Commit 2bb5c936 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Jeff Cody
Browse files

curl: do not do aio_poll when waiting for a free CURLState 



Instead, put the CURLAIOCB on a wait list and yield; curl_clean_state will
wake the corresponding coroutine.

Because of CURL's callback-based structure, we cannot easily convert
everything to CoMutex/CoQueue; keeping the QemuMutex is simpler.  However,
CoQueue is a simple wrapper around a linked list, so we can easily
use QSIMPLEQ and open-code a CoQueue, protected by the BDRVCURLState
QemuMutex instead of a CoMutex.

Reviewed-by: default avatarJeff Cody <jcody@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Message-id: 20170515100059.15795-8-pbonzini@redhat.com
Signed-off-by: default avatarJeff Cody <jcody@redhat.com>
parent 28256d82

block/curl.c

+15 −1
Original line number Diff line number Diff line
@@ -99,6 +99,8 @@ typedef struct CURLAIOCB { 


    size_t start;

    size_t end;



    QSIMPLEQ_ENTRY(CURLAIOCB) next;

} CURLAIOCB;



typedef struct CURLSocket {
@@ -134,6 +136,7 @@ typedef struct BDRVCURLState { 
    bool accept_range;

    AioContext *aio_context;

    QemuMutex mutex;

    QSIMPLEQ_HEAD(, CURLAIOCB) free_state_waitq;

    char *username;

    char *password;

    char *proxyusername;
@@ -533,6 +536,7 @@ static int curl_init_state(BDRVCURLState *s, CURLState *state) 
/* Called with s->mutex held.  */

static void curl_clean_state(CURLState *s)

{

    CURLAIOCB *next;

    int j;

    for (j = 0; j < CURL_NUM_ACB; j++) {

        assert(!s->acb[j]);
@@ -549,6 +553,14 @@ static void curl_clean_state(CURLState *s) 
    }



    s->in_use = 0;



    next = QSIMPLEQ_FIRST(&s->s->free_state_waitq);

    if (next) {

        QSIMPLEQ_REMOVE_HEAD(&s->s->free_state_waitq, next);

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

        aio_co_wake(next->co);

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

    }

}



static void curl_parse_filename(const char *filename, QDict *options,
@@ -766,6 +778,7 @@ static int curl_open(BlockDriverState *bs, QDict *options, int flags, 
    }



    DPRINTF("CURL: Opening %s\n", file);

    QSIMPLEQ_INIT(&s->free_state_waitq);

    s->aio_context = bdrv_get_aio_context(bs);

    s->url = g_strdup(file);

    qemu_mutex_lock(&s->mutex);
@@ -866,8 +879,9 @@ static void curl_setup_preadv(BlockDriverState *bs, CURLAIOCB *acb) 
        if (state) {

            break;

        }

        QSIMPLEQ_INSERT_TAIL(&s->free_state_waitq, acb, next);

        qemu_mutex_unlock(&s->mutex);

        aio_poll(bdrv_get_aio_context(bs), true);

        qemu_coroutine_yield();

        qemu_mutex_lock(&s->mutex);

    }