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David Vrabel

2011-Sep-13 11:05 UTC

[Xen-devel] Use xenbus API for mapping foreign pages

Xenbus provides an API for mapping foreign pages.  Make use of it in
the netback and blkback drivers so when the method for mapping foreign
pages is changed it only need to be updated in one place.

David


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David Vrabel

2011-Sep-13 11:05 UTC

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[Xen-devel] [PATCH 1/2] block: xen-blkback: use API provided by xenbus module to map rings

From: David Vrabel <david.vrabel@citrix.com>

The xenbus module provides xenbus_map_ring_valloc() and
xenbus_map_ring_vfree().  Use these to map the ring pages granted by
the frontend.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
---
 drivers/block/xen-blkback/common.h |    5 +--
 drivers/block/xen-blkback/xenbus.c |   54 ++++-------------------------------
 2 files changed, 8 insertions(+), 51 deletions(-)

diff --git a/drivers/block/xen-blkback/common.h
b/drivers/block/xen-blkback/common.h
index 9e40b28..07dd177 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -139,7 +139,7 @@ struct xen_blkif {
 	/* Comms information. */
 	enum blkif_protocol	blk_protocol;
 	union blkif_back_rings	blk_rings;
-	struct vm_struct	*blk_ring_area;
+	void			*blk_ring;
 	/* The VBD attached to this interface. */
 	struct xen_vbd		vbd;
 	/* Back pointer to the backend_info. */
@@ -163,9 +163,6 @@ struct xen_blkif {
 	int			st_wr_sect;
 
 	wait_queue_head_t	waiting_to_free;
-
-	grant_handle_t		shmem_handle;
-	grant_ref_t		shmem_ref;
 };
 
 
diff --git a/drivers/block/xen-blkback/xenbus.c
b/drivers/block/xen-blkback/xenbus.c
index 3f129b4..73703d5 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -120,38 +120,6 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
 	return blkif;
 }
 
-static int map_frontend_page(struct xen_blkif *blkif, unsigned long
shared_page)
-{
-	struct gnttab_map_grant_ref op;
-
-	gnttab_set_map_op(&op, (unsigned long)blkif->blk_ring_area->addr,
-			  GNTMAP_host_map, shared_page, blkif->domid);
-
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
-
-	if (op.status) {
-		DPRINTK("Grant table operation failure !\n");
-		return op.status;
-	}
-
-	blkif->shmem_ref = shared_page;
-	blkif->shmem_handle = op.handle;
-
-	return 0;
-}
-
-static void unmap_frontend_page(struct xen_blkif *blkif)
-{
-	struct gnttab_unmap_grant_ref op;
-
-	gnttab_set_unmap_op(&op, (unsigned long)blkif->blk_ring_area->addr,
-			    GNTMAP_host_map, blkif->shmem_handle);
-
-	if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
-		BUG();
-}
-
 static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page,
 			 unsigned int evtchn)
 {
@@ -161,35 +129,29 @@ static int xen_blkif_map(struct xen_blkif *blkif, unsigned
long shared_page,
 	if (blkif->irq)
 		return 0;
 
-	blkif->blk_ring_area = alloc_vm_area(PAGE_SIZE);
-	if (!blkif->blk_ring_area)
-		return -ENOMEM;
-
-	err = map_frontend_page(blkif, shared_page);
-	if (err) {
-		free_vm_area(blkif->blk_ring_area);
+	err = xenbus_map_ring_valloc(blkif->be->dev, shared_page,
&blkif->blk_ring);
+	if (err < 0)
 		return err;
-	}
 
 	switch (blkif->blk_protocol) {
 	case BLKIF_PROTOCOL_NATIVE:
 	{
 		struct blkif_sring *sring;
-		sring = (struct blkif_sring *)blkif->blk_ring_area->addr;
+		sring = (struct blkif_sring *)blkif->blk_ring;
 		BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE);
 		break;
 	}
 	case BLKIF_PROTOCOL_X86_32:
 	{
 		struct blkif_x86_32_sring *sring_x86_32;
-		sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring_area->addr;
+		sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring;
 		BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE);
 		break;
 	}
 	case BLKIF_PROTOCOL_X86_64:
 	{
 		struct blkif_x86_64_sring *sring_x86_64;
-		sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring_area->addr;
+		sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring;
 		BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE);
 		break;
 	}
@@ -201,8 +163,7 @@ static int xen_blkif_map(struct xen_blkif *blkif, unsigned
long shared_page,
 						    xen_blkif_be_int, 0,
 						    "blkif-backend", blkif);
 	if (err < 0) {
-		unmap_frontend_page(blkif);
-		free_vm_area(blkif->blk_ring_area);
+		xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring);
 		blkif->blk_rings.common.sring = NULL;
 		return err;
 	}
@@ -228,8 +189,7 @@ static void xen_blkif_disconnect(struct xen_blkif *blkif)
 	}
 
 	if (blkif->blk_rings.common.sring) {
-		unmap_frontend_page(blkif);
-		free_vm_area(blkif->blk_ring_area);
+		xenbus_unmap_ring_vfree(blkif->be->dev, blkif->blk_ring);
 		blkif->blk_rings.common.sring = NULL;
 	}
 }
-- 
1.7.2.5


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David Vrabel

2011-Sep-13 11:05 UTC

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[Xen-devel] [PATCH 2/2] net: xen-netback: use API provided by xenbus module to map rings

From: David Vrabel <david.vrabel@citrix.com>

The xenbus module provides xenbus_map_ring_valloc() and
xenbus_map_ring_vfree().  Use these to map the Tx and Rx ring pages
granted by the frontend.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
---
 drivers/net/xen-netback/common.h  |   11 ++---
 drivers/net/xen-netback/netback.c |   80 ++++++++-----------------------------
 2 files changed, 22 insertions(+), 69 deletions(-)

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 161f207..94b79c3 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -58,10 +58,6 @@ struct xenvif {
 	u8               fe_dev_addr[6];
 
 	/* Physical parameters of the comms window. */
-	grant_handle_t   tx_shmem_handle;
-	grant_ref_t      tx_shmem_ref;
-	grant_handle_t   rx_shmem_handle;
-	grant_ref_t      rx_shmem_ref;
 	unsigned int     irq;
 
 	/* List of frontends to notify after a batch of frames sent. */
@@ -70,8 +66,6 @@ struct xenvif {
 	/* The shared rings and indexes. */
 	struct xen_netif_tx_back_ring tx;
 	struct xen_netif_rx_back_ring rx;
-	struct vm_struct *tx_comms_area;
-	struct vm_struct *rx_comms_area;
 
 	/* Frontend feature information. */
 	u8 can_sg:1;
@@ -106,6 +100,11 @@ struct xenvif {
 	wait_queue_head_t waiting_to_free;
 };
 
+static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
+{
+	return to_xenbus_device(vif->dev->dev.parent);
+}
+
 #define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
 #define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
 
diff --git a/drivers/net/xen-netback/netback.c
b/drivers/net/xen-netback/netback.c
index fd00f25..3af2924 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1577,88 +1577,42 @@ static int xen_netbk_kthread(void *data)
 
 void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
 {
-	struct gnttab_unmap_grant_ref op;
-
-	if (vif->tx.sring) {
-		gnttab_set_unmap_op(&op, (unsigned long)vif->tx_comms_area->addr,
-				    GNTMAP_host_map, vif->tx_shmem_handle);
-
-		if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
-			BUG();
-	}
-
-	if (vif->rx.sring) {
-		gnttab_set_unmap_op(&op, (unsigned long)vif->rx_comms_area->addr,
-				    GNTMAP_host_map, vif->rx_shmem_handle);
-
-		if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
-			BUG();
-	}
-	if (vif->rx_comms_area)
-		free_vm_area(vif->rx_comms_area);
-	if (vif->tx_comms_area)
-		free_vm_area(vif->tx_comms_area);
+	if (vif->tx.sring)
+		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
+					vif->tx.sring);
+	if (vif->rx.sring)
+		xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
+					vif->rx.sring);
 }
 
 int xen_netbk_map_frontend_rings(struct xenvif *vif,
 				 grant_ref_t tx_ring_ref,
 				 grant_ref_t rx_ring_ref)
 {
-	struct gnttab_map_grant_ref op;
+	void *addr;
 	struct xen_netif_tx_sring *txs;
 	struct xen_netif_rx_sring *rxs;
 
 	int err = -ENOMEM;
 
-	vif->tx_comms_area = alloc_vm_area(PAGE_SIZE);
-	if (vif->tx_comms_area == NULL)
+	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
+				     tx_ring_ref, &addr);
+	if (err)
 		goto err;
 
-	vif->rx_comms_area = alloc_vm_area(PAGE_SIZE);
-	if (vif->rx_comms_area == NULL)
-		goto err;
-
-	gnttab_set_map_op(&op, (unsigned long)vif->tx_comms_area->addr,
-			  GNTMAP_host_map, tx_ring_ref, vif->domid);
-
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
-
-	if (op.status) {
-		netdev_warn(vif->dev,
-			    "failed to map tx ring. err=%d status=%d\n",
-			    err, op.status);
-		err = op.status;
-		goto err;
-	}
-
-	vif->tx_shmem_ref    = tx_ring_ref;
-	vif->tx_shmem_handle = op.handle;
-
-	txs = (struct xen_netif_tx_sring *)vif->tx_comms_area->addr;
+	txs = (struct xen_netif_tx_sring *)addr;
 	BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);
 
-	gnttab_set_map_op(&op, (unsigned long)vif->rx_comms_area->addr,
-			  GNTMAP_host_map, rx_ring_ref, vif->domid);
-
-	if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
-		BUG();
-
-	if (op.status) {
-		netdev_warn(vif->dev,
-			    "failed to map rx ring. err=%d status=%d\n",
-			    err, op.status);
-		err = op.status;
+	err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
+				     rx_ring_ref, &addr);
+	if (err)
 		goto err;
-	}
-
-	vif->rx_shmem_ref     = rx_ring_ref;
-	vif->rx_shmem_handle  = op.handle;
-	vif->rx_req_cons_peek = 0;
 
-	rxs = (struct xen_netif_rx_sring *)vif->rx_comms_area->addr;
+	rxs = (struct xen_netif_rx_sring *)addr;
 	BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE);
 
+	vif->rx_req_cons_peek = 0;
+
 	return 0;
 
 err:
-- 
1.7.2.5


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David Vrabel

2011-Sep-14 14:41 UTC

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Re: [Xen-devel] Use xenbus API for mapping foreign pages

On 13/09/11 12:05, David Vrabel wrote:> Xenbus provides an API for mapping foreign pages.  Make use of it in
> the netback and blkback drivers so when the method for mapping foreign
> pages is changed it only need to be updated in one place.ak
Don''t apply these.  I''ve taken a different approach that
obsoletes
xenbus_map_ring_valloc() and xenbus_map_ring_vfree().

David

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Konrad Rzeszutek Wilk

2011-Sep-14 15:07 UTC

head link

Re: [Xen-devel] Use xenbus API for mapping foreign pages

On Wed, Sep 14, 2011 at 03:41:53PM +0100, David Vrabel
wrote:> On 13/09/11 12:05, David Vrabel wrote:
> >Xenbus provides an API for mapping foreign pages.  Make use of it in
> >the netback and blkback drivers so when the method for mapping foreign
> >pages is changed it only need to be updated in one place.ak
> 
> Don''t apply these.  I''ve taken a different approach that
obsoletes
> xenbus_map_ring_valloc() and xenbus_map_ring_vfree().
Ok.

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Xen devel - Sep 2011 - Use xenbus API for mapping foreign pages

[Xen-devel] Use xenbus API for mapping foreign pages

[Xen-devel] [PATCH 1/2] block: xen-blkback: use API provided by xenbus module to map rings

[Xen-devel] [PATCH 2/2] net: xen-netback: use API provided by xenbus module to map rings

Re: [Xen-devel] Use xenbus API for mapping foreign pages

Re: [Xen-devel] Use xenbus API for mapping foreign pages