Revision ceb42de8 posix-aio-compat.c
| b/posix-aio-compat.c | ||
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| 33 | 33 |
static int idle_threads = 0; |
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static TAILQ_HEAD(, qemu_paiocb) request_list; |
| 35 | 35 |
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#ifdef HAVE_PREADV |
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static int preadv_present = 1; |
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#else |
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static int preadv_present = 0; |
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#endif |
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static void die2(int err, const char *what) |
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{
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fprintf(stderr, "%s failed: %s\n", what, strerror(err)); |
| ... | ... | |
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return ret; |
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} |
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#ifdef HAVE_PREADV |
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static ssize_t |
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qemu_preadv(int fd, const struct iovec *iov, int nr_iov, off_t offset) |
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{
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return preadv(fd, iov, nr_iov, offset); |
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} |
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static ssize_t |
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qemu_pwritev(int fd, const struct iovec *iov, int nr_iov, off_t offset) |
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{
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return pwritev(fd, iov, nr_iov, offset); |
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} |
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#else |
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static ssize_t |
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qemu_preadv(int fd, const struct iovec *iov, int nr_iov, off_t offset) |
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{
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return -ENOSYS; |
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} |
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static ssize_t |
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qemu_pwritev(int fd, const struct iovec *iov, int nr_iov, off_t offset) |
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{
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return -ENOSYS; |
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} |
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#endif |
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/* |
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* Check if we need to copy the data in the aiocb into a new |
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* properly aligned buffer. |
| ... | ... | |
| 104 | 140 |
return 0; |
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} |
| 106 | 142 |
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static size_t handle_aiocb_rw_vector(struct qemu_paiocb *aiocb) |
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{
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size_t offset = 0; |
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ssize_t len; |
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do {
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if (aiocb->aio_type == QEMU_PAIO_WRITE) |
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len = qemu_pwritev(aiocb->aio_fildes, |
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aiocb->aio_iov, |
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aiocb->aio_niov, |
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aiocb->aio_offset + offset); |
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else |
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len = qemu_preadv(aiocb->aio_fildes, |
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aiocb->aio_iov, |
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aiocb->aio_niov, |
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aiocb->aio_offset + offset); |
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} while (len == -1 && errno == EINTR); |
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if (len == -1) |
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return -errno; |
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return len; |
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} |
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static size_t handle_aiocb_rw_linear(struct qemu_paiocb *aiocb, char *buf) |
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{
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size_t offset = 0; |
| ... | ... | |
| 140 | 199 |
size_t nbytes; |
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char *buf; |
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if (!aiocb_needs_copy(aiocb) && aiocb->aio_niov == 1) {
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if (!aiocb_needs_copy(aiocb)) {
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/* |
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* If there is just a single buffer, and it is properly aligned |
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* we can just use plain pread/pwrite without any problems. |
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*/ |
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return handle_aiocb_rw_linear(aiocb, aiocb->aio_iov->iov_base); |
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if (aiocb->aio_niov == 1) |
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return handle_aiocb_rw_linear(aiocb, aiocb->aio_iov->iov_base); |
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/* |
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* We have more than one iovec, and all are properly aligned. |
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* |
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* Try preadv/pwritev first and fall back to linearizing the |
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* buffer if it's not supported. |
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*/ |
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if (preadv_present) {
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nbytes = handle_aiocb_rw_vector(aiocb); |
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if (nbytes == aiocb->aio_nbytes) |
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return nbytes; |
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if (nbytes < 0 && nbytes != -ENOSYS) |
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return nbytes; |
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preadv_present = 0; |
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} |
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/* |
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* XXX(hch): short read/write. no easy way to handle the reminder |
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* using these interfaces. For now retry using plain |
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* pread/pwrite? |
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*/ |
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} |
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/* |
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