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Diffstat (limited to 'runtime/relayfs/linux/relayfs_fs.h')
| -rw-r--r-- | runtime/relayfs/linux/relayfs_fs.h | 263 |
1 files changed, 263 insertions, 0 deletions
diff --git a/runtime/relayfs/linux/relayfs_fs.h b/runtime/relayfs/linux/relayfs_fs.h new file mode 100644 index 00000000..1f697c3b --- /dev/null +++ b/runtime/relayfs/linux/relayfs_fs.h @@ -0,0 +1,263 @@ +/* + * 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 + */ + +#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> +#include <linux/poll.h> +#include <linux/kref.h> + +/* + * Tracks changes to rchan_buf struct + */ +#define RELAYFS_CHANNEL_VERSION 3 + +/* + * Per-cpu relay channel buffer + */ +struct rchan_buf +{ + void *start; /* start of channel buffer */ + void *data; /* start of current sub-buffer */ + unsigned offset; /* current offset into sub-buffer */ + atomic_t subbufs_produced; /* count of sub-buffers produced */ + atomic_t subbufs_consumed; /* count of sub-buffers consumed */ + atomic_t unfull; /* state has gone from full to not */ + 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 */ + int page_count; /* number of current buffer pages */ + unsigned *padding; /* padding counts per sub-buffer */ + unsigned *commit; /* commit counts per sub-buffer */ + int finalized; /* buffer has been finalized */ +} ____cacheline_aligned; + +/* + * Relay channel data structure + */ +struct rchan +{ + u32 version; /* the version of this struct */ + unsigned subbuf_size; /* sub-buffer size */ + unsigned n_subbufs; /* number of sub-buffers per buffer */ + unsigned alloc_size; /* total buffer size allocated */ + int overwrite; /* overwrite buffer when full? */ + struct rchan_callbacks *cb; /* client callbacks */ + struct kref kref; /* channel refcount */ + struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */ +}; + +/* + * Relayfs inode + */ +struct relayfs_inode_info +{ + struct inode vfs_inode; + struct rchan_buf *buf; +}; + +static inline struct relayfs_inode_info *RELAYFS_I(struct inode *inode) +{ + return container_of(inode, struct relayfs_inode_info, vfs_inode); +} + +/* + * 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_idx: the previous sub-buffer's index + * @prev_subbuf: the start of the previous sub-buffer + * + * 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. + */ + int (*subbuf_start) (struct rchan_buf *buf, + void *subbuf, + unsigned prev_subbuf_idx, + void *prev_subbuf); + + /* + * deliver - deliver a guaranteed full sub-buffer to client + * @buf: the channel buffer containing the sub-buffer + * @subbuf_idx: the sub-buffer's index + * @subbuf: the start of the new sub-buffer + * + * Only works if relay_commit is also used + */ + void (*deliver) (struct rchan_buf *buf, + unsigned subbuf_idx, + void *subbuf); + + /* + * buf_mapped - relayfs buffer mmap notification + * @buf: the channel buffer + * @filp: relayfs file pointer + * + * Called when a relayfs file is successfully mmapped + */ + void (*buf_mapped)(struct rchan_buf *buf, + struct file *filp); + + /* + * buf_unmapped - relayfs buffer unmap notification + * @buf: the channel buffer + * @filp: relayfs file pointer + * + * Called when a relayfs file is successfully unmapped + */ + void (*buf_unmapped)(struct rchan_buf *buf, + struct file *filp); + + /* + * buf_full - relayfs buffer full notification + * @buf: the channel channel buffer + * @subbuf_idx: the current sub-buffer's index + * @subbuf: the start of the current sub-buffer + * + * Called when a relayfs buffer becomes full + */ + void (*buf_full)(struct rchan_buf *buf, + unsigned subbuf_idx, + void *subbuf); +}; + +/* + * relayfs kernel API, fs/relayfs/relay.c + */ + +struct rchan *relay_open(const char *base_filename, + struct dentry *parent, + unsigned subbuf_size, + unsigned n_subbufs, + int overwrite, + 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, + int cpu, + int subbufs_consumed); +extern void relay_reset(struct rchan *chan); +extern unsigned relay_switch_subbuf(struct rchan_buf *buf, + unsigned length); +extern void relay_commit(struct rchan_buf *buf, + void *reserved, + unsigned count); +extern struct dentry *relayfs_create_dir(const char *name, + struct dentry *parent); +extern int relayfs_remove_dir(struct dentry *dentry); + +/** + * 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 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 void relay_write(struct rchan *chan, + const void *data, + unsigned length) +{ + 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); +} + +/** + * __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 __relay_write(struct rchan *chan, + const void *data, + unsigned length) +{ + 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(); +} + +/** + * relay_reserve - reserve slot in channel buffer + * @chan: relay channel + * @length: number of bytes to reserve + * + * Returns pointer to reserved slot, NULL if full. + * + * Reserves a slot in the current cpu's channel buffer. + * Does not protect the buffer at all - caller must provide + * appropriate synchronization. + */ +static inline void *relay_reserve(struct rchan *chan, unsigned length) +{ + 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; +} + +/* + * exported relayfs file operations, fs/relayfs/inode.c + */ + +extern struct file_operations relayfs_file_operations; +extern int relayfs_open(struct inode *inode, struct file *filp); +extern unsigned int relayfs_poll(struct file *filp, poll_table *wait); +extern int relayfs_mmap(struct file *filp, struct vm_area_struct *vma); +extern int relayfs_release(struct inode *inode, struct file *filp); + +#endif /* _LINUX_RELAYFS_FS_H */ + |