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* [PATCH 00/18] xen: simplify frontend side ring setup
@ 2022-04-20 15:09 Juergen Gross
  2022-04-20 15:09 ` [PATCH 02/18] xen/netfront: switch netfront to use INVALID_GRANT_REF Juergen Gross
  2022-04-20 15:09 ` [PATCH 11/18] xen/netfront: use xenbus_setup_ring() and xenbus_teardown_ring() Juergen Gross
  0 siblings, 2 replies; 3+ messages in thread
From: Juergen Gross @ 2022-04-20 15:09 UTC (permalink / raw)
  To: xen-devel, linux-block, linux-kernel, netdev, linux-scsi,
	linux-usb, dri-devel, linux-integrity, linux-pci
  Cc: Juergen Gross, Boris Ostrovsky, Stefano Stabellini,
	Roger Pau Monné,
	Jens Axboe, David S. Miller, Jakub Kicinski, Paolo Abeni,
	James E.J. Bottomley, Martin K. Petersen, Greg Kroah-Hartman,
	Oleksandr Andrushchenko, David Airlie, Daniel Vetter,
	Jaroslav Kysela, Takashi Iwai, alsa-devel, Peter Huewe,
	Jarkko Sakkinen, Jason Gunthorpe, Bjorn Helgaas

Many Xen PV frontends share similar code for setting up a ring page
(allocating and granting access for the backend) and for tearing it
down.

Create new service functions doing all needed steps in one go.

This requires all frontends to use a common value for an invalid
grant reference in order to make the functions idempotent.

Juergen Gross (18):
  xen/blkfront: switch blkfront to use INVALID_GRANT_REF
  xen/netfront: switch netfront to use INVALID_GRANT_REF
  xen/scsifront: remove unused GRANT_INVALID_REF definition
  xen/usb: switch xen-hcd to use INVALID_GRANT_REF
  xen/drm: switch xen_drm_front to use INVALID_GRANT_REF
  xen/sound: switch xen_snd_front to use INVALID_GRANT_REF
  xen/dmabuf: switch gntdev-dmabuf to use INVALID_GRANT_REF
  xen/shbuf: switch xen-front-pgdir-shbuf to use INVALID_GRANT_REF
  xen/xenbus: add xenbus_setup_ring() service function
  xen/blkfront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/netfront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/tpmfront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/drmfront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/pcifront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/scsifront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/usbfront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/sndfront: use xenbus_setup_ring() and xenbus_teardown_ring()
  xen/xenbus: eliminate xenbus_grant_ring()

 drivers/block/xen-blkfront.c                | 54 ++++----------
 drivers/char/tpm/xen-tpmfront.c             | 18 +----
 drivers/gpu/drm/xen/xen_drm_front.h         |  9 ---
 drivers/gpu/drm/xen/xen_drm_front_evtchnl.c | 40 +++-------
 drivers/net/xen-netfront.c                  | 77 ++++++--------------
 drivers/pci/xen-pcifront.c                  | 19 +----
 drivers/scsi/xen-scsifront.c                | 30 ++------
 drivers/usb/host/xen-hcd.c                  | 59 ++++-----------
 drivers/xen/gntdev-dmabuf.c                 | 13 +---
 drivers/xen/xen-front-pgdir-shbuf.c         | 17 +----
 drivers/xen/xenbus/xenbus_client.c          | 81 ++++++++++++++++-----
 include/xen/xenbus.h                        |  4 +-
 sound/xen/xen_snd_front_evtchnl.c           | 41 +++--------
 sound/xen/xen_snd_front_evtchnl.h           |  9 ---
 14 files changed, 156 insertions(+), 315 deletions(-)

-- 
2.34.1


^ permalink raw reply	[flat|nested] 3+ messages in thread

* [PATCH 02/18] xen/netfront: switch netfront to use INVALID_GRANT_REF
  2022-04-20 15:09 [PATCH 00/18] xen: simplify frontend side ring setup Juergen Gross
@ 2022-04-20 15:09 ` Juergen Gross
  2022-04-20 15:09 ` [PATCH 11/18] xen/netfront: use xenbus_setup_ring() and xenbus_teardown_ring() Juergen Gross
  1 sibling, 0 replies; 3+ messages in thread
From: Juergen Gross @ 2022-04-20 15:09 UTC (permalink / raw)
  To: xen-devel, netdev, linux-kernel
  Cc: Juergen Gross, Boris Ostrovsky, Stefano Stabellini,
	David S. Miller, Jakub Kicinski, Paolo Abeni

Instead of using a private macro for an invalid grant reference use
the common one.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/net/xen-netfront.c | 36 +++++++++++++++++-------------------
 1 file changed, 17 insertions(+), 19 deletions(-)

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index e2b4a1893a13..af3d3de7d9fa 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -78,8 +78,6 @@ struct netfront_cb {
 
 #define RX_COPY_THRESHOLD 256
 
-#define GRANT_INVALID_REF	0
-
 #define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, XEN_PAGE_SIZE)
 #define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, XEN_PAGE_SIZE)
 
@@ -224,7 +222,7 @@ static grant_ref_t xennet_get_rx_ref(struct netfront_queue *queue,
 {
 	int i = xennet_rxidx(ri);
 	grant_ref_t ref = queue->grant_rx_ref[i];
-	queue->grant_rx_ref[i] = GRANT_INVALID_REF;
+	queue->grant_rx_ref[i] = INVALID_GRANT_REF;
 	return ref;
 }
 
@@ -432,7 +430,7 @@ static bool xennet_tx_buf_gc(struct netfront_queue *queue)
 			}
 			gnttab_release_grant_reference(
 				&queue->gref_tx_head, queue->grant_tx_ref[id]);
-			queue->grant_tx_ref[id] = GRANT_INVALID_REF;
+			queue->grant_tx_ref[id] = INVALID_GRANT_REF;
 			queue->grant_tx_page[id] = NULL;
 			add_id_to_list(&queue->tx_skb_freelist, queue->tx_link, id);
 			dev_kfree_skb_irq(skb);
@@ -1021,7 +1019,7 @@ static int xennet_get_responses(struct netfront_queue *queue,
 		 * the backend driver. In future this should flag the bad
 		 * situation to the system controller to reboot the backend.
 		 */
-		if (ref == GRANT_INVALID_REF) {
+		if (ref == INVALID_GRANT_REF) {
 			if (net_ratelimit())
 				dev_warn(dev, "Bad rx response id %d.\n",
 					 rx->id);
@@ -1390,7 +1388,7 @@ static void xennet_release_tx_bufs(struct netfront_queue *queue)
 		gnttab_end_foreign_access(queue->grant_tx_ref[i],
 					  (unsigned long)page_address(queue->grant_tx_page[i]));
 		queue->grant_tx_page[i] = NULL;
-		queue->grant_tx_ref[i] = GRANT_INVALID_REF;
+		queue->grant_tx_ref[i] = INVALID_GRANT_REF;
 		add_id_to_list(&queue->tx_skb_freelist, queue->tx_link, i);
 		dev_kfree_skb_irq(skb);
 	}
@@ -1411,7 +1409,7 @@ static void xennet_release_rx_bufs(struct netfront_queue *queue)
 			continue;
 
 		ref = queue->grant_rx_ref[id];
-		if (ref == GRANT_INVALID_REF)
+		if (ref == INVALID_GRANT_REF)
 			continue;
 
 		page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
@@ -1422,7 +1420,7 @@ static void xennet_release_rx_bufs(struct netfront_queue *queue)
 		get_page(page);
 		gnttab_end_foreign_access(ref,
 					  (unsigned long)page_address(page));
-		queue->grant_rx_ref[id] = GRANT_INVALID_REF;
+		queue->grant_rx_ref[id] = INVALID_GRANT_REF;
 
 		kfree_skb(skb);
 	}
@@ -1761,7 +1759,7 @@ static int netfront_probe(struct xenbus_device *dev,
 static void xennet_end_access(int ref, void *page)
 {
 	/* This frees the page as a side-effect */
-	if (ref != GRANT_INVALID_REF)
+	if (ref != INVALID_GRANT_REF)
 		gnttab_end_foreign_access(ref, (unsigned long)page);
 }
 
@@ -1798,8 +1796,8 @@ static void xennet_disconnect_backend(struct netfront_info *info)
 		xennet_end_access(queue->tx_ring_ref, queue->tx.sring);
 		xennet_end_access(queue->rx_ring_ref, queue->rx.sring);
 
-		queue->tx_ring_ref = GRANT_INVALID_REF;
-		queue->rx_ring_ref = GRANT_INVALID_REF;
+		queue->tx_ring_ref = INVALID_GRANT_REF;
+		queue->rx_ring_ref = INVALID_GRANT_REF;
 		queue->tx.sring = NULL;
 		queue->rx.sring = NULL;
 
@@ -1927,8 +1925,8 @@ static int setup_netfront(struct xenbus_device *dev,
 	grant_ref_t gref;
 	int err;
 
-	queue->tx_ring_ref = GRANT_INVALID_REF;
-	queue->rx_ring_ref = GRANT_INVALID_REF;
+	queue->tx_ring_ref = INVALID_GRANT_REF;
+	queue->rx_ring_ref = INVALID_GRANT_REF;
 	queue->rx.sring = NULL;
 	queue->tx.sring = NULL;
 
@@ -1978,17 +1976,17 @@ static int setup_netfront(struct xenbus_device *dev,
 	 * granted pages because backend is not accessing it at this point.
 	 */
  fail:
-	if (queue->rx_ring_ref != GRANT_INVALID_REF) {
+	if (queue->rx_ring_ref != INVALID_GRANT_REF) {
 		gnttab_end_foreign_access(queue->rx_ring_ref,
 					  (unsigned long)rxs);
-		queue->rx_ring_ref = GRANT_INVALID_REF;
+		queue->rx_ring_ref = INVALID_GRANT_REF;
 	} else {
 		free_page((unsigned long)rxs);
 	}
-	if (queue->tx_ring_ref != GRANT_INVALID_REF) {
+	if (queue->tx_ring_ref != INVALID_GRANT_REF) {
 		gnttab_end_foreign_access(queue->tx_ring_ref,
 					  (unsigned long)txs);
-		queue->tx_ring_ref = GRANT_INVALID_REF;
+		queue->tx_ring_ref = INVALID_GRANT_REF;
 	} else {
 		free_page((unsigned long)txs);
 	}
@@ -2020,7 +2018,7 @@ static int xennet_init_queue(struct netfront_queue *queue)
 	queue->tx_pend_queue = TX_LINK_NONE;
 	for (i = 0; i < NET_TX_RING_SIZE; i++) {
 		queue->tx_link[i] = i + 1;
-		queue->grant_tx_ref[i] = GRANT_INVALID_REF;
+		queue->grant_tx_ref[i] = INVALID_GRANT_REF;
 		queue->grant_tx_page[i] = NULL;
 	}
 	queue->tx_link[NET_TX_RING_SIZE - 1] = TX_LINK_NONE;
@@ -2028,7 +2026,7 @@ static int xennet_init_queue(struct netfront_queue *queue)
 	/* Clear out rx_skbs */
 	for (i = 0; i < NET_RX_RING_SIZE; i++) {
 		queue->rx_skbs[i] = NULL;
-		queue->grant_rx_ref[i] = GRANT_INVALID_REF;
+		queue->grant_rx_ref[i] = INVALID_GRANT_REF;
 	}
 
 	/* A grant for every tx ring slot */
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* [PATCH 11/18] xen/netfront: use xenbus_setup_ring() and xenbus_teardown_ring()
  2022-04-20 15:09 [PATCH 00/18] xen: simplify frontend side ring setup Juergen Gross
  2022-04-20 15:09 ` [PATCH 02/18] xen/netfront: switch netfront to use INVALID_GRANT_REF Juergen Gross
@ 2022-04-20 15:09 ` Juergen Gross
  1 sibling, 0 replies; 3+ messages in thread
From: Juergen Gross @ 2022-04-20 15:09 UTC (permalink / raw)
  To: xen-devel, netdev, linux-kernel
  Cc: Juergen Gross, Boris Ostrovsky, Stefano Stabellini,
	David S. Miller, Jakub Kicinski, Paolo Abeni

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

Signed-off-by: Juergen Gross <jgross@suse.com>
---
 drivers/net/xen-netfront.c | 49 +++++++++-----------------------------
 1 file changed, 11 insertions(+), 38 deletions(-)

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index af3d3de7d9fa..880b10d435d9 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1921,8 +1921,7 @@ static int setup_netfront(struct xenbus_device *dev,
 			struct netfront_queue *queue, unsigned int feature_split_evtchn)
 {
 	struct xen_netif_tx_sring *txs;
-	struct xen_netif_rx_sring *rxs = NULL;
-	grant_ref_t gref;
+	struct xen_netif_rx_sring *rxs;
 	int err;
 
 	queue->tx_ring_ref = INVALID_GRANT_REF;
@@ -1930,34 +1929,22 @@ static int setup_netfront(struct xenbus_device *dev,
 	queue->rx.sring = NULL;
 	queue->tx.sring = NULL;
 
-	txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
-	if (!txs) {
-		err = -ENOMEM;
-		xenbus_dev_fatal(dev, err, "allocating tx ring page");
+	err = xenbus_setup_ring(dev, GFP_NOIO | __GFP_HIGH, (void **)&txs,
+				1, &queue->tx_ring_ref);
+	if (err)
 		goto fail;
-	}
+
 	SHARED_RING_INIT(txs);
 	FRONT_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
 
-	err = xenbus_grant_ring(dev, txs, 1, &gref);
-	if (err < 0)
+	err = xenbus_setup_ring(dev, GFP_NOIO | __GFP_HIGH, (void **)&rxs,
+				1, &queue->rx_ring_ref);
+	if (err)
 		goto fail;
-	queue->tx_ring_ref = gref;
 
-	rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
-	if (!rxs) {
-		err = -ENOMEM;
-		xenbus_dev_fatal(dev, err, "allocating rx ring page");
-		goto fail;
-	}
 	SHARED_RING_INIT(rxs);
 	FRONT_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
 
-	err = xenbus_grant_ring(dev, rxs, 1, &gref);
-	if (err < 0)
-		goto fail;
-	queue->rx_ring_ref = gref;
-
 	if (feature_split_evtchn)
 		err = setup_netfront_split(queue);
 	/* setup single event channel if
@@ -1972,24 +1959,10 @@ static int setup_netfront(struct xenbus_device *dev,
 
 	return 0;
 
-	/* If we fail to setup netfront, it is safe to just revoke access to
-	 * granted pages because backend is not accessing it at this point.
-	 */
  fail:
-	if (queue->rx_ring_ref != INVALID_GRANT_REF) {
-		gnttab_end_foreign_access(queue->rx_ring_ref,
-					  (unsigned long)rxs);
-		queue->rx_ring_ref = INVALID_GRANT_REF;
-	} else {
-		free_page((unsigned long)rxs);
-	}
-	if (queue->tx_ring_ref != INVALID_GRANT_REF) {
-		gnttab_end_foreign_access(queue->tx_ring_ref,
-					  (unsigned long)txs);
-		queue->tx_ring_ref = INVALID_GRANT_REF;
-	} else {
-		free_page((unsigned long)txs);
-	}
+	xenbus_teardown_ring((void **)&queue->rx.sring, 1, &queue->rx_ring_ref);
+	xenbus_teardown_ring((void **)&queue->tx.sring, 1, &queue->tx_ring_ref);
+
 	return err;
 }
 
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2022-04-20 15:10 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-04-20 15:09 [PATCH 00/18] xen: simplify frontend side ring setup Juergen Gross
2022-04-20 15:09 ` [PATCH 02/18] xen/netfront: switch netfront to use INVALID_GRANT_REF Juergen Gross
2022-04-20 15:09 ` [PATCH 11/18] xen/netfront: use xenbus_setup_ring() and xenbus_teardown_ring() Juergen Gross

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