This patch introduces blk_co_preadv() as a central function on the
BlockBackend level that is supposed to handle all read requests from the
BB to its root BDS eventually.
Signed-off-by: Kevin Wolf <kw...@redhat.com>
---
block/block-backend.c | 64 ++++++++++++++++++++++++++++++++++++++++++++---
block/io.c | 5 +---
include/block/block_int.h | 4 +++
3 files changed, 65 insertions(+), 8 deletions(-)
diff --git a/block/block-backend.c b/block/block-backend.c
index 5de7850..c058785 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -22,6 +22,8 @@
/* Number of coroutines to reserve per attached device model */
#define COROUTINE_POOL_RESERVATION 64
+#define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress
*/
+
static AioContext *blk_aiocb_get_aio_context(BlockAIOCB *acb);
struct BlockBackend {
@@ -693,15 +695,69 @@ static int blk_check_request(BlockBackend *blk, int64_t
sector_num,
nb_sectors * BDRV_SECTOR_SIZE);
}
-int blk_read(BlockBackend *blk, int64_t sector_num, uint8_t *buf,
- int nb_sectors)
+static int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset,
+ unsigned int bytes, QEMUIOVector *qiov,
+ BdrvRequestFlags flags)
{
- int ret = blk_check_request(blk, sector_num, nb_sectors);
+ int ret = blk_check_byte_request(blk, offset, bytes);
if (ret < 0) {
return ret;
}
- return bdrv_read(blk_bs(blk), sector_num, buf, nb_sectors);
+ return bdrv_co_do_preadv(blk_bs(blk), offset, bytes, qiov, flags);
+}
+
+typedef struct BlkRwCo {
+ BlockBackend *blk;
+ int64_t offset;
+ QEMUIOVector *qiov;
+ int ret;
+ BdrvRequestFlags flags;
+} BlkRwCo;
+
+static void blk_read_entry(void *opaque)
+{
+ BlkRwCo *rwco = opaque;
+
+ rwco->ret = blk_co_preadv(rwco->blk, rwco->offset, rwco->qiov->size,
+ rwco->qiov, rwco->flags);
+}
+
+int blk_read(BlockBackend *blk, int64_t sector_num, uint8_t *buf,
+ int nb_sectors)
+{
+ AioContext *aio_context;
+ QEMUIOVector qiov;
+ struct iovec iov;
+ Coroutine *co;
+ BlkRwCo rwco;
+
+ if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
+ return -EINVAL;
+ }
+
+ iov = (struct iovec) {
+ .iov_base = buf,
+ .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
+ };
+ qemu_iovec_init_external(&qiov, &iov, 1);
+
+ rwco = (BlkRwCo) {
+ .blk = blk,
+ .offset = sector_num << BDRV_SECTOR_BITS,
+ .qiov = &qiov,
+ .ret = NOT_DONE,
+ };
+
+ co = qemu_coroutine_create(blk_read_entry);
+ qemu_coroutine_enter(co, &rwco);
+
+ aio_context = blk_get_aio_context(blk);
+ while (rwco.ret == NOT_DONE) {
+ aio_poll(aio_context, true);
+ }
+
+ return rwco.ret;
}
int blk_read_unthrottled(BlockBackend *blk, int64_t sector_num, uint8_t *buf,
diff --git a/block/io.c b/block/io.c
index 5f9b6d6..c7084e4 100644
--- a/block/io.c
+++ b/block/io.c
@@ -44,9 +44,6 @@ static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs,
static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs,
int64_t sector_num, int nb_sectors,
QEMUIOVector *iov);
-static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs,
- int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
- BdrvRequestFlags flags);
static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs,
int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags);
@@ -939,7 +936,7 @@ out:
/*
* Handle a read request in coroutine context
*/
-static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs,
+int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs,
int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags)
{
diff --git a/include/block/block_int.h b/include/block/block_int.h
index c031db4..b78be8d 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -508,6 +508,10 @@ extern BlockDriver bdrv_qcow2;
*/
void bdrv_setup_io_funcs(BlockDriver *bdrv);
+int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs,
+ int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
+ BdrvRequestFlags flags);
+
int get_tmp_filename(char *filename, int size);
BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size,
const char *filename);
--
1.8.3.1
