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linux-aio: Honour AsyncContext 

Also for Linux AIO, don't call callbacks that don't belong to the active
AsyncContext.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Kevin Wolf 2009-10-22 17:54:41 +02:00 committed by Anthony Liguori
parent e5f37649c6
commit db0ffc2402
1 changed files with 72 additions and 15 deletions
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87
linux-aio.c
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@ -31,12 +31,15 @@ struct qemu_laiocb {
struct iocb iocb;
ssize_t ret;
size_t nbytes;
int async_context_id;
QLIST_ENTRY(qemu_laiocb) node;
};
struct qemu_laio_state {
io_context_t ctx;
int efd;
int count;
QLIST_HEAD(, qemu_laiocb) completed_reqs;
};
static inline ssize_t io_event_ret(struct io_event *ev)
@ -44,6 +47,69 @@ static inline ssize_t io_event_ret(struct io_event *ev)
return (ssize_t)(((uint64_t)ev->res2 << 32) | ev->res);
}
/*
* Completes an AIO request (calls the callback and frees the ACB).
* Be sure to be in the right AsyncContext before calling this function.
*/
static void qemu_laio_process_completion(struct qemu_laio_state *s,
struct qemu_laiocb *laiocb)
{
int ret;
s->count--;
ret = laiocb->ret;
if (ret != -ECANCELED) {
if (ret == laiocb->nbytes)
ret = 0;
else if (ret >= 0)
ret = -EINVAL;
laiocb->common.cb(laiocb->common.opaque, ret);
}
qemu_aio_release(laiocb);
}
/*
* Processes all queued AIO requests, i.e. requests that have return from OS
* but their callback was not called yet. Requests that cannot have their
* callback called in the current AsyncContext, remain in the queue.
*
* Returns 1 if at least one request could be completed, 0 otherwise.
*/
static int qemu_laio_process_requests(void *opaque)
{
struct qemu_laio_state *s = opaque;
struct qemu_laiocb *laiocb, *next;
int res = 0;
QLIST_FOREACH_SAFE (laiocb, &s->completed_reqs, node, next) {
if (laiocb->async_context_id == get_async_context_id()) {
qemu_laio_process_completion(s, laiocb);
QLIST_REMOVE(laiocb, node);
res = 1;
}
}
return res;
}
/*
* Puts a request in the completion queue so that its callback is called the
* next time when it's possible. If we already are in the right AsyncContext,
* the request is completed immediately instead.
*/
static void qemu_laio_enqueue_completed(struct qemu_laio_state *s,
struct qemu_laiocb* laiocb)
{
if (laiocb->async_context_id == get_async_context_id()) {
qemu_laio_process_completion(s, laiocb);
} else {
QLIST_INSERT_HEAD(&s->completed_reqs, laiocb, node);
}
}
static void qemu_laio_completion_cb(void *opaque)
{
struct qemu_laio_state *s = opaque;
@ -74,19 +140,8 @@ static void qemu_laio_completion_cb(void *opaque)
struct qemu_laiocb *laiocb =
container_of(iocb, struct qemu_laiocb, iocb);
s->count--;
ret = laiocb->ret = io_event_ret(&events[i]);
if (ret != -ECANCELED) {
if (ret == laiocb->nbytes)
ret = 0;
else if (ret >= 0)
ret = -EINVAL;
laiocb->common.cb(laiocb->common.opaque, ret);
}
qemu_aio_release(laiocb);
laiocb->ret = io_event_ret(&events[i]);
qemu_laio_enqueue_completed(s, laiocb);
}
}
}
@ -149,6 +204,7 @@ BlockDriverAIOCB *laio_submit(BlockDriverState *bs, void *aio_ctx, int fd,
laiocb->nbytes = nb_sectors * 512;
laiocb->ctx = s;
laiocb->ret = -EINPROGRESS;
laiocb->async_context_id = get_async_context_id();
iocbs = &laiocb->iocb;
@ -183,6 +239,7 @@ void *laio_init(void)
struct qemu_laio_state *s;
s = qemu_mallocz(sizeof(*s));
QLIST_INIT(&s->completed_reqs);
s->efd = eventfd(0, 0);
if (s->efd == -1)
goto out_free_state;
@ -191,8 +248,8 @@ void *laio_init(void)
if (io_setup(MAX_EVENTS, &s->ctx) != 0)
goto out_close_efd;
qemu_aio_set_fd_handler(s->efd, qemu_laio_completion_cb,
NULL, qemu_laio_flush_cb, NULL, s);
qemu_aio_set_fd_handler(s->efd, qemu_laio_completion_cb, NULL,
qemu_laio_flush_cb, qemu_laio_process_requests, s);
return s;