block-backend: drop blk_prw, use block-coroutine-wrapper

Let's drop hand-made coroutine wrappers and use coroutine wrapper
generation like in block/io.c.

Now, blk_foo() functions are written in same way as blk_co_foo() ones,
but wrap blk_do_foo() instead of blk_co_do_foo().

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211006131718.214235-8-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: spelling fix]
Signed-off-by: Eric Blake <eblake@redhat.com>

1 files changed, 58 insertions, 93 deletions

diff --git a/block/block-backend.c b/block/block-backend.c
index cecac67485..2e6ccce7ef 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -14,6 +14,7 @@
 #include "sysemu/block-backend.h"
 #include "block/block_int.h"
 #include "block/blockjob.h"
+#include "block/coroutines.h"
 #include "block/throttle-groups.h"
 #include "hw/qdev-core.h"
 #include "sysemu/blockdev.h"
@@ -1204,7 +1205,7 @@ static void coroutine_fn blk_wait_while_drained(BlockBackend *blk)
 }
 
 /* To be called between exactly one pair of blk_inc/dec_in_flight() */
-static int coroutine_fn
+int coroutine_fn
 blk_co_do_preadv(BlockBackend *blk, int64_t offset, int64_t bytes,
                  QEMUIOVector *qiov, BdrvRequestFlags flags)
 {
@@ -1249,7 +1250,7 @@ int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset,
 }
 
 /* To be called between exactly one pair of blk_inc/dec_in_flight() */
-static int coroutine_fn
+int coroutine_fn
 blk_co_do_pwritev_part(BlockBackend *blk, int64_t offset, int64_t bytes,
                        QEMUIOVector *qiov, size_t qiov_offset,
                        BdrvRequestFlags flags)
@@ -1306,6 +1307,20 @@ int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset,
     return blk_co_pwritev_part(blk, offset, bytes, qiov, 0, flags);
 }
 
+static int coroutine_fn blk_pwritev_part(BlockBackend *blk, int64_t offset,
+                                         int64_t bytes,
+                                         QEMUIOVector *qiov, size_t qiov_offset,
+                                         BdrvRequestFlags flags)
+{
+    int ret;
+
+    blk_inc_in_flight(blk);
+    ret = blk_do_pwritev_part(blk, offset, bytes, qiov, qiov_offset, flags);
+    blk_dec_in_flight(blk);
+
+    return ret;
+}
+
 typedef struct BlkRwCo {
     BlockBackend *blk;
     int64_t offset;
@@ -1314,58 +1329,11 @@ typedef struct BlkRwCo {
     BdrvRequestFlags flags;
 } BlkRwCo;
 
-static void blk_read_entry(void *opaque)
-{
-    BlkRwCo *rwco = opaque;
-    QEMUIOVector *qiov = rwco->iobuf;
-
-    rwco->ret = blk_co_do_preadv(rwco->blk, rwco->offset, qiov->size,
-                                 qiov, rwco->flags);
-    aio_wait_kick();
-}
-
-static void blk_write_entry(void *opaque)
-{
-    BlkRwCo *rwco = opaque;
-    QEMUIOVector *qiov = rwco->iobuf;
-
-    rwco->ret = blk_co_do_pwritev_part(rwco->blk, rwco->offset, qiov->size,
-                                       qiov, 0, rwco->flags);
-    aio_wait_kick();
-}
-
-static int blk_prw(BlockBackend *blk, int64_t offset, uint8_t *buf,
-                   int64_t bytes, CoroutineEntry co_entry,
-                   BdrvRequestFlags flags)
-{
-    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
-    BlkRwCo rwco = {
-        .blk    = blk,
-        .offset = offset,
-        .iobuf  = &qiov,
-        .flags  = flags,
-        .ret    = NOT_DONE,
-    };
-
-    blk_inc_in_flight(blk);
-    if (qemu_in_coroutine()) {
-        /* Fast-path if already in coroutine context */
-        co_entry(&rwco);
-    } else {
-        Coroutine *co = qemu_coroutine_create(co_entry, &rwco);
-        bdrv_coroutine_enter(blk_bs(blk), co);
-        BDRV_POLL_WHILE(blk_bs(blk), rwco.ret == NOT_DONE);
-    }
-    blk_dec_in_flight(blk);
-
-    return rwco.ret;
-}
-
 int blk_pwrite_zeroes(BlockBackend *blk, int64_t offset,
                       int bytes, BdrvRequestFlags flags)
 {
-    return blk_prw(blk, offset, NULL, bytes, blk_write_entry,
-                   flags | BDRV_REQ_ZERO_WRITE);
+    return blk_pwritev_part(blk, offset, bytes, NULL, 0,
+                            flags | BDRV_REQ_ZERO_WRITE);
 }
 
 int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags)
@@ -1510,22 +1478,25 @@ BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset,
 
 int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int count)
 {
-    int ret = blk_prw(blk, offset, buf, count, blk_read_entry, 0);
-    if (ret < 0) {
-        return ret;
-    }
-    return count;
+    int ret;
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, count);
+
+    blk_inc_in_flight(blk);
+    ret = blk_do_preadv(blk, offset, count, &qiov, 0);
+    blk_dec_in_flight(blk);
+
+    return ret < 0 ? ret : count;
 }
 
 int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf, int count,
                BdrvRequestFlags flags)
 {
-    int ret = blk_prw(blk, offset, (void *) buf, count, blk_write_entry,
-                      flags);
-    if (ret < 0) {
-        return ret;
-    }
-    return count;
+    int ret;
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, count);
+
+    ret = blk_pwritev_part(blk, offset, count, &qiov, 0, flags);
+
+    return ret < 0 ? ret : count;
 }
 
 int64_t blk_getlength(BlockBackend *blk)
@@ -1582,7 +1553,7 @@ void blk_aio_cancel_async(BlockAIOCB *acb)
 }
 
 /* To be called between exactly one pair of blk_inc/dec_in_flight() */
-static int coroutine_fn
+int coroutine_fn
 blk_co_do_ioctl(BlockBackend *blk, unsigned long int req, void *buf)
 {
     blk_wait_while_drained(blk);
@@ -1594,18 +1565,15 @@ blk_co_do_ioctl(BlockBackend *blk, unsigned long int req, void *buf)
     return bdrv_co_ioctl(blk_bs(blk), req, buf);
 }
 
-static void blk_ioctl_entry(void *opaque)
+int blk_ioctl(BlockBackend *blk, unsigned long int req, void *buf)
 {
-    BlkRwCo *rwco = opaque;
-    QEMUIOVector *qiov = rwco->iobuf;
+    int ret;
 
-    rwco->ret = blk_co_do_ioctl(rwco->blk, rwco->offset, qiov->iov[0].iov_base);
-    aio_wait_kick();
-}
+    blk_inc_in_flight(blk);
+    ret = blk_do_ioctl(blk, req, buf);
+    blk_dec_in_flight(blk);
 
-int blk_ioctl(BlockBackend *blk, unsigned long int req, void *buf)
-{
-    return blk_prw(blk, req, buf, 0, blk_ioctl_entry, 0);
+    return ret;
 }
 
 static void blk_aio_ioctl_entry(void *opaque)
@@ -1625,7 +1593,7 @@ BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf,
 }
 
 /* To be called between exactly one pair of blk_inc/dec_in_flight() */
-static int coroutine_fn
+int coroutine_fn
 blk_co_do_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes)
 {
     int ret;
@@ -1669,22 +1637,19 @@ int coroutine_fn blk_co_pdiscard(BlockBackend *blk, int64_t offset,
     return ret;
 }
 
-static void blk_pdiscard_entry(void *opaque)
+int blk_pdiscard(BlockBackend *blk, int64_t offset, int bytes)
 {
-    BlkRwCo *rwco = opaque;
-    QEMUIOVector *qiov = rwco->iobuf;
+    int ret;
 
-    rwco->ret = blk_co_do_pdiscard(rwco->blk, rwco->offset, qiov->size);
-    aio_wait_kick();
-}
+    blk_inc_in_flight(blk);
+    ret = blk_do_pdiscard(blk, offset, bytes);
+    blk_dec_in_flight(blk);
 
-int blk_pdiscard(BlockBackend *blk, int64_t offset, int bytes)
-{
-    return blk_prw(blk, offset, NULL, bytes, blk_pdiscard_entry, 0);
+    return ret;
 }
 
 /* To be called between exactly one pair of blk_inc/dec_in_flight() */
-static int coroutine_fn blk_co_do_flush(BlockBackend *blk)
+int coroutine_fn blk_co_do_flush(BlockBackend *blk)
 {
     blk_wait_while_drained(blk);
 
@@ -1721,16 +1686,15 @@ int coroutine_fn blk_co_flush(BlockBackend *blk)
     return ret;
 }
 
-static void blk_flush_entry(void *opaque)
-{
-    BlkRwCo *rwco = opaque;
-    rwco->ret = blk_co_do_flush(rwco->blk);
-    aio_wait_kick();
-}
-
 int blk_flush(BlockBackend *blk)
 {
-    return blk_prw(blk, 0, NULL, 0, blk_flush_entry, 0);
+    int ret;
+
+    blk_inc_in_flight(blk);
+    ret = blk_do_flush(blk);
+    blk_dec_in_flight(blk);
+
+    return ret;
 }
 
 void blk_drain(BlockBackend *blk)
@@ -2224,8 +2188,9 @@ int coroutine_fn blk_co_pwrite_zeroes(BlockBackend *blk, int64_t offset,
 int blk_pwrite_compressed(BlockBackend *blk, int64_t offset, const void *buf,
                           int count)
 {
-    return blk_prw(blk, offset, (void *) buf, count, blk_write_entry,
-                   BDRV_REQ_WRITE_COMPRESSED);
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, count);
+    return blk_pwritev_part(blk, offset, count, &qiov, 0,
+                            BDRV_REQ_WRITE_COMPRESSED);
 }
 
 int blk_truncate(BlockBackend *blk, int64_t offset, bool exact,