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authorKevin Wolf <kwolf@redhat.com>2011-07-15 16:36:40 +0200
committerKevin Wolf <kwolf@redhat.com>2011-08-02 15:53:41 +0200
commit384acbf46b70edf0d2c1648aa1a92a90bcf7057d (patch)
tree38459f728adf03df6b83a6273484f61d05e0dd01 /linux-aio.c
parent52b8eb60132b27ad53476490e9d7579003390cfa (diff)
async: Remove AsyncContext
The purpose of AsyncContexts was to protect qcow and qcow2 against reentrancy during an emulated bdrv_read/write (which includes a qemu_aio_wait() call and can run AIO callbacks of different requests if it weren't for AsyncContexts). Now both qcow and qcow2 are protected by CoMutexes and AsyncContexts can be removed. Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'linux-aio.c')
-rw-r--r--linux-aio.c43
1 files changed, 4 insertions, 39 deletions
diff --git a/linux-aio.c b/linux-aio.c
index 68f4b3d757..dc3faf2499 100644
--- a/linux-aio.c
+++ b/linux-aio.c
@@ -31,7 +31,6 @@ struct qemu_laiocb {
struct iocb iocb;
ssize_t ret;
size_t nbytes;
- int async_context_id;
QLIST_ENTRY(qemu_laiocb) node;
};
@@ -39,7 +38,6 @@ 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)
@@ -49,7 +47,6 @@ static inline ssize_t io_event_ret(struct io_event *ev)
/*
* 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)
@@ -72,42 +69,12 @@ static void qemu_laio_process_completion(struct qemu_laio_state *s,
}
/*
- * 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.
+ * All requests are directly processed when they complete, so there's nothing
+ * left to do during qemu_aio_wait().
*/
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);
- }
+ return 0;
}
static void qemu_laio_completion_cb(void *opaque)
@@ -141,7 +108,7 @@ static void qemu_laio_completion_cb(void *opaque)
container_of(iocb, struct qemu_laiocb, iocb);
laiocb->ret = io_event_ret(&events[i]);
- qemu_laio_enqueue_completed(s, laiocb);
+ qemu_laio_process_completion(s, laiocb);
}
}
}
@@ -204,7 +171,6 @@ 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;
@@ -239,7 +205,6 @@ 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;