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: Jeff Cody <jcody@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170515100059.15795-8-pbonzini@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
This commit is contained in:
Paolo Bonzini 2017-05-15 12:00:59 +02:00 committed by Jeff Cody
parent 28256d8246
commit 2bb5c936c5

View File

@ -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);
}