diff options
Diffstat (limited to 'posix-aio-compat.c')
| -rw-r--r-- | posix-aio-compat.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/posix-aio-compat.c b/posix-aio-compat.c new file mode 100644 index 0000000000..232b511f92 --- /dev/null +++ b/posix-aio-compat.c @@ -0,0 +1,202 @@ +/* + * 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. + * + */ + +#include <pthread.h> +#include <unistd.h> +#include <errno.h> +#include <sys/time.h> +#include "osdep.h" + +#include "posix-aio-compat.h" + +static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER; +static pthread_cond_t cond = PTHREAD_COND_INITIALIZER; +static pthread_t thread_id; +static int max_threads = 64; +static int cur_threads = 0; +static int idle_threads = 0; +static TAILQ_HEAD(, qemu_paiocb) request_list; + +static void *aio_thread(void *unused) +{ + sigset_t set; + + /* block all signals */ + sigfillset(&set); + sigprocmask(SIG_BLOCK, &set, NULL); + + while (1) { + struct qemu_paiocb *aiocb; + size_t offset; + int ret = 0; + + pthread_mutex_lock(&lock); + + while (TAILQ_EMPTY(&request_list) && + !(ret == ETIMEDOUT)) { + struct timespec ts = { 0 }; + qemu_timeval tv; + + qemu_gettimeofday(&tv); + ts.tv_sec = tv.tv_sec + 10; + ret = pthread_cond_timedwait(&cond, &lock, &ts); + } + + if (ret == ETIMEDOUT) + break; + + aiocb = TAILQ_FIRST(&request_list); + TAILQ_REMOVE(&request_list, aiocb, node); + + offset = 0; + aiocb->active = 1; + + idle_threads--; + pthread_mutex_unlock(&lock); + + while (offset < aiocb->aio_nbytes) { + ssize_t len; + + if (aiocb->is_write) + len = pwrite(aiocb->aio_fildes, + (const char *)aiocb->aio_buf + offset, + aiocb->aio_nbytes - offset, + aiocb->aio_offset + offset); + else + len = pread(aiocb->aio_fildes, + (char *)aiocb->aio_buf + offset, + aiocb->aio_nbytes - offset, + aiocb->aio_offset + offset); + + if (len == -1 && errno == EINTR) + continue; + else if (len == -1) { + pthread_mutex_lock(&lock); + aiocb->ret = -errno; + pthread_mutex_unlock(&lock); + break; + } else if (len == 0) + break; + + offset += len; + + pthread_mutex_lock(&lock); + aiocb->ret = offset; + pthread_mutex_unlock(&lock); + } + + pthread_mutex_lock(&lock); + idle_threads++; + pthread_mutex_unlock(&lock); + + sigqueue(getpid(), + aiocb->aio_sigevent.sigev_signo, + aiocb->aio_sigevent.sigev_value); + } + + idle_threads--; + cur_threads--; + pthread_mutex_unlock(&lock); + + return NULL; +} + +static int spawn_thread(void) +{ + pthread_attr_t attr; + int ret; + + cur_threads++; + idle_threads++; + + pthread_attr_init(&attr); + pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); + ret = pthread_create(&thread_id, &attr, aio_thread, NULL); + pthread_attr_destroy(&attr); + + return ret; +} + +int qemu_paio_init(struct qemu_paioinit *aioinit) +{ + TAILQ_INIT(&request_list); + + return 0; +} + +static int qemu_paio_submit(struct qemu_paiocb *aiocb, int is_write) +{ + aiocb->is_write = is_write; + aiocb->ret = -EINPROGRESS; + aiocb->active = 0; + pthread_mutex_lock(&lock); + if (idle_threads == 0 && cur_threads < max_threads) + spawn_thread(); + TAILQ_INSERT_TAIL(&request_list, aiocb, node); + pthread_mutex_unlock(&lock); + pthread_cond_broadcast(&cond); + + return 0; +} + +int qemu_paio_read(struct qemu_paiocb *aiocb) +{ + return qemu_paio_submit(aiocb, 0); +} + +int qemu_paio_write(struct qemu_paiocb *aiocb) +{ + return qemu_paio_submit(aiocb, 1); +} + +ssize_t qemu_paio_return(struct qemu_paiocb *aiocb) +{ + ssize_t ret; + + pthread_mutex_lock(&lock); + ret = aiocb->ret; + pthread_mutex_unlock(&lock); + + return ret; +} + +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; +} + +int qemu_paio_cancel(int fd, struct qemu_paiocb *aiocb) +{ + int ret; + + pthread_mutex_lock(&lock); + if (!aiocb->active) { + TAILQ_REMOVE(&request_list, aiocb, node); + aiocb->ret = -ECANCELED; + ret = QEMU_PAIO_CANCELED; + } else if (aiocb->ret == -EINPROGRESS) + ret = QEMU_PAIO_NOTCANCELED; + else + ret = QEMU_PAIO_ALLDONE; + pthread_mutex_unlock(&lock); + + return ret; +} + |