diff options
Diffstat (limited to 'posix-aio-compat.c')
| -rw-r--r-- | posix-aio-compat.c | 679 |
1 files changed, 0 insertions, 679 deletions
diff --git a/posix-aio-compat.c b/posix-aio-compat.c deleted file mode 100644 index 96e4daf..0000000 --- a/posix-aio-compat.c +++ /dev/null @@ -1,679 +0,0 @@ -/* - * QEMU posix-aio emulation - * - * Copyright IBM, Corp. 2008 - * - * Authors: - * Anthony Liguori <aliguori@us.ibm.com> - * - * This work is licensed under the terms of the GNU GPL, version 2. See - * the COPYING file in the top-level directory. - * - * Contributions after 2012-01-13 are licensed under the terms of the - * GNU GPL, version 2 or (at your option) any later version. - */ - -#include <sys/ioctl.h> -#include <sys/types.h> -#include <pthread.h> -#include <unistd.h> -#include <errno.h> -#include <time.h> -#include <string.h> -#include <stdlib.h> -#include <stdio.h> - -#include "qemu-queue.h" -#include "osdep.h" -#include "sysemu.h" -#include "qemu-common.h" -#include "trace.h" -#include "block_int.h" -#include "iov.h" - -#include "block/raw-posix-aio.h" - -static void do_spawn_thread(void); - -struct qemu_paiocb { - BlockDriverAIOCB common; - int aio_fildes; - union { - struct iovec *aio_iov; - void *aio_ioctl_buf; - }; - int aio_niov; - size_t aio_nbytes; -#define aio_ioctl_cmd aio_nbytes /* for QEMU_AIO_IOCTL */ - off_t aio_offset; - - QTAILQ_ENTRY(qemu_paiocb) node; - int aio_type; - ssize_t ret; - int active; - struct qemu_paiocb *next; -}; - -typedef struct PosixAioState { - int rfd, wfd; - struct qemu_paiocb *first_aio; -} PosixAioState; - - -static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER; -static pthread_cond_t cond = PTHREAD_COND_INITIALIZER; -static pthread_t thread_id; -static pthread_attr_t attr; -static int max_threads = 64; -static int cur_threads = 0; -static int idle_threads = 0; -static int new_threads = 0; /* backlog of threads we need to create */ -static int pending_threads = 0; /* threads created but not running yet */ -static QEMUBH *new_thread_bh; -static QTAILQ_HEAD(, qemu_paiocb) request_list; - -#ifdef CONFIG_PREADV -static int preadv_present = 1; -#else -static int preadv_present = 0; -#endif - -static void die2(int err, const char *what) -{ - fprintf(stderr, "%s failed: %s\n", what, strerror(err)); - abort(); -} - -static void die(const char *what) -{ - die2(errno, what); -} - -static void mutex_lock(pthread_mutex_t *mutex) -{ - int ret = pthread_mutex_lock(mutex); - if (ret) die2(ret, "pthread_mutex_lock"); -} - -static void mutex_unlock(pthread_mutex_t *mutex) -{ - int ret = pthread_mutex_unlock(mutex); - if (ret) die2(ret, "pthread_mutex_unlock"); -} - -static int cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex, - struct timespec *ts) -{ - int ret = pthread_cond_timedwait(cond, mutex, ts); - if (ret && ret != ETIMEDOUT) die2(ret, "pthread_cond_timedwait"); - return ret; -} - -static void cond_signal(pthread_cond_t *cond) -{ - int ret = pthread_cond_signal(cond); - if (ret) die2(ret, "pthread_cond_signal"); -} - -static void thread_create(pthread_t *thread, pthread_attr_t *attr, - void *(*start_routine)(void*), void *arg) -{ - int ret = pthread_create(thread, attr, start_routine, arg); - if (ret) die2(ret, "pthread_create"); -} - -static ssize_t handle_aiocb_ioctl(struct qemu_paiocb *aiocb) -{ - int ret; - - ret = ioctl(aiocb->aio_fildes, aiocb->aio_ioctl_cmd, aiocb->aio_ioctl_buf); - if (ret == -1) - return -errno; - - /* - * This looks weird, but the aio code only considers a request - * successful if it has written the full number of bytes. - * - * Now we overload aio_nbytes as aio_ioctl_cmd for the ioctl command, - * so in fact we return the ioctl command here to make posix_aio_read() - * happy.. - */ - return aiocb->aio_nbytes; -} - -static ssize_t handle_aiocb_flush(struct qemu_paiocb *aiocb) -{ - int ret; - - ret = qemu_fdatasync(aiocb->aio_fildes); - if (ret == -1) - return -errno; - return 0; -} - -#ifdef CONFIG_PREADV - -static ssize_t -qemu_preadv(int fd, const struct iovec *iov, int nr_iov, off_t offset) -{ - return preadv(fd, iov, nr_iov, offset); -} - -static ssize_t -qemu_pwritev(int fd, const struct iovec *iov, int nr_iov, off_t offset) -{ - return pwritev(fd, iov, nr_iov, offset); -} - -#else - -static ssize_t -qemu_preadv(int fd, const struct iovec *iov, int nr_iov, off_t offset) -{ - return -ENOSYS; -} - -static ssize_t -qemu_pwritev(int fd, const struct iovec *iov, int nr_iov, off_t offset) -{ - return -ENOSYS; -} - -#endif - -static ssize_t handle_aiocb_rw_vector(struct qemu_paiocb *aiocb) -{ - ssize_t len; - - do { - if (aiocb->aio_type & QEMU_AIO_WRITE) - len = qemu_pwritev(aiocb->aio_fildes, - aiocb->aio_iov, - aiocb->aio_niov, - aiocb->aio_offset); - else - len = qemu_preadv(aiocb->aio_fildes, - aiocb->aio_iov, - aiocb->aio_niov, - aiocb->aio_offset); - } while (len == -1 && errno == EINTR); - - if (len == -1) - return -errno; - return len; -} - -/* - * Read/writes the data to/from a given linear buffer. - * - * Returns the number of bytes handles or -errno in case of an error. Short - * reads are only returned if the end of the file is reached. - */ -static ssize_t handle_aiocb_rw_linear(struct qemu_paiocb *aiocb, char *buf) -{ - ssize_t offset = 0; - ssize_t len; - - while (offset < aiocb->aio_nbytes) { - if (aiocb->aio_type & QEMU_AIO_WRITE) - len = pwrite(aiocb->aio_fildes, - (const char *)buf + offset, - aiocb->aio_nbytes - offset, - aiocb->aio_offset + offset); - else - len = pread(aiocb->aio_fildes, - buf + offset, - aiocb->aio_nbytes - offset, - aiocb->aio_offset + offset); - - if (len == -1 && errno == EINTR) - continue; - else if (len == -1) { - offset = -errno; - break; - } else if (len == 0) - break; - - offset += len; - } - - return offset; -} - -static ssize_t handle_aiocb_rw(struct qemu_paiocb *aiocb) -{ - ssize_t nbytes; - char *buf; - - if (!(aiocb->aio_type & QEMU_AIO_MISALIGNED)) { - /* - * If there is just a single buffer, and it is properly aligned - * we can just use plain pread/pwrite without any problems. - */ - if (aiocb->aio_niov == 1) - return handle_aiocb_rw_linear(aiocb, aiocb->aio_iov->iov_base); - - /* - * We have more than one iovec, and all are properly aligned. - * - * Try preadv/pwritev first and fall back to linearizing the - * buffer if it's not supported. - */ - if (preadv_present) { - nbytes = handle_aiocb_rw_vector(aiocb); - if (nbytes == aiocb->aio_nbytes) - return nbytes; - if (nbytes < 0 && nbytes != -ENOSYS) - return nbytes; - preadv_present = 0; - } - - /* - * XXX(hch): short read/write. no easy way to handle the reminder - * using these interfaces. For now retry using plain - * pread/pwrite? - */ - } - - /* - * Ok, we have to do it the hard way, copy all segments into - * a single aligned buffer. - */ - buf = qemu_blockalign(aiocb->common.bs, aiocb->aio_nbytes); - if (aiocb->aio_type & QEMU_AIO_WRITE) { - char *p = buf; - int i; - - for (i = 0; i < aiocb->aio_niov; ++i) { - memcpy(p, aiocb->aio_iov[i].iov_base, aiocb->aio_iov[i].iov_len); - p += aiocb->aio_iov[i].iov_len; - } - } - - nbytes = handle_aiocb_rw_linear(aiocb, buf); - if (!(aiocb->aio_type & QEMU_AIO_WRITE)) { - char *p = buf; - size_t count = aiocb->aio_nbytes, copy; - int i; - - for (i = 0; i < aiocb->aio_niov && count; ++i) { - copy = count; - if (copy > aiocb->aio_iov[i].iov_len) - copy = aiocb->aio_iov[i].iov_len; - memcpy(aiocb->aio_iov[i].iov_base, p, copy); - p += copy; - count -= copy; - } - } - qemu_vfree(buf); - - return nbytes; -} - -static void posix_aio_notify_event(void); - -static void *aio_thread(void *unused) -{ - mutex_lock(&lock); - pending_threads--; - mutex_unlock(&lock); - do_spawn_thread(); - - while (1) { - struct qemu_paiocb *aiocb; - ssize_t ret = 0; - qemu_timeval tv; - struct timespec ts; - - qemu_gettimeofday(&tv); - ts.tv_sec = tv.tv_sec + 10; - ts.tv_nsec = 0; - - mutex_lock(&lock); - - while (QTAILQ_EMPTY(&request_list) && - !(ret == ETIMEDOUT)) { - idle_threads++; - ret = cond_timedwait(&cond, &lock, &ts); - idle_threads--; - } - - if (QTAILQ_EMPTY(&request_list)) - break; - - aiocb = QTAILQ_FIRST(&request_list); - QTAILQ_REMOVE(&request_list, aiocb, node); - aiocb->active = 1; - mutex_unlock(&lock); - - switch (aiocb->aio_type & QEMU_AIO_TYPE_MASK) { - case QEMU_AIO_READ: - ret = handle_aiocb_rw(aiocb); - if (ret >= 0 && ret < aiocb->aio_nbytes && aiocb->common.bs->growable) { - /* A short read means that we have reached EOF. Pad the buffer - * with zeros for bytes after EOF. */ - iov_memset(aiocb->aio_iov, aiocb->aio_niov, ret, - 0, aiocb->aio_nbytes - ret); - - ret = aiocb->aio_nbytes; - } - break; - case QEMU_AIO_WRITE: - ret = handle_aiocb_rw(aiocb); - break; - case QEMU_AIO_FLUSH: - ret = handle_aiocb_flush(aiocb); - break; - case QEMU_AIO_IOCTL: - ret = handle_aiocb_ioctl(aiocb); - break; - default: - fprintf(stderr, "invalid aio request (0x%x)\n", aiocb->aio_type); - ret = -EINVAL; - break; - } - - mutex_lock(&lock); - aiocb->ret = ret; - mutex_unlock(&lock); - - posix_aio_notify_event(); - } - - cur_threads--; - mutex_unlock(&lock); - - return NULL; -} - -static void do_spawn_thread(void) -{ - sigset_t set, oldset; - - mutex_lock(&lock); - if (!new_threads) { - mutex_unlock(&lock); - return; - } - - new_threads--; - pending_threads++; - - mutex_unlock(&lock); - - /* block all signals */ - if (sigfillset(&set)) die("sigfillset"); - if (sigprocmask(SIG_SETMASK, &set, &oldset)) die("sigprocmask"); - - thread_create(&thread_id, &attr, aio_thread, NULL); - - if (sigprocmask(SIG_SETMASK, &oldset, NULL)) die("sigprocmask restore"); -} - -static void spawn_thread_bh_fn(void *opaque) -{ - do_spawn_thread(); -} - -static void spawn_thread(void) -{ - cur_threads++; - new_threads++; - /* If there are threads being created, they will spawn new workers, so - * we don't spend time creating many threads in a loop holding a mutex or - * starving the current vcpu. - * - * If there are no idle threads, ask the main thread to create one, so we - * inherit the correct affinity instead of the vcpu affinity. - */ - if (!pending_threads) { - qemu_bh_schedule(new_thread_bh); - } -} - -static void qemu_paio_submit(struct qemu_paiocb *aiocb) -{ - aiocb->ret = -EINPROGRESS; - aiocb->active = 0; - mutex_lock(&lock); - if (idle_threads == 0 && cur_threads < max_threads) - spawn_thread(); - QTAILQ_INSERT_TAIL(&request_list, aiocb, node); - mutex_unlock(&lock); - cond_signal(&cond); -} - -static ssize_t qemu_paio_return(struct qemu_paiocb *aiocb) -{ - ssize_t ret; - - mutex_lock(&lock); - ret = aiocb->ret; - mutex_unlock(&lock); - - return ret; -} - -static int qemu_paio_error(struct qemu_paiocb *aiocb) -{ - ssize_t ret = qemu_paio_return(aiocb); - - if (ret < 0) - ret = -ret; - else - ret = 0; - - return ret; -} - -static void posix_aio_read(void *opaque) -{ - PosixAioState *s = opaque; - struct qemu_paiocb *acb, **pacb; - int ret; - ssize_t len; - - /* read all bytes from signal pipe */ - for (;;) { - char bytes[16]; - - len = read(s->rfd, bytes, sizeof(bytes)); - if (len == -1 && errno == EINTR) - continue; /* try again */ - if (len == sizeof(bytes)) - continue; /* more to read */ - break; - } - - for(;;) { - pacb = &s->first_aio; - for(;;) { - acb = *pacb; - if (!acb) - return; - - ret = qemu_paio_error(acb); - if (ret == ECANCELED) { - /* remove the request */ - *pacb = acb->next; - qemu_aio_release(acb); - } else if (ret != EINPROGRESS) { - /* end of aio */ - if (ret == 0) { - ret = qemu_paio_return(acb); - if (ret == acb->aio_nbytes) - ret = 0; - else - ret = -EINVAL; - } else { - ret = -ret; - } - - trace_paio_complete(acb, acb->common.opaque, ret); - - /* remove the request */ - *pacb = acb->next; - /* call the callback */ - acb->common.cb(acb->common.opaque, ret); - qemu_aio_release(acb); - break; - } else { - pacb = &acb->next; - } - } - } -} - -static int posix_aio_flush(void *opaque) -{ - PosixAioState *s = opaque; - return !!s->first_aio; -} - -static PosixAioState *posix_aio_state; - -static void posix_aio_notify_event(void) -{ - char byte = 0; - ssize_t ret; - - ret = write(posix_aio_state->wfd, &byte, sizeof(byte)); - if (ret < 0 && errno != EAGAIN) - die("write()"); -} - -static void paio_remove(struct qemu_paiocb *acb) -{ - struct qemu_paiocb **pacb; - - /* remove the callback from the queue */ - pacb = &posix_aio_state->first_aio; - for(;;) { - if (*pacb == NULL) { - fprintf(stderr, "paio_remove: aio request not found!\n"); - break; - } else if (*pacb == acb) { - *pacb = acb->next; - qemu_aio_release(acb); - break; - } - pacb = &(*pacb)->next; - } -} - -static void paio_cancel(BlockDriverAIOCB *blockacb) -{ - struct qemu_paiocb *acb = (struct qemu_paiocb *)blockacb; - int active = 0; - - trace_paio_cancel(acb, acb->common.opaque); - - mutex_lock(&lock); - if (!acb->active) { - QTAILQ_REMOVE(&request_list, acb, node); - acb->ret = -ECANCELED; - } else if (acb->ret == -EINPROGRESS) { - active = 1; - } - mutex_unlock(&lock); - - if (active) { - /* fail safe: if the aio could not be canceled, we wait for - it */ - while (qemu_paio_error(acb) == EINPROGRESS) - ; - } - - paio_remove(acb); -} - -static AIOPool raw_aio_pool = { - .aiocb_size = sizeof(struct qemu_paiocb), - .cancel = paio_cancel, -}; - -BlockDriverAIOCB *paio_submit(BlockDriverState *bs, int fd, - int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, - BlockDriverCompletionFunc *cb, void *opaque, int type) -{ - struct qemu_paiocb *acb; - - acb = qemu_aio_get(&raw_aio_pool, bs, cb, opaque); - acb->aio_type = type; - acb->aio_fildes = fd; - - if (qiov) { - acb->aio_iov = qiov->iov; - acb->aio_niov = qiov->niov; - } - acb->aio_nbytes = nb_sectors * 512; - acb->aio_offset = sector_num * 512; - - acb->next = posix_aio_state->first_aio; - posix_aio_state->first_aio = acb; - - trace_paio_submit(acb, opaque, sector_num, nb_sectors, type); - qemu_paio_submit(acb); - return &acb->common; -} - -BlockDriverAIOCB *paio_ioctl(BlockDriverState *bs, int fd, - unsigned long int req, void *buf, - BlockDriverCompletionFunc *cb, void *opaque) -{ - struct qemu_paiocb *acb; - - acb = qemu_aio_get(&raw_aio_pool, bs, cb, opaque); - acb->aio_type = QEMU_AIO_IOCTL; - acb->aio_fildes = fd; - acb->aio_offset = 0; - acb->aio_ioctl_buf = buf; - acb->aio_ioctl_cmd = req; - - acb->next = posix_aio_state->first_aio; - posix_aio_state->first_aio = acb; - - qemu_paio_submit(acb); - return &acb->common; -} - -int paio_init(void) -{ - PosixAioState *s; - int fds[2]; - int ret; - - if (posix_aio_state) - return 0; - - s = g_malloc(sizeof(PosixAioState)); - - s->first_aio = NULL; - if (qemu_pipe(fds) == -1) { - fprintf(stderr, "failed to create pipe\n"); - g_free(s); - return -1; - } - - s->rfd = fds[0]; - s->wfd = fds[1]; - - fcntl(s->rfd, F_SETFL, O_NONBLOCK); - fcntl(s->wfd, F_SETFL, O_NONBLOCK); - - qemu_aio_set_fd_handler(s->rfd, posix_aio_read, NULL, posix_aio_flush, s); - - ret = pthread_attr_init(&attr); - if (ret) - die2(ret, "pthread_attr_init"); - - ret = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); - if (ret) - die2(ret, "pthread_attr_setdetachstate"); - - QTAILQ_INIT(&request_list); - new_thread_bh = qemu_bh_new(spawn_thread_bh_fn, NULL); - - posix_aio_state = s; - return 0; -} |