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Subject[PATCH 0001/001] xen: multi page ring support for block devices
From: Santosh Jodh <santosh.jodh@citrix.com>

Add support for multi page ring for block devices.
The number of pages is configurable for blkback via module parameter.
blkback reports max-ring-page-order to blkfront via xenstore.
blkfront reports its supported ring-page-order to blkback via xenstore.
blkfront reports multi page ring references via ring-refNN in xenstore.
The change allows newer blkfront to work with older blkback and
vice-versa.
Based on original patch by Paul Durrant.

Signed-off-by: Santosh Jodh <santosh.jodh@citrix.com>
---
diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
index 0088bf6..72f2e18 100644
--- a/drivers/block/xen-blkback/blkback.c
+++ b/drivers/block/xen-blkback/blkback.c
@@ -60,6 +60,39 @@ static int xen_blkif_reqs = 64;
module_param_named(reqs, xen_blkif_reqs, int, 0);
MODULE_PARM_DESC(reqs, "Number of blkback requests to allocate");

+/* Order of maximum shared ring size advertised to the front end. */
+int xen_blkif_max_ring_order = XENBUS_MAX_RING_ORDER;
+
+#define BLK_RING_SIZE(_order) __CONST_RING_SIZE(blkif, PAGE_SIZE << (_order))
+
+static int set_max_ring_order(const char *buf, struct kernel_param *kp)
+{
+ int err;
+ unsigned long order;
+
+ err = kstrtol(buf, 0, &order);
+ if (err ||
+ order < 0 ||
+ order > XENBUS_MAX_RING_ORDER)
+ return -EINVAL;
+
+ if (xen_blkif_reqs < BLK_RING_SIZE(order))
+ printk(KERN_WARNING "WARNING: "
+ "I/O request space (%d reqs) < ring order %ld, "
+ "consider increasing %s.reqs to >= %ld.",
+ xen_blkif_reqs, order, KBUILD_MODNAME,
+ roundup_pow_of_two(BLK_RING_SIZE(order)));
+
+ xen_blkif_max_ring_order = order;
+
+ return 0;
+}
+
+module_param_call(max_ring_order,
+ set_max_ring_order, param_get_int,
+ &xen_blkif_max_ring_order, 0644);
+MODULE_PARM_DESC(max_ring_order, "log2 of maximum ring size, in pages.");
+
/* Run-time switchable: /sys/module/blkback/parameters/ */
static unsigned int log_stats;
module_param(log_stats, int, 0644);
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h
index d0ee7ed..5f33a1a 100644
--- a/drivers/block/xen-blkback/common.h
+++ b/drivers/block/xen-blkback/common.h
@@ -126,6 +126,8 @@ struct blkif_x86_64_response {
int16_t status; /* BLKIF_RSP_??? */
};

+extern int xen_blkif_max_ring_order;
+
DEFINE_RING_TYPES(blkif_common, struct blkif_common_request,
struct blkif_common_response);
DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request,
diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c
index 24a2fb5..7a9d71d 100644
--- a/drivers/block/xen-blkback/xenbus.c
+++ b/drivers/block/xen-blkback/xenbus.c
@@ -122,8 +122,8 @@ static struct xen_blkif *xen_blkif_alloc(domid_t domid)
return blkif;
}

-static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page,
- unsigned int evtchn)
+static int xen_blkif_map(struct xen_blkif *blkif, int ring_ref[],
+ unsigned int ring_order, unsigned int evtchn)
{
int err;

@@ -131,7 +131,8 @@ static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page,
if (blkif->irq)
return 0;

- err = xenbus_map_ring_valloc(blkif->be->dev, shared_page, &blkif->blk_ring);
+ err = xenbus_map_ring_valloc(blkif->be->dev, ring_ref, 1 << ring_order,
+ &blkif->blk_ring);
if (err < 0)
return err;

@@ -140,21 +141,24 @@ static int xen_blkif_map(struct xen_blkif *blkif, unsigned long shared_page,
{
struct blkif_sring *sring;
sring = (struct blkif_sring *)blkif->blk_ring;
- BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE);
+ BACK_RING_INIT(&blkif->blk_rings.native, sring,
+ PAGE_SIZE << ring_order);
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;
- BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE);
+ BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32,
+ PAGE_SIZE << ring_order);
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;
- BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE);
+ BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64,
+ PAGE_SIZE << ring_order);
break;
}
default:
@@ -497,6 +501,11 @@ static int xen_blkbk_probe(struct xenbus_device *dev,
if (err)
goto fail;

+ err = xenbus_printf(XBT_NIL, dev->nodename, "max-ring-page-order",
+ "%u", xen_blkif_max_ring_order);
+ if (err)
+ goto fail;
+
err = xenbus_switch_state(dev, XenbusStateInitWait);
if (err)
goto fail;
@@ -744,22 +753,80 @@ again:
static int connect_ring(struct backend_info *be)
{
struct xenbus_device *dev = be->dev;
- unsigned long ring_ref;
+ int ring_ref[XENBUS_MAX_RING_PAGES];
+ unsigned int ring_order;
unsigned int evtchn;
char protocol[64] = "";
int err;

DPRINTK("%s", dev->otherend);

- err = xenbus_gather(XBT_NIL, dev->otherend, "ring-ref", "%lu",
- &ring_ref, "event-channel", "%u", &evtchn, NULL);
- if (err) {
- xenbus_dev_fatal(dev, err,
- "reading %s/ring-ref and event-channel",
+ err = xenbus_scanf(XBT_NIL, dev->otherend, "event-channel", "%u",
+ &evtchn);
+ if (err != 1) {
+ err = -EINVAL;
+
+ xenbus_dev_fatal(dev, err, "reading %s/event-channel",
dev->otherend);
return err;
}

+ printk(KERN_INFO "blkback: event-channel %u\n", evtchn);
+
+ err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-page-order", "%u",
+ &ring_order);
+ if (err != 1) {
+ DPRINTK("%s: using single page handshake", dev->otherend);
+
+ ring_order = 0;
+
+ err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-ref",
+ "%d", &ring_ref[0]);
+ if (err != 1) {
+ err = -EINVAL;
+
+ xenbus_dev_fatal(dev, err, "reading %s/ring-ref",
+ dev->otherend);
+ return err;
+ }
+
+ printk(KERN_INFO "blkback: ring-ref %d\n", ring_ref[0]);
+ } else {
+ unsigned int i;
+
+ if (ring_order > xen_blkif_max_ring_order) {
+ err = -EINVAL;
+
+ xenbus_dev_fatal(dev, err,
+ "%s/ring-page-order too big",
+ dev->otherend);
+ return err;
+ }
+
+ for (i = 0; i < (1u << ring_order); i++) {
+ char ring_ref_name[10];
+
+ snprintf(ring_ref_name, sizeof(ring_ref_name),
+ "ring-ref%u", i);
+
+ err = xenbus_scanf(XBT_NIL, dev->otherend,
+ ring_ref_name, "%d",
+ &ring_ref[i]);
+ if (err != 1) {
+ err = -EINVAL;
+
+ xenbus_dev_fatal(dev, err,
+ "reading %s/%s",
+ dev->otherend,
+ ring_ref_name);
+ return err;
+ }
+
+ printk(KERN_INFO "blkback: ring-ref%u %d\n", i,
+ ring_ref[i]);
+ }
+ }
+
be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
"%63s", protocol, NULL);
@@ -775,14 +842,11 @@ static int connect_ring(struct backend_info *be)
xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
return -1;
}
- pr_info(DRV_PFX "ring-ref %ld, event-channel %d, protocol %d (%s)\n",
- ring_ref, evtchn, be->blkif->blk_protocol, protocol);

/* Map the shared frame, irq etc. */
- err = xen_blkif_map(be->blkif, ring_ref, evtchn);
+ err = xen_blkif_map(be->blkif, ring_ref, ring_order, evtchn);
if (err) {
- xenbus_dev_fatal(dev, err, "mapping ring-ref %lu port %u",
- ring_ref, evtchn);
+ xenbus_dev_fatal(dev, err, "mapping ring-refs and evtchn");
return err;
}

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 2f22874..485813a 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -57,6 +57,10 @@

#include <asm/xen/hypervisor.h>

+static int xen_blkif_ring_order;
+module_param_named(reqs, xen_blkif_ring_order, int, 0);
+MODULE_PARM_DESC(reqs, "log2 of requested ring size, in pages.");
+
enum blkif_state {
BLKIF_STATE_DISCONNECTED,
BLKIF_STATE_CONNECTED,
@@ -72,7 +76,8 @@ struct blk_shadow {
static DEFINE_MUTEX(blkfront_mutex);
static const struct block_device_operations xlvbd_block_fops;

-#define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE)
+#define BLK_RING_SIZE(_order) __CONST_RING_SIZE(blkif, PAGE_SIZE << (_order))
+#define BLK_MAX_RING_SIZE BLK_RING_SIZE(XENBUS_MAX_RING_ORDER)

/*
* We have one of these per vbd, whether ide, scsi or 'other'. They
@@ -87,14 +92,15 @@ struct blkfront_info
int vdevice;
blkif_vdev_t handle;
enum blkif_state connected;
- int ring_ref;
+ int ring_ref[XENBUS_MAX_RING_PAGES];
+ int ring_order;
struct blkif_front_ring ring;
struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
unsigned int evtchn, irq;
struct request_queue *rq;
struct work_struct work;
struct gnttab_free_callback callback;
- struct blk_shadow shadow[BLK_RING_SIZE];
+ struct blk_shadow shadow[BLK_MAX_RING_SIZE];
unsigned long shadow_free;
unsigned int feature_flush;
unsigned int flush_op;
@@ -111,9 +117,7 @@ static unsigned int nr_minors;
static unsigned long *minors;
static DEFINE_SPINLOCK(minor_lock);

-#define MAXIMUM_OUTSTANDING_BLOCK_REQS \
- (BLKIF_MAX_SEGMENTS_PER_REQUEST * BLK_RING_SIZE)
-#define GRANT_INVALID_REF 0
+#define GRANT_INVALID_REF 0

#define PARTS_PER_DISK 16
#define PARTS_PER_EXT_DISK 256
@@ -135,7 +139,7 @@ static DEFINE_SPINLOCK(minor_lock);
static int get_id_from_freelist(struct blkfront_info *info)
{
unsigned long free = info->shadow_free;
- BUG_ON(free >= BLK_RING_SIZE);
+ BUG_ON(free >= BLK_MAX_RING_SIZE);
info->shadow_free = info->shadow[free].req.u.rw.id;
info->shadow[free].req.u.rw.id = 0x0fffffee; /* debug */
return free;
@@ -683,6 +687,8 @@ static void blkif_restart_queue(struct work_struct *work)

static void blkif_free(struct blkfront_info *info, int suspend)
{
+ int i;
+
/* Prevent new requests being issued until we fix things up. */
spin_lock_irq(&blkif_io_lock);
info->connected = suspend ?
@@ -698,16 +704,19 @@ static void blkif_free(struct blkfront_info *info, int suspend)
flush_work_sync(&info->work);

/* Free resources associated with old device channel. */
- if (info->ring_ref != GRANT_INVALID_REF) {
- gnttab_end_foreign_access(info->ring_ref, 0,
- (unsigned long)info->ring.sring);
- info->ring_ref = GRANT_INVALID_REF;
- info->ring.sring = NULL;
+ for (i = 0; i < (1 << info->ring_order); i++) {
+ if (info->ring_ref[i] != GRANT_INVALID_REF) {
+ gnttab_end_foreign_access(info->ring_ref[i], 0, 0);
+ info->ring_ref[i] = GRANT_INVALID_REF;
+ }
}
+
+ free_pages((unsigned long)info->ring.sring, info->ring_order);
+ info->ring.sring = NULL;
+
if (info->irq)
unbind_from_irqhandler(info->irq, info);
info->evtchn = info->irq = 0;
-
}

static void blkif_completion(struct blk_shadow *s)
@@ -828,25 +837,24 @@ static int setup_blkring(struct xenbus_device *dev,
struct blkif_sring *sring;
int err;

- info->ring_ref = GRANT_INVALID_REF;
-
- sring = (struct blkif_sring *)__get_free_page(GFP_NOIO | __GFP_HIGH);
+ sring = (struct blkif_sring *)__get_free_pages(GFP_NOIO | __GFP_HIGH,
+ info->ring_order);
if (!sring) {
xenbus_dev_fatal(dev, -ENOMEM, "allocating shared ring");
return -ENOMEM;
}
SHARED_RING_INIT(sring);
- FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
+ FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE << info->ring_order);

sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);

- err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
+ err = xenbus_grant_ring(dev, info->ring.sring, 1 << info->ring_order,
+ info->ring_ref);
if (err < 0) {
- free_page((unsigned long)sring);
+ free_pages((unsigned long)sring, info->ring_order);
info->ring.sring = NULL;
goto fail;
}
- info->ring_ref = err;

err = xenbus_alloc_evtchn(dev, &info->evtchn);
if (err)
@@ -875,8 +883,27 @@ static int talk_to_blkback(struct xenbus_device *dev,
{
const char *message = NULL;
struct xenbus_transaction xbt;
+ unsigned int ring_order;
+ int legacy_backend;
+ int i;
int err;

+ for (i = 0; i < (1 << info->ring_order); i++)
+ info->ring_ref[i] = GRANT_INVALID_REF;
+
+ err = xenbus_scanf(XBT_NIL, dev->otherend, "max-ring-page-order", "%u",
+ &ring_order);
+
+ legacy_backend = !(err == 1);
+
+ if (legacy_backend) {
+ info->ring_order = 0;
+ } else {
+ info->ring_order = (ring_order <= xen_blkif_ring_order) ?
+ ring_order :
+ xen_blkif_ring_order;
+ }
+
/* Create shared ring, alloc event channel. */
err = setup_blkring(dev, info);
if (err)
@@ -889,12 +916,35 @@ again:
goto destroy_blkring;
}

- err = xenbus_printf(xbt, dev->nodename,
- "ring-ref", "%u", info->ring_ref);
- if (err) {
- message = "writing ring-ref";
- goto abort_transaction;
+ if (legacy_backend) {
+ err = xenbus_printf(xbt, dev->nodename,
+ "ring-ref", "%d", info->ring_ref[0]);
+ if (err) {
+ message = "writing ring-ref";
+ goto abort_transaction;
+ }
+ } else {
+ for (i = 0; i < (1 << info->ring_order); i++) {
+ char key[sizeof("ring-ref") + 2];
+
+ sprintf(key, "ring-ref%d", i);
+
+ err = xenbus_printf(xbt, dev->nodename,
+ key, "%d", info->ring_ref[i]);
+ if (err) {
+ message = "writing ring-ref";
+ goto abort_transaction;
+ }
+ }
+
+ err = xenbus_printf(xbt, dev->nodename,
+ "ring-page-order", "%u", info->ring_order);
+ if (err) {
+ message = "writing ring-order";
+ goto abort_transaction;
+ }
}
+
err = xenbus_printf(xbt, dev->nodename,
"event-channel", "%u", info->evtchn);
if (err) {
@@ -996,21 +1046,14 @@ static int blkfront_probe(struct xenbus_device *dev,
info->connected = BLKIF_STATE_DISCONNECTED;
INIT_WORK(&info->work, blkif_restart_queue);

- for (i = 0; i < BLK_RING_SIZE; i++)
+ for (i = 0; i < BLK_MAX_RING_SIZE; i++)
info->shadow[i].req.u.rw.id = i+1;
- info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
+ info->shadow[BLK_MAX_RING_SIZE-1].req.u.rw.id = 0x0fffffff;

/* Front end dir is a number, which is used as the id. */
info->handle = simple_strtoul(strrchr(dev->nodename, '/')+1, NULL, 0);
dev_set_drvdata(&dev->dev, info);

- err = talk_to_blkback(dev, info);
- if (err) {
- kfree(info);
- dev_set_drvdata(&dev->dev, NULL);
- return err;
- }
-
return 0;
}

@@ -1031,13 +1074,13 @@ static int blkif_recover(struct blkfront_info *info)

/* Stage 2: Set up free list. */
memset(&info->shadow, 0, sizeof(info->shadow));
- for (i = 0; i < BLK_RING_SIZE; i++)
+ for (i = 0; i < BLK_MAX_RING_SIZE; i++)
info->shadow[i].req.u.rw.id = i+1;
info->shadow_free = info->ring.req_prod_pvt;
- info->shadow[BLK_RING_SIZE-1].req.u.rw.id = 0x0fffffff;
+ info->shadow[BLK_MAX_RING_SIZE-1].req.u.rw.id = 0x0fffffff;

/* Stage 3: Find pending requests and requeue them. */
- for (i = 0; i < BLK_RING_SIZE; i++) {
+ for (i = 0; i < BLK_RING_SIZE(info->ring_order); i++) {
/* Not in use? */
if (!copy[i].request)
continue;
@@ -1299,7 +1342,6 @@ static void blkback_changed(struct xenbus_device *dev,

switch (backend_state) {
case XenbusStateInitialising:
- case XenbusStateInitWait:
case XenbusStateInitialised:
case XenbusStateReconfiguring:
case XenbusStateReconfigured:
@@ -1307,6 +1349,10 @@ static void blkback_changed(struct xenbus_device *dev,
case XenbusStateClosed:
break;

+ case XenbusStateInitWait:
+ talk_to_blkback(dev, info);
+ break;
+
case XenbusStateConnected:
blkfront_connect(info);
break;
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 94b79c3..f93b59a 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -130,8 +130,8 @@ int xen_netbk_must_stop_queue(struct xenvif *vif);
/* (Un)Map communication rings. */
void xen_netbk_unmap_frontend_rings(struct xenvif *vif);
int xen_netbk_map_frontend_rings(struct xenvif *vif,
- grant_ref_t tx_ring_ref,
- grant_ref_t rx_ring_ref);
+ int tx_ring_ref,
+ int rx_ring_ref);

/* (De)Register a xenvif with the netback backend. */
void xen_netbk_add_xenvif(struct xenvif *vif);
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 59effac..0b014cf 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1594,8 +1594,8 @@ void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
}

int xen_netbk_map_frontend_rings(struct xenvif *vif,
- grant_ref_t tx_ring_ref,
- grant_ref_t rx_ring_ref)
+ int tx_ring_ref,
+ int rx_ring_ref)
{
void *addr;
struct xen_netif_tx_sring *txs;
@@ -1604,7 +1604,7 @@ int xen_netbk_map_frontend_rings(struct xenvif *vif,
int err = -ENOMEM;

err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
- tx_ring_ref, &addr);
+ &tx_ring_ref, 1, &addr);
if (err)
goto err;

@@ -1612,7 +1612,7 @@ int xen_netbk_map_frontend_rings(struct xenvif *vif,
BACK_RING_INIT(&vif->tx, txs, PAGE_SIZE);

err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(vif),
- rx_ring_ref, &addr);
+ &rx_ring_ref, 1, &addr);
if (err)
goto err;

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 698b905..521a595 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1496,13 +1496,12 @@ static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)
SHARED_RING_INIT(txs);
FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);

- err = xenbus_grant_ring(dev, virt_to_mfn(txs));
+ err = xenbus_grant_ring(dev, txs, 1, &info->tx_ring_ref);
if (err < 0) {
free_page((unsigned long)txs);
goto fail;
}

- info->tx_ring_ref = err;
rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
if (!rxs) {
err = -ENOMEM;
@@ -1512,12 +1511,11 @@ static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)
SHARED_RING_INIT(rxs);
FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE);

- err = xenbus_grant_ring(dev, virt_to_mfn(rxs));
+ err = xenbus_grant_ring(dev, rxs, 1, &info->rx_ring_ref);
if (err < 0) {
free_page((unsigned long)rxs);
goto fail;
}
- info->rx_ring_ref = err;

err = xenbus_alloc_evtchn(dev, &info->evtchn);
if (err)
diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
index 1620088..95109d8 100644
--- a/drivers/pci/xen-pcifront.c
+++ b/drivers/pci/xen-pcifront.c
@@ -768,12 +768,10 @@ static int pcifront_publish_info(struct pcifront_device *pdev)
int err = 0;
struct xenbus_transaction trans;

- err = xenbus_grant_ring(pdev->xdev, virt_to_mfn(pdev->sh_info));
+ err = xenbus_grant_ring(pdev->xdev, pdev->sh_info, 1, &pdev->gnt_ref);
if (err < 0)
goto out;

- pdev->gnt_ref = err;
-
err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn);
if (err)
goto out;
diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
index 64b11f9..e0834cd 100644
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c
@@ -108,7 +108,7 @@ static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,
"Attaching to frontend resources - gnt_ref=%d evtchn=%d\n",
gnt_ref, remote_evtchn);

- err = xenbus_map_ring_valloc(pdev->xdev, gnt_ref, &vaddr);
+ err = xenbus_map_ring_valloc(pdev->xdev, &gnt_ref, 1, &vaddr);
if (err < 0) {
xenbus_dev_fatal(pdev->xdev, err,
"Error mapping other domain page in ours.");
diff --git a/drivers/xen/xenbus/xenbus_client.c b/drivers/xen/xenbus/xenbus_client.c
index 566d2ad..3a14524 100644
--- a/drivers/xen/xenbus/xenbus_client.c
+++ b/drivers/xen/xenbus/xenbus_client.c
@@ -53,14 +53,16 @@ struct xenbus_map_node {
struct vm_struct *area; /* PV */
struct page *page; /* HVM */
};
- grant_handle_t handle;
+ grant_handle_t handle[XENBUS_MAX_RING_PAGES];
+ unsigned int nr_handles;
};

static DEFINE_SPINLOCK(xenbus_valloc_lock);
static LIST_HEAD(xenbus_valloc_pages);

struct xenbus_ring_ops {
- int (*map)(struct xenbus_device *dev, int gnt, void **vaddr);
+ int (*map)(struct xenbus_device *dev, int gnt[], int nr_gnts,
+ void **vaddr);
int (*unmap)(struct xenbus_device *dev, void *vaddr);
};

@@ -356,17 +358,38 @@ static void xenbus_switch_fatal(struct xenbus_device *dev, int depth, int err,
/**
* xenbus_grant_ring
* @dev: xenbus device
- * @ring_mfn: mfn of ring to grant
-
- * Grant access to the given @ring_mfn to the peer of the given device. Return
- * 0 on success, or -errno on error. On error, the device will switch to
- * XenbusStateClosing, and the error will be saved in the store.
+ * @vaddr: starting virtual address of the ring
+ * @nr_pages: number of page to be granted
+ * @grefs: grant reference array to be filled in
+ * Grant access to the given @vaddr to the peer of the given device.
+ * Then fill in @grefs with grant references. Return 0 on success, or
+ * -errno on error. On error, the device will switch to
+ * XenbusStateClosing, and the first error will be saved in the store.
*/
-int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn)
+int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
+ int nr_pages, int grefs[])
{
- int err = gnttab_grant_foreign_access(dev->otherend_id, ring_mfn, 0);
- if (err < 0)
- xenbus_dev_fatal(dev, err, "granting access to ring page");
+ int i;
+ int err;
+
+ for (i = 0; i < nr_pages; i++) {
+ unsigned long addr = (unsigned long)vaddr +
+ (PAGE_SIZE * i);
+ err = gnttab_grant_foreign_access(dev->otherend_id,
+ virt_to_mfn(addr), 0);
+ if (err < 0) {
+ xenbus_dev_fatal(dev, err,
+ "granting access to ring page");
+ goto fail;
+ }
+ grefs[i] = err;
+ }
+
+ return 0;
+
+fail:
+ for ( ; i >= 0; i--)
+ gnttab_end_foreign_access_ref(grefs[i], 0);
return err;
}
EXPORT_SYMBOL_GPL(xenbus_grant_ring);
@@ -447,7 +470,8 @@ EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
/**
* xenbus_map_ring_valloc
* @dev: xenbus device
- * @gnt_ref: grant reference
+ * @gnt_ref: grant reference array
+ * @nr_grefs: number of grant reference
* @vaddr: pointer to address to be filled out by mapping
*
* Based on Rusty Russell's skeleton driver's map_page.
@@ -458,23 +482,28 @@ EXPORT_SYMBOL_GPL(xenbus_free_evtchn);
* or -ENOMEM on error. If an error is returned, device will switch to
* XenbusStateClosing and the error message will be saved in XenStore.
*/
-int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void **vaddr)
+int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref[],
+ int nr_grefs, void **vaddr)
{
- return ring_ops->map(dev, gnt_ref, vaddr);
+ return ring_ops->map(dev, gnt_ref, nr_grefs, vaddr);
}
EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc);

+static int __xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev,
+ struct xenbus_map_node *node);
+
static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
- int gnt_ref, void **vaddr)
+ int gnt_ref[], int nr_grefs, void **vaddr)
{
- struct gnttab_map_grant_ref op = {
- .flags = GNTMAP_host_map | GNTMAP_contains_pte,
- .ref = gnt_ref,
- .dom = dev->otherend_id,
- };
+ struct gnttab_map_grant_ref op[XENBUS_MAX_RING_PAGES];
struct xenbus_map_node *node;
struct vm_struct *area;
- pte_t *pte;
+ pte_t *pte[XENBUS_MAX_RING_PAGES];
+ int i;
+ int err = 0;
+
+ if (nr_grefs > XENBUS_MAX_RING_PAGES)
+ return -EINVAL;

*vaddr = NULL;

@@ -482,28 +511,44 @@ static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
if (!node)
return -ENOMEM;

- area = alloc_vm_area(PAGE_SIZE, &pte);
+ area = alloc_vm_area(PAGE_SIZE * nr_grefs, pte);
if (!area) {
kfree(node);
return -ENOMEM;
}

- op.host_addr = arbitrary_virt_to_machine(pte).maddr;
+ for (i = 0; i < nr_grefs; i++) {
+ op[i].flags = GNTMAP_host_map | GNTMAP_contains_pte,
+ op[i].ref = gnt_ref[i],
+ op[i].dom = dev->otherend_id,
+ op[i].host_addr = arbitrary_virt_to_machine(pte[i]).maddr;
+ };

if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
BUG();

- if (op.status != GNTST_okay) {
- free_vm_area(area);
- kfree(node);
- xenbus_dev_fatal(dev, op.status,
- "mapping in shared page %d from domain %d",
- gnt_ref, dev->otherend_id);
- return op.status;
+ node->nr_handles = nr_grefs;
+ node->area = area;
+
+ for (i = 0; i < nr_grefs; i++) {
+ if (op[i].status != GNTST_okay) {
+ err = op[i].status;
+ node->handle[i] = INVALID_GRANT_HANDLE;
+ continue;
+ }
+ node->handle[i] = op[i].handle;
}

- node->handle = op.handle;
- node->area = area;
+ if (err != 0) {
+ for (i = 0; i < nr_grefs; i++)
+ xenbus_dev_fatal(dev, op[i].status,
+ "mapping in shared page %d from domain %d",
+ gnt_ref[i], dev->otherend_id);
+
+ __xenbus_unmap_ring_vfree_pv(dev, node);
+
+ return err;
+ }

spin_lock(&xenbus_valloc_lock);
list_add(&node->next, &xenbus_valloc_pages);
@@ -514,25 +559,29 @@ static int xenbus_map_ring_valloc_pv(struct xenbus_device *dev,
}

static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
- int gnt_ref, void **vaddr)
+ int gnt_ref[], int nr_grefs, void **vaddr)
{
struct xenbus_map_node *node;
int err;
void *addr;

+ if (nr_grefs > XENBUS_MAX_RING_PAGES)
+ return -EINVAL;
+
*vaddr = NULL;

node = kzalloc(sizeof(*node), GFP_KERNEL);
if (!node)
return -ENOMEM;

- err = alloc_xenballooned_pages(1, &node->page, false /* lowmem */);
+ err = alloc_xenballooned_pages(nr_grefs, &node->page,
+ false /* lowmem */);
if (err)
goto out_err;

addr = pfn_to_kaddr(page_to_pfn(node->page));

- err = xenbus_map_ring(dev, gnt_ref, &node->handle, addr);
+ err = xenbus_map_ring(dev, gnt_ref, nr_grefs, node->handle, addr);
if (err)
goto out_err;

@@ -544,7 +593,7 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
return 0;

out_err:
- free_xenballooned_pages(1, &node->page);
+ free_xenballooned_pages(nr_grefs, &node->page);
kfree(node);
return err;
}
@@ -553,36 +602,51 @@ static int xenbus_map_ring_valloc_hvm(struct xenbus_device *dev,
/**
* xenbus_map_ring
* @dev: xenbus device
- * @gnt_ref: grant reference
- * @handle: pointer to grant handle to be filled
+ * @gnt_ref: grant reference array
+ * @nr_grefs: number of grant references
+ * @handle: pointer to grant handle array to be filled, mind the size
* @vaddr: address to be mapped to
*
- * Map a page of memory into this domain from another domain's grant table.
+ * Map pages of memory into this domain from another domain's grant table.
* xenbus_map_ring does not allocate the virtual address space (you must do
- * this yourself!). It only maps in the page to the specified address.
+ * this yourself!). It only maps in the pages to the specified address.
* Returns 0 on success, and GNTST_* (see xen/include/interface/grant_table.h)
* or -ENOMEM on error. If an error is returned, device will switch to
- * XenbusStateClosing and the error message will be saved in XenStore.
+ * XenbusStateClosing and the last error message will be saved in XenStore.
*/
-int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
- grant_handle_t *handle, void *vaddr)
+int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref[], int nr_grefs,
+ grant_handle_t handle[], void *vaddr)
{
- struct gnttab_map_grant_ref op;
-
- gnttab_set_map_op(&op, (phys_addr_t)vaddr, GNTMAP_host_map, gnt_ref,
- dev->otherend_id);
+ struct gnttab_map_grant_ref op[XENBUS_MAX_RING_PAGES];
+ int i;
+ int err = GNTST_okay; /* 0 */
+
+ for (i = 0; i < nr_grefs; i++) {
+ unsigned long addr = (unsigned long)vaddr +
+ (PAGE_SIZE * i);
+ gnttab_set_map_op(&op[i], (phys_addr_t)addr,
+ GNTMAP_host_map, gnt_ref[i],
+ dev->otherend_id);
+ }

- if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
+ if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, op, nr_grefs))
BUG();

- if (op.status != GNTST_okay) {
- xenbus_dev_fatal(dev, op.status,
- "mapping in shared page %d from domain %d",
- gnt_ref, dev->otherend_id);
- } else
- *handle = op.handle;
+ for (i = 0; i < nr_grefs; i++) {
+ if (op[i].status != GNTST_okay) {
+ err = op[i].status;
+ xenbus_dev_fatal(dev, err,
+ "mapping in shared page %d from domain %d",
+ gnt_ref[i], dev->otherend_id);
+ handle[i] = INVALID_GRANT_HANDLE;
+ } else
+ handle[i] = op[i].handle;
+ }

- return op.status;
+ if (err != GNTST_okay)
+ xenbus_unmap_ring(dev, handle, nr_grefs, vaddr);
+
+ return err;
}
EXPORT_SYMBOL_GPL(xenbus_map_ring);

@@ -605,13 +669,53 @@ int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr)
}
EXPORT_SYMBOL_GPL(xenbus_unmap_ring_vfree);

+static int __xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev,
+ struct xenbus_map_node *node)
+{
+ struct gnttab_unmap_grant_ref op[XENBUS_MAX_RING_PAGES];
+ unsigned int level;
+ int i, j;
+ int err = GNTST_okay;
+
+ j = 0;
+ for (i = 0; i < node->nr_handles; i++) {
+ unsigned long vaddr = (unsigned long)node->area->addr +
+ (PAGE_SIZE * i);
+ if (node->handle[i] != INVALID_GRANT_HANDLE) {
+ memset(&op[j], 0, sizeof(op[0]));
+ op[j].host_addr = arbitrary_virt_to_machine(
+ lookup_address(vaddr, &level)).maddr;
+ op[j].handle = node->handle[i];
+ j++;
+ node->handle[i] = INVALID_GRANT_HANDLE;
+ }
+ }
+
+ if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, op, j))
+ BUG();
+
+ node->nr_handles = 0;
+
+ for (i = 0; i < j; i++) {
+ if (op[i].status != GNTST_okay) {
+ err = op[i].status;
+ xenbus_dev_error(dev, err,
+ "unmapping page %d at handle %d error %d",
+ i, op[i].handle, err);
+ }
+ }
+
+ if (err == GNTST_okay)
+ free_vm_area(node->area);
+
+ kfree(node);
+
+ return err;
+}
+
static int xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev, void *vaddr)
{
struct xenbus_map_node *node;
- struct gnttab_unmap_grant_ref op = {
- .host_addr = (unsigned long)vaddr,
- };
- unsigned int level;

spin_lock(&xenbus_valloc_lock);
list_for_each_entry(node, &xenbus_valloc_pages, next) {
@@ -626,33 +730,18 @@ static int xenbus_unmap_ring_vfree_pv(struct xenbus_device *dev, void *vaddr)

if (!node) {
xenbus_dev_error(dev, -ENOENT,
- "can't find mapped virtual address %p", vaddr);
+ "can't find mapped virtual address %p", vaddr);
return GNTST_bad_virt_addr;
}

- op.handle = node->handle;
- op.host_addr = arbitrary_virt_to_machine(
- lookup_address((unsigned long)vaddr, &level)).maddr;
-
- if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
- BUG();
-
- if (op.status == GNTST_okay)
- free_vm_area(node->area);
- else
- xenbus_dev_error(dev, op.status,
- "unmapping page at handle %d error %d",
- node->handle, op.status);
-
- kfree(node);
- return op.status;
+ return __xenbus_unmap_ring_vfree_pv(dev, node);
}

static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
{
int rv;
struct xenbus_map_node *node;
- void *addr;
+ void *addr = NULL;

spin_lock(&xenbus_valloc_lock);
list_for_each_entry(node, &xenbus_valloc_pages, next) {
@@ -668,14 +757,14 @@ static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)

if (!node) {
xenbus_dev_error(dev, -ENOENT,
- "can't find mapped virtual address %p", vaddr);
+ "can't find mapped virtual address %p", vaddr);
return GNTST_bad_virt_addr;
}

- rv = xenbus_unmap_ring(dev, node->handle, addr);
+ rv = xenbus_unmap_ring(dev, node->handle, node->nr_handles, addr);

if (!rv)
- free_xenballooned_pages(1, &node->page);
+ free_xenballooned_pages(node->nr_handles, &node->page);
else
WARN(1, "Leaking %p\n", vaddr);

@@ -687,6 +776,7 @@ static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
* xenbus_unmap_ring
* @dev: xenbus device
* @handle: grant handle
+ * @nr_handles: number of grant handle
* @vaddr: addr to unmap
*
* Unmap a page of memory in this domain that was imported from another domain.
@@ -694,21 +784,37 @@ static int xenbus_unmap_ring_vfree_hvm(struct xenbus_device *dev, void *vaddr)
* (see xen/include/interface/grant_table.h).
*/
int xenbus_unmap_ring(struct xenbus_device *dev,
- grant_handle_t handle, void *vaddr)
+ grant_handle_t handle[], int nr_handles,
+ void *vaddr)
{
- struct gnttab_unmap_grant_ref op;
-
- gnttab_set_unmap_op(&op, (phys_addr_t)vaddr, GNTMAP_host_map, handle);
+ struct gnttab_unmap_grant_ref op[XENBUS_MAX_RING_PAGES];
+ int i, j;
+ int err = GNTST_okay;
+
+ j = 0;
+ for (i = 0; i < nr_handles; i++) {
+ unsigned long addr = (unsigned long)vaddr +
+ (PAGE_SIZE * i);
+ if (handle[i] != INVALID_GRANT_HANDLE) {
+ gnttab_set_unmap_op(&op[j++], (phys_addr_t)addr,
+ GNTMAP_host_map, handle[i]);
+ handle[i] = INVALID_GRANT_HANDLE;
+ }
+ }

- if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
+ if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, op, j))
BUG();

- if (op.status != GNTST_okay)
- xenbus_dev_error(dev, op.status,
- "unmapping page at handle %d error %d",
- handle, op.status);
+ for (i = 0; i < j; i++) {
+ if (op[i].status != GNTST_okay) {
+ err = op[i].status;
+ xenbus_dev_error(dev, err,
+ "unmapping page at handle %d error %d",
+ handle[i], err);
+ }
+ }

- return op.status;
+ return err;
}
EXPORT_SYMBOL_GPL(xenbus_unmap_ring);

diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index 3864967..62b92d2 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -718,6 +718,7 @@ static int __init xenstored_local_init(void)
return err;
}

+extern void xenbus_ring_ops_init(void);
static int __init xenbus_init(void)
{
int err = 0;
@@ -767,6 +768,8 @@ static int __init xenbus_init(void)
proc_mkdir("xen", NULL);
#endif

+ xenbus_ring_ops_init();
+
out_error:
return err;
}
diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h
index e8c599b..cdbd948 100644
--- a/include/xen/xenbus.h
+++ b/include/xen/xenbus.h
@@ -195,15 +195,23 @@ int xenbus_watch_pathfmt(struct xenbus_device *dev, struct xenbus_watch *watch,
const char *pathfmt, ...);

int xenbus_switch_state(struct xenbus_device *dev, enum xenbus_state new_state);
-int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn);
-int xenbus_map_ring_valloc(struct xenbus_device *dev,
- int gnt_ref, void **vaddr);
-int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref,
- grant_handle_t *handle, void *vaddr);
+
+#define XENBUS_MAX_RING_ORDER 2
+#define XENBUS_MAX_RING_PAGES (1 << XENBUS_MAX_RING_ORDER)
+
+#define INVALID_GRANT_HANDLE (~0U)
+
+int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr,
+ int nr_pages, int grefs[]);
+int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref[],
+ int nr_grefs, void **vaddr);
+int xenbus_map_ring(struct xenbus_device *dev, int gnt_ref[], int nr_grefs,
+ grant_handle_t handle[], void *vaddr);

int xenbus_unmap_ring_vfree(struct xenbus_device *dev, void *vaddr);
int xenbus_unmap_ring(struct xenbus_device *dev,
- grant_handle_t handle, void *vaddr);
+ grant_handle_t handle[], int nr_handles,
+ void *vaddr);

int xenbus_alloc_evtchn(struct xenbus_device *dev, int *port);
int xenbus_bind_evtchn(struct xenbus_device *dev, int remote_port, int *port);

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  Last update: 2012-03-05 22:51    [from the cache]
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