From 952ef02c7ee3c2bdbe1856c394ff68b2677b3702 Mon Sep 17 00:00:00 2001

From: Paolo Bonzini <pbonzini@redhat.com>

Date: Wed, 17 May 2017 13:09:20 +0200

Subject: [PATCH 14/27] curl: convert readv to coroutines

RH-Author: Paolo Bonzini <pbonzini@redhat.com>

Message-id: <20170517130921.27402-7-pbonzini@redhat.com>

Patchwork-id: 75268

O-Subject: [RHEL7.4 qemu-kvm PATCH v2 6/7] curl: convert readv to coroutines

Bugzilla: 1437393

RH-Acked-by: Max Reitz <mreitz@redhat.com>

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Jeffrey Cody <jcody@redhat.com>

This is pretty simple.  The bottom half goes away because, unlike

bdrv_aio_readv, coroutine-based read can return immediately without

yielding.  However, for simplicity I kept the former bottom half

handler in a separate function.

Reviewed-by: Jeff Cody <jcody@redhat.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Reviewed-by: Max Reitz <mreitz@redhat.com>

Message-id: 20170515100059.15795-7-pbonzini@redhat.com

Signed-off-by: Jeff Cody <jcody@redhat.com>

(cherry picked from commit 28256d8246f8905cc41cae3db50e5967059d4600)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 block/curl.c | 94 ++++++++++++++++++++++++------------------------------------

 1 file changed, 38 insertions(+), 56 deletions(-)

diff --git a/block/curl.c b/block/curl.c

index cca6386..acfbe52 100644

--- a/block/curl.c

+++ b/block/curl.c

@@ -76,10 +76,6 @@ static CURLMcode __curl_multi_socket_action(CURLM *multi_handle,

 #define CURL_TIMEOUT_DEFAULT 5

 #define CURL_TIMEOUT_MAX 10000

-#define FIND_RET_NONE   0

-#define FIND_RET_OK     1

-#define FIND_RET_WAIT   2

-

 #define CURL_BLOCK_OPT_URL       "url"

 #define CURL_BLOCK_OPT_READAHEAD "readahead"

 #define CURL_BLOCK_OPT_SSLVERIFY "sslverify"

@@ -93,11 +89,12 @@ static CURLMcode __curl_multi_socket_action(CURLM *multi_handle,

 struct BDRVCURLState;

 typedef struct CURLAIOCB {

-    BlockAIOCB common;

+    Coroutine *co;

     QEMUIOVector *qiov;

     uint64_t offset;

     uint64_t bytes;

+    int ret;

     size_t start;

     size_t end;

@@ -268,11 +265,11 @@ static size_t curl_read_cb(void *ptr, size_t size, size_t nmemb, void *opaque)

                                   request_length - offset);

             }

+            acb->ret = 0;

+            s->acb[i] = NULL;

             qemu_mutex_unlock(&s->s->mutex);

-            acb->common.cb(acb->common.opaque, 0);

+            aio_co_wake(acb->co);

             qemu_mutex_lock(&s->s->mutex);

-            qemu_aio_unref(acb);

-            s->acb[i] = NULL;

         }

     }

@@ -282,8 +279,8 @@ read_end:

 }

 /* Called with s->mutex held.  */

-static int curl_find_buf(BDRVCURLState *s, uint64_t start, uint64_t len,

-                         CURLAIOCB *acb)

+static bool curl_find_buf(BDRVCURLState *s, uint64_t start, uint64_t len,

+                          CURLAIOCB *acb)

 {

     int i;

     uint64_t end = start + len;

@@ -312,7 +309,8 @@ static int curl_find_buf(BDRVCURLState *s, uint64_t start, uint64_t len,

             if (clamped_len < len) {

                 qemu_iovec_memset(acb->qiov, clamped_len, 0, len - clamped_len);

             }

-            return FIND_RET_OK;

+            acb->ret = 0;

+            return true;

         }

         // Wait for unfinished chunks

@@ -330,13 +328,13 @@ static int curl_find_buf(BDRVCURLState *s, uint64_t start, uint64_t len,

             for (j=0; j

                 if (!state->acb[j]) {

                     state->acb[j] = acb;

-                    return FIND_RET_WAIT;

+                    return true;

                 }

             }

         }

     }

-    return FIND_RET_NONE;

+    return false;

 }

 /* Called with s->mutex held.  */

@@ -381,11 +379,11 @@ static void curl_multi_check_completion(BDRVCURLState *s)

                         continue;

                     }

+                    acb->ret = -EIO;

+                    state->acb[i] = NULL;

                     qemu_mutex_unlock(&s->mutex);

-                    acb->common.cb(acb->common.opaque, -EIO);

+                    aio_co_wake(acb->co);

                     qemu_mutex_lock(&s->mutex);

-                    qemu_aio_unref(acb);

-                    state->acb[i] = NULL;

                 }

             }

@@ -822,19 +820,11 @@ out_noclean:

     return -EINVAL;

 }

-static const AIOCBInfo curl_aiocb_info = {

-    .aiocb_size         = sizeof(CURLAIOCB),

-};

-

-

-static void curl_readv_bh_cb(void *p)

+static void curl_setup_preadv(BlockDriverState *bs, CURLAIOCB *acb)

 {

     CURLState *state;

     int running;

-    int ret = -EINPROGRESS;

-    CURLAIOCB *acb = p;

-    BlockDriverState *bs = acb->common.bs;

     BDRVCURLState *s = bs->opaque;

     uint64_t start = acb->offset;

@@ -844,14 +834,8 @@ static void curl_readv_bh_cb(void *p)

     // In case we have the requested data already (e.g. read-ahead),

     // we can just call the callback and be done.

-    switch (curl_find_buf(s, start, acb->bytes, acb)) {

-        case FIND_RET_OK:

-            ret = 0;

-            goto out;

-        case FIND_RET_WAIT:

-            goto out;

-        default:

-            break;

+    if (curl_find_buf(s, start, acb->bytes, acb)) {

+        goto out;

     }

     // No cache found, so let's start a new request

@@ -867,7 +851,7 @@ static void curl_readv_bh_cb(void *p)

     if (curl_init_state(s, state) < 0) {

         curl_clean_state(state);

-        ret = -EIO;

+        acb->ret = -EIO;

         goto out;

     }

@@ -882,7 +866,7 @@ static void curl_readv_bh_cb(void *p)

     state->orig_buf = g_try_malloc(state->buf_len);

     if (state->buf_len && state->orig_buf == NULL) {

         curl_clean_state(state);

-        ret = -ENOMEM;

+        acb->ret = -ENOMEM;

         goto out;

     }

     state->acb[0] = acb;

@@ -899,26 +883,24 @@ static void curl_readv_bh_cb(void *p)

 out:

     qemu_mutex_unlock(&s->mutex);

-    if (ret != -EINPROGRESS) {

-        acb->common.cb(acb->common.opaque, ret);

-        qemu_aio_unref(acb);

-    }

 }

-static BlockAIOCB *curl_aio_readv(BlockDriverState *bs,

-        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,

-        BlockCompletionFunc *cb, void *opaque)

+static int coroutine_fn curl_co_preadv(BlockDriverState *bs,

+        uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags)

 {

-    CURLAIOCB *acb;

-

-    acb = qemu_aio_get(&curl_aiocb_info, bs, cb, opaque);

-

-    acb->qiov = qiov;

-    acb->offset = sector_num * BDRV_SECTOR_SIZE;

-    acb->bytes = nb_sectors * BDRV_SECTOR_SIZE;

-

-    aio_bh_schedule_oneshot(bdrv_get_aio_context(bs), curl_readv_bh_cb, acb);

-    return &acb->common;

+    CURLAIOCB acb = {

+        .co = qemu_coroutine_self(),

+        .ret = -EINPROGRESS,

+        .qiov = qiov,

+        .offset = offset,

+        .bytes = bytes

+    };

+

+    curl_setup_preadv(bs, &acb;;

+    while (acb.ret == -EINPROGRESS) {

+        qemu_coroutine_yield();

+    }

+    return acb.ret;

 }

 static void curl_close(BlockDriverState *bs)

@@ -949,7 +931,7 @@ static BlockDriver bdrv_http = {

     .bdrv_close                 = curl_close,

     .bdrv_getlength             = curl_getlength,

-    .bdrv_aio_readv             = curl_aio_readv,

+    .bdrv_co_preadv             = curl_co_preadv,

     .bdrv_detach_aio_context    = curl_detach_aio_context,

     .bdrv_attach_aio_context    = curl_attach_aio_context,

@@ -965,7 +947,7 @@ static BlockDriver bdrv_https = {

     .bdrv_close                 = curl_close,

     .bdrv_getlength             = curl_getlength,

-    .bdrv_aio_readv             = curl_aio_readv,

+    .bdrv_co_preadv             = curl_co_preadv,

     .bdrv_detach_aio_context    = curl_detach_aio_context,

     .bdrv_attach_aio_context    = curl_attach_aio_context,

@@ -981,7 +963,7 @@ static BlockDriver bdrv_ftp = {

     .bdrv_close                 = curl_close,

     .bdrv_getlength             = curl_getlength,

-    .bdrv_aio_readv             = curl_aio_readv,

+    .bdrv_co_preadv             = curl_co_preadv,

     .bdrv_detach_aio_context    = curl_detach_aio_context,

     .bdrv_attach_aio_context    = curl_attach_aio_context,

@@ -997,7 +979,7 @@ static BlockDriver bdrv_ftps = {

     .bdrv_close                 = curl_close,

     .bdrv_getlength             = curl_getlength,

-    .bdrv_aio_readv             = curl_aio_readv,

+    .bdrv_co_preadv             = curl_co_preadv,

     .bdrv_detach_aio_context    = curl_detach_aio_context,

     .bdrv_attach_aio_context    = curl_attach_aio_context,

-- 

1.8.3.1