From 82c45371ba698ff63e9d3d4792a34593f73e54d8 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 22 Sep 2022 10:48:59 +0200 Subject: [PATCH] block/nvme: separate nvme_get_free_req cases for coroutine/non-coroutine context nvme_get_free_req has very difference semantics when called in coroutine context (where it waits) and in non-coroutine context (where it doesn't). Split the two cases to make it clear what is being requested. Cc: qemu-block@nongnu.org Reviewed-by: Alberto Faria Signed-off-by: Paolo Bonzini Message-Id: <20220922084924.201610-2-pbonzini@redhat.com> [kwolf: Fixed up coding style] Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- block/nvme.c | 48 ++++++++++++++++++++++++++++-------------------- 1 file changed, 28 insertions(+), 20 deletions(-) diff --git a/block/nvme.c b/block/nvme.c index 01fb28aa63..0870f87bc6 100644 --- a/block/nvme.c +++ b/block/nvme.c @@ -293,34 +293,42 @@ static void nvme_kick(NVMeQueuePair *q) q->need_kick = 0; } -/* Find a free request element if any, otherwise: - * a) if in coroutine context, try to wait for one to become available; - * b) if not in coroutine, return NULL; - */ -static NVMeRequest *nvme_get_free_req(NVMeQueuePair *q) +static NVMeRequest *nvme_get_free_req_nofail_locked(NVMeQueuePair *q) { NVMeRequest *req; - qemu_mutex_lock(&q->lock); - - while (q->free_req_head == -1) { - if (qemu_in_coroutine()) { - trace_nvme_free_req_queue_wait(q->s, q->index); - qemu_co_queue_wait(&q->free_req_queue, &q->lock); - } else { - qemu_mutex_unlock(&q->lock); - return NULL; - } - } - req = &q->reqs[q->free_req_head]; q->free_req_head = req->free_req_next; req->free_req_next = -1; - - qemu_mutex_unlock(&q->lock); return req; } +/* Return a free request element if any, otherwise return NULL. */ +static NVMeRequest *nvme_get_free_req_nowait(NVMeQueuePair *q) +{ + QEMU_LOCK_GUARD(&q->lock); + if (q->free_req_head == -1) { + return NULL; + } + return nvme_get_free_req_nofail_locked(q); +} + +/* + * Wait for a free request to become available if necessary, then + * return it. + */ +static coroutine_fn NVMeRequest *nvme_get_free_req(NVMeQueuePair *q) +{ + QEMU_LOCK_GUARD(&q->lock); + + while (q->free_req_head == -1) { + trace_nvme_free_req_queue_wait(q->s, q->index); + qemu_co_queue_wait(&q->free_req_queue, &q->lock); + } + + return nvme_get_free_req_nofail_locked(q); +} + /* With q->lock */ static void nvme_put_free_req_locked(NVMeQueuePair *q, NVMeRequest *req) { @@ -506,7 +514,7 @@ static int nvme_admin_cmd_sync(BlockDriverState *bs, NvmeCmd *cmd) AioContext *aio_context = bdrv_get_aio_context(bs); NVMeRequest *req; int ret = -EINPROGRESS; - req = nvme_get_free_req(q); + req = nvme_get_free_req_nowait(q); if (!req) { return -EBUSY; }