Re: [Qemu-devel] support for non aio host os's?

[Enache Adrian]

On Fri, Mar 16, 2007 at 04:31:36PM -0500, Todd T. Fries wrote:
> .. so now that aio is in, and whatever existed before is out, has anybody
> come up with a way to support host os's that do not have aio?

This is what I'm using.
Just manage to have '#define CONFIG_NO_AIO 1' in ./config-host.h.

Patch is against qemu-cvs, and also includes a raw_getlength()
function that works with disk devices on OpenBSD.

Adi

--- /home/src/qemu/block-raw.c  Sat Jan 20 14:10:33 2007
+++ ./block-raw.c       Sat Mar 17 01:34:36 2007
@@ -25,7 +25,10 @@
 #include "block_int.h"
 #include <assert.h>
 #ifndef _WIN32
+
+#ifndef CONFIG_NO_AIO
 #include <aio.h>
+#endif
 
 #ifndef QEMU_TOOL
 #include "exec-all.h"
@@ -57,6 +60,13 @@
 #include <sys/disk.h>
 #endif
 
+#ifdef __OpenBSD__
+#include <sys/ioctl.h>
+#include <sys/disklabel.h>
+#include <sys/dkio.h>
+#endif
+
+
 //#define DEBUG_FLOPPY
 
 #define FTYPE_FILE   0
@@ -158,6 +168,7 @@ static int raw_pwrite(BlockDriverState *
 }
 
 /***********************************************************/
+#ifndef CONFIG_NO_AIO
 /* Unix AIO using POSIX AIO */
 
 typedef struct RawAIOCB {
@@ -380,6 +391,37 @@ static void raw_aio_cancel(BlockDriverAI
     }
 }
 
+#else /* !CONFIG_NO_AIO */
+
+void qemu_aio_init(void)
+{
+}
+
+void qemu_aio_poll(void)
+{
+}
+
+void qemu_aio_flush(void)
+{
+}
+
+void qemu_aio_wait_start(void)
+{
+}
+
+void qemu_aio_wait(void)
+{
+#ifndef QEMU_TOOL
+    qemu_bh_poll();
+#endif
+}
+
+void qemu_aio_wait_end(void)
+{
+}
+
+#endif /* !CONFIG_NO_AIO */
+
 static void raw_close(BlockDriverState *bs)
 {
     BDRVRawState *s = bs->opaque;
@@ -399,8 +441,28 @@ static int raw_truncate(BlockDriverState
     return 0;
 }
 
+#ifdef __OpenBSD__
+
 static int64_t  raw_getlength(BlockDriverState *bs)
 {
+    int fd = ((BDRVRawState*)bs->opaque)->fd;
+    struct stat st;
+    if(fstat(fd, &st))
+       return -1;
+    if(S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)){
+       struct disklabel dl;
+       if(ioctl(fd, DIOCGDINFO, &dl))
+           return -1;
+       return (int64_t)dl.d_secsize *
+               dl.d_partitions[DISKPART(st.st_rdev)].p_size;
+    }else
+       return st.st_size;
+}
+
+#else /* !__OpenBSD__ */
+
+static int64_t  raw_getlength(BlockDriverState *bs)
+{
     BDRVRawState *s = bs->opaque;
     int fd = s->fd;
     int64_t size;
@@ -446,6 +508,8 @@ static int64_t  raw_getlength(BlockDrive
     return size;
 }
 
+#endif /* !__OpenBSD__ */
+
 static int raw_create(const char *filename, int64_t total_size,
                       const char *backing_file, int flags)
 {
@@ -480,10 +544,12 @@ BlockDriver bdrv_raw = {
     raw_create,
     raw_flush,
     
+#ifndef CONFIG_NO_AIO
     .bdrv_aio_read = raw_aio_read,
     .bdrv_aio_write = raw_aio_write,
     .bdrv_aio_cancel = raw_aio_cancel,
     .aiocb_size = sizeof(RawAIOCB),
+#endif /* !CONFIG_NO_AIO */
     .protocol_name = "file",
     .bdrv_pread = raw_pread,
     .bdrv_pwrite = raw_pwrite,
@@ -816,10 +882,12 @@ BlockDriver bdrv_host_device = {
     NULL,
     raw_flush,
     
+#ifndef CONFIG_NO_AIO
     .bdrv_aio_read = raw_aio_read,
     .bdrv_aio_write = raw_aio_write,
     .bdrv_aio_cancel = raw_aio_cancel,
     .aiocb_size = sizeof(RawAIOCB),
+#endif /* !CONFIG_NO_AIO */
     .bdrv_pread = raw_pread,
     .bdrv_pwrite = raw_pwrite,
     .bdrv_getlength = raw_getlength,