From 207dc8620ffb1a1bdbfaddba5208a82f93058b2c Mon Sep 17 00:00:00 2001
From: Maxim Levitsky <mlevitsk@redhat.com>
Date: Wed, 5 Jun 2019 13:57:02 +0200
Subject: [PATCH 14/23] file-posix: Avoid aio_worker() for
 QEMU_AIO_WRITE_ZEROES

RH-Author: Maxim Levitsky <mlevitsk@redhat.com>
Message-id: <20190605135705.24526-7-mlevitsk@redhat.com>
Patchwork-id: 88561
O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH 6/9] file-posix: Avoid aio_worker() for QEMU_AIO_WRITE_ZEROES
Bugzilla: 1648622
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: John Snow <jsnow@redhat.com>

From: Kevin Wolf <kwolf@redhat.com>

aio_worker() doesn't add anything interesting, it's only a useless
indirection. Call the handler function directly instead.

As we know that this handler function is only called from coroutine
context and the coroutine stays around until the worker thread finishes,
we can keep RawPosixAIOData on the stack.

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

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1648622

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
(Cherry picked from 7154d8ae66c75c97b08c8f1c80dd6f46f0dbffca)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 block/file-posix.c | 53 ++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 34 insertions(+), 19 deletions(-)

diff --git a/block/file-posix.c b/block/file-posix.c
index 74da336..90c719f 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1465,8 +1465,9 @@ static ssize_t handle_aiocb_write_zeroes_block(RawPosixAIOData *aiocb)
     return ret;
 }
 
-static ssize_t handle_aiocb_write_zeroes(RawPosixAIOData *aiocb)
+static int handle_aiocb_write_zeroes(void *opaque)
 {
+    RawPosixAIOData *aiocb = opaque;
 #if defined(CONFIG_FALLOCATE) || defined(CONFIG_XFS)
     BDRVRawState *s = aiocb->bs->opaque;
 #endif
@@ -1530,8 +1531,9 @@ static ssize_t handle_aiocb_write_zeroes(RawPosixAIOData *aiocb)
     return -ENOTSUP;
 }
 
-static ssize_t handle_aiocb_write_zeroes_unmap(RawPosixAIOData *aiocb)
+static int handle_aiocb_write_zeroes_unmap(void *opaque)
 {
+    RawPosixAIOData *aiocb = opaque;
     BDRVRawState *s G_GNUC_UNUSED = aiocb->bs->opaque;
     int ret;
 
@@ -1797,11 +1799,7 @@ static int aio_worker(void *arg)
         ret = handle_aiocb_discard(aiocb);
         break;
     case QEMU_AIO_WRITE_ZEROES:
-        ret = handle_aiocb_write_zeroes(aiocb);
-        break;
     case QEMU_AIO_WRITE_ZEROES | QEMU_AIO_DISCARD:
-        ret = handle_aiocb_write_zeroes_unmap(aiocb);
-        break;
     case QEMU_AIO_COPY_RANGE:
         ret = handle_aiocb_copy_range(aiocb);
         break;
@@ -2518,18 +2516,41 @@ static coroutine_fn BlockAIOCB *raw_aio_pdiscard(BlockDriverState *bs,
                        cb, opaque, QEMU_AIO_DISCARD);
 }
 
-static int coroutine_fn raw_co_pwrite_zeroes(
-    BlockDriverState *bs, int64_t offset,
-    int bytes, BdrvRequestFlags flags)
+static int coroutine_fn
+raw_do_pwrite_zeroes(BlockDriverState *bs, int64_t offset, int bytes,
+                     BdrvRequestFlags flags, bool blkdev)
 {
     BDRVRawState *s = bs->opaque;
-    int operation = QEMU_AIO_WRITE_ZEROES;
+    RawPosixAIOData acb;
+    ThreadPoolFunc *handler;
+
+    acb = (RawPosixAIOData) {
+        .bs             = bs,
+        .aio_fildes     = s->fd,
+        .aio_type       = QEMU_AIO_WRITE_ZEROES,
+        .aio_offset     = offset,
+        .aio_nbytes     = bytes,
+    };
+
+    if (blkdev) {
+        acb.aio_type |= QEMU_AIO_BLKDEV;
+    }
 
     if (flags & BDRV_REQ_MAY_UNMAP) {
-        operation |= QEMU_AIO_DISCARD;
+        acb.aio_type |= QEMU_AIO_DISCARD;
+        handler = handle_aiocb_write_zeroes_unmap;
+    } else {
+        handler = handle_aiocb_write_zeroes;
     }
 
-    return paio_submit_co(bs, s->fd, offset, NULL, bytes, operation);
+    return raw_thread_pool_submit(bs, handler, &acb);
+}
+
+static int coroutine_fn raw_co_pwrite_zeroes(
+    BlockDriverState *bs, int64_t offset,
+    int bytes, BdrvRequestFlags flags)
+{
+    return raw_do_pwrite_zeroes(bs, offset, bytes, flags, false);
 }
 
 static int raw_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
@@ -3093,8 +3114,6 @@ static coroutine_fn BlockAIOCB *hdev_aio_pdiscard(BlockDriverState *bs,
 static coroutine_fn int hdev_co_pwrite_zeroes(BlockDriverState *bs,
     int64_t offset, int bytes, BdrvRequestFlags flags)
 {
-    BDRVRawState *s = bs->opaque;
-    int operation = QEMU_AIO_WRITE_ZEROES | QEMU_AIO_BLKDEV;
     int rc;
 
     rc = fd_open(bs);
@@ -3102,11 +3121,7 @@ static coroutine_fn int hdev_co_pwrite_zeroes(BlockDriverState *bs,
         return rc;
     }
 
-    if (flags & BDRV_REQ_MAY_UNMAP) {
-        operation |= QEMU_AIO_DISCARD;
-    }
-
-    return paio_submit_co(bs, s->fd, offset, NULL, bytes, operation);
+    return raw_do_pwrite_zeroes(bs, offset, bytes, flags, true);
 }
 
 static int coroutine_fn hdev_co_create_opts(const char *filename, QemuOpts *opts,
-- 
1.8.3.1