1c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/* 2c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * linux/include/linux/relay.h 3c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 4c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp 5c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com) 6c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 7c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * CONFIG_RELAY definitions and declarations 8c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 9c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 10c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#ifndef _LINUX_RELAY_H 11c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#define _LINUX_RELAY_H 12c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 13c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#include <linux/types.h> 14c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#include <linux/sched.h> 15c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#include <linux/wait.h> 16c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#include <linux/list.h> 17c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#include <linux/fs.h> 18c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#include <linux/poll.h> 19c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#include <linux/kref.h> 20c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 21c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/* Needs a _much_ better name... */ 22c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#define FIX_SIZE(x) ((((x) - 1) & PAGE_MASK) + PAGE_SIZE) 23c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 24c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/* 25c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Tracks changes to rchan/rchan_buf structs 26c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 27c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#define RELAYFS_CHANNEL_VERSION 6 28c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 29c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/* 30c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Per-cpu relay channel buffer 31c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 32c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Querustruct rchan_buf 33c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru{ 34c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru void *start; /* start of channel buffer */ 35c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru void *data; /* start of current sub-buffer */ 36c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t offset; /* current offset into sub-buffer */ 37c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t subbufs_produced; /* count of sub-buffers produced */ 38c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t subbufs_consumed; /* count of sub-buffers consumed */ 39c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct rchan *chan; /* associated channel */ 40c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru wait_queue_head_t read_wait; /* reader wait queue */ 41c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct work_struct wake_readers; /* reader wake-up work struct */ 42c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct dentry *dentry; /* channel file dentry */ 43c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct kref kref; /* channel buffer refcount */ 44c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct page **page_array; /* array of current buffer pages */ 45c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru unsigned int page_count; /* number of current buffer pages */ 46c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru unsigned int finalized; /* buffer has been finalized */ 47c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t *padding; /* padding counts per sub-buffer */ 48c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t prev_padding; /* temporary variable */ 49c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t bytes_consumed; /* bytes consumed in cur read subbuf */ 50c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru unsigned int cpu; /* this buf's cpu */ 51c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru} ____cacheline_aligned; 52c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 53c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/* 54c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Relay channel data structure 55c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 56c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Querustruct rchan 57c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru{ 58c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru u32 version; /* the version of this struct */ 59c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t subbuf_size; /* sub-buffer size */ 60c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t n_subbufs; /* number of sub-buffers per buffer */ 61c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t alloc_size; /* total buffer size allocated */ 62c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct rchan_callbacks *cb; /* client callbacks */ 63c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct kref kref; /* channel refcount */ 64c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru void *private_data; /* for user-defined data */ 65c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t last_toobig; /* tried to log event > subbuf size */ 66c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */ 67c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru}; 68c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 69c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/* 70c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Relay channel client callbacks 71c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 72c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Querustruct rchan_callbacks 73c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru{ 74c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru /* 75c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * subbuf_start - called on buffer-switch to a new sub-buffer 76c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @buf: the channel buffer containing the new sub-buffer 77c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @subbuf: the start of the new sub-buffer 78c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @prev_subbuf: the start of the previous sub-buffer 79c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @prev_padding: unused space at the end of previous sub-buffer 80c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 81c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * The client should return 1 to continue logging, 0 to stop 82c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * logging. 83c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 84c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * NOTE: subbuf_start will also be invoked when the buffer is 85c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * created, so that the first sub-buffer can be initialized 86c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * if necessary. In this case, prev_subbuf will be NULL. 87c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 88c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * NOTE: the client can reserve bytes at the beginning of the new 89c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * sub-buffer by calling subbuf_start_reserve() in this callback. 90c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 91c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru int (*subbuf_start) (struct rchan_buf *buf, 92c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru void *subbuf, 93c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru void *prev_subbuf, 94c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t prev_padding); 95c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 96c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru /* 97c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * buf_mapped - relay buffer mmap notification 98c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @buf: the channel buffer 99c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @filp: relay file pointer 100c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 101c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Called when a relay file is successfully mmapped 102c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 103c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru void (*buf_mapped)(struct rchan_buf *buf, 104c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct file *filp); 105c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 106c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru /* 107c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * buf_unmapped - relay buffer unmap notification 108c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @buf: the channel buffer 109c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @filp: relay file pointer 110c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 111c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Called when a relay file is successfully unmapped 112c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 113c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru void (*buf_unmapped)(struct rchan_buf *buf, 114c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct file *filp); 115c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru /* 116c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * create_buf_file - create file to represent a relay channel buffer 117c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @filename: the name of the file to create 118c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @parent: the parent of the file to create 119c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @mode: the mode of the file to create 120c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @buf: the channel buffer 121c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @is_global: outparam - set non-zero if the buffer should be global 122c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 123c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Called during relay_open(), once for each per-cpu buffer, 124c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * to allow the client to create a file to be used to 125c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * represent the corresponding channel buffer. If the file is 126c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * created outside of relay, the parent must also exist in 127c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * that filesystem. 128c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 129c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * The callback should return the dentry of the file created 130c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * to represent the relay buffer. 131c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 132c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Setting the is_global outparam to a non-zero value will 133c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * cause relay_open() to create a single global buffer rather 134c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * than the default set of per-cpu buffers. 135c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 136c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * See Documentation/filesystems/relayfs.txt for more info. 137c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 138c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct dentry *(*create_buf_file)(const char *filename, 139c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct dentry *parent, 140c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru int mode, 141c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct rchan_buf *buf, 142c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru int *is_global); 143c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 144c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru /* 145c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * remove_buf_file - remove file representing a relay channel buffer 146c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @dentry: the dentry of the file to remove 147c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 148c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Called during relay_close(), once for each per-cpu buffer, 149c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * to allow the client to remove a file used to represent a 150c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * channel buffer. 151c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 152c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * The callback should return 0 if successful, negative if not. 153c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 154c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru int (*remove_buf_file)(struct dentry *dentry); 155c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru}; 156c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 157c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/* 158c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * CONFIG_RELAY kernel API, kernel/relay.c 159c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 160c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 161c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Querustruct rchan *relay_open(const char *base_filename, 162c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct dentry *parent, 163c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t subbuf_size, 164c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t n_subbufs, 165c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct rchan_callbacks *cb); 166c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queruextern void relay_close(struct rchan *chan); 167c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queruextern void relay_flush(struct rchan *chan); 168c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queruextern void relay_subbufs_consumed(struct rchan *chan, 169c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru unsigned int cpu, 170c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t consumed); 171c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queruextern void relay_reset(struct rchan *chan); 172c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queruextern int relay_buf_full(struct rchan_buf *buf); 173c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 174c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queruextern size_t relay_switch_subbuf(struct rchan_buf *buf, 175c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t length); 176c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 177c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/** 178c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * relay_write - write data into the channel 179c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @chan: relay channel 180c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @data: data to be written 181c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @length: number of bytes to write 182c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 183c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Writes data into the current cpu's channel buffer. 184c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 185c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Protects the buffer by disabling interrupts. Use this 186c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * if you might be logging from interrupt context. Try 187c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * __relay_write() if you know you won't be logging from 188c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * interrupt context. 189c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 190c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Querustatic inline void relay_write(struct rchan *chan, 191c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru const void *data, 192c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t length) 193c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru{ 194c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru unsigned long flags; 195c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct rchan_buf *buf; 196c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 197c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru local_irq_save(flags); 198c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru buf = chan->buf[smp_processor_id()]; 199c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru if (unlikely(buf->offset + length > chan->subbuf_size)) 200c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru length = relay_switch_subbuf(buf, length); 201c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru memcpy(buf->data + buf->offset, data, length); 202c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru buf->offset += length; 203c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru local_irq_restore(flags); 204c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru} 205c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 206c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/** 207c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * __relay_write - write data into the channel 208c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @chan: relay channel 209c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @data: data to be written 210c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @length: number of bytes to write 211c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 212c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Writes data into the current cpu's channel buffer. 213c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 214c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Protects the buffer by disabling preemption. Use 215c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * relay_write() if you might be logging from interrupt 216c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * context. 217c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 218c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Querustatic inline void __relay_write(struct rchan *chan, 219c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru const void *data, 220c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t length) 221c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru{ 222c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct rchan_buf *buf; 223c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 224c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru buf = chan->buf[get_cpu()]; 225c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru if (unlikely(buf->offset + length > buf->chan->subbuf_size)) 226c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru length = relay_switch_subbuf(buf, length); 227c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru memcpy(buf->data + buf->offset, data, length); 228c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru buf->offset += length; 229c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru put_cpu(); 230c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru} 231c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 232c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/** 233c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * relay_reserve - reserve slot in channel buffer 234c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @chan: relay channel 235c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @length: number of bytes to reserve 236c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 237c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Returns pointer to reserved slot, NULL if full. 238c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 239c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Reserves a slot in the current cpu's channel buffer. 240c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Does not protect the buffer at all - caller must provide 241c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * appropriate synchronization. 242c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 243c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Querustatic inline void *relay_reserve(struct rchan *chan, size_t length) 244c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru{ 245c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru void *reserved; 246c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru struct rchan_buf *buf = chan->buf[smp_processor_id()]; 247c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 248c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru if (unlikely(buf->offset + length > buf->chan->subbuf_size)) { 249c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru length = relay_switch_subbuf(buf, length); 250c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru if (!length) 251c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru return NULL; 252c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru } 253c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru reserved = buf->data + buf->offset; 254c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru buf->offset += length; 255c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 256c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru return reserved; 257c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru} 258c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 259c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/** 260c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * subbuf_start_reserve - reserve bytes at the start of a sub-buffer 261c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @buf: relay channel buffer 262c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * @length: number of bytes to reserve 263c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * 264c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * Helper function used to reserve bytes at the beginning of 265c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * a sub-buffer in the subbuf_start() callback. 266c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 267c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Querustatic inline void subbuf_start_reserve(struct rchan_buf *buf, 268c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru size_t length) 269c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru{ 270c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru BUG_ON(length >= buf->chan->subbuf_size - 1); 271c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru buf->offset = length; 272c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru} 273c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 274c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru/* 275c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru * exported relay file operations, kernel/relay.c 276c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru */ 277c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queruextern struct file_operations relay_file_operations; 278c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 279c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru#endif /* _LINUX_RELAY_H */ 280c559cd81139f97cecad1ad91a0b2e25a5936d53Jean-Baptiste Queru 281