* 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
#include <linux/wait.h>
#include <linux/list.h>
#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/kref.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
-
-/*
- * Flags for needs_resize() callback
+ * Tracks changes to rchan/rchan_buf structs
*/
-#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
+#define RELAYFS_CHANNEL_VERSION 6
/*
- * Values for fileop_notify() callback
+ * Per-cpu relay channel buffer
*/
-enum relay_fileop
+struct rchan_buf
{
- RELAY_FILE_OPEN,
- RELAY_FILE_CLOSE,
- RELAY_FILE_MAP,
- RELAY_FILE_UNMAP
-};
+ void *start; /* start of channel buffer */
+ void *data; /* start of current sub-buffer */
+ size_t offset; /* current offset into sub-buffer */
+ size_t subbufs_produced; /* count of sub-buffers produced */
+ size_t subbufs_consumed; /* count of sub-buffers consumed */
+ struct rchan *chan; /* associated channel */
+ wait_queue_head_t read_wait; /* reader wait queue */
+ struct work_struct wake_readers; /* reader wake-up work struct */
+ struct dentry *dentry; /* channel file dentry */
+ struct kref kref; /* channel buffer refcount */
+ struct page **page_array; /* array of current buffer pages */
+ unsigned int page_count; /* number of current buffer pages */
+ unsigned int finalized; /* buffer has been finalized */
+ size_t *padding; /* padding counts per sub-buffer */
+ size_t prev_padding; /* temporary variable */
+ size_t bytes_consumed; /* bytes consumed in cur read subbuf */
+ unsigned int cpu; /* this buf's cpu */
+} ____cacheline_aligned;
/*
- * Data structure returned by relay_info()
+ * Relay channel data structure
*/
-struct rchan_info
+struct rchan
{
- 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 */
+ u32 version; /* the version of this struct */
+ size_t subbuf_size; /* sub-buffer size */
+ size_t n_subbufs; /* number of sub-buffers per buffer */
+ size_t alloc_size; /* total buffer size allocated */
+ struct rchan_callbacks *cb; /* client callbacks */
+ struct kref kref; /* channel refcount */
+ void *private_data; /* for user-defined data */
+ size_t last_toobig; /* tried to log event > subbuf size */
+ struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */
};
/*
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
+ * subbuf_start - called on buffer-switch to a new sub-buffer
+ * @buf: the channel buffer containing the new sub-buffer
+ * @subbuf: the start of the new sub-buffer
+ * @prev_subbuf: the start of the previous sub-buffer
+ * @prev_padding: unused space at the end of previous sub-buffer
*
- * Return value should be the number of bytes written by the client.
+ * The client should return 1 to continue logging, 0 to stop
+ * logging.
*
- * 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
+ * NOTE: subbuf_start will also be invoked when the buffer is
+ * created, so that the first sub-buffer can be initialized
+ * if necessary. In this case, prev_subbuf will be NULL.
*
- * Return value should be the number of bytes written by the client.
- *
- * See Documentation/filesystems/relayfs.txt for details.
+ * NOTE: the client can reserve bytes at the beginning of the new
+ * sub-buffer by calling subbuf_start_reserve() in this callback.
*/
- int (*buffer_end) (int rchan_id,
- char *current_write_pos,
- char *end_of_buffer,
- struct timeval end_time,
- u32 end_tsc,
- int using_tsc);
+ int (*subbuf_start) (struct rchan_buf *buf,
+ void *subbuf,
+ void *prev_subbuf,
+ size_t prev_padding);
/*
- * 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
+ * buf_mapped - relayfs buffer mmap notification
+ * @buf: the channel buffer
+ * @filp: relayfs file pointer
*
- * See Documentation/filesystems/relayfs.txt for details.
+ * Called when a relayfs file is successfully mmapped
*/
- void (*deliver) (int rchan_id, char *from, u32 len);
+ void (*buf_mapped)(struct rchan_buf *buf,
+ struct file *filp);
/*
- * 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
+ * buf_unmapped - relayfs buffer unmap notification
+ * @buf: the channel buffer
+ * @filp: relayfs file pointer
*
- * See Documentation/filesystems/relayfs.txt for details.
+ * Called when a relayfs file is successfully unmapped
*/
- void (*user_deliver) (int rchan_id, char *from, u32 len);
-
+ void (*buf_unmapped)(struct rchan_buf *buf,
+ struct file *filp);
/*
- * 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
+ * create_buf_file - create file to represent a relayfs channel buffer
+ * @filename: the name of the file to create
+ * @parent: the parent of the file to create
+ * @mode: the mode of the file to create
+ * @buf: the channel buffer
+ * @is_global: outparam - set non-zero if the buffer should be global
*
- * 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
+ * Called during relay_open(), once for each per-cpu buffer,
+ * to allow the client to create a file to be used to
+ * represent the corresponding channel buffer. If the file is
+ * created outside of relayfs, the parent must also exist in
+ * that filesystem.
+ *
+ * The callback should return the dentry of the file created
+ * to represent the relay buffer.
*
- * The return value can direct the outcome of the operation.
+ * Setting the is_global outparam to a non-zero value will
+ * cause relay_open() to create a single global buffer rather
+ * than the default set of per-cpu buffers.
*
- * See Documentation/filesystems/relayfs.txt for details.
+ * See Documentation/filesystems/relayfs.txt for more info.
*/
- int (*fileop_notify)(int rchan_id,
- struct file *filp,
- enum relay_fileop fileop);
+ struct dentry *(*create_buf_file)(const char *filename,
+ struct dentry *parent,
+ int mode,
+ struct rchan_buf *buf,
+ int *is_global);
/*
- * ioctl - called in ioctl context from userspace
- * @rchan_id: the channel id
- * @cmd: ioctl cmd
- * @arg: ioctl cmd arg
+ * remove_buf_file - remove file representing a relayfs channel buffer
+ * @dentry: the dentry of the file to remove
*
- * The return value is returned as the value from the ioctl call.
+ * Called during relay_close(), once for each per-cpu buffer,
+ * to allow the client to remove a file used to represent a
+ * channel buffer.
*
- * See Documentation/filesystems/relayfs.txt for details.
+ * The callback should return 0 if successful, negative if not.
*/
- int (*ioctl) (int rchan_id, unsigned int cmd, unsigned long arg);
+ int (*remove_buf_file)(struct dentry *dentry);
};
/*
- * Lockless scheme-specific data
+ * relayfs kernel API, fs/relayfs/relay.c
*/
-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 */
-
- 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)
+struct rchan *relay_open(const char *base_filename,
+ struct dentry *parent,
+ size_t subbuf_size,
+ size_t n_subbufs,
+ struct rchan_callbacks *cb);
+extern void relay_close(struct rchan *chan);
+extern void relay_flush(struct rchan *chan);
+extern void relay_subbufs_consumed(struct rchan *chan,
+ unsigned int cpu,
+ size_t consumed);
+extern void relay_reset(struct rchan *chan);
+extern int relay_buf_full(struct rchan_buf *buf);
+
+extern size_t relay_switch_subbuf(struct rchan_buf *buf,
+ size_t length);
+extern struct dentry *relayfs_create_dir(const char *name,
+ struct dentry *parent);
+extern int relayfs_remove_dir(struct dentry *dentry);
+extern struct dentry *relayfs_create_file(const char *name,
+ struct dentry *parent,
+ int mode,
+ struct file_operations *fops,
+ void *data);
+extern int relayfs_remove_file(struct dentry *dentry);
/**
- * calc_time_delta - utility function for time delta calculation
- * @now: current time
- * @start: start time
+ * relay_write - write data into the channel
+ * @chan: relay channel
+ * @data: data to be written
+ * @length: number of bytes to write
+ *
+ * Writes data into the current cpu's channel buffer.
*
- * Returns the time delta produced by subtracting start time from now.
+ * Protects the buffer by disabling interrupts. Use this
+ * if you might be logging from interrupt context. Try
+ * __relay_write() if you know you won't be logging from
+ * interrupt context.
*/
-static inline u32
-calc_time_delta(struct timeval *now,
- struct timeval *start)
+static inline void relay_write(struct rchan *chan,
+ const void *data,
+ size_t length)
{
- return (now->tv_sec - start->tv_sec) * 1000000
- + (now->tv_usec - start->tv_usec);
+ unsigned long flags;
+ struct rchan_buf *buf;
+
+ local_irq_save(flags);
+ buf = chan->buf[smp_processor_id()];
+ if (unlikely(buf->offset + length > chan->subbuf_size))
+ length = relay_switch_subbuf(buf, length);
+ memcpy(buf->data + buf->offset, data, length);
+ buf->offset += length;
+ local_irq_restore(flags);
}
/**
- * recalc_time_delta - utility function for time delta recalculation
- * @now: current time
- * @new_delta: the new time delta calculated
- * @cpu: the associated CPU id
+ * __relay_write - write data into the channel
+ * @chan: relay channel
+ * @data: data to be written
+ * @length: number of bytes to write
+ *
+ * Writes data into the current cpu's channel buffer.
+ *
+ * Protects the buffer by disabling preemption. Use
+ * relay_write() if you might be logging from interrupt
+ * context.
*/
-static inline void
-recalc_time_delta(struct timeval *now,
- u32 *new_delta,
- struct rchan *rchan)
+static inline void __relay_write(struct rchan *chan,
+ const void *data,
+ size_t length)
{
- if (using_tsc(rchan) == 0)
- *new_delta = calc_time_delta(now, &rchan->buf_start_time);
+ struct rchan_buf *buf;
+
+ buf = chan->buf[get_cpu()];
+ if (unlikely(buf->offset + length > buf->chan->subbuf_size))
+ length = relay_switch_subbuf(buf, length);
+ memcpy(buf->data + buf->offset, data, length);
+ buf->offset += length;
+ put_cpu();
}
/**
- * have_cmpxchg - does this architecture have a cmpxchg?
+ * relay_reserve - reserve slot in channel buffer
+ * @chan: relay channel
+ * @length: number of bytes to reserve
+ *
+ * Returns pointer to reserved slot, NULL if full.
*
- * Returns 1 if this architecture has a cmpxchg useable by
- * the lockless scheme, 0 otherwise.
+ * Reserves a slot in the current cpu's channel buffer.
+ * Does not protect the buffer at all - caller must provide
+ * appropriate synchronization.
*/
-static inline int
-have_cmpxchg(void)
+static inline void *relay_reserve(struct rchan *chan, size_t length)
{
-#if defined(__HAVE_ARCH_CMPXCHG)
- return 1;
-#else
- return 0;
-#endif
+ void *reserved;
+ struct rchan_buf *buf = chan->buf[smp_processor_id()];
+
+ if (unlikely(buf->offset + length > buf->chan->subbuf_size)) {
+ length = relay_switch_subbuf(buf, length);
+ if (!length)
+ return NULL;
+ }
+ reserved = buf->data + buf->offset;
+ buf->offset += length;
+
+ return reserved;
}
/**
- * 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
+ * subbuf_start_reserve - reserve bytes at the start of a sub-buffer
+ * @buf: relay channel buffer
+ * @length: number of bytes to reserve
*
- * 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);
-
-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
+ * Helper function used to reserve bytes at the beginning of
+ * a sub-buffer in the subbuf_start() callback.
*/
-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);
+static inline void subbuf_start_reserve(struct rchan_buf *buf,
+ size_t length)
+{
+ BUG_ON(length >= buf->chan->subbuf_size - 1);
+ buf->offset = length;
+}
/*
- * Scheme-specific channel ops
+ * exported relay file operations, fs/relayfs/inode.c
*/
-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);
-};
+extern struct file_operations relay_file_operations;
#endif /* _LINUX_RELAYFS_FS_H */
-
-
-
-
git://git.onelab.eu / linux-2.6.git / blobdiff