[PATCH 4/4] relayfs for 2.6.10: headers

* [PATCH 4/4] relayfs for 2.6.10: headers
@ 2005-01-14  3:04 Karim Yaghmour
  2005-01-14 19:07 ` Greg KH
  2005-01-14 19:10 ` Greg KH
  0 siblings, 2 replies; 6+ messages in thread
From: Karim Yaghmour @ 2005-01-14  3:04 UTC (permalink / raw)
  To: linux-kernel, LTT-Dev


Signed-off-by: Karim Yaghmour (karim@opersys.com)

Karim

--- linux-2.6.10/include/asm-alpha/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-alpha/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_ALPHA_RELAY_H
+#define _ASM_ALPHA_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-arm/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-arm/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_ARM_RELAY_H
+#define _ASM_ARM_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-arm26/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-arm26/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_ARM_RELAY_H
+#define _ASM_ARM_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-cris/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-cris/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_CRIS_RELAY_H
+#define _ASM_CRIS_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-generic/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-generic/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,76 @@
+#ifndef _ASM_GENERIC_RELAY_H
+#define _ASM_GENERIC_RELAY_H
+/*
+ * linux/include/asm-generic/relay.h
+ *
+ * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
+ * Copyright (C) 2002 - Karim Yaghmour (karim@opersys.com)
+ *
+ * Architecture-independent definitions for relayfs
+ */
+
+#include <linux/relayfs_fs.h>
+
+/**
+ *	get_time_delta - utility function for getting time delta
+ *	@now: pointer to a timeval struct that may be given current time
+ *	@rchan: the channel
+ *
+ *	Returns the time difference between the current time and the buffer
+ *	start time.
+ */
+static inline u32
+get_time_delta(struct timeval *now, struct rchan *rchan)
+{
+	u32 time_delta;
+
+	do_gettimeofday(now);
+	time_delta = calc_time_delta(now, &rchan->buf_start_time);
+
+	return time_delta;
+}
+
+/**
+ *	get_timestamp - utility function for getting a time and TSC pair
+ *	@now: current time
+ *	@tsc: the TSC associated with now
+ *	@rchan: the channel
+ *
+ *	Sets the value pointed to by now to the current time. Value pointed to
+ *	by tsc is not set since there is no generic TSC support.
+ */
+static inline void
+get_timestamp(struct timeval *now,
+	      u32 *tsc,
+	      struct rchan *rchan)
+{
+	do_gettimeofday(now);
+}
+
+/**
+ *	get_time_or_tsc: - Utility function for getting a time or a TSC.
+ *	@now: current time
+ *	@tsc: current TSC
+ *	@rchan: the channel
+ *
+ *	Sets the value pointed to by now to the current time.
+ */
+static inline void
+get_time_or_tsc(struct timeval *now,
+		u32 *tsc,
+		struct rchan *rchan)
+{
+	do_gettimeofday(now);
+}
+
+/**
+ *	have_tsc - does this platform have a useable TSC?
+ *
+ *	Returns 0.
+ */
+static inline int
+have_tsc(void)
+{
+	return 0;
+}
+#endif
--- linux-2.6.10/include/asm-h8300/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-h8300/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_H8300_RELAY_H
+#define _ASM_H8300_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-i386/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-i386/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,101 @@
+#ifndef _ASM_I386_RELAY_H
+#define _ASM_I386_RELAY_H
+/*
+ * linux/include/asm-i386/relay.h
+ *
+ * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
+ * Copyright (C) 2002 - Karim Yaghmour (karim@opersys.com)
+ *
+ * i386 definitions for relayfs
+ */
+
+#include <linux/relayfs_fs.h>
+
+#ifdef CONFIG_X86_TSC
+#include <asm/msr.h>
+
+/**
+ *	get_time_delta - utility function for getting time delta
+ *	@now: pointer to a timeval struct that may be given current time
+ *	@rchan: the channel
+ *
+ *	Returns either the TSC if TSCs are being used, or the time and the
+ *	time difference between the current time and the buffer start time
+ *	if TSCs are not being used.
+ */
+static inline u32
+get_time_delta(struct timeval *now, struct rchan *rchan)
+{
+	u32 time_delta;
+
+	if ((using_tsc(rchan) == 1) && cpu_has_tsc)
+		rdtscl(time_delta);
+	else {
+		do_gettimeofday(now);
+		time_delta = calc_time_delta(now, &rchan->buf_start_time);
+	}
+
+	return time_delta;
+}
+
+/**
+ *	get_timestamp - utility function for getting a time and TSC pair
+ *	@now: current time
+ *	@tsc: the TSC associated with now
+ *	@rchan: the channel
+ *
+ *	Sets the value pointed to by now to the current time and the value
+ *	pointed to by tsc to the tsc associated with that time, if the
+ *	platform supports TSC.
+ */
+static inline void
+get_timestamp(struct timeval *now,
+	      u32 *tsc,
+	      struct rchan *rchan)
+{
+	do_gettimeofday(now);
+
+	if ((using_tsc(rchan) == 1) && cpu_has_tsc)
+		rdtscl(*tsc);
+}
+
+/**
+ *	get_time_or_tsc - utility function for getting a time or a TSC
+ *	@now: current time
+ *	@tsc: current TSC
+ *	@rchan: the channel
+ *
+ *	Sets the value pointed to by now to the current time or the value
+ *	pointed to by tsc to the current tsc, depending on whether we're
+ *	using TSCs or not.
+ */
+static inline void
+get_time_or_tsc(struct timeval *now,
+		u32 *tsc,
+		struct rchan *rchan)
+{
+	if ((using_tsc(rchan) == 1) && cpu_has_tsc)
+		rdtscl(*tsc);
+	else
+		do_gettimeofday(now);
+}
+
+/**
+ *	have_tsc - does this platform have a useable TSC?
+ *
+ *	Returns 1 if this platform has a useable TSC counter for
+ *	timestamping purposes, 0 otherwise.
+ */
+static inline int
+have_tsc(void)
+{
+	if (cpu_has_tsc)
+		return 1;
+	else
+		return 0;
+}
+
+#else /* No TSC support (#ifdef CONFIG_X86_TSC) */
+#include <asm-generic/relay.h>
+#endif /* #ifdef CONFIG_X86_TSC */
+#endif
--- linux-2.6.10/include/asm-ia64/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-ia64/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_IA64_RELAY_H
+#define _ASM_IA64_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-m68k/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-m68k/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_M68K_RELAY_H
+#define _ASM_M68K_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-m68knommu/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-m68knommu/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_M68KNOMMU_RELAY_H
+#define _ASM_M68KNOMMU_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-mips/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-mips/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_RELAY_H
+#define _ASM_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-mips64/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-mips64/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_RELAY_H
+#define _ASM_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-parisc/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-parisc/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_PARISC_RELAY_H
+#define _ASM_PARISC_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-ppc/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-ppc/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_PPC_RELAY_H
+#define _ASM_PPC_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-ppc64/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-ppc64/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_PPC64_RELAY_H
+#define _ASM_PPC64_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-s390/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-s390/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_S390_RELAY_H
+#define _ASM_S390_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-sh/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-sh/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_SH_RELAY_H
+#define _ASM_SH_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-sparc/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-sparc/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_SPARC_RELAY_H
+#define _ASM_SPARC_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-sparc64/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-sparc64/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_SPARC64_RELAY_H
+#define _ASM_SPARC64_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-v850/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-v850/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef __V850_RELAY_H
+#define __V850_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/asm-x86_64/relay.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/asm-x86_64/relay.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,5 @@
+#ifndef _ASM_X86_64_RELAY_H
+#define _ASM_X86_64_RELAY_H
+
+#include <asm-generic/relay.h>
+#endif
--- linux-2.6.10/include/linux/klog.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/linux/klog.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,24 @@
+/*
+ * KLOG		Generic Logging facility built upon the relayfs infrastructure
+ *
+ * Authors:	Hubertus Frankeh  (frankeh@us.ibm.com)
+ *		Tom Zanussi  (zanussi@us.ibm.com)
+ *
+ *		Please direct all questions/comments to zanussi@us.ibm.com
+ *
+ *		Copyright (C) 2003, IBM Corp
+ *
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _LINUX_KLOG_H
+#define _LINUX_KLOG_H
+
+extern int klog(const char *fmt, ...);
+extern int klog_raw(const char *buf,int len);
+
+#endif	/* _LINUX_KLOG_H */
--- linux-2.6.10/include/linux/relayfs_fs.h	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.10-relayfs/include/linux/relayfs_fs.h	2005-01-13 10:40:25.000000000 -0800
@@ -0,0 +1,689 @@
+/*
+ * linux/include/linux/relayfs_fs.h
+ *
+ * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
+ * Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com)
+ *
+ * RelayFS definitions and declarations
+ *
+ * Please see Documentation/filesystems/relayfs.txt for more info.
+ */
+
+#ifndef _LINUX_RELAYFS_FS_H
+#define _LINUX_RELAYFS_FS_H
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/list.h>
+#include <linux/fs.h>
+
+/*
+ * Tracks changes to rchan struct
+ */
+#define RELAYFS_CHANNEL_VERSION		1
+
+/*
+ * Maximum number of simultaneously open channels
+ */
+#define RELAY_MAX_CHANNELS		256
+
+/*
+ * Relay properties
+ */
+#define RELAY_MIN_BUFS			2
+#define RELAY_MIN_BUFSIZE		4096
+#define RELAY_MAX_BUFS			256
+#define RELAY_MAX_BUF_SIZE		0x1000000
+#define RELAY_MAX_TOTAL_BUF_SIZE	0x8000000
+
+/*
+ * Lockless scheme utility macros
+ */
+#define RELAY_MAX_BUFNO(bufno_bits) (1UL << (bufno_bits))
+#define RELAY_BUF_SIZE(offset_bits) (1UL << (offset_bits))
+#define RELAY_BUF_OFFSET_MASK(offset_bits) (RELAY_BUF_SIZE(offset_bits) - 1)
+#define RELAY_BUFNO_GET(index, offset_bits) ((index) >> (offset_bits))
+#define RELAY_BUF_OFFSET_GET(index, mask) ((index) & (mask))
+#define RELAY_BUF_OFFSET_CLEAR(index, mask) ((index) & ~(mask))
+
+/*
+ * Flags returned by relay_reserve()
+ */
+#define RELAY_BUFFER_SWITCH_NONE	0x0
+#define RELAY_WRITE_DISCARD_NONE	0x0
+#define RELAY_BUFFER_SWITCH		0x1
+#define RELAY_WRITE_DISCARD		0x2
+#define RELAY_WRITE_TOO_LONG		0x4
+
+/*
+ * Relay attribute flags
+ */
+#define RELAY_DELIVERY_BULK		0x1
+#define RELAY_DELIVERY_PACKET		0x2
+#define RELAY_SCHEME_LOCKLESS		0x4
+#define RELAY_SCHEME_LOCKING		0x8
+#define RELAY_SCHEME_ANY		0xC
+#define RELAY_TIMESTAMP_TSC		0x10
+#define RELAY_TIMESTAMP_GETTIMEOFDAY	0x20
+#define RELAY_TIMESTAMP_ANY		0x30
+#define RELAY_USAGE_SMP			0x40
+#define RELAY_USAGE_GLOBAL		0x80
+#define RELAY_MODE_CONTINUOUS		0x100
+#define RELAY_MODE_NO_OVERWRITE		0x200
+#define RELAY_MODE_START_AT_ZERO	0x400
+
+/*
+ * Flags for needs_resize() callback
+ */
+#define RELAY_RESIZE_NONE	0x0
+#define RELAY_RESIZE_EXPAND	0x1
+#define RELAY_RESIZE_SHRINK	0x2
+#define RELAY_RESIZE_REPLACE	0x4
+#define RELAY_RESIZE_REPLACED	0x8
+
+/*
+ * Values for fileop_notify() callback
+ */
+enum relay_fileop
+{
+	RELAY_FILE_OPEN,
+	RELAY_FILE_CLOSE,
+	RELAY_FILE_MAP,
+	RELAY_FILE_UNMAP
+};
+
+/*
+ * Data structure returned by relay_info()
+ */
+struct rchan_info
+{
+	u32 flags;		/* relay attribute flags for channel */
+	u32 buf_size;		/* channel's sub-buffer size */
+	char *buf_addr;		/* address of channel start */
+	u32 alloc_size;		/* total buffer size actually allocated */
+	u32 n_bufs;		/* number of sub-buffers in channel */
+	u32 cur_idx;		/* current write index into channel */
+	u32 bufs_produced;	/* current count of sub-buffers produced */
+	u32 bufs_consumed;	/* current count of sub-buffers consumed */
+	u32 buf_id;		/* buf_id of current sub-buffer */
+	int buffer_complete[RELAY_MAX_BUFS];	/* boolean per sub-buffer */
+	int unused_bytes[RELAY_MAX_BUFS];	/* count per sub-buffer */
+};
+
+/*
+ * Relay channel client callbacks
+ */
+struct rchan_callbacks
+{
+	/*
+	 * buffer_start - called at the beginning of a new sub-buffer
+	 * @rchan_id: the channel id
+	 * @current_write_pos: position in sub-buffer client should write to
+	 * @buffer_id: the id of the new sub-buffer
+	 * @start_time: the timestamp associated with the start of sub-buffer
+	 * @start_tsc: the TSC associated with the timestamp, if using_tsc
+	 * @using_tsc: boolean, indicates whether start_tsc is valid
+	 *
+	 * Return value should be the number of bytes written by the client.
+	 *
+	 * See Documentation/filesystems/relayfs.txt for details.
+	 */
+	int (*buffer_start) (int rchan_id,
+			     char *current_write_pos,
+			     u32 buffer_id,
+			     struct timeval start_time,
+			     u32 start_tsc,
+			     int using_tsc);
+
+	/*
+	 * buffer_end - called at the end of a sub-buffer
+	 * @rchan_id: the channel id
+	 * @current_write_pos: position in sub-buffer of end of data
+	 * @end_of_buffer: the position of the end of the sub-buffer
+	 * @end_time: the timestamp associated with the end of the sub-buffer
+	 * @end_tsc: the TSC associated with the end_time, if using_tsc
+	 * @using_tsc: boolean, indicates whether end_tsc is valid
+	 *
+	 * Return value should be the number of bytes written by the client.
+	 *
+	 * See Documentation/filesystems/relayfs.txt for details.
+	 */
+	int (*buffer_end) (int rchan_id,
+			   char *current_write_pos,
+			   char *end_of_buffer,
+			   struct timeval end_time,
+			   u32 end_tsc,
+			   int using_tsc);
+
+	/*
+	 * deliver - called when data is ready for the client
+	 * @rchan_id: the channel id
+	 * @from: the start of the delivered data
+	 * @len: the length of the delivered data
+	 *
+	 * See Documentation/filesystems/relayfs.txt for details.
+	 */
+	void (*deliver) (int rchan_id, char *from, u32 len);
+
+	/*
+	 * user_deliver - called when data has been written from userspace
+	 * @rchan_id: the channel id
+	 * @from: the start of the delivered data
+	 * @len: the length of the delivered data
+	 *
+	 * See Documentation/filesystems/relayfs.txt for details.
+	 */
+	void (*user_deliver) (int rchan_id, char *from, u32 len);
+
+	/*
+	 * needs_resize - called when a resizing event occurs
+	 * @rchan_id: the channel id
+	 * @resize_type: the type of resizing event
+	 * @suggested_buf_size: the suggested new sub-buffer size
+	 * @suggested_buf_size: the suggested new number of sub-buffers
+	 *
+	 * See Documentation/filesystems/relayfs.txt for details.
+	 */
+	void (*needs_resize)(int rchan_id,
+			     int resize_type,
+			     u32 suggested_buf_size,
+			     u32 suggested_n_bufs);
+
+	/*
+	 * fileop_notify - called on open/close/mmap/munmap of a relayfs file
+	 * @rchan_id: the channel id
+	 * @filp: relayfs file pointer
+	 * @fileop: which file operation is in progress
+	 *
+	 * The return value can direct the outcome of the operation.
+	 *
+	 * See Documentation/filesystems/relayfs.txt for details.
+	 */
+        int (*fileop_notify)(int rchan_id,
+			     struct file *filp,
+			     enum relay_fileop fileop);
+
+	/*
+	 * ioctl - called in ioctl context from userspace
+	 * @rchan_id: the channel id
+	 * @cmd: ioctl cmd
+	 * @arg: ioctl cmd arg
+	 *
+	 * The return value is returned as the value from the ioctl call.
+	 *
+	 * See Documentation/filesystems/relayfs.txt for details.
+	 */
+	int (*ioctl) (int rchan_id, unsigned int cmd, unsigned long arg);
+};
+
+/*
+ * Lockless scheme-specific data
+ */
+struct lockless_rchan
+{
+	u8 bufno_bits;		/* # bits used for sub-buffer id */
+	u8 offset_bits;		/* # bits used for offset within sub-buffer */
+	u32 index;		/* current index = sub-buffer id and offset */
+	u32 offset_mask;	/* used to obtain offset portion of index */
+	u32 index_mask;		/* used to mask off unused bits index */
+	atomic_t fill_count[RELAY_MAX_BUFS];	/* fill count per sub-buffer */
+};
+
+/*
+ * Locking scheme-specific data
+ */
+struct locking_rchan
+{
+	char *write_buf;		/* start of write sub-buffer */
+	char *write_buf_end;		/* end of write sub-buffer */
+	char *current_write_pos;	/* current write pointer */
+	char *write_limit;		/* takes reserves into account */
+	char *in_progress_event_pos;	/* used for interrupted writes */
+	u16 in_progress_event_size;	/* used for interrupted writes */
+	char *interrupted_pos;		/* used for interrupted writes */
+	u16 interrupting_size;		/* used for interrupted writes */
+	spinlock_t lock;		/* channel lock for locking scheme */
+};
+
+struct relay_ops;
+
+/*
+ * Offset resizing data structure
+ */
+struct resize_offset
+{
+	u32 ge;
+	u32 le;
+	int delta;
+};
+
+/*
+ * Relay channel data structure
+ */
+struct rchan
+{
+	u32 version;			/* the version of this struct */
+	char *buf;			/* the channel buffer */
+	union
+	{
+		struct lockless_rchan lockless;
+		struct locking_rchan locking;
+	} scheme;			/* scheme-specific channel data */
+
+	int id;				/* the channel id */
+	struct rchan_callbacks *callbacks;	/* client callbacks */
+	u32 flags;			/* relay channel attributes */
+	u32 buf_id;			/* current sub-buffer id */
+	u32 buf_idx;			/* current sub-buffer index */
+
+	atomic_t mapped;		/* map count */
+
+	atomic_t suspended;		/* channel suspended i.e full? */
+	int half_switch;		/* used internally for suspend */
+
+	struct timeval  buf_start_time;	/* current sub-buffer start time */
+	u32 buf_start_tsc;		/* current sub-buffer start TSC */
+	
+	u32 buf_size;			/* sub-buffer size */
+	u32 alloc_size;			/* total buffer size allocated */
+	u32 n_bufs;			/* number of sub-buffers */
+
+	u32 bufs_produced;		/* count of sub-buffers produced */
+	u32 bufs_consumed;		/* count of sub-buffers consumed */
+	u32 bytes_consumed;		/* bytes consumed in cur sub-buffer */
+	u32 read_start;			/* start VFS readers here */
+
+	int initialized;		/* first buffer initialized? */
+	int finalized;			/* channel finalized? */
+
+	u32 start_reserve;		/* reserve at start of sub-buffers */
+	u32 end_reserve;		/* reserve at end of sub-buffers */
+	u32 rchan_start_reserve;	/* additional reserve sub-buffer 0 */
+	
+	struct dentry *dentry;		/* channel file dentry */
+
+	wait_queue_head_t read_wait;	/* VFS read wait queue */
+	wait_queue_head_t write_wait;	/* VFS write wait queue */
+	struct work_struct wake_readers; /* reader wake-up work struct */
+	struct work_struct wake_writers; /* reader wake-up work struct */
+	atomic_t refcount;		/* channel refcount */
+
+	struct relay_ops *relay_ops;	/* scheme-specific channel ops */
+
+	int unused_bytes[RELAY_MAX_BUFS]; /* unused count per sub-buffer */
+
+	struct semaphore resize_sem;	/* serializes alloc/repace */
+	struct work_struct work;	/* resize allocation work struct */
+
+	struct list_head open_readers;	/* open readers for this channel */
+	rwlock_t open_readers_lock;	/* protection for open_readers list */
+
+	char *init_buf;			/* init channel buffer, if non-NULL */
+	
+	u32 resize_min;			/* minimum resized total buffer size */
+	u32 resize_max;			/* maximum resized total buffer size */
+	char *resize_buf;		/* for autosize alloc/free */
+	u32 resize_buf_size;		/* resized sub-buffer size */
+	u32 resize_n_bufs;		/* resized number of sub-buffers */
+	u32 resize_alloc_size;		/* resized actual total size */
+	int resizing;			/* is resizing in progress? */
+	int resize_err;			/* resizing err code */
+	int resize_failures;		/* number of resize failures */
+	int replace_buffer;		/* is the alloced buffer ready?  */
+	struct resize_offset resize_offset; /* offset change */
+	struct timer_list shrink_timer;	/* timer used for shrinking */
+	int resize_order;		/* size of last resize */
+	u32 expand_buf_id;		/* subbuf id expand will occur at */
+
+	struct page **buf_page_array;	/* array of current buffer pages */
+	int buf_page_count;		/* number of current buffer pages */
+	struct page **expand_page_array;/* new pages to be inserted */
+	int expand_page_count;		/* number of new pages */
+	struct page **shrink_page_array;/* old pages to be freed */
+	int shrink_page_count;		/* number of old pages */
+	struct page **resize_page_array;/* will become current pages */
+	int resize_page_count;		/* number of resize pages */
+	struct page **old_buf_page_array; /* hold for freeing */
+} ____cacheline_aligned;
+
+/*
+ * Relay channel reader struct
+ */
+struct rchan_reader
+{
+	struct list_head list;		/* for list inclusion */
+	struct rchan *rchan;		/* the channel we're reading from */
+	int auto_consume;		/* does this reader auto-consume? */
+	u32 bufs_consumed;		/* buffers this reader has consumed */
+	u32 bytes_consumed;		/* bytes consumed in cur sub-buffer */
+	int offset_changed;		/* have channel offsets changed? */
+	int vfs_reader;			/* are we a VFS reader? */
+	int map_reader;			/* are we an mmap reader? */
+
+	union
+	{
+		struct file *file;
+		u32 f_pos;
+	} pos;				/* current read offset */
+};
+
+/*
+ * These help make union member access less tedious
+ */
+#define channel_buffer(rchan) ((rchan)->buf)
+#define idx(rchan) ((rchan)->scheme.lockless.index)
+#define bufno_bits(rchan) ((rchan)->scheme.lockless.bufno_bits)
+#define offset_bits(rchan) ((rchan)->scheme.lockless.offset_bits)
+#define offset_mask(rchan) ((rchan)->scheme.lockless.offset_mask)
+#define idx_mask(rchan) ((rchan)->scheme.lockless.index_mask)
+#define bulk_delivery(rchan) (((rchan)->flags & RELAY_DELIVERY_BULK) ? 1 : 0)
+#define packet_delivery(rchan) (((rchan)->flags & RELAY_DELIVERY_PACKET) ? 1 : 0)
+#define using_lockless(rchan) (((rchan)->flags & RELAY_SCHEME_LOCKLESS) ? 1 : 0)
+#define using_locking(rchan) (((rchan)->flags & RELAY_SCHEME_LOCKING) ? 1 : 0)
+#define using_tsc(rchan) (((rchan)->flags & RELAY_TIMESTAMP_TSC) ? 1 : 0)
+#define using_gettimeofday(rchan) (((rchan)->flags & RELAY_TIMESTAMP_GETTIMEOFDAY) ? 1 : 0)
+#define usage_smp(rchan) (((rchan)->flags & RELAY_USAGE_SMP) ? 1 : 0)
+#define usage_global(rchan) (((rchan)->flags & RELAY_USAGE_GLOBAL) ? 1 : 0)
+#define mode_continuous(rchan) (((rchan)->flags & RELAY_MODE_CONTINUOUS) ? 1 : 0)
+#define fill_count(rchan, i) ((rchan)->scheme.lockless.fill_count[(i)])
+#define write_buf(rchan) ((rchan)->scheme.locking.write_buf)
+#define read_buf(rchan) ((rchan)->scheme.locking.read_buf)
+#define write_buf_end(rchan) ((rchan)->scheme.locking.write_buf_end)
+#define read_buf_end(rchan) ((rchan)->scheme.locking.read_buf_end)
+#define cur_write_pos(rchan) ((rchan)->scheme.locking.current_write_pos)
+#define read_limit(rchan) ((rchan)->scheme.locking.read_limit)
+#define write_limit(rchan) ((rchan)->scheme.locking.write_limit)
+#define in_progress_event_pos(rchan) ((rchan)->scheme.locking.in_progress_event_pos)
+#define in_progress_event_size(rchan) ((rchan)->scheme.locking.in_progress_event_size)
+#define interrupted_pos(rchan) ((rchan)->scheme.locking.interrupted_pos)
+#define interrupting_size(rchan) ((rchan)->scheme.locking.interrupting_size)
+#define channel_lock(rchan) ((rchan)->scheme.locking.lock)
+
+
+/**
+ *	calc_time_delta - utility function for time delta calculation
+ *	@now: current time
+ *	@start: start time
+ *
+ *	Returns the time delta produced by subtracting start time from now.
+ */
+static inline u32
+calc_time_delta(struct timeval *now,
+		struct timeval *start)
+{
+	return (now->tv_sec - start->tv_sec) * 1000000
+		+ (now->tv_usec - start->tv_usec);
+}
+
+/**
+ *	recalc_time_delta - utility function for time delta recalculation
+ *	@now: current time
+ *	@new_delta: the new time delta calculated
+ *	@cpu: the associated CPU id
+ */
+static inline void
+recalc_time_delta(struct timeval *now,
+		  u32 *new_delta,
+		  struct rchan *rchan)
+{
+	if (using_tsc(rchan) == 0)
+		*new_delta = calc_time_delta(now, &rchan->buf_start_time);
+}
+
+/**
+ *	have_cmpxchg - does this architecture have a cmpxchg?
+ *
+ *	Returns 1 if this architecture has a cmpxchg useable by
+ *	the lockless scheme, 0 otherwise.
+ */
+static inline int
+have_cmpxchg(void)
+{
+#if defined(__HAVE_ARCH_CMPXCHG)
+	return 1;
+#else
+	return 0;
+#endif
+}
+
+/**
+ *	relay_write_direct - write data directly into destination buffer
+ */
+#define relay_write_direct(DEST, SRC, SIZE) \
+do\
+{\
+   memcpy(DEST, SRC, SIZE);\
+   DEST += SIZE;\
+} while (0);
+
+/**
+ *	relay_lock_channel - lock the relay channel if applicable
+ *
+ *	This macro only affects the locking scheme.  If the locking scheme
+ *	is in use and the channel usage is SMP, does a local_irq_save.  If the
+ *	locking sheme is in use and the channel usage is GLOBAL, uses
+ *	spin_lock_irqsave.  FLAGS is initialized to 0 since we know that
+ *	it is being initialized prior to use and we avoid the compiler warning.
+ */
+#define relay_lock_channel(RCHAN, FLAGS) \
+do\
+{\
+   FLAGS = 0;\
+   if (using_locking(RCHAN)) {\
+      if (usage_smp(RCHAN)) {\
+         local_irq_save(FLAGS); \
+      } else {\
+         spin_lock_irqsave(&(RCHAN)->scheme.locking.lock, FLAGS); \
+      }\
+   }\
+} while (0);
+
+/**
+ *	relay_unlock_channel - unlock the relay channel if applicable
+ *
+ *	This macro only affects the locking scheme.  See relay_lock_channel.
+ */
+#define relay_unlock_channel(RCHAN, FLAGS) \
+do\
+{\
+   if (using_locking(RCHAN)) {\
+      if (usage_smp(RCHAN)) {\
+         local_irq_restore(FLAGS); \
+      } else {\
+         spin_unlock_irqrestore(&(RCHAN)->scheme.locking.lock, FLAGS); \
+      }\
+   }\
+} while (0);
+
+/*
+ * Define cmpxchg if we don't have it
+ */
+#ifndef __HAVE_ARCH_CMPXCHG
+#define cmpxchg(p,o,n) 0
+#endif
+
+/*
+ * High-level relayfs kernel API, fs/relayfs/relay.c
+ */
+extern int
+relay_open(const char *chanpath,
+	   int bufsize,
+	   int nbufs,
+	   u32 flags,
+	   struct rchan_callbacks *channel_callbacks,
+	   u32 start_reserve,
+	   u32 end_reserve,
+	   u32 rchan_start_reserve,
+	   u32 resize_min,
+	   u32 resize_max,
+	   int mode,
+	   char *init_buf,
+	   u32 init_buf_size);
+
+extern int
+relay_close(int rchan_id);
+
+extern int
+relay_write(int rchan_id,
+	    const void *data_ptr,
+	    size_t count,
+	    int td_offset,
+	    void **wrote_pos);
+
+extern ssize_t
+relay_read(struct rchan_reader *reader,
+	   char *buf,
+	   size_t count,
+	   int wait,
+	   u32 *actual_read_offset,
+	   u32 *new_offset);
+
+extern int
+relay_discard_init_buf(int rchan_id);
+
+extern struct rchan_reader *
+add_rchan_reader(int rchan_id, int autoconsume);
+
+extern int
+remove_rchan_reader(struct rchan_reader *reader);
+
+extern struct rchan_reader *
+add_map_reader(int rchan_id);
+
+extern int
+remove_map_reader(struct rchan_reader *reader);
+
+extern int
+relay_info(int rchan_id, struct rchan_info *rchan_info);
+
+extern void
+relay_buffers_consumed(struct rchan_reader *reader, u32 buffers_consumed);
+
+extern void
+relay_bytes_consumed(struct rchan_reader *reader, u32 bytes_consumed, u32 read_offset);
+
+extern ssize_t
+relay_bytes_avail(struct rchan_reader *reader);
+
+extern int
+relay_realloc_buffer(int rchan_id, u32 new_nbufs, int in_background);
+
+extern int
+relay_replace_buffer(int rchan_id);
+
+extern int
+rchan_empty(struct rchan_reader *reader);
+
+extern int
+rchan_full(struct rchan_reader *reader);
+
+extern void
+update_readers_consumed(struct rchan *rchan, u32 bufs_consumed, u32 bytes_consumed);
+
+extern int
+__relay_mmap_buffer(struct rchan *rchan, struct vm_area_struct *vma);
+
+extern struct rchan_reader *
+__add_rchan_reader(struct rchan *rchan, struct file *filp, int auto_consume, int map_reader);
+
+extern void
+__remove_rchan_reader(struct rchan_reader *reader);
+
+/*
+ * Low-level relayfs kernel API, fs/relayfs/relay.c
+ */
+extern struct rchan *
+rchan_get(int rchan_id);
+
+extern void
+rchan_put(struct rchan *rchan);
+
+extern char *
+relay_reserve(struct rchan *rchan,
+	      u32 data_len,
+	      struct timeval *time_stamp,
+	      u32 *time_delta,
+	      int *errcode,
+	      int *interrupting);
+
+extern void
+relay_commit(struct rchan *rchan,
+	     char *from,
+	     u32 len,
+	     int reserve_code,
+	     int interrupting);
+
+extern u32
+relay_get_offset(struct rchan *rchan, u32 *max_offset);
+
+extern int
+relay_reset(int rchan_id);
+
+/*
+ * VFS functions, fs/relayfs/inode.c
+ */
+extern int
+relayfs_create_dir(const char *name,
+		   struct dentry *parent,
+		   struct dentry **dentry);
+
+extern int
+relayfs_create_file(const char * name,
+		    struct dentry *parent,
+		    struct dentry **dentry,
+		    void * data,
+		    int mode);
+
+extern int
+relayfs_remove_file(struct dentry *dentry);
+
+extern int
+reset_index(struct rchan *rchan, u32 old_index);
+
+
+/*
+ * klog functions, fs/relayfs/klog.c
+ */
+extern int
+create_klog_channel(void);
+
+extern int
+remove_klog_channel(void);
+
+/*
+ * Scheme-specific channel ops
+ */
+struct relay_ops
+{
+	char * (*reserve) (struct rchan *rchan,
+			   u32 slot_len,
+			   struct timeval *time_stamp,
+			   u32 *tsc,
+			   int * errcode,
+			   int * interrupting);
+	
+	void (*commit) (struct rchan *rchan,
+			char *from,
+			u32 len,
+			int deliver,
+			int interrupting);
+
+	u32 (*get_offset) (struct rchan *rchan,
+			   u32 *max_offset);
+	
+	void (*resume) (struct rchan *rchan);
+	void (*finalize) (struct rchan *rchan);
+	void (*reset) (struct rchan *rchan,
+		       int init);
+	int (*reset_index) (struct rchan *rchan,
+			    u32 old_index);
+};
+
+#endif /* _LINUX_RELAYFS_FS_H */
+
+
+
+
+

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