qemu-e2k/hw/block/dataplane/xen-block.h
Stefan Hajnoczi f6eac904f6 xen-block: implement BlockDevOps->drained_begin()
Detach event channels during drained sections to stop I/O submission
from the ring. xen-block is no longer reliant on aio_disable_external()
after this patch. This will allow us to remove the
aio_disable_external() API once all other code that relies on it is
converted.

Extend xen_device_set_event_channel_context() to allow ctx=NULL. The
event channel still exists but the event loop does not monitor the file
descriptor. Event channel processing can resume by calling
xen_device_set_event_channel_context() with a non-NULL ctx.

Factor out xen_device_set_event_channel_context() calls in
hw/block/dataplane/xen-block.c into attach/detach helper functions.
Incidentally, these don't require the AioContext lock because
aio_set_fd_handler() is thread-safe.

It's safer to register BlockDevOps after the dataplane instance has been
created. The BlockDevOps .drained_begin/end() callbacks depend on the
dataplane instance, so move the blk_set_dev_ops() call after
xen_block_dataplane_create().

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230516190238.8401-12-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2023-05-30 17:32:02 +02:00

33 lines
1.3 KiB
C

/*
* Copyright (c) 2018 Citrix Systems Inc.
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef HW_BLOCK_DATAPLANE_XEN_BLOCK_H
#define HW_BLOCK_DATAPLANE_XEN_BLOCK_H
#include "hw/block/block.h"
#include "hw/xen/xen-bus.h"
#include "sysemu/iothread.h"
typedef struct XenBlockDataPlane XenBlockDataPlane;
XenBlockDataPlane *xen_block_dataplane_create(XenDevice *xendev,
BlockBackend *blk,
unsigned int sector_size,
IOThread *iothread);
void xen_block_dataplane_destroy(XenBlockDataPlane *dataplane);
void xen_block_dataplane_start(XenBlockDataPlane *dataplane,
const unsigned int ring_ref[],
unsigned int nr_ring_ref,
unsigned int event_channel,
unsigned int protocol,
Error **errp);
void xen_block_dataplane_stop(XenBlockDataPlane *dataplane);
void xen_block_dataplane_attach(XenBlockDataPlane *dataplane);
void xen_block_dataplane_detach(XenBlockDataPlane *dataplane);
#endif /* HW_BLOCK_DATAPLANE_XEN_BLOCK_H */