[PATCH v3 20/21] xen/sndfront: use xenbus_setup_ring() and xenbus_teardown_ring()

Juergen Gross
2022-05-05T08:19:19Z

Simplify sndfront's ring creation and removal via xenbus_setup_ring()
and xenbus_teardown_ring().

Signed-off-by: Juergen Gross <jgross@suse.com>
---
sound/xen/xen_snd_front_evtchnl.c | 44 +++++++------------------------
1 file changed, 10 insertions(+), 34 deletions(-)

diff --git a/sound/xen/xen_snd_front_evtchnl.c b/sound/xen/xen_snd_front_evtchnl.c
index 3e21369c8216..26d1b3987887 100644
--- a/sound/xen/xen_snd_front_evtchnl.c
+++ b/sound/xen/xen_snd_front_evtchnl.c
@@ -143,12 +143,12 @@ void xen_snd_front_evtchnl_flush(struct xen_snd_front_evtchnl *channel)
static void evtchnl_free(struct xen_snd_front_info *front_info,
struct xen_snd_front_evtchnl *channel)
{
- unsigned long page = 0;
+ void *page = NULL;

if (channel->type == EVTCHNL_TYPE_REQ)
- page = (unsigned long)channel->u.req.ring.sring;
+ page = channel->u.req.ring.sring;
else if (channel->type == EVTCHNL_TYPE_EVT)
- page = (unsigned long)channel->u.evt.page;
+ page = channel->u.evt.page;

if (!page)
return;
@@ -167,10 +167,7 @@ static void evtchnl_free(struct xen_snd_front_info *front_info,
xenbus_free_evtchn(front_info->xb_dev, channel->port);

/* End access and free the page. */
- if (channel->gref != INVALID_GRANT_REF)
- gnttab_end_foreign_access(channel->gref, page);
- else
- free_page(page);
+ xenbus_teardown_ring(&page, 1, &channel->gref);

memset(channel, 0, sizeof(*channel));
}
@@ -196,8 +193,7 @@ static int evtchnl_alloc(struct xen_snd_front_info *front_info, int index,
enum xen_snd_front_evtchnl_type type)
{
struct xenbus_device *xb_dev = front_info->xb_dev;
- unsigned long page;
- grant_ref_t gref;
+ void *page;
irq_handler_t handler;
char *handler_name = NULL;
int ret;
@@ -207,12 +203,9 @@ static int evtchnl_alloc(struct xen_snd_front_info *front_info, int index,
channel->index = index;
channel->front_info = front_info;
channel->state = EVTCHNL_STATE_DISCONNECTED;
- channel->gref = INVALID_GRANT_REF;
- page = get_zeroed_page(GFP_KERNEL);
- if (!page) {
- ret = -ENOMEM;
+ ret = xenbus_setup_ring(xb_dev, GFP_KERNEL, &page, 1, &channel->gref);
+ if (ret)
goto fail;
- }

handler_name = kasprintf(GFP_KERNEL, "%s-%s", XENSND_DRIVER_NAME,
type == EVTCHNL_TYPE_REQ ?
@@ -226,33 +219,18 @@ static int evtchnl_alloc(struct xen_snd_front_info *front_info, int index,
mutex_init(&channel->ring_io_lock);

if (type == EVTCHNL_TYPE_REQ) {
- struct xen_sndif_sring *sring = (struct xen_sndif_sring *)page;
+ struct xen_sndif_sring *sring = page;

init_completion(&channel->u.req.completion);
mutex_init(&channel->u.req.req_io_lock);
- SHARED_RING_INIT(sring);
- FRONT_RING_INIT(&channel->u.req.ring, sring, XEN_PAGE_SIZE);
-
- ret = xenbus_grant_ring(xb_dev, sring, 1, &gref);
- if (ret < 0) {
- channel->u.req.ring.sring = NULL;
- goto fail;
- }
+ XEN_FRONT_RING_INIT(&channel->u.req.ring, sring, XEN_PAGE_SIZE);

handler = evtchnl_interrupt_req;
} else {
- ret = gnttab_grant_foreign_access(xb_dev->otherend_id,
- virt_to_gfn((void *)page), 0);
- if (ret < 0)
- goto fail;
-
- channel->u.evt.page = (struct xensnd_event_page *)page;
- gref = ret;
+ channel->u.evt.page = page;
handler = evtchnl_interrupt_evt;
}

- channel->gref = gref;
-
ret = xenbus_alloc_evtchn(xb_dev, &channel->port);
if (ret < 0)
goto fail;
@@ -279,8 +257,6 @@ static int evtchnl_alloc(struct xen_snd_front_info *front_info, int index,
return 0;

fail:
- if (page)
- free_page(page);
kfree(handler_name);
dev_err(&xb_dev->dev, "Failed to allocate ring: %d\n", ret);
return ret;
--
2.35.3