From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49128) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XOnRN-0007rX-TW for qemu-devel@nongnu.org; Tue, 02 Sep 2014 08:44:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XOnRG-0003jH-Sl for qemu-devel@nongnu.org; Tue, 02 Sep 2014 08:44:05 -0400 Received: from averel.grnet-hq.admin.grnet.gr ([195.251.29.3]:55551) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XOnRG-0003dq-84 for qemu-devel@nongnu.org; Tue, 02 Sep 2014 08:43:58 -0400 From: Chrysostomos Nanakos Date: Tue, 2 Sep 2014 15:41:34 +0300 Message-Id: <1409661695-32038-1-git-send-email-cnanakos@grnet.gr> Subject: [Qemu-devel] [PATCH] block/archipelago: Use QEMU atomic builtins List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, pbonzini@redhat.com, Chrysostomos Nanakos , stefanha@redhat.com Replace __sync builtins with ones provided by QEMU for atomic operations. Special thanks goes to Paolo Bonzini for his refactoring suggestion in order to use the already existing atomic builtins interface. Signed-off-by: Chrysostomos Nanakos --- block/archipelago.c | 76 ++++++++++++++++----------------------------------- 1 file changed, 23 insertions(+), 53 deletions(-) diff --git a/block/archipelago.c b/block/archipelago.c index 34f72dc..22a7daa 100644 --- a/block/archipelago.c +++ b/block/archipelago.c @@ -57,6 +57,7 @@ #include "qapi/qmp/qint.h" #include "qapi/qmp/qstring.h" #include "qapi/qmp/qjson.h" +#include "qemu/atomic.h" #include #include @@ -214,7 +215,7 @@ static void xseg_request_handler(void *state) xseg_put_request(s->xseg, req, s->srcport); - if ((__sync_add_and_fetch(&segreq->ref, -1)) == 0) { + if (atomic_fetch_dec(&segreq->ref) == 1) { if (!segreq->failed) { reqdata->aio_cb->ret = segreq->count; archipelago_finish_aiocb(reqdata); @@ -233,7 +234,7 @@ static void xseg_request_handler(void *state) segreq->count += req->serviced; xseg_put_request(s->xseg, req, s->srcport); - if ((__sync_add_and_fetch(&segreq->ref, -1)) == 0) { + if (atomic_fetch_dec(&segreq->ref) == 1) { if (!segreq->failed) { reqdata->aio_cb->ret = segreq->count; archipelago_finish_aiocb(reqdata); @@ -824,78 +825,47 @@ static int archipelago_aio_segmented_rw(BDRVArchipelagoState *s, ArchipelagoAIOCB *aio_cb, int op) { - int i, ret, segments_nr, last_segment_size; + int ret, segments_nr; + size_t pos = 0; ArchipelagoSegmentedRequest *segreq; - segreq = g_new(ArchipelagoSegmentedRequest, 1); + segreq = g_new0(ArchipelagoSegmentedRequest, 1); if (op == ARCHIP_OP_FLUSH) { segments_nr = 1; - segreq->ref = segments_nr; - segreq->total = count; - segreq->count = 0; - segreq->failed = 0; - ret = archipelago_submit_request(s, 0, count, offset, aio_cb, - segreq, ARCHIP_OP_FLUSH); - if (ret < 0) { - goto err_exit; - } - return 0; + } else { + segments_nr = (int)(count / MAX_REQUEST_SIZE) + \ + ((count % MAX_REQUEST_SIZE) ? 1 : 0); } - - segments_nr = (int)(count / MAX_REQUEST_SIZE) + \ - ((count % MAX_REQUEST_SIZE) ? 1 : 0); - last_segment_size = (int)(count % MAX_REQUEST_SIZE); - - segreq->ref = segments_nr; segreq->total = count; - segreq->count = 0; - segreq->failed = 0; + atomic_mb_set(&segreq->ref, segments_nr); - for (i = 0; i < segments_nr - 1; i++) { - ret = archipelago_submit_request(s, i * MAX_REQUEST_SIZE, - MAX_REQUEST_SIZE, - offset + i * MAX_REQUEST_SIZE, - aio_cb, segreq, op); + while (segments_nr > 1) { + ret = archipelago_submit_request(s, pos, + MAX_REQUEST_SIZE, + offset + pos, + aio_cb, segreq, op); if (ret < 0) { goto err_exit; } + count -= MAX_REQUEST_SIZE; + pos += MAX_REQUEST_SIZE; + segments_nr--; } - - if ((segments_nr > 1) && last_segment_size) { - ret = archipelago_submit_request(s, i * MAX_REQUEST_SIZE, - last_segment_size, - offset + i * MAX_REQUEST_SIZE, - aio_cb, segreq, op); - } else if ((segments_nr > 1) && !last_segment_size) { - ret = archipelago_submit_request(s, i * MAX_REQUEST_SIZE, - MAX_REQUEST_SIZE, - offset + i * MAX_REQUEST_SIZE, - aio_cb, segreq, op); - } else if (segments_nr == 1) { - ret = archipelago_submit_request(s, 0, count, offset, aio_cb, - segreq, op); - } + ret = archipelago_submit_request(s, pos, count, offset + pos, + aio_cb, segreq, op); if (ret < 0) { goto err_exit; } - return 0; err_exit: - __sync_add_and_fetch(&segreq->failed, 1); - if (segments_nr == 1) { - if (__sync_add_and_fetch(&segreq->ref, -1) == 0) { - g_free(segreq); - } - } else { - if ((__sync_add_and_fetch(&segreq->ref, -segments_nr + i)) == 0) { - g_free(segreq); - } + segreq->failed = 1; + if (atomic_fetch_sub(&segreq->ref, segments_nr) == segments_nr) { + g_free(segreq); } - return ret; } -- 1.7.10.4