push down vector linearization to posix-aio-compat.c (Christoph Hellwig)

Make all AIO requests vectored and defer linearization until the actual
I/O thread.  This prepares for using native preadv/pwritev.

Also enables asynchronous direct I/O by handling that case in the I/O thread.

Qcow and qcow2 propably want to be adopted to directly deal with multi-segment
requests, but that can be implemented later.


Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7020 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 8 insertions, 1 deletions

diff --git a/posix-aio-compat.h b/posix-aio-compat.h
index a1cdfd7..1c5dcbd 100644
--- a/posix-aio-compat.h
+++ b/posix-aio-compat.h
@@ -27,11 +27,18 @@
 struct qemu_paiocb
 {
     int aio_fildes;
-    void *aio_buf;
+    union {
+        struct iovec *aio_iov;
+	void *aio_ioctl_buf;
+    };
+    int aio_niov;
     size_t aio_nbytes;
 #define aio_ioctl_cmd   aio_nbytes /* for QEMU_PAIO_IOCTL */
     int ev_signo;
     off_t aio_offset;
+    unsigned aio_flags;
+/* 512 byte alignment required for buffer, offset and length */
+#define QEMU_AIO_SECTOR_ALIGNED	0x01
 
     /* private */
     TAILQ_ENTRY(qemu_paiocb) node;