LXR qemu/hw/9pfs/coth.h

   1/*
   2 * 9p backend
   3 *
   4 * Copyright IBM, Corp. 2010
   5 *
   6 * Authors:
   7 *  Harsh Prateek Bora <harsh@linux.vnet.ibm.com>
   8 *  Venkateswararao Jujjuri(JV) <jvrao@linux.vnet.ibm.com>
   9 *
  10 * This work is licensed under the terms of the GNU GPL, version 2.  See
  11 * the COPYING file in the top-level directory.
  12 *
  13 */
  14
  15#ifndef QEMU_9P_COTH_H
  16#define QEMU_9P_COTH_H
  17
  18#include "qemu/thread.h"
  19#include "qemu/coroutine.h"
  20#include "9p.h"
  21
  22/*
  23 * we want to use bottom half because we want to make sure the below
  24 * sequence of events.
  25 *
  26 *   1. Yield the coroutine in the QEMU thread.
  27 *   2. Submit the coroutine to a worker thread.
  28 *   3. Enter the coroutine in the worker thread.
  29 * we cannot swap step 1 and 2, because that would imply worker thread
  30 * can enter coroutine while step1 is still running
  31 *
  32 * PERFORMANCE CONSIDERATIONS: As a rule of thumb, keep in mind
  33 * that hopping between threads adds @b latency! So when handling a
  34 * 9pfs request, avoid calling v9fs_co_run_in_worker() too often, because
  35 * this might otherwise sum up to a significant, huge overall latency for
  36 * providing the response for just a single request. For that reason it
  37 * is highly recommended to fetch all data from fs driver with a single
  38 * fs driver request on a background I/O thread (bottom half) in one rush
  39 * first and then eventually assembling the final response from that data
  40 * on main I/O thread (top half).
  41 */
  42#define v9fs_co_run_in_worker(code_block)                               \
  43    do {                                                                \
  44        QEMUBH *co_bh;                                                  \
  45        co_bh = qemu_bh_new(co_run_in_worker_bh,                        \
  46                            qemu_coroutine_self());                     \
  47        qemu_bh_schedule(co_bh);                                        \
  48        /*                                                              \
  49         * yield in qemu thread and re-enter back                       \
  50         * in worker thread                                             \
  51         */                                                             \
  52        qemu_coroutine_yield();                                         \
  53        qemu_bh_delete(co_bh);                                          \
  54        do {                                                            \
  55            code_block;                                                 \
  56        } while (0);                                                    \
  57        /* re-enter back to qemu thread */                              \
  58        qemu_coroutine_yield();                                         \
  59    } while (0)
  60
  61void co_run_in_worker_bh(void *);
  62int coroutine_fn v9fs_co_readlink(V9fsPDU *, V9fsPath *, V9fsString *);
  63int coroutine_fn v9fs_co_readdir(V9fsPDU *, V9fsFidState *, struct dirent **);
  64int coroutine_fn v9fs_co_readdir_many(V9fsPDU *, V9fsFidState *,
  65                                      struct V9fsDirEnt **, off_t, int32_t,
  66                                      bool);
  67off_t coroutine_fn v9fs_co_telldir(V9fsPDU *, V9fsFidState *);
  68void coroutine_fn v9fs_co_seekdir(V9fsPDU *, V9fsFidState *, off_t);
  69void coroutine_fn v9fs_co_rewinddir(V9fsPDU *, V9fsFidState *);
  70int coroutine_fn v9fs_co_statfs(V9fsPDU *, V9fsPath *, struct statfs *);
  71int coroutine_fn v9fs_co_lstat(V9fsPDU *, V9fsPath *, struct stat *);
  72int coroutine_fn v9fs_co_chmod(V9fsPDU *, V9fsPath *, mode_t);
  73int coroutine_fn v9fs_co_utimensat(V9fsPDU *, V9fsPath *, struct timespec [2]);
  74int coroutine_fn v9fs_co_chown(V9fsPDU *, V9fsPath *, uid_t, gid_t);
  75int coroutine_fn v9fs_co_truncate(V9fsPDU *, V9fsPath *, off_t);
  76int coroutine_fn v9fs_co_llistxattr(V9fsPDU *, V9fsPath *, void *, size_t);
  77int coroutine_fn v9fs_co_lgetxattr(V9fsPDU *, V9fsPath *,
  78                                   V9fsString *, void *, size_t);
  79int coroutine_fn v9fs_co_mknod(V9fsPDU *, V9fsFidState *, V9fsString *, uid_t,
  80                               gid_t, dev_t, mode_t, struct stat *);
  81int coroutine_fn v9fs_co_mkdir(V9fsPDU *, V9fsFidState *, V9fsString *,
  82                               mode_t, uid_t, gid_t, struct stat *);
  83int coroutine_fn v9fs_co_remove(V9fsPDU *, V9fsPath *);
  84int coroutine_fn v9fs_co_rename(V9fsPDU *, V9fsPath *, V9fsPath *);
  85int coroutine_fn v9fs_co_unlinkat(V9fsPDU *, V9fsPath *, V9fsString *,
  86                                  int flags);
  87int coroutine_fn v9fs_co_renameat(V9fsPDU *, V9fsPath *, V9fsString *,
  88                                  V9fsPath *, V9fsString *);
  89int coroutine_fn v9fs_co_fstat(V9fsPDU *, V9fsFidState *, struct stat *);
  90int coroutine_fn v9fs_co_opendir(V9fsPDU *, V9fsFidState *);
  91int coroutine_fn v9fs_co_open(V9fsPDU *, V9fsFidState *, int);
  92int coroutine_fn v9fs_co_open2(V9fsPDU *, V9fsFidState *, V9fsString *,
  93                               gid_t, int, int, struct stat *);
  94int coroutine_fn v9fs_co_lsetxattr(V9fsPDU *, V9fsPath *, V9fsString *,
  95                                   void *, size_t, int);
  96int coroutine_fn v9fs_co_lremovexattr(V9fsPDU *, V9fsPath *, V9fsString *);
  97int coroutine_fn v9fs_co_closedir(V9fsPDU *, V9fsFidOpenState *);
  98int coroutine_fn v9fs_co_close(V9fsPDU *, V9fsFidOpenState *);
  99int coroutine_fn v9fs_co_fsync(V9fsPDU *, V9fsFidState *, int);
 100int coroutine_fn v9fs_co_symlink(V9fsPDU *, V9fsFidState *, V9fsString *,
 101                                 const char *, gid_t, struct stat *);
 102int coroutine_fn v9fs_co_link(V9fsPDU *, V9fsFidState *,
 103                              V9fsFidState *, V9fsString *);
 104int coroutine_fn v9fs_co_pwritev(V9fsPDU *, V9fsFidState *,
 105                                 struct iovec *, int, int64_t);
 106int coroutine_fn v9fs_co_preadv(V9fsPDU *, V9fsFidState *,
 107                                struct iovec *, int, int64_t);
 108int coroutine_fn v9fs_co_name_to_path(V9fsPDU *, V9fsPath *,
 109                                      const char *, V9fsPath *);
 110int coroutine_fn v9fs_co_st_gen(V9fsPDU *pdu, V9fsPath *path, mode_t,
 111                                V9fsStatDotl *v9stat);
 112
 113#endif
 114