	} else {
+		rc->areas = NULL;
 	}
 
 	/* initialize members */
 
 	spin_lock_init(&rc->lock);
-	rc->page_order  = page_order;
-	rc->nr_areas    = nr_areas;
-	rc->active_area = 0;
-	rc->level       = DEBUG_DEFAULT_LEVEL;
-	rc->buf_size    = buf_size;
-	rc->entry_size  = sizeof(debug_entry_t) + buf_size;
-	strlcpy(rc->name, name, sizeof(rc->name));
+	rc->pages_per_area = pages_per_area;
+	rc->nr_areas       = nr_areas;
+	rc->active_area    = 0;
+	rc->level          = level;
+	rc->buf_size       = buf_size;
+	rc->entry_size     = sizeof(debug_entry_t) + buf_size;
+	strlcpy(rc->name, name, sizeof(rc->name)-1);
 	memset(rc->views, 0, DEBUG_MAX_VIEWS * sizeof(struct debug_view *));
-#ifdef CONFIG_PROC_FS
-	memset(rc->proc_entries, 0 ,DEBUG_MAX_VIEWS *
-		sizeof(struct proc_dir_entry*));
-#endif /* CONFIG_PROC_FS */
+	memset(rc->debugfs_entries, 0 ,DEBUG_MAX_VIEWS *
+		sizeof(struct dentry*));
 	atomic_set(&(rc->ref_count), 0);
 
 	return rc;
 
-fail_malloc_areas2:
-	kfree(rc->areas);
 fail_malloc_areas:
-	kfree(rc->active_entry);
-fail_malloc_active_entry:
+	kfree(rc->active_pages);
+fail_malloc_active_pages:
+	kfree(rc->active_entries);
+fail_malloc_active_entries:
 	kfree(rc);
 fail_malloc_rc:
 	return NULL;
 }
 
 /*
- * debug_info_free
- * - free memory debug-info
+ * debug_areas_free
+ * - free all debug areas
  */
 
-static void debug_info_free(debug_info_t* db_info){
-	int i;
+static void
+debug_areas_free(debug_info_t* db_info)
+{
+	int i,j;
+
+	if(!db_info->areas)
+		return;
 	for (i = 0; i < db_info->nr_areas; i++) {
-		free_pages((unsigned long) db_info->areas[i],
-		db_info->page_order);
+		for(j = 0; j < db_info->pages_per_area; j++) {
+			kfree(db_info->areas[i][j]);
+		}
+		kfree(db_info->areas[i]);
 	}
 	kfree(db_info->areas);
-	kfree(db_info->active_entry);
+	db_info->areas = NULL;
+}
+
+/*
+ * debug_info_free
+ * - free memory debug-info
+ */
+
+static void
+debug_info_free(debug_info_t* db_info){
+	debug_areas_free(db_info);
+	kfree(db_info->active_entries);
+	kfree(db_info->active_pages);
 	kfree(db_info);
 }
 
@@ -249,21 +332,22 @@ static void debug_info_free(debug_info_t* db_info){
  * - create new debug-info
  */
 
-static debug_info_t*  debug_info_create(char *name, int page_order, 
-                                        int nr_areas, int buf_size)
+static debug_info_t*
+debug_info_create(char *name, int pages_per_area, int nr_areas, int buf_size)
 {
 	debug_info_t* rc;
 
-        rc = debug_info_alloc(name, page_order, nr_areas, buf_size);
+        rc = debug_info_alloc(name, pages_per_area, nr_areas, buf_size,
+				DEBUG_DEFAULT_LEVEL, ALL_AREAS);
         if(!rc) 
 		goto out;
 
-
-	/* create proc rood directory */
-        rc->proc_root_entry = proc_mkdir(rc->name, debug_proc_root_entry);
+	/* create root directory */
+        rc->debugfs_root_entry = debugfs_create_dir(rc->name,
+					debug_debugfs_root_entry);
 
 	/* append new element to linked list */
-        if (debug_area_first == NULL) {
+        if (!debug_area_first) {
                 /* first element in list */
                 debug_area_first = rc;
                 rc->prev = NULL;
@@ -285,17 +369,21 @@ out:
  * - copy debug-info
  */
 
-static debug_info_t* debug_info_copy(debug_info_t* in)
+static debug_info_t*
+debug_info_copy(debug_info_t* in, int mode)
 {
-        int i;
+        int i,j;
         debug_info_t* rc;
-        rc = debug_info_alloc(in->name, in->page_order, 
-                                in->nr_areas, in->buf_size);
-        if(!rc)
+
+        rc = debug_info_alloc(in->name, in->pages_per_area, in->nr_areas,
+				in->buf_size, in->level, mode);
+        if(!rc || (mode == NO_AREAS))
                 goto out;
 
         for(i = 0; i < in->nr_areas; i++){
-                memcpy(rc->areas[i],in->areas[i], PAGE_SIZE << in->page_order);
+		for(j = 0; j < in->pages_per_area; j++) {
+			memcpy(rc->areas[i][j], in->areas[i][j],PAGE_SIZE);
+		}
         }
 out:
         return rc;
@@ -306,7 +394,8 @@ out:
  * - increments reference count for debug-info
  */
 
-static void debug_info_get(debug_info_t * db_info)
+static void
+debug_info_get(debug_info_t * db_info)
 {
 	if (db_info)
 		atomic_inc(&db_info->ref_count);
@@ -317,29 +406,20 @@ static void debug_info_get(debug_info_t * db_info)
  * - decreases reference count for debug-info and frees it if necessary
  */
 
-static void debug_info_put(debug_info_t *db_info)
+static void
+debug_info_put(debug_info_t *db_info)
 {
 	int i;
 
 	if (!db_info)
 		return;
 	if (atomic_dec_and_test(&db_info->ref_count)) {
-#ifdef DEBUG
-		printk(KERN_INFO "debug: freeing debug area %p (%s)\n",
-		       db_info, db_info->name);
-#endif
 		for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
-			if (db_info->views[i] == NULL)
+			if (!db_info->views[i])
 				continue;
-#ifdef CONFIG_PROC_FS
-			remove_proc_entry(db_info->proc_entries[i]->name,
-					  db_info->proc_root_entry);
-#endif
+			debugfs_remove(db_info->debugfs_entries[i]);
 		}
-#ifdef CONFIG_PROC_FS
-		remove_proc_entry(db_info->proc_root_entry->name,
-				  debug_proc_root_entry);
-#endif
+		debugfs_remove(db_info->debugfs_root_entry);
 		if(db_info == debug_area_first)
 			debug_area_first = db_info->next;
 		if(db_info == debug_area_last)
@@ -355,9 +435,9 @@ static void debug_info_put(debug_info_t *db_info)
  * - format one debug entry and return size of formated data
  */
 
-static int debug_format_entry(file_private_info_t *p_info)
+static int
+debug_format_entry(file_private_info_t *p_info)
 {
-	debug_info_t *id_org    = p_info->debug_info_org;
 	debug_info_t *id_snap   = p_info->debug_info_snap;
 	struct debug_view *view = p_info->view;
 	debug_entry_t *act_entry;
@@ -365,22 +445,23 @@ static int debug_format_entry(file_private_info_t *p_info)
 	if(p_info->act_entry == DEBUG_PROLOG_ENTRY){
 		/* print prolog */
         	if (view->prolog_proc)
-                	len += view->prolog_proc(id_org, view,p_info->temp_buf);
+                	len += view->prolog_proc(id_snap,view,p_info->temp_buf);
 		goto out;
 	}
-
-	act_entry = (debug_entry_t *) ((char*)id_snap->areas[p_info->act_area] +
-					p_info->act_entry);
+	if (!id_snap->areas) /* this is true, if we have a prolog only view */
+		goto out;    /* or if 'pages_per_area' is 0 */
+	act_entry = (debug_entry_t *) ((char*)id_snap->areas[p_info->act_area]
+				[p_info->act_page] + p_info->act_entry);
                         
 	if (act_entry->id.stck == 0LL)
 			goto out;  /* empty entry */
 	if (view->header_proc)
-		len += view->header_proc(id_org, view, p_info->act_area, 
+		len += view->header_proc(id_snap, view, p_info->act_area,
 					act_entry, p_info->temp_buf + len);
 	if (view->format_proc)
-		len += view->format_proc(id_org, view, p_info->temp_buf + len,
+		len += view->format_proc(id_snap, view, p_info->temp_buf + len,
 						DEBUG_DATA(act_entry));
-      out:
+out:
         return len;
 }
 
@@ -389,20 +470,30 @@ static int debug_format_entry(file_private_info_t *p_info)
  * - goto next entry in p_info
  */
 
-extern inline int debug_next_entry(file_private_info_t *p_info)
+extern inline int
+debug_next_entry(file_private_info_t *p_info)
 {
-	debug_info_t *id = p_info->debug_info_snap;
+	debug_info_t *id;
+
+	id = p_info->debug_info_snap;
 	if(p_info->act_entry == DEBUG_PROLOG_ENTRY){
 		p_info->act_entry = 0;
+		p_info->act_page  = 0;
 		goto out;
 	}
-	if ((p_info->act_entry += id->entry_size)
-		> ((PAGE_SIZE << (id->page_order)) 
-		- id->entry_size)){
-
-		/* next area */
+	if(!id->areas)
+		return 1;
+	p_info->act_entry += id->entry_size;
+	/* switch to next page, if we reached the end of the page  */
+	if (p_info->act_entry > (PAGE_SIZE - id->entry_size)){
+		/* next page */
 		p_info->act_entry = 0;
-        	p_info->act_area++;
+		p_info->act_page += 1;
+		if((p_info->act_page % id->pages_per_area) == 0) {
+			/* next area */
+        		p_info->act_area++;
+			p_info->act_page=0;
+		}
         	if(p_info->act_area >= id->nr_areas)
 			return 1;
 	}
@@ -416,13 +507,14 @@ out:
  * - copies formated debug entries to the user buffer
  */
 
-static ssize_t debug_output(struct file *file,		/* file descriptor */
-			    char __user *user_buf,	/* user buffer */
-			    size_t  len,		/* length of buffer */
-			    loff_t *offset)	      /* offset in the file */
+static ssize_t
+debug_output(struct file *file,		/* file descriptor */
+	    char __user *user_buf,	/* user buffer */
+	    size_t  len,		/* length of buffer */
+	    loff_t *offset)		/* offset in the file */
 {
 	size_t count = 0;
-	size_t entry_offset, size = 0;
+	size_t entry_offset;
 	file_private_info_t *p_info;
 
 	p_info = ((file_private_info_t *) file->private_data);
@@ -430,27 +522,33 @@ static ssize_t debug_output(struct file *file,		/* file descriptor */
 		return -EPIPE;
 	if(p_info->act_area >= p_info->debug_info_snap->nr_areas)
 		return 0;
-
 	entry_offset = p_info->act_entry_offset;
-
 	while(count < len){
-		size = debug_format_entry(p_info);
-		size = min((len - count), (size - entry_offset));
-
-		if(size){
-			if (copy_to_user(user_buf + count, 
-					p_info->temp_buf + entry_offset, size))
-			return -EFAULT;
+		int formatted_line_size;
+		int formatted_line_residue;
+		int user_buf_residue;
+		size_t copy_size;
+
+		formatted_line_size = debug_format_entry(p_info);
+		formatted_line_residue = formatted_line_size - entry_offset;
+		user_buf_residue = len-count;
+		copy_size = min(user_buf_residue, formatted_line_residue);
+		if(copy_size){
+			if (copy_to_user(user_buf + count, p_info->temp_buf
+					+ entry_offset, copy_size))
+				return -EFAULT;
+			count += copy_size;
+			entry_offset += copy_size;
 		}
-		count += size;
-		entry_offset = 0;
-		if(count != len)
-			if(debug_next_entry(p_info)) 
+		if(copy_size == formatted_line_residue){
+			entry_offset = 0;
+			if(debug_next_entry(p_info))
 				goto out;
+		}
 	}
 out:
 	p_info->offset           = *offset + count;
-	p_info->act_entry_offset = size;	
+	p_info->act_entry_offset = entry_offset;
 	*offset = p_info->offset;
 	return count;
 }
@@ -461,9 +559,9 @@ out:
  * - calls input function of view
  */
 
-static ssize_t debug_input(struct file *file,
-			   const char __user *user_buf, size_t length,
-			   loff_t *offset)
+static ssize_t
+debug_input(struct file *file, const char __user *user_buf, size_t length,
+		loff_t *offset)
 {
 	int rc = 0;
 	file_private_info_t *p_info;
@@ -487,26 +585,23 @@ static ssize_t debug_input(struct file *file,
  *   handle
  */
 
-static int debug_open(struct inode *inode, struct file *file)
+static int
+debug_open(struct inode *inode, struct file *file)
 {
 	int i = 0, rc = 0;
 	file_private_info_t *p_info;
 	debug_info_t *debug_info, *debug_info_snapshot;
 
-#ifdef DEBUG
-	printk("debug_open\n");
-#endif
 	down(&debug_lock);
 
 	/* find debug log and view */
-
 	debug_info = debug_area_first;
 	while(debug_info != NULL){
 		for (i = 0; i < DEBUG_MAX_VIEWS; i++) {
-			if (debug_info->views[i] == NULL)
+			if (!debug_info->views[i])
 				continue;
-			else if (debug_info->proc_entries[i] ==
-				 PDE(file->f_dentry->d_inode)) {
+			else if (debug_info->debugfs_entries[i] ==
+				 file->f_dentry) {
 				goto found;	/* found view ! */
 			}
 		}
@@ -516,41 +611,42 @@ static int debug_open(struct inode *inode, struct file *file)
 	rc = -EINVAL;
 	goto out;
 
-      found:
+found:
 
-	/* make snapshot of current debug areas to get it consistent */
+	/* Make snapshot of current debug areas to get it consistent.     */
+	/* To copy all the areas is only needed, if we have a view which  */
+	/* formats the debug areas. */
 
-	debug_info_snapshot = debug_info_copy(debug_info);
+	if(!debug_info->views[i]->format_proc &&
+		!debug_info->views[i]->header_proc){
+		debug_info_snapshot = debug_info_copy(debug_info, NO_AREAS);
+	} else {
+		debug_info_snapshot = debug_info_copy(debug_info, ALL_AREAS);
+	}
 
 	if(!debug_info_snapshot){
-#ifdef DEBUG
-		printk(KERN_ERR "debug_open: debug_info_copy failed (out of mem)\n");
-#endif
 		rc = -ENOMEM;
 		goto out;
 	}
-
-	if ((file->private_data =
-	     kmalloc(sizeof(file_private_info_t), GFP_ATOMIC)) == 0) {
-#ifdef DEBUG
-		printk(KERN_ERR "debug_open: kmalloc failed\n");
-#endif
-		debug_info_free(debug_info_snapshot);	
+	p_info = (file_private_info_t *) kmalloc(sizeof(file_private_info_t),
+						GFP_KERNEL);
+	if(!p_info){
+		if(debug_info_snapshot)
+			debug_info_free(debug_info_snapshot);
 		rc = -ENOMEM;
 		goto out;
 	}
-	p_info = (file_private_info_t *) file->private_data;
 	p_info->offset = 0;
 	p_info->debug_info_snap = debug_info_snapshot;
 	p_info->debug_info_org  = debug_info;
 	p_info->view = debug_info->views[i];
 	p_info->act_area = 0;
+	p_info->act_page = 0;
 	p_info->act_entry = DEBUG_PROLOG_ENTRY;
 	p_info->act_entry_offset = 0;
-
+	file->private_data = p_info;
 	debug_info_get(debug_info);
-