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 61 void co_run_in_worker_bh(void *); 62 int coroutine_fn v9fs_co_readlink(V9fsPDU *, V9fsPath *, V9fsString *); 63 int coroutine_fn v9fs_co_readdir(V9fsPDU *, V9fsFidState *, struct dirent **); 64 int coroutine_fn v9fs_co_readdir_many(V9fsPDU *, V9fsFidState *, 65 struct V9fsDirEnt **, off_t, int32_t, 66 bool); 67 off_t coroutine_fn v9fs_co_telldir(V9fsPDU *, V9fsFidState *); 68 void coroutine_fn v9fs_co_seekdir(V9fsPDU *, V9fsFidState *, off_t); 69 void coroutine_fn v9fs_co_rewinddir(V9fsPDU *, V9fsFidState *); 70 int coroutine_fn v9fs_co_statfs(V9fsPDU *, V9fsPath *, struct statfs *); 71 int coroutine_fn v9fs_co_lstat(V9fsPDU *, V9fsPath *, struct stat *); 72 int coroutine_fn v9fs_co_chmod(V9fsPDU *, V9fsPath *, mode_t); 73 int coroutine_fn v9fs_co_utimensat(V9fsPDU *, V9fsPath *, struct timespec [2]); 74 int coroutine_fn v9fs_co_chown(V9fsPDU *, V9fsPath *, uid_t, gid_t); 75 int coroutine_fn v9fs_co_truncate(V9fsPDU *, V9fsPath *, off_t); 76 int coroutine_fn v9fs_co_llistxattr(V9fsPDU *, V9fsPath *, void *, size_t); 77 int coroutine_fn v9fs_co_lgetxattr(V9fsPDU *, V9fsPath *, 78 V9fsString *, void *, size_t); 79 int coroutine_fn v9fs_co_mknod(V9fsPDU *, V9fsFidState *, V9fsString *, uid_t, 80 gid_t, dev_t, mode_t, struct stat *); 81 int coroutine_fn v9fs_co_mkdir(V9fsPDU *, V9fsFidState *, V9fsString *, 82 mode_t, uid_t, gid_t, struct stat *); 83 int coroutine_fn v9fs_co_remove(V9fsPDU *, V9fsPath *); 84 int coroutine_fn v9fs_co_rename(V9fsPDU *, V9fsPath *, V9fsPath *); 85 int coroutine_fn v9fs_co_unlinkat(V9fsPDU *, V9fsPath *, V9fsString *, 86 int flags); 87 int coroutine_fn v9fs_co_renameat(V9fsPDU *, V9fsPath *, V9fsString *, 88 V9fsPath *, V9fsString *); 89 int coroutine_fn v9fs_co_fstat(V9fsPDU *, V9fsFidState *, struct stat *); 90 int coroutine_fn v9fs_co_opendir(V9fsPDU *, V9fsFidState *); 91 int coroutine_fn v9fs_co_open(V9fsPDU *, V9fsFidState *, int); 92 int coroutine_fn v9fs_co_open2(V9fsPDU *, V9fsFidState *, V9fsString *, 93 gid_t, int, int, struct stat *); 94 int coroutine_fn v9fs_co_lsetxattr(V9fsPDU *, V9fsPath *, V9fsString *, 95 void *, size_t, int); 96 int coroutine_fn v9fs_co_lremovexattr(V9fsPDU *, V9fsPath *, V9fsString *); 97 int coroutine_fn v9fs_co_closedir(V9fsPDU *, V9fsFidOpenState *); 98 int coroutine_fn v9fs_co_close(V9fsPDU *, V9fsFidOpenState *); 99 int coroutine_fn v9fs_co_fsync(V9fsPDU *, V9fsFidState *, int); 100 int coroutine_fn v9fs_co_symlink(V9fsPDU *, V9fsFidState *, V9fsString *, 101 const char *, gid_t, struct stat *); 102 int coroutine_fn v9fs_co_link(V9fsPDU *, V9fsFidState *, 103 V9fsFidState *, V9fsString *); 104 int coroutine_fn v9fs_co_pwritev(V9fsPDU *, V9fsFidState *, 105 struct iovec *, int, int64_t); 106 int coroutine_fn v9fs_co_preadv(V9fsPDU *, V9fsFidState *, 107 struct iovec *, int, int64_t); 108 int coroutine_fn v9fs_co_name_to_path(V9fsPDU *, V9fsPath *, 109 const char *, V9fsPath *); 110 int coroutine_fn v9fs_co_st_gen(V9fsPDU *pdu, V9fsPath *path, mode_t, 111 V9fsStatDotl *v9stat); 112 113 #endif 114