--- /dev/null
+/*
+ * linux/include/linux/ltt-relay.h
+ *
+ * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
+ * Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com)
+ * Copyright (C) 2008 - Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
+ *
+ * CONFIG_RELAY definitions and declarations
+ */
+
+#ifndef _LINUX_LTT_RELAY_H
+#define _LINUX_LTT_RELAY_H
+
+//ust// #include <linux/types.h>
+//ust// #include <linux/sched.h>
+//ust// #include <linux/timer.h>
+//ust// #include <linux/wait.h>
+//ust// #include <linux/list.h>
+//ust// #include <linux/fs.h>
+//ust// #include <linux/poll.h>
+//ust// #include <linux/kref.h>
+//ust// #include <linux/mm.h>
+//ust// #include <linux/ltt-core.h>
+#include "kref.h"
+#include "list.h"
+
+/* Needs a _much_ better name... */
+#define FIX_SIZE(x) ((((x) - 1) & PAGE_MASK) + PAGE_SIZE)
+
+/*
+ * Tracks changes to rchan/rchan_buf structs
+ */
+#define LTT_RELAY_CHANNEL_VERSION 8
+
+struct rchan_buf;
+
+struct buf_page {
+ struct page *page;
+ struct rchan_buf *buf; /* buffer the page belongs to */
+ size_t offset; /* page offset in the buffer */
+ struct list_head list; /* buffer linked list */
+};
+
+/*
+ * Per-cpu relay channel buffer
+ */
+struct rchan_buf {
+ struct rchan *chan; /* associated channel */
+//ust// wait_queue_head_t read_wait; /* reader wait queue */
+//ust// struct timer_list timer; /* reader wake-up timer */
+//ust// struct dentry *dentry; /* channel file dentry */
+ struct kref kref; /* channel buffer refcount */
+//ust// struct list_head pages; /* list of buffer pages */
+ void *buf_data; //ust//
+ size_t buf_size;
+//ust// struct buf_page *wpage; /* current write page (cache) */
+//ust// struct buf_page *hpage[2]; /* current subbuf header page (cache) */
+//ust// struct buf_page *rpage; /* current subbuf read page (cache) */
+//ust// unsigned int page_count; /* number of current buffer pages */
+ unsigned int finalized; /* buffer has been finalized */
+//ust// unsigned int cpu; /* this buf's cpu */
+ int shmid; /* the shmid of the buffer data pages */
+} ____cacheline_aligned;
+
+/*
+ * Relay channel data structure
+ */
+struct rchan {
+ 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 */
+//ust// struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */
+ struct rchan_buf *buf;
+ struct list_head list; /* for channel list */
+ struct dentry *parent; /* parent dentry passed to open */
+ int subbuf_size_order; /* order of sub-buffer size */
+//ust// char base_filename[NAME_MAX]; /* saved base filename */
+};
+
+/*
+ * Relay channel client callbacks
+ */
+struct rchan_callbacks {
+ /*
+ * 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
+ *
+ * The client should return 1 to continue logging, 0 to stop
+ * logging.
+ *
+ * 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.
+ *
+ * NOTE: the client can reserve bytes at the beginning of the new
+ * sub-buffer by calling subbuf_start_reserve() in this callback.
+ */
+ int (*subbuf_start) (struct rchan_buf *buf,
+ void *subbuf,
+ void *prev_subbuf,
+ size_t prev_padding);
+
+ /*
+ * create_buf_file - create file to represent a relay 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
+ *
+ * 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 relay, the parent must also exist in
+ * that filesystem.
+ *
+ * The callback should return the dentry of the file created
+ * to represent the relay buffer.
+ *
+ * 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 more info.
+ */
+ struct dentry *(*create_buf_file)(const char *filename,
+ struct dentry *parent,
+ int mode,
+ struct rchan_buf *buf);
+
+ /*
+ * remove_buf_file - remove file representing a relay channel buffer
+ * @dentry: the dentry of the file to remove
+ *
+ * Called during relay_close(), once for each per-cpu buffer,
+ * to allow the client to remove a file used to represent a
+ * channel buffer.
+ *
+ * The callback should return 0 if successful, negative if not.
+ */
+//ust// int (*remove_buf_file)(struct rchan_buf *buf);
+};
+
+extern struct buf_page *ltt_relay_find_prev_page(struct rchan_buf *buf,
+ struct buf_page *page, size_t offset, ssize_t diff_offset);
+
+extern struct buf_page *ltt_relay_find_next_page(struct rchan_buf *buf,
+ struct buf_page *page, size_t offset, ssize_t diff_offset);
+
+extern void _ltt_relay_write(struct rchan_buf *buf, size_t offset,
+ const void *src, size_t len, ssize_t cpy);
+
+extern int ltt_relay_read(struct rchan_buf *buf, size_t offset,
+ void *dest, size_t len);
+
+extern struct buf_page *ltt_relay_read_get_page(struct rchan_buf *buf,
+ size_t offset);
+
+/*
+ * Return the address where a given offset is located.
+ * Should be used to get the current subbuffer header pointer. Given we know
+ * it's never on a page boundary, it's safe to write directly to this address,
+ * as long as the write is never bigger than a page size.
+ */
+extern void *ltt_relay_offset_address(struct rchan_buf *buf,
+ size_t offset);
+
+/*
+ * Find the page containing "offset". Cache it if it is after the currently
+ * cached page.
+ */
+static inline struct buf_page *ltt_relay_cache_page(struct rchan_buf *buf,
+ struct buf_page **page_cache,
+ struct buf_page *page, size_t offset)
+{
+ ssize_t diff_offset;
+ ssize_t half_buf_size = buf->chan->alloc_size >> 1;
+
+ /*
+ * Make sure this is the page we want to write into. The current
+ * page is changed concurrently by other writers. [wrh]page are
+ * used as a cache remembering the last page written
+ * to/read/looked up for header address. No synchronization;
+ * could have to find the previous page is a nested write
+ * occured. Finding the right page is done by comparing the
+ * dest_offset with the buf_page offsets.
+ * When at the exact opposite of the buffer, bias towards forward search
+ * because it will be cached.
+ */
+
+ diff_offset = (ssize_t)offset - (ssize_t)page->offset;
+ if (diff_offset <= -(ssize_t)half_buf_size)
+ diff_offset += buf->chan->alloc_size;
+ else if (diff_offset > half_buf_size)
+ diff_offset -= buf->chan->alloc_size;
+
+ if (unlikely(diff_offset >= (ssize_t)PAGE_SIZE)) {
+ page = ltt_relay_find_next_page(buf, page, offset, diff_offset);
+ *page_cache = page;
+ } else if (unlikely(diff_offset < 0)) {
+ page = ltt_relay_find_prev_page(buf, page, offset, diff_offset);
+ }
+ return page;
+}
+
+//ust// #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
+ static inline void ltt_relay_do_copy(void *dest, const void *src, size_t len)
+{
+ switch (len) {
+ case 0: break;
+ case 1: *(u8 *)dest = *(const u8 *)src;
+ break;
+ case 2: *(u16 *)dest = *(const u16 *)src;
+ break;
+ case 4: *(u32 *)dest = *(const u32 *)src;
+ break;
+//ust// #if (BITS_PER_LONG == 64)
+ case 8: *(u64 *)dest = *(const u64 *)src;
+ break;
+//ust// #endif
+ default:
+ memcpy(dest, src, len);
+ }
+}
+//ust// #else
+//ust// /*
+//ust// * Returns whether the dest and src addresses are aligned on
+//ust// * min(sizeof(void *), len). Call this with statically known len for efficiency.
+//ust// */
+//ust// static inline int addr_aligned(const void *dest, const void *src, size_t len)
+//ust// {
+//ust// if (ltt_align((size_t)dest, len))
+//ust// return 0;
+//ust// if (ltt_align((size_t)src, len))
+//ust// return 0;
+//ust// return 1;
+//ust// }
+//ust//
+//ust// static inline void ltt_relay_do_copy(void *dest, const void *src, size_t len)
+//ust// {
+//ust// switch (len) {
+//ust// case 0: break;
+//ust// case 1: *(u8 *)dest = *(const u8 *)src;
+//ust// break;
+//ust// case 2: if (unlikely(!addr_aligned(dest, src, 2)))
+//ust// goto memcpy_fallback;
+//ust// *(u16 *)dest = *(const u16 *)src;
+//ust// break;
+//ust// case 4: if (unlikely(!addr_aligned(dest, src, 4)))
+//ust// goto memcpy_fallback;
+//ust// *(u32 *)dest = *(const u32 *)src;
+//ust// break;
+//ust// #if (BITS_PER_LONG == 64)
+//ust// case 8: if (unlikely(!addr_aligned(dest, src, 8)))
+//ust// goto memcpy_fallback;
+//ust// *(u64 *)dest = *(const u64 *)src;
+//ust// break;
+//ust// #endif
+//ust// default:
+//ust// goto memcpy_fallback;
+//ust// }
+//ust// return;
+//ust// memcpy_fallback:
+//ust// memcpy(dest, src, len);
+//ust// }
+//ust// #endif
+
+static inline int ltt_relay_write(struct rchan_buf *buf, size_t offset,
+ const void *src, size_t len)
+{
+//ust// struct buf_page *page;
+//ust// ssize_t pagecpy;
+//ust//
+//ust// offset &= buf->chan->alloc_size - 1;
+//ust// page = buf->wpage;
+//ust//
+//ust// page = ltt_relay_cache_page(buf, &buf->wpage, page, offset);
+//ust// pagecpy = min_t(size_t, len, PAGE_SIZE - (offset & ~PAGE_MASK));
+//ust// ltt_relay_do_copy(page_address(page->page)
+//ust// + (offset & ~PAGE_MASK), src, pagecpy);
+//ust//
+//ust// if (unlikely(len != pagecpy))
+//ust// _ltt_relay_write(buf, offset, src, len, page, pagecpy);
+//ust// return len;
+
+
+ size_t cpy;
+ cpy = min_t(size_t, len, buf->buf_size - offset);
+ ltt_relay_do_copy(buf->buf_data + offset, src, cpy);
+
+ if (unlikely(len != cpy))
+ _ltt_relay_write(buf, offset, src, len, cpy);
+ return len;
+}
+
+/*
+ * CONFIG_LTT_RELAY kernel API, ltt/ltt-relay-alloc.c
+ */
+
+struct rchan *ltt_relay_open(const char *base_filename,
+ struct dentry *parent,
+ size_t subbuf_size,
+ size_t n_subbufs,
+ void *private_data);
+extern void ltt_relay_close(struct rchan *chan);
+
+/*
+ * exported ltt_relay file operations, ltt/ltt-relay-alloc.c
+ */
+extern const struct file_operations ltt_relay_file_operations;
+
+
+/* LTTng lockless logging buffer info */
+struct ltt_channel_buf_struct {
+ /* First 32 bytes cache-hot cacheline */
+ local_t offset; /* Current offset in the buffer */
+//ust// local_t *commit_count; /* Commit count per sub-buffer */
+ atomic_long_t consumed; /*
+ * Current offset in the buffer
+ * standard atomic access (shared)
+ */
+ unsigned long last_tsc; /*
+ * Last timestamp written in the buffer.
+ */
+ /* End of first 32 bytes cacheline */
+ atomic_long_t active_readers; /*
+ * Active readers count
+ * standard atomic access (shared)
+ */
+ local_t events_lost;
+ local_t corrupted_subbuffers;
+//ust// spinlock_t full_lock; /*
+//ust// * buffer full condition spinlock, only
+//ust// * for userspace tracing blocking mode
+//ust// * synchronization with reader.
+//ust// */
+//ust// wait_queue_head_t write_wait; /*
+//ust// * Wait queue for blocking user space
+//ust// * writers
+//ust// */
+//ust// atomic_t wakeup_readers; /* Boolean : wakeup readers waiting ? */
+ /* one byte is written to this pipe when data is available, in order
+ to wake the consumer */
+ /* portability: Single byte writes must be as quick as possible. The kernel-side
+ buffer must be large enough so the writer doesn't block. From the pipe(7)
+ man page: Since linux 2.6.11, the pipe capacity is 65536 bytes. */
+ int data_ready_fd_write;
+ /* the reading end of the pipe */
+ int data_ready_fd_read;
+
+ /* commit count per subbuffer; must be at end of struct */
+ local_t commit_count[0] ____cacheline_aligned;
+} ____cacheline_aligned;
+
+int ltt_do_get_subbuf(struct rchan_buf *buf, struct ltt_channel_buf_struct *ltt_buf, long *pconsumed_old);
+
+int ltt_do_put_subbuf(struct rchan_buf *buf, struct ltt_channel_buf_struct *ltt_buf, u32 uconsumed_old);
+
+
+#endif /* _LINUX_LTT_RELAY_H */
+
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