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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 <afaria@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220922084924.201610-2-pbonzini@redhat.com>
[kwolf: Fixed up coding style]
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Paolo Bonzini 2022-09-22 10:48:59 +02:00 committed by Kevin Wolf
parent ef770f8101
commit 82c45371ba
1 changed files with 28 additions and 20 deletions
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48
block/nvme.c
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@ -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;
}