block: Add bdrv_co_readv/writev

Add new block driver callbacks bdrv_co_readv/writev, which work on a
QEMUIOVector like bdrv_aio_*, but don't need a callback. The function may only
be called inside a coroutine, so a block driver implementing this interface can
yield instead of blocking during I/O.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Makefile.objs

@@ -25,6 +25,7 @@ coroutine-obj-$(CONFIG_WIN32) += coroutine-win32.o
 
 block-obj-y = cutils.o cache-utils.o qemu-malloc.o qemu-option.o module.o async.o
 block-obj-y += nbd.o block.o aio.o aes.o qemu-config.o qemu-progress.o qemu-sockets.o
+block-obj-y += $(coroutine-obj-y)
 block-obj-$(CONFIG_POSIX) += posix-aio-compat.o
 block-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
 
@@ -79,7 +80,6 @@ common-obj-y += readline.o console.o cursor.o qemu-error.o
 common-obj-y += $(oslib-obj-y)
 common-obj-$(CONFIG_WIN32) += os-win32.o
 common-obj-$(CONFIG_POSIX) += os-posix.o
-common-obj-y += $(coroutine-obj-y)
 
 common-obj-y += tcg-runtime.o host-utils.o
 common-obj-y += irq.o ioport.o input.o

block.c

@@ -1110,6 +1110,51 @@ int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset,
     return 0;
 }
 
+int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
+    int nb_sectors, QEMUIOVector *qiov)
+{
+    BlockDriver *drv = bs->drv;
+
+    trace_bdrv_co_readv(bs, sector_num, nb_sectors);
+
+    if (!drv) {
+        return -ENOMEDIUM;
+    }
+    if (bdrv_check_request(bs, sector_num, nb_sectors)) {
+        return -EIO;
+    }
+
+    return drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
+}
+
+int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num,
+    int nb_sectors, QEMUIOVector *qiov)
+{
+    BlockDriver *drv = bs->drv;
+
+    trace_bdrv_co_writev(bs, sector_num, nb_sectors);
+
+    if (!bs->drv) {
+        return -ENOMEDIUM;
+    }
+    if (bs->read_only) {
+        return -EACCES;
+    }
+    if (bdrv_check_request(bs, sector_num, nb_sectors)) {
+        return -EIO;
+    }
+
+    if (bs->dirty_bitmap) {
+        set_dirty_bitmap(bs, sector_num, nb_sectors, 1);
+    }
+
+    if (bs->wr_highest_sector < sector_num + nb_sectors - 1) {
+        bs->wr_highest_sector = sector_num + nb_sectors - 1;
+    }
+
+    return drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov);
+}
+
 /**
  * Truncate file to 'offset' bytes (needed only for file protocols)
  */

block.h

@@ -4,6 +4,7 @@
 #include "qemu-aio.h"
 #include "qemu-common.h"
 #include "qemu-option.h"
+#include "qemu-coroutine.h"
 #include "qobject.h"
 
 /* block.c */
@@ -85,6 +86,10 @@ int bdrv_pwrite(BlockDriverState *bs, int64_t offset,
                 const void *buf, int count);
 int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset,
     const void *buf, int count);
+int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
+    int nb_sectors, QEMUIOVector *qiov);
+int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num,
+    int nb_sectors, QEMUIOVector *qiov);
 int bdrv_truncate(BlockDriverState *bs, int64_t offset);
 int64_t bdrv_getlength(BlockDriverState *bs);
 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);

block_int.h

@@ -27,6 +27,7 @@
 #include "block.h"
 #include "qemu-option.h"
 #include "qemu-queue.h"
+#include "qemu-coroutine.h"
 
 #define BLOCK_FLAG_ENCRYPT	1
 #define BLOCK_FLAG_COMPAT6	4
@@ -77,6 +78,11 @@ struct BlockDriver {
     int (*bdrv_discard)(BlockDriverState *bs, int64_t sector_num,
                         int nb_sectors);
 
+    int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs,
+        int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
+    int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs,
+        int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
+
     int (*bdrv_aio_multiwrite)(BlockDriverState *bs, BlockRequest *reqs,
         int num_reqs);
     int (*bdrv_merge_requests)(BlockDriverState *bs, BlockRequest* a,

trace-events

@@ -66,6 +66,8 @@ disable bdrv_aio_flush(void *bs, void *opaque) "bs %p opaque %p"
 disable bdrv_aio_readv(void *bs, int64_t sector_num, int nb_sectors, void *opaque) "bs %p sector_num %"PRId64" nb_sectors %d opaque %p"
 disable bdrv_aio_writev(void *bs, int64_t sector_num, int nb_sectors, void *opaque) "bs %p sector_num %"PRId64" nb_sectors %d opaque %p"
 disable bdrv_set_locked(void *bs, int locked) "bs %p locked %d"
+disable bdrv_co_readv(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
+disable bdrv_co_writev(void *bs, int64_t sector_num, int nb_sector) "bs %p sector_num %"PRId64" nb_sectors %d"
 
 # hw/virtio-blk.c
 disable virtio_blk_req_complete(void *req, int status) "req %p status %d"