get:
Show a patch.

patch:
Update a patch.

put:
Update a patch.

GET /api/patches/816238/?format=api
HTTP 200 OK
Allow: GET, PUT, PATCH, HEAD, OPTIONS
Content-Type: application/json
Vary: Accept

{
    "id": 816238,
    "url": "http://patchwork.ozlabs.org/api/patches/816238/?format=api",
    "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170920102311.25736-2-el13635@mail.ntua.gr/",
    "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": "<20170920102311.25736-2-el13635@mail.ntua.gr>",
    "list_archive_url": null,
    "date": "2017-09-20T10:23:09",
    "name": "[1/3] block: add bdrv_co_drain_end callback",
    "commit_ref": null,
    "pull_url": null,
    "state": "new",
    "archived": false,
    "hash": "6699fc132f2fd048c72e3abae0e2a38aaa243352",
    "submitter": {
        "id": 71571,
        "url": "http://patchwork.ozlabs.org/api/people/71571/?format=api",
        "name": "Manos Pitsidianakis",
        "email": "el13635@mail.ntua.gr"
    },
    "delegate": null,
    "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20170920102311.25736-2-el13635@mail.ntua.gr/mbox/",
    "series": [
        {
            "id": 4124,
            "url": "http://patchwork.ozlabs.org/api/series/4124/?format=api",
            "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=4124",
            "date": "2017-09-20T10:23:09",
            "name": "add bdrv_co_drain_begin/end BlockDriver callbacks",
            "version": 1,
            "mbox": "http://patchwork.ozlabs.org/series/4124/mbox/"
        }
    ],
    "comments": "http://patchwork.ozlabs.org/api/patches/816238/comments/",
    "check": "pending",
    "checks": "http://patchwork.ozlabs.org/api/patches/816238/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>)",
        "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 3xy1bg3NZKz9s7h\n\tfor <incoming@patchwork.ozlabs.org>;\n\tThu, 21 Sep 2017 00:00:31 +1000 (AEST)",
            "from localhost ([::1]:48267 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 1dufYD-0005qy-He\n\tfor incoming@patchwork.ozlabs.org; Wed, 20 Sep 2017 10:00:29 -0400",
            "from eggs.gnu.org ([2001:4830:134:3::10]:41727)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <el13635@mail.ntua.gr>) id 1dufAV-00024V-PE\n\tfor qemu-devel@nongnu.org; Wed, 20 Sep 2017 09:36:00 -0400",
            "from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from <el13635@mail.ntua.gr>) id 1dufAT-00011q-0S\n\tfor qemu-devel@nongnu.org; Wed, 20 Sep 2017 09:35:59 -0400",
            "from smtp1.ntua.gr ([2001:648:2000:de::183]:20570)\n\tby eggs.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from <el13635@mail.ntua.gr>)\n\tid 1dufAP-0000sM-HV; Wed, 20 Sep 2017 09:35:53 -0400",
            "from mail.ntua.gr (carp0.noc.ntua.gr [147.102.222.60])\n\t(authenticated bits=0)\n\tby smtp1.ntua.gr (8.15.2/8.15.2) with ESMTPSA id v8KANNHw022771\n\t(version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256\n\tverify=NOT); Wed, 20 Sep 2017 13:23:24 +0300 (EEST)\n\t(envelope-from el13635@mail.ntua.gr)"
        ],
        "X-Authentication-Warning": "smtp1.ntua.gr: Host carp0.noc.ntua.gr\n\t[147.102.222.60] claimed to be mail.ntua.gr",
        "From": "Manos Pitsidianakis <el13635@mail.ntua.gr>",
        "To": "qemu-devel <qemu-devel@nongnu.org>",
        "Date": "Wed, 20 Sep 2017 13:23:09 +0300",
        "Message-Id": "<20170920102311.25736-2-el13635@mail.ntua.gr>",
        "X-Mailer": "git-send-email 2.11.0",
        "In-Reply-To": "<20170920102311.25736-1-el13635@mail.ntua.gr>",
        "References": "<20170920102311.25736-1-el13635@mail.ntua.gr>",
        "X-detected-operating-system": "by eggs.gnu.org: Genre and OS details not\n\trecognized.",
        "X-Received-From": "2001:648:2000:de::183",
        "Subject": "[Qemu-devel] [PATCH 1/3] block: add bdrv_co_drain_end callback",
        "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\tStefan Hajnoczi <stefanha@redhat.com>,\n\tqemu-block <qemu-block@nongnu.org>, Max Reitz <mreitz@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": "BlockDriverState has a bdrv_do_drain() callback but no equivalent for the end\nof the drain. The throttle driver (block/throttle.c) needs a way to mark the\nend of the drain in order to toggle io_limits_disabled correctly, thus\nbdrv_co_drain_end is needed.\n\nSigned-off-by: Manos Pitsidianakis <el13635@mail.ntua.gr>\n---\n include/block/block_int.h |  2 ++\n block/io.c                | 43 +++++++++++++++++++++++++++++++------------\n 2 files changed, 33 insertions(+), 12 deletions(-)",
    "diff": "diff --git a/include/block/block_int.h b/include/block/block_int.h\nindex ba4c383393..ea1326e3c7 100644\n--- a/include/block/block_int.h\n+++ b/include/block/block_int.h\n@@ -359,6 +359,8 @@ struct BlockDriver {\n      */\n     void coroutine_fn (*bdrv_co_drain)(BlockDriverState *bs);\n \n+    void coroutine_fn (*bdrv_co_drain_end)(BlockDriverState *bs);\n+\n     void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState *child,\n                            Error **errp);\n     void (*bdrv_del_child)(BlockDriverState *parent, BdrvChild *child,\ndiff --git a/block/io.c b/block/io.c\nindex 4378ae4c7d..465345289d 100644\n--- a/block/io.c\n+++ b/block/io.c\n@@ -153,6 +153,7 @@ typedef struct {\n     Coroutine *co;\n     BlockDriverState *bs;\n     bool done;\n+    bool begin;\n } BdrvCoDrainData;\n \n static void coroutine_fn bdrv_drain_invoke_entry(void *opaque)\n@@ -160,18 +161,23 @@ static void coroutine_fn bdrv_drain_invoke_entry(void *opaque)\n     BdrvCoDrainData *data = opaque;\n     BlockDriverState *bs = data->bs;\n \n-    bs->drv->bdrv_co_drain(bs);\n+    if (data->begin) {\n+        bs->drv->bdrv_co_drain(bs);\n+    } else {\n+        bs->drv->bdrv_co_drain_end(bs);\n+    }\n \n     /* Set data->done before reading bs->wakeup.  */\n     atomic_mb_set(&data->done, true);\n     bdrv_wakeup(bs);\n }\n \n-static void bdrv_drain_invoke(BlockDriverState *bs)\n+static void bdrv_drain_invoke(BlockDriverState *bs, bool begin)\n {\n-    BdrvCoDrainData data = { .bs = bs, .done = false };\n+    BdrvCoDrainData data = { .bs = bs, .done = false, .begin = begin};\n \n-    if (!bs->drv || !bs->drv->bdrv_co_drain) {\n+    if (!bs->drv || (begin && !bs->drv->bdrv_co_drain) ||\n+            (!begin && !bs->drv->bdrv_co_drain_end)) {\n         return;\n     }\n \n@@ -180,7 +186,7 @@ static void bdrv_drain_invoke(BlockDriverState *bs)\n     BDRV_POLL_WHILE(bs, !data.done);\n }\n \n-static bool bdrv_drain_recurse(BlockDriverState *bs)\n+static bool bdrv_drain_recurse(BlockDriverState *bs, bool begin)\n {\n     BdrvChild *child, *tmp;\n     bool waited;\n@@ -188,7 +194,7 @@ static bool bdrv_drain_recurse(BlockDriverState *bs)\n     waited = BDRV_POLL_WHILE(bs, atomic_read(&bs->in_flight) > 0);\n \n     /* Ensure any pending metadata writes are submitted to bs->file.  */\n-    bdrv_drain_invoke(bs);\n+    bdrv_drain_invoke(bs, begin);\n \n     QLIST_FOREACH_SAFE(child, &bs->children, next, tmp) {\n         BlockDriverState *bs = child->bs;\n@@ -205,7 +211,7 @@ static bool bdrv_drain_recurse(BlockDriverState *bs)\n              */\n             bdrv_ref(bs);\n         }\n-        waited |= bdrv_drain_recurse(bs);\n+        waited |= bdrv_drain_recurse(bs, begin);\n         if (in_main_loop) {\n             bdrv_unref(bs);\n         }\n@@ -221,12 +227,18 @@ static void bdrv_co_drain_bh_cb(void *opaque)\n     BlockDriverState *bs = data->bs;\n \n     bdrv_dec_in_flight(bs);\n-    bdrv_drained_begin(bs);\n+    if (data->begin) {\n+        bdrv_drained_begin(bs);\n+    } else {\n+        bdrv_drained_end(bs);\n+    }\n+\n     data->done = true;\n     aio_co_wake(co);\n }\n \n-static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs)\n+static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,\n+                                                bool begin)\n {\n     BdrvCoDrainData data;\n \n@@ -239,6 +251,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs)\n         .co = qemu_coroutine_self(),\n         .bs = bs,\n         .done = false,\n+        .begin = begin,\n     };\n     bdrv_inc_in_flight(bs);\n     aio_bh_schedule_oneshot(bdrv_get_aio_context(bs),\n@@ -253,7 +266,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs)\n void bdrv_drained_begin(BlockDriverState *bs)\n {\n     if (qemu_in_coroutine()) {\n-        bdrv_co_yield_to_drain(bs);\n+        bdrv_co_yield_to_drain(bs, true);\n         return;\n     }\n \n@@ -262,17 +275,22 @@ void bdrv_drained_begin(BlockDriverState *bs)\n         bdrv_parent_drained_begin(bs);\n     }\n \n-    bdrv_drain_recurse(bs);\n+    bdrv_drain_recurse(bs, true);\n }\n \n void bdrv_drained_end(BlockDriverState *bs)\n {\n+    if (qemu_in_coroutine()) {\n+        bdrv_co_yield_to_drain(bs, false);\n+        return;\n+    }\n     assert(bs->quiesce_counter > 0);\n     if (atomic_fetch_dec(&bs->quiesce_counter) > 1) {\n         return;\n     }\n \n     bdrv_parent_drained_end(bs);\n+    bdrv_drain_recurse(bs, false);\n     aio_enable_external(bdrv_get_aio_context(bs));\n }\n \n@@ -350,7 +368,7 @@ void bdrv_drain_all_begin(void)\n             aio_context_acquire(aio_context);\n             for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {\n                 if (aio_context == bdrv_get_aio_context(bs)) {\n-                    waited |= bdrv_drain_recurse(bs);\n+                    waited |= bdrv_drain_recurse(bs, true);\n                 }\n             }\n             aio_context_release(aio_context);\n@@ -371,6 +389,7 @@ void bdrv_drain_all_end(void)\n         aio_context_acquire(aio_context);\n         aio_enable_external(aio_context);\n         bdrv_parent_drained_end(bs);\n+        bdrv_drain_recurse(bs, false);\n         aio_context_release(aio_context);\n     }\n \n",
    "prefixes": [
        "1/3"
    ]
}