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GET /api/patches/813562/?format=api
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{
    "id": 813562,
    "url": "http://patchwork.ozlabs.org/api/patches/813562/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170913181910.29688-6-mreitz@redhat.com/",
    "project": {
        "id": 14,
        "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api",
        "name": "QEMU Development",
        "link_name": "qemu-devel",
        "list_id": "qemu-devel.nongnu.org",
        "list_email": "qemu-devel@nongnu.org",
        "web_url": "",
        "scm_url": "",
        "webscm_url": "",
        "list_archive_url": "",
        "list_archive_url_format": "",
        "commit_url_format": ""
    },
    "msgid": "<20170913181910.29688-6-mreitz@redhat.com>",
    "list_archive_url": null,
    "date": "2017-09-13T18:18:57",
    "name": "[05/18] block/mirror: Convert to coroutines",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "5d756ac3652fb51ea3cc77705efe29afe7928dee",
    "submitter": {
        "id": 36836,
        "url": "http://patchwork.ozlabs.org/api/people/36836/?format=api",
        "name": "Max Reitz",
        "email": "mreitz@redhat.com"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170913181910.29688-6-mreitz@redhat.com/mbox/",
    "series": [
        {
            "id": 2960,
            "url": "http://patchwork.ozlabs.org/api/series/2960/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=2960",
            "date": "2017-09-13T18:18:52",
            "name": "block/mirror: Add active-sync mirroring",
            "version": 1,
            "mbox": "http://patchwork.ozlabs.org/series/2960/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/813562/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/813562/checks/",
    "tags": {},
    "related": [],
    "headers": {
        "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>",
        "X-Original-To": "incoming@patchwork.ozlabs.org",
        "Delivered-To": "patchwork-incoming@bilbo.ozlabs.org",
        "Authentication-Results": [
            "ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=<UNKNOWN>)",
            "ext-mx10.extmail.prod.ext.phx2.redhat.com;\n\tdmarc=none (p=none dis=none) header.from=redhat.com",
            "ext-mx10.extmail.prod.ext.phx2.redhat.com;\n\tspf=fail smtp.mailfrom=mreitz@redhat.com"
        ],
        "Received": [
            "from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xsqql25gJz9s3T\n\tfor <incoming@patchwork.ozlabs.org>;\n\tThu, 14 Sep 2017 04:26:27 +1000 (AEST)",
            "from localhost ([::1]:44023 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>)\n\tid 1dsCMj-0004K1-AW\n\tfor incoming@patchwork.ozlabs.org; Wed, 13 Sep 2017 14:26:25 -0400",
            "from eggs.gnu.org ([2001:4830:134:3::10]:36676)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <mreitz@redhat.com>) id 1dsCGn-0008Do-IJ\n\tfor qemu-devel@nongnu.org; Wed, 13 Sep 2017 14:20:19 -0400",
            "from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from <mreitz@redhat.com>) id 1dsCGm-00057n-7y\n\tfor qemu-devel@nongnu.org; Wed, 13 Sep 2017 14:20:17 -0400",
            "from mx1.redhat.com ([209.132.183.28]:58496)\n\tby eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32)\n\t(Exim 4.71) (envelope-from <mreitz@redhat.com>)\n\tid 1dsCGf-0004yt-1r; Wed, 13 Sep 2017 14:20:09 -0400",
            "from smtp.corp.redhat.com\n\t(int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15])\n\t(using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby mx1.redhat.com (Postfix) with ESMTPS id 1E1435D689;\n\tWed, 13 Sep 2017 18:20:08 +0000 (UTC)",
            "from localhost (ovpn-204-23.brq.redhat.com [10.40.204.23])\n\tby smtp.corp.redhat.com (Postfix) with ESMTPS id 130495D6AE;\n\tWed, 13 Sep 2017 18:19:58 +0000 (UTC)"
        ],
        "DMARC-Filter": "OpenDMARC Filter v1.3.2 mx1.redhat.com 1E1435D689",
        "From": "Max Reitz <mreitz@redhat.com>",
        "To": "qemu-block@nongnu.org",
        "Date": "Wed, 13 Sep 2017 20:18:57 +0200",
        "Message-Id": "<20170913181910.29688-6-mreitz@redhat.com>",
        "In-Reply-To": "<20170913181910.29688-1-mreitz@redhat.com>",
        "References": "<20170913181910.29688-1-mreitz@redhat.com>",
        "X-Scanned-By": "MIMEDefang 2.79 on 10.5.11.15",
        "X-Greylist": "Sender IP whitelisted, not delayed by milter-greylist-4.5.16\n\t(mx1.redhat.com [10.5.110.39]);\n\tWed, 13 Sep 2017 18:20:08 +0000 (UTC)",
        "X-detected-operating-system": "by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic]\n\t[fuzzy]",
        "X-Received-From": "209.132.183.28",
        "Subject": "[Qemu-devel] [PATCH 05/18] block/mirror: Convert to coroutines",
        "X-BeenThere": "qemu-devel@nongnu.org",
        "X-Mailman-Version": "2.1.21",
        "Precedence": "list",
        "List-Id": "<qemu-devel.nongnu.org>",
        "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n\t<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>",
        "List-Archive": "<http://lists.nongnu.org/archive/html/qemu-devel/>",
        "List-Post": "<mailto:qemu-devel@nongnu.org>",
        "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>",
        "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n\t<mailto:qemu-devel-request@nongnu.org?subject=subscribe>",
        "Cc": "Kevin Wolf <kwolf@redhat.com>, Fam Zheng <famz@redhat.com>,\n\tqemu-devel@nongnu.org, Max Reitz <mreitz@redhat.com>,\n\tStefan Hajnoczi <stefanha@redhat.com>, John Snow <jsnow@redhat.com>",
        "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org",
        "Sender": "\"Qemu-devel\"\n\t<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>"
    },
    "content": "In order to talk to the source BDS (and maybe in the future to the\ntarget BDS as well) directly, we need to convert our existing AIO\nrequests into coroutine I/O requests.\n\nSigned-off-by: Max Reitz <mreitz@redhat.com>\n---\n block/mirror.c | 134 +++++++++++++++++++++++++++++++++------------------------\n 1 file changed, 78 insertions(+), 56 deletions(-)",
    "diff": "diff --git a/block/mirror.c b/block/mirror.c\nindex 4664b0516f..2b3297aa61 100644\n--- a/block/mirror.c\n+++ b/block/mirror.c\n@@ -80,6 +80,9 @@ typedef struct MirrorOp {\n     QEMUIOVector qiov;\n     int64_t offset;\n     uint64_t bytes;\n+\n+    /* Set by mirror_co_read() before yielding for the first time */\n+    uint64_t bytes_copied;\n } MirrorOp;\n \n typedef enum MirrorMethod {\n@@ -101,7 +104,7 @@ static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read,\n     }\n }\n \n-static void mirror_iteration_done(MirrorOp *op, int ret)\n+static void coroutine_fn mirror_iteration_done(MirrorOp *op, int ret)\n {\n     MirrorBlockJob *s = op->s;\n     struct iovec *iov;\n@@ -138,9 +141,8 @@ static void mirror_iteration_done(MirrorOp *op, int ret)\n     }\n }\n \n-static void mirror_write_complete(void *opaque, int ret)\n+static void coroutine_fn mirror_write_complete(MirrorOp *op, int ret)\n {\n-    MirrorOp *op = opaque;\n     MirrorBlockJob *s = op->s;\n \n     aio_context_acquire(blk_get_aio_context(s->common.blk));\n@@ -158,9 +160,8 @@ static void mirror_write_complete(void *opaque, int ret)\n     aio_context_release(blk_get_aio_context(s->common.blk));\n }\n \n-static void mirror_read_complete(void *opaque, int ret)\n+static void coroutine_fn mirror_read_complete(MirrorOp *op, int ret)\n {\n-    MirrorOp *op = opaque;\n     MirrorBlockJob *s = op->s;\n \n     aio_context_acquire(blk_get_aio_context(s->common.blk));\n@@ -176,8 +177,11 @@ static void mirror_read_complete(void *opaque, int ret)\n \n         mirror_iteration_done(op, ret);\n     } else {\n-        blk_aio_pwritev(s->target, op->offset, &op->qiov,\n-                        0, mirror_write_complete, op);\n+        int ret;\n+\n+        ret = blk_co_pwritev(s->target, op->offset,\n+                             op->qiov.size, &op->qiov, 0);\n+        mirror_write_complete(op, ret);\n     }\n     aio_context_release(blk_get_aio_context(s->common.blk));\n }\n@@ -242,53 +246,49 @@ static inline void mirror_wait_for_io(MirrorBlockJob *s)\n  *          (new_end - offset) if tail is rounded up or down due to\n  *          alignment or buffer limit.\n  */\n-static uint64_t mirror_do_read(MirrorBlockJob *s, int64_t offset,\n-                               uint64_t bytes)\n+static void coroutine_fn mirror_co_read(void *opaque)\n {\n+    MirrorOp *op = opaque;\n+    MirrorBlockJob *s = op->s;\n     BlockBackend *source = s->common.blk;\n     int nb_chunks;\n     uint64_t ret;\n-    MirrorOp *op;\n     uint64_t max_bytes;\n \n     max_bytes = s->granularity * s->max_iov;\n \n     /* We can only handle as much as buf_size at a time. */\n-    bytes = MIN(s->buf_size, MIN(max_bytes, bytes));\n-    assert(bytes);\n-    assert(bytes < BDRV_REQUEST_MAX_BYTES);\n-    ret = bytes;\n+    op->bytes = MIN(s->buf_size, MIN(max_bytes, op->bytes));\n+    assert(op->bytes);\n+    assert(op->bytes < BDRV_REQUEST_MAX_BYTES);\n+    op->bytes_copied = op->bytes;\n \n     if (s->cow_bitmap) {\n-        ret += mirror_cow_align(s, &offset, &bytes);\n+        op->bytes_copied += mirror_cow_align(s, &op->offset, &op->bytes);\n     }\n-    assert(bytes <= s->buf_size);\n+    /* Cannot exceed BDRV_REQUEST_MAX_BYTES + INT_MAX */\n+    assert(op->bytes_copied <= UINT_MAX);\n+    assert(op->bytes <= s->buf_size);\n     /* The offset is granularity-aligned because:\n      * 1) Caller passes in aligned values;\n      * 2) mirror_cow_align is used only when target cluster is larger. */\n-    assert(QEMU_IS_ALIGNED(offset, s->granularity));\n+    assert(QEMU_IS_ALIGNED(op->offset, s->granularity));\n     /* The range is sector-aligned, since bdrv_getlength() rounds up. */\n-    assert(QEMU_IS_ALIGNED(bytes, BDRV_SECTOR_SIZE));\n-    nb_chunks = DIV_ROUND_UP(bytes, s->granularity);\n+    assert(QEMU_IS_ALIGNED(op->bytes, BDRV_SECTOR_SIZE));\n+    nb_chunks = DIV_ROUND_UP(op->bytes, s->granularity);\n \n     while (s->buf_free_count < nb_chunks) {\n-        trace_mirror_yield_in_flight(s, offset, s->in_flight);\n+        trace_mirror_yield_in_flight(s, op->offset, s->in_flight);\n         mirror_wait_for_io(s);\n     }\n \n-    /* Allocate a MirrorOp that is used as an AIO callback.  */\n-    op = g_new(MirrorOp, 1);\n-    op->s = s;\n-    op->offset = offset;\n-    op->bytes = bytes;\n-\n     /* Now make a QEMUIOVector taking enough granularity-sized chunks\n      * from s->buf_free.\n      */\n     qemu_iovec_init(&op->qiov, nb_chunks);\n     while (nb_chunks-- > 0) {\n         MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free);\n-        size_t remaining = bytes - op->qiov.size;\n+        size_t remaining = op->bytes - op->qiov.size;\n \n         QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next);\n         s->buf_free_count--;\n@@ -297,53 +297,75 @@ static uint64_t mirror_do_read(MirrorBlockJob *s, int64_t offset,\n \n     /* Copy the dirty cluster.  */\n     s->in_flight++;\n-    s->bytes_in_flight += bytes;\n-    trace_mirror_one_iteration(s, offset, bytes);\n+    s->bytes_in_flight += op->bytes;\n+    trace_mirror_one_iteration(s, op->offset, op->bytes);\n \n-    blk_aio_preadv(source, offset, &op->qiov, 0, mirror_read_complete, op);\n-    return ret;\n+    ret = blk_co_preadv(source, op->offset, op->bytes, &op->qiov, 0);\n+    mirror_read_complete(op, ret);\n }\n \n-static void mirror_do_zero_or_discard(MirrorBlockJob *s,\n-                                      int64_t offset,\n-                                      uint64_t bytes,\n-                                      bool is_discard)\n+static void coroutine_fn mirror_co_zero(void *opaque)\n {\n-    MirrorOp *op;\n+    MirrorOp *op = opaque;\n+    int ret;\n \n-    /* Allocate a MirrorOp that is used as an AIO callback. The qiov is zeroed\n-     * so the freeing in mirror_iteration_done is nop. */\n-    op = g_new0(MirrorOp, 1);\n-    op->s = s;\n-    op->offset = offset;\n-    op->bytes = bytes;\n+    op->s->in_flight++;\n+    op->s->bytes_in_flight += op->bytes;\n \n-    s->in_flight++;\n-    s->bytes_in_flight += bytes;\n-    if (is_discard) {\n-        blk_aio_pdiscard(s->target, offset,\n-                         op->bytes, mirror_write_complete, op);\n-    } else {\n-        blk_aio_pwrite_zeroes(s->target, offset,\n-                              op->bytes, s->unmap ? BDRV_REQ_MAY_UNMAP : 0,\n-                              mirror_write_complete, op);\n-    }\n+    ret = blk_co_pwrite_zeroes(op->s->target, op->offset, op->bytes,\n+                               op->s->unmap ? BDRV_REQ_MAY_UNMAP : 0);\n+    mirror_write_complete(op, ret);\n+}\n+\n+static void coroutine_fn mirror_co_discard(void *opaque)\n+{\n+    MirrorOp *op = opaque;\n+    int ret;\n+\n+    op->s->in_flight++;\n+    op->s->bytes_in_flight += op->bytes;\n+\n+    ret = blk_co_pdiscard(op->s->target, op->offset, op->bytes);\n+    mirror_write_complete(op, ret);\n }\n \n static unsigned mirror_perform(MirrorBlockJob *s, int64_t offset,\n                                unsigned bytes, MirrorMethod mirror_method)\n {\n+    MirrorOp *op;\n+    Coroutine *co;\n+    unsigned ret = bytes;\n+\n+    op = g_new(MirrorOp, 1);\n+    *op = (MirrorOp){\n+        .s      = s,\n+        .offset = offset,\n+        .bytes  = bytes,\n+    };\n+\n     switch (mirror_method) {\n     case MIRROR_METHOD_COPY:\n-        return mirror_do_read(s, offset, bytes);\n+        co = qemu_coroutine_create(mirror_co_read, op);\n+        break;\n     case MIRROR_METHOD_ZERO:\n+        co = qemu_coroutine_create(mirror_co_zero, op);\n+        break;\n     case MIRROR_METHOD_DISCARD:\n-        mirror_do_zero_or_discard(s, offset, bytes,\n-                                  mirror_method == MIRROR_METHOD_DISCARD);\n-        return bytes;\n+        co = qemu_coroutine_create(mirror_co_discard, op);\n+        break;\n     default:\n         abort();\n     }\n+\n+    qemu_coroutine_enter(co);\n+\n+    if (mirror_method == MIRROR_METHOD_COPY) {\n+        /* Same assertion as in mirror_co_read() */\n+        assert(op->bytes_copied <= UINT_MAX);\n+        ret = op->bytes_copied;\n+    }\n+\n+    return ret;\n }\n \n static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)\n",
    "prefixes": [
        "05/18"
    ]
}