From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38817) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XQwYr-00041l-BR for qemu-devel@nongnu.org; Mon, 08 Sep 2014 06:52:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XQwYj-0007m2-BH for qemu-devel@nongnu.org; Mon, 08 Sep 2014 06:52:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60701) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XQwYj-0007lw-4o for qemu-devel@nongnu.org; Mon, 08 Sep 2014 06:52:33 -0400 From: Stefan Hajnoczi Date: Mon, 8 Sep 2014 11:51:38 +0100 Message-Id: <1410173509-26667-14-git-send-email-stefanha@redhat.com> In-Reply-To: <1410173509-26667-1-git-send-email-stefanha@redhat.com> References: <1410173509-26667-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PULL 13/24] block/archipelago: Use QEMU atomic builtins List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Chrysostomos Nanakos , Peter Maydell , Stefan Hajnoczi From: Chrysostomos Nanakos 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 Signed-off-by: Stefan Hajnoczi --- 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; } -- 1.9.3