static int idle_threads = 0;
static TAILQ_HEAD(, qemu_paiocb) request_list;
+#ifdef HAVE_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));
ret = ioctl(aiocb->aio_fildes, aiocb->aio_ioctl_cmd, aiocb->aio_ioctl_buf);
if (ret == -1)
return -errno;
- return ret;
+
+ /*
+ * This looks weird, but the aio code only consideres a request
+ * successfull if it has written the number 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;
+}
+
+#ifdef HAVE_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
+
/*
* Check if we need to copy the data in the aiocb into a new
* properly aligned buffer.
return 0;
}
+static size_t handle_aiocb_rw_vector(struct qemu_paiocb *aiocb)
+{
+ size_t offset = 0;
+ ssize_t len;
+
+ do {
+ if (aiocb->aio_type == QEMU_PAIO_WRITE)
+ len = qemu_pwritev(aiocb->aio_fildes,
+ aiocb->aio_iov,
+ aiocb->aio_niov,
+ aiocb->aio_offset + offset);
+ else
+ len = qemu_preadv(aiocb->aio_fildes,
+ aiocb->aio_iov,
+ aiocb->aio_niov,
+ aiocb->aio_offset + offset);
+ } while (len == -1 && errno == EINTR);
+
+ if (len == -1)
+ return -errno;
+ return len;
+}
+
static size_t handle_aiocb_rw_linear(struct qemu_paiocb *aiocb, char *buf)
{
size_t offset = 0;
size_t nbytes;
char *buf;
- if (!aiocb_needs_copy(aiocb) && aiocb->aio_niov == 1) {
+ if (!aiocb_needs_copy(aiocb)) {
/*
* If there is just a single buffer, and it is properly aligned
* we can just use plain pread/pwrite without any problems.
*/
- return handle_aiocb_rw_linear(aiocb, aiocb->aio_iov->iov_base);
+ 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?
+ */
}
/*