summaryrefslogtreecommitdiff
path: root/block.c
diff options
context:
space:
mode:
authorStefan Hajnoczi <stefanha@linux.vnet.ibm.com>2011-10-13 13:08:22 +0100
committerKevin Wolf <kwolf@redhat.com>2011-10-13 15:02:53 +0200
commit1c9805a398cc1125b4defa6367172c8c2c0bca9f (patch)
tree9c1c4be25e12bfbeaf673f6d9e2378dbd540bbcf /block.c
parentc5fbe57111ef59c315a71cd80e8b0af59e36ff21 (diff)
downloadqemu-1c9805a398cc1125b4defa6367172c8c2c0bca9f.tar.gz
qemu-1c9805a398cc1125b4defa6367172c8c2c0bca9f.tar.bz2
qemu-1c9805a398cc1125b4defa6367172c8c2c0bca9f.zip
block: switch bdrv_read()/bdrv_write() to coroutines
The bdrv_read()/bdrv_write() functions call .bdrv_read()/.bdrv_write(). They should go through bdrv_co_do_readv() and bdrv_co_do_writev() instead in order to unify request processing code across sync, aio, and coroutine interfaces. This is also an important step towards removing BlockDriverState .bdrv_read()/.bdrv_write() in the future. Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block.c')
-rw-r--r--block.c112
1 files changed, 62 insertions, 50 deletions
diff --git a/block.c b/block.c
index f4731eca6f..ae8fc80ffb 100644
--- a/block.c
+++ b/block.c
@@ -44,6 +44,8 @@
#include <windows.h>
#endif
+#define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
+
static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load);
static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs,
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
@@ -74,6 +76,8 @@ static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs,
static int coroutine_fn bdrv_co_flush_em(BlockDriverState *bs);
static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
+static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
+ int64_t sector_num, int nb_sectors, QEMUIOVector *qiov);
static QTAILQ_HEAD(, BlockDriverState) bdrv_states =
QTAILQ_HEAD_INITIALIZER(bdrv_states);
@@ -1042,30 +1046,69 @@ static inline bool bdrv_has_async_flush(BlockDriver *drv)
return drv->bdrv_aio_flush != bdrv_aio_flush_em;
}
-/* return < 0 if error. See bdrv_write() for the return codes */
-int bdrv_read(BlockDriverState *bs, int64_t sector_num,
- uint8_t *buf, int nb_sectors)
+typedef struct RwCo {
+ BlockDriverState *bs;
+ int64_t sector_num;
+ int nb_sectors;
+ QEMUIOVector *qiov;
+ bool is_write;
+ int ret;
+} RwCo;
+
+static void coroutine_fn bdrv_rw_co_entry(void *opaque)
{
- BlockDriver *drv = bs->drv;
+ RwCo *rwco = opaque;
- if (!drv)
- return -ENOMEDIUM;
+ if (!rwco->is_write) {
+ rwco->ret = bdrv_co_do_readv(rwco->bs, rwco->sector_num,
+ rwco->nb_sectors, rwco->qiov);
+ } else {
+ rwco->ret = bdrv_co_do_writev(rwco->bs, rwco->sector_num,
+ rwco->nb_sectors, rwco->qiov);
+ }
+}
- if (bdrv_has_async_rw(drv) && qemu_in_coroutine()) {
- QEMUIOVector qiov;
- struct iovec iov = {
- .iov_base = (void *)buf,
- .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
- };
+/*
+ * Process a synchronous request using coroutines
+ */
+static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf,
+ int nb_sectors, bool is_write)
+{
+ QEMUIOVector qiov;
+ struct iovec iov = {
+ .iov_base = (void *)buf,
+ .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
+ };
+ Coroutine *co;
+ RwCo rwco = {
+ .bs = bs,
+ .sector_num = sector_num,
+ .nb_sectors = nb_sectors,
+ .qiov = &qiov,
+ .is_write = is_write,
+ .ret = NOT_DONE,
+ };
- qemu_iovec_init_external(&qiov, &iov, 1);
- return bdrv_co_readv(bs, sector_num, nb_sectors, &qiov);
- }
+ qemu_iovec_init_external(&qiov, &iov, 1);
- if (bdrv_check_request(bs, sector_num, nb_sectors))
- return -EIO;
+ if (qemu_in_coroutine()) {
+ /* Fast-path if already in coroutine context */
+ bdrv_rw_co_entry(&rwco);
+ } else {
+ co = qemu_coroutine_create(bdrv_rw_co_entry);
+ qemu_coroutine_enter(co, &rwco);
+ while (rwco.ret == NOT_DONE) {
+ qemu_aio_wait();
+ }
+ }
+ return rwco.ret;
+}
- return drv->bdrv_read(bs, sector_num, buf, nb_sectors);
+/* return < 0 if error. See bdrv_write() for the return codes */
+int bdrv_read(BlockDriverState *bs, int64_t sector_num,
+ uint8_t *buf, int nb_sectors)
+{
+ return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false);
}
static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num,
@@ -1105,36 +1148,7 @@ static void set_dirty_bitmap(BlockDriverState *bs, int64_t sector_num,
int bdrv_write(BlockDriverState *bs, int64_t sector_num,
const uint8_t *buf, int nb_sectors)
{
- BlockDriver *drv = bs->drv;
-
- if (!bs->drv)
- return -ENOMEDIUM;
-
- if (bdrv_has_async_rw(drv) && qemu_in_coroutine()) {
- QEMUIOVector qiov;
- struct iovec iov = {
- .iov_base = (void *)buf,
- .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
- };
-
- qemu_iovec_init_external(&qiov, &iov, 1);
- return bdrv_co_writev(bs, sector_num, nb_sectors, &qiov);
- }
-
- 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_write(bs, sector_num, buf, nb_sectors);
+ return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true);
}
int bdrv_pread(BlockDriverState *bs, int64_t offset,
@@ -2912,8 +2926,6 @@ static void bdrv_rw_em_cb(void *opaque, int ret)
*(int *)opaque = ret;
}
-#define NOT_DONE 0x7fffffff
-
static int bdrv_read_em(BlockDriverState *bs, int64_t sector_num,
uint8_t *buf, int nb_sectors)
{