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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 1/2] Add multi-page ring support to xen-blkback.
Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
---
drivers/xen/blkback/common.h | 10 +++-
drivers/xen/blkback/interface.c | 113 +++++++++++++++++++++++++++-----------
drivers/xen/blkback/xenbus.c | 100 ++++++++++++++++++++++++++++++-----
3 files changed, 174 insertions(+), 49 deletions(-)
diff --git a/drivers/xen/blkback/common.h b/drivers/xen/blkback/common.h
index d12d4d5..6404a4a 100644
--- a/drivers/xen/blkback/common.h
+++ b/drivers/xen/blkback/common.h
@@ -58,6 +58,9 @@ struct vbd {
struct backend_info;
+#define BLKIF_MAX_RING_PAGE_ORDER 2
+#define BLKIF_MAX_RING_PAGES (1<<BLKIF_MAX_RING_PAGE_ORDER)
+
typedef struct blkif_st {
/* Unique identifier for this interface. */
domid_t domid;
@@ -92,14 +95,15 @@ typedef struct blkif_st {
wait_queue_head_t waiting_to_free;
- grant_handle_t shmem_handle;
- grant_ref_t shmem_ref;
+ unsigned int nr_shared_pages;
+ grant_handle_t shmem_handle[BLKIF_MAX_RING_PAGES];
} blkif_t;
blkif_t *blkif_alloc(domid_t domid);
void blkif_disconnect(blkif_t *blkif);
void blkif_free(blkif_t *blkif);
-int blkif_map(blkif_t *blkif, unsigned long shared_page, unsigned int evtchn);
+int blkif_map(blkif_t *blkif, unsigned long shared_pages[],
+ unsigned int nr_shared_pages, unsigned int evtchn);
#define blkif_get(_b) (atomic_inc(&(_b)->refcnt))
#define blkif_put(_b) \
diff --git a/drivers/xen/blkback/interface.c b/drivers/xen/blkback/interface.c
index e397a41..8951543 100644
--- a/drivers/xen/blkback/interface.c
+++ b/drivers/xen/blkback/interface.c
@@ -56,50 +56,93 @@ blkif_t *blkif_alloc(domid_t domid)
return blkif;
}
-static int map_frontend_page(blkif_t *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);
+#define INVALID_GRANT_HANDLE ((grant_handle_t)~0U)
- if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
- BUG();
-
- if (op.status) {
- DPRINTK(" Grant table operation failure !\n");
- return op.status;
+static void unmap_frontend_pages(blkif_t *blkif)
+{
+ struct vm_struct *area = blkif->blk_ring_area;
+ struct gnttab_unmap_grant_ref op[BLKIF_MAX_RING_PAGES];
+ unsigned int i;
+ unsigned int j;
+
+ j = 0;
+ for (i = 0; i < blkif->nr_shared_pages; i++) {
+ unsigned long addr = (unsigned long)area->addr +
+ (i * PAGE_SIZE);
+
+ if (blkif->shmem_handle[i] != INVALID_GRANT_HANDLE) {
+ gnttab_set_unmap_op(&op[j++], addr,
+ GNTMAP_host_map,
+ blkif->shmem_handle[i]);
+
+ blkif->shmem_handle[i] = INVALID_GRANT_HANDLE;
+ }
}
- blkif->shmem_ref = shared_page;
- blkif->shmem_handle = op.handle;
+ blkif->nr_shared_pages = 0;
- return 0;
+ if (j != 0) {
+ if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
+ op, j))
+ BUG();
+ }
}
-static void unmap_frontend_page(blkif_t *blkif)
+static int map_frontend_pages(blkif_t *blkif, unsigned long shared_pages[],
+ unsigned int nr_shared_pages)
{
- struct gnttab_unmap_grant_ref op;
+ struct vm_struct *area = blkif->blk_ring_area;
+ struct gnttab_map_grant_ref op[BLKIF_MAX_RING_PAGES];
+ unsigned int i;
+ int status = 0;
- gnttab_set_unmap_op(&op, (unsigned long)blkif->blk_ring_area->addr,
- GNTMAP_host_map, blkif->shmem_handle);
+ for (i = 0; i < nr_shared_pages; i++) {
+ unsigned long addr = (unsigned long)area->addr +
+ (i * PAGE_SIZE);
+
+ gnttab_set_map_op(&op[i], addr, GNTMAP_host_map,
+ shared_pages[i], blkif->domid);
+ }
- if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
+ if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, op,
+ nr_shared_pages))
BUG();
+
+ for (i = 0; i < nr_shared_pages; i++) {
+ status = op[i].status;
+ if (status != 0) {
+ blkif->shmem_handle[i] = INVALID_GRANT_HANDLE;
+ continue;
+ }
+
+ blkif->shmem_handle[i] = op[i].handle;
+ }
+
+ blkif->nr_shared_pages = nr_shared_pages;
+
+ if (status != 0) {
+ DPRINTK(" Grant table operation failure !\n");
+ unmap_frontend_pages(blkif);
+ }
+
+ return status;
}
-int blkif_map(blkif_t *blkif, unsigned long shared_page, unsigned int evtchn)
+int blkif_map(blkif_t *blkif, unsigned long shared_pages[],
+ unsigned int nr_shared_pages, unsigned int evtchn)
{
+ unsigned long size = nr_shared_pages * PAGE_SIZE;
int err;
/* Already connected through? */
if (blkif->irq)
return 0;
- if ( (blkif->blk_ring_area = alloc_vm_area(PAGE_SIZE)) == NULL )
+ blkif->blk_ring_area = alloc_vm_area(size);
+ if (blkif->blk_ring_area == NULL)
return -ENOMEM;
- err = map_frontend_page(blkif, shared_page);
+ err = map_frontend_pages(blkif, shared_pages, nr_shared_pages);
if (err) {
free_vm_area(blkif->blk_ring_area);
return err;
@@ -110,21 +153,21 @@ int blkif_map(blkif_t *blkif, unsigned long shared_page,
unsigned int evtchn)
{
struct blkif_sring *sring;
sring = (struct blkif_sring *)blkif->blk_ring_area->addr;
- BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE);
+ BACK_RING_INIT(&blkif->blk_rings.native, sring, 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;
- BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32,
PAGE_SIZE);
+ struct blkif_x86_32_sring *sring;
+ sring = (struct blkif_x86_32_sring *)blkif->blk_ring_area->addr;
+ BACK_RING_INIT(&blkif->blk_rings.x86_32, sring, 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;
- BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64,
PAGE_SIZE);
+ struct blkif_x86_64_sring *sring;
+ sring = (struct blkif_x86_64_sring *)blkif->blk_ring_area->addr;
+ BACK_RING_INIT(&blkif->blk_rings.x86_64, sring, size);
break;
}
default:
@@ -132,14 +175,17 @@ int blkif_map(blkif_t *blkif, unsigned long shared_page,
unsigned int evtchn)
}
err = bind_interdomain_evtchn_to_irqhandler(
- blkif->domid, evtchn, blkif_be_int, 0, "blkif-backend", blkif);
+ blkif->domid, evtchn, blkif_be_int, 0, "blkif-backend",
+ blkif);
if (err < 0)
{
- unmap_frontend_page(blkif);
+ unmap_frontend_pages(blkif);
free_vm_area(blkif->blk_ring_area);
+ blkif->blk_ring_area = NULL;
blkif->blk_rings.common.sring = NULL;
return err;
}
+
blkif->irq = err;
return 0;
@@ -162,8 +208,9 @@ void blkif_disconnect(blkif_t *blkif)
}
if (blkif->blk_rings.common.sring) {
- unmap_frontend_page(blkif);
+ unmap_frontend_pages(blkif);
free_vm_area(blkif->blk_ring_area);
+ blkif->blk_ring_area = NULL;
blkif->blk_rings.common.sring = NULL;
}
}
diff --git a/drivers/xen/blkback/xenbus.c b/drivers/xen/blkback/xenbus.c
index 04c0a12..4ee10b8 100644
--- a/drivers/xen/blkback/xenbus.c
+++ b/drivers/xen/blkback/xenbus.c
@@ -42,6 +42,11 @@ static int connect_ring(struct backend_info *);
static void backend_changed(struct xenbus_watch *, const char **,
unsigned int);
+/* Order of maximum shared ring size advertised to the front end. */
+static int blkif_max_ring_page_order;
+module_param_named(max_ring_page_order, blkif_max_ring_page_order, int, 0);
+MODULE_PARM_DESC(max_ring_page_order, "Order of maximum VM shared ring size");
+
static int blkback_name(blkif_t *blkif, char *buf)
{
char *devpath, *devname;
@@ -243,6 +248,11 @@ static int blkback_probe(struct xenbus_device *dev,
if (err)
goto fail;
+ err = xenbus_printf(XBT_NIL, dev->nodename, "max-ring-page-order",
+ "%u", blkif_max_ring_page_order);
+ if (err)
+ goto fail;
+
err = xenbus_switch_state(dev, XenbusStateInitWait);
if (err)
goto fail;
@@ -469,22 +479,82 @@ again:
static int connect_ring(struct backend_info *be)
{
struct xenbus_device *dev = be->dev;
- unsigned long ring_ref;
unsigned int evtchn;
+ unsigned int ring_order;
+ unsigned long ring_ref[BLKIF_MAX_RING_PAGES];
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",
+ "%lu", &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 %lu\n", ring_ref[0]);
+ } else {
+ unsigned int i;
+
+ if (ring_order > blkif_max_ring_page_order) {
+ err = -EINVAL;
+
+ xenbus_dev_fatal(dev, err,
+ "%s/ring-page-order too big",
+ dev->otherend);
+ return err;
+ }
+
+ DPRINTK("%s: using %u page(s)", dev->otherend,
+ (1 << ring_order));
+
+ for (i = 0; i < (1u << ring_order); i++) {
+ char ring_ref_name[10];
+
+ snprintf(ring_ref_name, sizeof(ring_ref_name),
+ "ring-ref%1u", i);
+ err = xenbus_scanf(XBT_NIL, dev->otherend,
+ ring_ref_name, "%lu",
+ &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 %lu\n", i,
+ ring_ref[i]);
+ }
+ }
+
be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
"%63s", protocol, NULL);
@@ -497,18 +567,19 @@ static int connect_ring(struct backend_info *be)
else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64))
be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64;
else {
+ err = -EINVAL;
+
xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
- return -1;
+ return err;
}
- printk(KERN_INFO
- "blkback: ring-ref %ld, event-channel %d, protocol %d (%s)\n",
- ring_ref, evtchn, be->blkif->blk_protocol, protocol);
+
+ printk(KERN_INFO "blkback: protocol %d (%s)\n",
+ be->blkif->blk_protocol, protocol);
/* Map the shared frame, irq etc. */
- err = blkif_map(be->blkif, ring_ref, evtchn);
+ err = blkif_map(be->blkif, ring_ref, (1u << 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;
}
@@ -537,5 +608,8 @@ static struct xenbus_driver blkback = {
int blkif_xenbus_init(void)
{
+ if (blkif_max_ring_page_order > BLKIF_MAX_RING_PAGE_ORDER)
+ blkif_max_ring_page_order = BLKIF_MAX_RING_PAGE_ORDER;
+
return xenbus_register_backend(&blkback);
}
--
1.5.6.5
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