1 /* $NetBSD: rumpuser_bio.c,v 1.7 2013/05/15 14:58:24 pooka Exp $ */ 2 3 /*- 4 * Copyright (c) 2013 Antti Kantee. All Rights Reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 18 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include "rumpuser_port.h" 29 30 #include <sys/types.h> 31 32 #include <assert.h> 33 #include <errno.h> 34 #include <pthread.h> 35 #include <stdint.h> 36 #include <stdio.h> 37 #include <string.h> 38 #include <unistd.h> 39 40 #include <rump/rumpuser.h> 41 42 #include "rumpuser_int.h" 43 44 struct rumpuser_bio { 45 int bio_fd; 46 int bio_op; 47 void *bio_data; 48 size_t bio_dlen; 49 off_t bio_off; 50 51 rump_biodone_fn bio_done; 52 void *bio_donearg; 53 }; 54 55 #define N_BIOS 128 56 static pthread_mutex_t biomtx = PTHREAD_MUTEX_INITIALIZER; 57 static pthread_cond_t biocv = PTHREAD_COND_INITIALIZER; 58 static int bio_head, bio_tail; 59 static struct rumpuser_bio bios[N_BIOS]; 60 61 static void 62 dobio(struct rumpuser_bio *biop) 63 { 64 ssize_t rv; 65 int error, dummy; 66 67 assert(biop->bio_donearg != NULL); 68 if (biop->bio_op & RUMPUSER_BIO_READ) { 69 error = 0; 70 rv = pread(biop->bio_fd, biop->bio_data, 71 biop->bio_dlen, biop->bio_off); 72 if (rv < 0) { 73 rv = 0; 74 error = errno; 75 } 76 } else { 77 error = 0; 78 rv = pwrite(biop->bio_fd, biop->bio_data, 79 biop->bio_dlen, biop->bio_off); 80 if (rv < 0) { 81 rv = 0; 82 error = errno; 83 } else if (biop->bio_op & RUMPUSER_BIO_SYNC) { 84 #ifdef __NetBSD__ 85 fsync_range(biop->bio_fd, FDATASYNC, 86 biop->bio_off, biop->bio_dlen); 87 #else 88 fsync(biop->bio_fd); 89 #endif 90 } 91 } 92 rumpkern_sched(0, NULL); 93 biop->bio_done(biop->bio_donearg, (size_t)rv, error); 94 rumpkern_unsched(&dummy, NULL); 95 96 /* paranoia */ 97 biop->bio_donearg = NULL; 98 } 99 100 static void * 101 biothread(void *arg) 102 { 103 struct rumpuser_bio *biop; 104 int rv; 105 106 rumpuser__hyp.hyp_schedule(); 107 rv = rumpuser__hyp.hyp_lwproc_newlwp(0); 108 assert(rv == 0); 109 rumpuser__hyp.hyp_unschedule(); 110 NOFAIL_ERRNO(pthread_mutex_lock(&biomtx)); 111 for (;;) { 112 while (bio_head == bio_tail) 113 NOFAIL_ERRNO(pthread_cond_wait(&biocv, &biomtx)); 114 115 biop = &bios[bio_tail]; 116 pthread_mutex_unlock(&biomtx); 117 118 dobio(biop); 119 120 NOFAIL_ERRNO(pthread_mutex_lock(&biomtx)); 121 bio_tail = (bio_tail+1) % N_BIOS; 122 pthread_cond_signal(&biocv); 123 } 124 125 /* unreachable */ 126 abort(); 127 } 128 129 void 130 rumpuser_bio(int fd, int op, void *data, size_t dlen, int64_t doff, 131 rump_biodone_fn biodone, void *bioarg) 132 { 133 struct rumpuser_bio bio; 134 static int inited = 0; 135 static int usethread = 1; 136 int nlocks; 137 138 rumpkern_unsched(&nlocks, NULL); 139 140 if (!inited) { 141 pthread_mutex_lock(&biomtx); 142 if (!inited) { 143 char buf[16]; 144 pthread_t pt; 145 146 /* 147 * duplicates policy of rump kernel. maybe a bit 148 * questionable, but since the setting is not 149 * used in normal circumstances, let's not care 150 */ 151 if (getenv_r("RUMP_THREADS", buf, sizeof(buf)) == 0) 152 usethread = *buf != '0'; 153 154 if (usethread) 155 pthread_create(&pt, NULL, biothread, NULL); 156 inited = 1; 157 } 158 pthread_mutex_unlock(&biomtx); 159 assert(inited); 160 } 161 162 bio.bio_fd = fd; 163 bio.bio_op = op; 164 bio.bio_data = data; 165 bio.bio_dlen = dlen; 166 bio.bio_off = (off_t)doff; 167 bio.bio_done = biodone; 168 bio.bio_donearg = bioarg; 169 170 if (!usethread) { 171 dobio(&bio); 172 } else { 173 pthread_mutex_lock(&biomtx); 174 while ((bio_head+1) % N_BIOS == bio_tail) 175 pthread_cond_wait(&biocv, &biomtx); 176 177 bios[bio_head] = bio; 178 bio_head = (bio_head+1) % N_BIOS; 179 180 pthread_cond_signal(&biocv); 181 pthread_mutex_unlock(&biomtx); 182 } 183 184 rumpkern_sched(nlocks, NULL); 185 } 186