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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [patch/rfc] multiprotocol blkback drivers (32-on-64)
Hi,
This is a patch for the block interface, frontend drivers, backend
drivers and tools to support multiple ring protocols. Right there are
now just two: the 32bit and the 64bit one. If needed it can be extended.
Interface changes (io/blkif.h)
* Have both request structs there, with "v1" and "v2" added to the
name. The old name is aliased to the native protocol of the
architecture.
* Add helper functions to convert v1/v2 requests to native.
Frontend changes:
* Create a new node "protocol", add the protocol number it speaks
there.
Backend changes:
* Look at the "protocol" number of the frontend and switch ring
handling accordingly. If the protocol node isn't present it assumes
native protocol.
* As the request struct is copied anyway before being processed (for
security reasons) it is converted to native at that point so most
backend code doesn't need to know what the frontend speaks.
* In case of blktap this is completely transparent to userspace, the
kernel/userspace ring is always native no matter what the frontend
speaks.
Tools changes:
* Add one more option to the disk configuration, so one can specify the
protocol the frontend speaks in the config file. This is needed for
old frontends which don't advertise the protocol they are speaking
themself.
I'm not that happy with this approach, but it works for now and I'm
kida lost in the stack of python classes doing domain and device
handling ...
Consider the code experimental, not all frontend/backend combinations
are tested.
Comments? Questions? Suggesions?
cheers,
Gerd
PS: Anyone working on blkback/blktap code sharing? While walking
through the code I've noticed quite alot of it is cut&paste ...
--
Gerd Hoffmann <kraxel@xxxxxxx>
---
linux-2.6-xen-sparse/drivers/xen/blkback/blkback.c | 79 ++++++++++++-----
linux-2.6-xen-sparse/drivers/xen/blkback/common.h | 4
linux-2.6-xen-sparse/drivers/xen/blkback/interface.c | 17 ++-
linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c | 14 +++
linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c | 6 +
linux-2.6-xen-sparse/drivers/xen/blktap/blktap.c | 86 +++++++++++++------
linux-2.6-xen-sparse/drivers/xen/blktap/common.h | 4
linux-2.6-xen-sparse/drivers/xen/blktap/interface.c | 17 ++-
linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c | 14 +++
tools/python/xen/xend/server/blkif.py | 3
tools/python/xen/xm/create.py | 7 +
xen/include/public/io/blkif.h | 81 +++++++++++++++--
12 files changed, 264 insertions(+), 68 deletions(-)
Index:
build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blkback/blkback.c
===================================================================
---
build-64-release304-12901.orig/linux-2.6-xen-sparse/drivers/xen/blkback/blkback.c
+++ build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blkback/blkback.c
@@ -298,17 +298,33 @@ irqreturn_t blkif_be_int(int irq, void *
static int do_block_io_op(blkif_t *blkif)
{
- blkif_back_ring_t *blk_ring = &blkif->blk_ring;
+ blkif_v1_back_ring_t *blk_v1_ring = NULL;
+ blkif_v2_back_ring_t *blk_v2_ring = NULL;
blkif_request_t req;
pending_req_t *pending_req;
RING_IDX rc, rp;
int more_to_do = 0;
- rc = blk_ring->req_cons;
- rp = blk_ring->sring->req_prod;
+ if (1 == blkif->blk_protocol) {
+ blk_v1_ring = &blkif->blk_v1_ring;
+ rc = blk_v1_ring->req_cons;
+ rp = blk_v1_ring->sring->req_prod;
+ } else {
+ blk_v2_ring = &blkif->blk_v2_ring;
+ rc = blk_v2_ring->req_cons;
+ rp = blk_v2_ring->sring->req_prod;
+ }
rmb(); /* Ensure we see queued requests up to 'rp'. */
- while ((rc != rp) && !RING_REQUEST_CONS_OVERFLOW(blk_ring, rc)) {
+ while ((rc != rp)) {
+
+ if (1 == blkif->blk_protocol) {
+ if (RING_REQUEST_CONS_OVERFLOW(blk_v1_ring, rc))
+ break;
+ } else {
+ if (RING_REQUEST_CONS_OVERFLOW(blk_v2_ring, rc))
+ break;
+ }
pending_req = alloc_req();
if (NULL == pending_req) {
@@ -317,8 +333,13 @@ static int do_block_io_op(blkif_t *blkif
break;
}
- memcpy(&req, RING_GET_REQUEST(blk_ring, rc), sizeof(req));
- blk_ring->req_cons = ++rc; /* before make_response() */
+ if (1 == blkif->blk_protocol) {
+ blkif_get_v1_req(&req, RING_GET_REQUEST(blk_v1_ring,
rc));
+ blk_v1_ring->req_cons = ++rc; /* before make_response()
*/
+ } else {
+ blkif_get_v2_req(&req, RING_GET_REQUEST(blk_v2_ring,
rc));
+ blk_v2_ring->req_cons = ++rc; /* before make_response()
*/
+ }
switch (req.operation) {
case BLKIF_OP_READ:
@@ -500,32 +521,48 @@ static void make_response(blkif_t *blkif
{
blkif_response_t *resp;
unsigned long flags;
- blkif_back_ring_t *blk_ring = &blkif->blk_ring;
+ blkif_v1_back_ring_t *blk_v1_ring = NULL;
+ blkif_v2_back_ring_t *blk_v2_ring = NULL;
int more_to_do = 0;
int notify;
spin_lock_irqsave(&blkif->blk_ring_lock, flags);
/* Place on the response ring for the relevant domain. */
- resp = RING_GET_RESPONSE(blk_ring, blk_ring->rsp_prod_pvt);
+ if (1 == blkif->blk_protocol) {
+ blk_v1_ring = &blkif->blk_v1_ring;
+ resp = RING_GET_RESPONSE(blk_v1_ring,
blk_v1_ring->rsp_prod_pvt);
+ } else {
+ blk_v2_ring = &blkif->blk_v2_ring;
+ resp = RING_GET_RESPONSE(blk_v2_ring,
blk_v2_ring->rsp_prod_pvt);
+ }
resp->id = id;
resp->operation = op;
resp->status = st;
- blk_ring->rsp_prod_pvt++;
- RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(blk_ring, notify);
-
- if (blk_ring->rsp_prod_pvt == blk_ring->req_cons) {
- /*
- * Tail check for pending requests. Allows frontend to avoid
- * notifications if requests are already in flight (lower
- * overheads and promotes batching).
- */
- RING_FINAL_CHECK_FOR_REQUESTS(blk_ring, more_to_do);
-
- } else if (RING_HAS_UNCONSUMED_REQUESTS(blk_ring)) {
- more_to_do = 1;
+ if (1 == blkif->blk_protocol) {
+ blk_v1_ring->rsp_prod_pvt++;
+ RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(blk_v1_ring, notify);
+ if (blk_v1_ring->rsp_prod_pvt == blk_v1_ring->req_cons) {
+ /*
+ * Tail check for pending requests. Allows frontend to
avoid
+ * notifications if requests are already in flight
(lower
+ * overheads and promotes batching).
+ */
+ RING_FINAL_CHECK_FOR_REQUESTS(blk_v1_ring, more_to_do);
+ } else if (RING_HAS_UNCONSUMED_REQUESTS(blk_v1_ring)) {
+ more_to_do = 1;
+ }
+ } else {
+ blk_v2_ring->rsp_prod_pvt++;
+ RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(blk_v2_ring, notify);
+ if (blk_v2_ring->rsp_prod_pvt == blk_v2_ring->req_cons) {
+ RING_FINAL_CHECK_FOR_REQUESTS(blk_v2_ring, more_to_do);
+ } else if (RING_HAS_UNCONSUMED_REQUESTS(blk_v2_ring)) {
+ more_to_do = 1;
+ }
}
+
spin_unlock_irqrestore(&blkif->blk_ring_lock, flags);
if (more_to_do)
Index:
build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blkback/common.h
===================================================================
---
build-64-release304-12901.orig/linux-2.6-xen-sparse/drivers/xen/blkback/common.h
+++ build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blkback/common.h
@@ -68,7 +68,9 @@ typedef struct blkif_st {
unsigned int evtchn;
unsigned int irq;
/* Comms information. */
- blkif_back_ring_t blk_ring;
+ int blk_protocol;
+ blkif_v1_back_ring_t blk_v1_ring;
+ blkif_v2_back_ring_t blk_v2_ring;
struct vm_struct *blk_ring_area;
/* The VBD attached to this interface. */
struct vbd vbd;
Index:
build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blkback/interface.c
===================================================================
---
build-64-release304-12901.orig/linux-2.6-xen-sparse/drivers/xen/blkback/interface.c
+++
build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blkback/interface.c
@@ -95,7 +95,8 @@ static void unmap_frontend_page(blkif_t
int blkif_map(blkif_t *blkif, unsigned long shared_page, unsigned int evtchn)
{
- blkif_sring_t *sring;
+ blkif_v1_sring_t *sring_v1;
+ blkif_v2_sring_t *sring_v2;
int err;
struct evtchn_bind_interdomain bind_interdomain;
@@ -125,8 +126,13 @@ int blkif_map(blkif_t *blkif, unsigned l
blkif->evtchn = bind_interdomain.local_port;
- sring = (blkif_sring_t *)blkif->blk_ring_area->addr;
- BACK_RING_INIT(&blkif->blk_ring, sring, PAGE_SIZE);
+ if (1 == blkif->blk_protocol) {
+ sring_v1 = (blkif_v1_sring_t *)blkif->blk_ring_area->addr;
+ BACK_RING_INIT(&blkif->blk_v1_ring, sring_v1, PAGE_SIZE);
+ } else {
+ sring_v2 = (blkif_v2_sring_t *)blkif->blk_ring_area->addr;
+ BACK_RING_INIT(&blkif->blk_v2_ring, sring_v2, PAGE_SIZE);
+ }
blkif->irq = bind_evtchn_to_irqhandler(
blkif->evtchn, blkif_be_int, 0, "blkif-backend", blkif);
@@ -150,10 +156,11 @@ void blkif_disconnect(blkif_t *blkif)
blkif->irq = 0;
}
- if (blkif->blk_ring.sring) {
+ if (blkif->blk_v1_ring.sring || blkif->blk_v2_ring.sring) {
unmap_frontend_page(blkif);
free_vm_area(blkif->blk_ring_area);
- blkif->blk_ring.sring = NULL;
+ blkif->blk_v1_ring.sring = NULL;
+ blkif->blk_v2_ring.sring = NULL;
}
}
Index:
build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
===================================================================
---
build-64-release304-12901.orig/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
+++ build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blkback/xenbus.c
@@ -435,6 +435,7 @@ static int connect_ring(struct backend_i
struct xenbus_device *dev = be->dev;
unsigned long ring_ref;
unsigned int evtchn;
+ unsigned int protocol;
int err;
DPRINTK("%s", dev->otherend);
@@ -448,6 +449,19 @@ static int connect_ring(struct backend_i
return err;
}
+ err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
+ "%u", &protocol, NULL);
+ if (err)
+ protocol = BLKIF_NATIVE_PROTOCOL;
+ if (protocol < 1 || protocol > 2) {
+ xenbus_dev_fatal(dev, err, "unknown fe protocol %d", protocol);
+ return -1;
+ }
+ be->blkif->blk_protocol = protocol;
+
+ printk("blkback: ring-ref %ld, event-channel %d, protocol %d\n",
+ ring_ref, evtchn, protocol);
+
/* Map the shared frame, irq etc. */
err = blkif_map(be->blkif, ring_ref, evtchn);
if (err) {
Index:
build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c
===================================================================
---
build-64-release304-12901.orig/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c
+++
build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blkfront/blkfront.c
@@ -180,6 +180,12 @@ again:
message = "writing event-channel";
goto abort_transaction;
}
+ err = xenbus_printf(xbt, dev->nodename,
+ "protocol", "%u", BLKIF_NATIVE_PROTOCOL);
+ if (err) {
+ message = "writing protocol";
+ goto abort_transaction;
+ }
err = xenbus_transaction_end(xbt, 0);
if (err) {
Index: build-64-release304-12901/xen/include/public/io/blkif.h
===================================================================
--- build-64-release304-12901.orig/xen/include/public/io/blkif.h
+++ build-64-release304-12901/xen/include/public/io/blkif.h
@@ -71,20 +71,36 @@
*/
#define BLKIF_MAX_SEGMENTS_PER_REQUEST 11
-struct blkif_request {
+struct blkif_request_segment {
+ grant_ref_t gref; /* reference to I/O buffer frame */
+ /* @first_sect: first sector in frame to transfer (inclusive). */
+ /* @last_sect: last sector in frame to transfer (inclusive). */
+ uint8_t first_sect, last_sect;
+};
+
+/* i386 protocol version */
+#pragma pack(push, 4)
+struct blkif_v1_request {
uint8_t operation; /* BLKIF_OP_??? */
uint8_t nr_segments; /* number of segments */
blkif_vdev_t handle; /* only for read/write requests */
uint64_t id; /* private guest value, echoed in resp */
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
- struct blkif_request_segment {
- grant_ref_t gref; /* reference to I/O buffer frame */
- /* @first_sect: first sector in frame to transfer (inclusive). */
- /* @last_sect: last sector in frame to transfer (inclusive). */
- uint8_t first_sect, last_sect;
- } seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
};
-typedef struct blkif_request blkif_request_t;
+typedef struct blkif_v1_request blkif_v1_request_t;
+#pragma pack(pop)
+
+/* x86_64 protocol version */
+struct blkif_v2_request {
+ uint8_t operation; /* BLKIF_OP_??? */
+ uint8_t nr_segments; /* number of segments */
+ blkif_vdev_t handle; /* only for read/write requests */
+ uint64_t __attribute__((__aligned__(8))) id;
+ blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
+ struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+};
+typedef struct blkif_v2_request blkif_v2_request_t;
struct blkif_response {
uint64_t id; /* copied from request */
@@ -107,7 +123,54 @@ typedef struct blkif_response blkif_resp
* Generate blkif ring structures and types.
*/
-DEFINE_RING_TYPES(blkif, struct blkif_request, struct blkif_response);
+DEFINE_RING_TYPES(blkif_v1, struct blkif_v1_request, struct blkif_response);
+DEFINE_RING_TYPES(blkif_v2, struct blkif_v2_request, struct blkif_response);
+
+#if defined(__i386__)
+
+#define BLKIF_NATIVE_PROTOCOL 1
+typedef struct blkif_v1_request blkif_request_t;
+DEFINE_RING_TYPES(blkif, struct blkif_v1_request, struct blkif_response);
+
+#elif defined(__x86_64__)
+
+#define BLKIF_NATIVE_PROTOCOL 2
+typedef struct blkif_v2_request blkif_request_t;
+DEFINE_RING_TYPES(blkif, struct blkif_v2_request, struct blkif_response);
+
+#else
+# error arch fixup needed here
+#endif
+
+#ifdef __KERNEL__
+
+/* translate requests: v1/v2 to native */
+#if 1 == BLKIF_NATIVE_PROTOCOL
+static void inline blkif_get_v1_req(blkif_request_t *dst, blkif_v1_request_t
*src)
+#else
+static void inline blkif_get_v2_req(blkif_request_t *dst, blkif_v2_request_t
*src)
+#endif
+{
+ memcpy(dst, src, sizeof(*dst));
+}
+
+#if 1 == BLKIF_NATIVE_PROTOCOL
+static void inline blkif_get_v2_req(blkif_request_t *dst, blkif_v2_request_t
*src)
+#else
+static void inline blkif_get_v1_req(blkif_request_t *dst, blkif_v1_request_t
*src)
+#endif
+{
+ int i;
+ dst->operation = src->operation;
+ dst->nr_segments = src->nr_segments;
+ dst->handle = src->handle;
+ dst->id = src->id;
+ dst->sector_number = src->sector_number;
+ for (i = 0; i < src->nr_segments; i++)
+ dst->seg[i] = src->seg[i];
+}
+
+#endif
#define VDISK_CDROM 0x1
#define VDISK_REMOVABLE 0x2
Index: build-64-release304-12901/tools/python/xen/xend/server/blkif.py
===================================================================
--- build-64-release304-12901.orig/tools/python/xen/xend/server/blkif.py
+++ build-64-release304-12901/tools/python/xen/xend/server/blkif.py
@@ -38,6 +38,7 @@ class BlkifController(DevController):
"""@see DevController.getDeviceDetails"""
uname = config.get('uname', '')
dev = config.get('dev', '')
+ protocol = config.get('protocol')
if 'ioemu:' in dev:
(_, dev) = string.split(dev, ':', 1)
@@ -85,6 +86,8 @@ class BlkifController(DevController):
front = { 'virtual-device' : "%i" % devid,
'device-type' : dev_type
}
+ if protocol:
+ front.update({ 'protocol' : protocol });
return (devid, back, front)
Index: build-64-release304-12901/tools/python/xen/xm/create.py
===================================================================
--- build-64-release304-12901.orig/tools/python/xen/xm/create.py
+++ build-64-release304-12901/tools/python/xen/xm/create.py
@@ -531,7 +531,7 @@ def configure_image(vals):
def configure_disks(config_devs, vals):
"""Create the config for disks (virtual block devices).
"""
- for (uname, dev, mode, backend) in vals.disk:
+ for (uname, dev, mode, backend, protocol) in vals.disk:
if uname.startswith('tap:'):
cls = 'tap'
else:
@@ -543,6 +543,8 @@ def configure_disks(config_devs, vals):
['mode', mode ] ]
if backend:
config_vbd.append(['backend', backend])
+ if protocol:
+ config_vbd.append(['protocol', protocol])
config_devs.append(['device', config_vbd])
def configure_pci(config_devs, vals):
@@ -787,7 +789,10 @@ def preprocess_disk(vals):
n = len(d)
if n == 3:
d.append(None)
+ d.append(None)
elif n == 4:
+ d.append(None)
+ elif n == 5:
pass
else:
err('Invalid disk specifier: ' + v)
Index:
build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blktap/blktap.c
===================================================================
---
build-64-release304-12901.orig/linux-2.6-xen-sparse/drivers/xen/blktap/blktap.c
+++ build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blktap/blktap.c
@@ -1094,15 +1094,24 @@ irqreturn_t tap_blkif_be_int(int irq, vo
static int print_dbug = 1;
static int do_block_io_op(blkif_t *blkif)
{
- blkif_back_ring_t *blk_ring = &blkif->blk_ring;
+ blkif_v1_back_ring_t *blk_v1_ring = NULL;
+ blkif_v2_back_ring_t *blk_v2_ring = NULL;
blkif_request_t req;
pending_req_t *pending_req;
RING_IDX rc, rp;
- int more_to_do = 0;
+ int retval, more_to_do = 0;
tap_blkif_t *info;
- rc = blk_ring->req_cons;
- rp = blk_ring->sring->req_prod;
+ if (1 == blkif->blk_protocol) {
+ blk_v1_ring = &blkif->blk_v1_ring;
+ rc = blk_v1_ring->req_cons;
+ rp = blk_v1_ring->sring->req_prod;
+ } else {
+ blk_v2_ring = &blkif->blk_v2_ring;
+ rc = blk_v2_ring->req_cons;
+ rp = blk_v2_ring->sring->req_prod;
+ }
+
rmb(); /* Ensure we see queued requests up to 'rp'. */
/*Check blkif has corresponding UE ring*/
@@ -1133,8 +1142,11 @@ static int do_block_io_op(blkif_t *blkif
more_to_do = 1;
break;
}
-
- if (RING_REQUEST_CONS_OVERFLOW(blk_ring, rc)) {
+
+ retval = (1 == blkif->blk_protocol)
+ ? RING_REQUEST_CONS_OVERFLOW(blk_v1_ring, rc)
+ : RING_REQUEST_CONS_OVERFLOW(blk_v2_ring, rc);
+ if (retval) {
WPRINTK("RING_REQUEST_CONS_OVERFLOW!"
" More to do\n");
more_to_do = 1;
@@ -1148,8 +1160,13 @@ static int do_block_io_op(blkif_t *blkif
break;
}
- memcpy(&req, RING_GET_REQUEST(blk_ring, rc), sizeof(req));
- blk_ring->req_cons = ++rc; /* before make_response() */
+ if (1 == blkif->blk_protocol) {
+ blkif_get_v1_req(&req, RING_GET_REQUEST(blk_v1_ring,
rc));
+ blk_v1_ring->req_cons = ++rc; /* before make_response()
*/
+ } else {
+ blkif_get_v2_req(&req, RING_GET_REQUEST(blk_v2_ring,
rc));
+ blk_v2_ring->req_cons = ++rc; /* before make_response()
*/
+ }
switch (req.operation) {
case BLKIF_OP_READ:
@@ -1225,7 +1242,9 @@ static void dispatch_rw_block_io(blkif_t
WPRINTK("blktap: fe_ring is full, can't add "
"IO Request will be dropped. %d %d\n",
RING_SIZE(&info->ufe_ring),
- RING_SIZE(&blkif->blk_ring));
+ (1 == blkif->blk_protocol)
+ ? RING_SIZE(&blkif->blk_v1_ring)
+ : RING_SIZE(&blkif->blk_v2_ring));
goto fail_response;
}
@@ -1415,30 +1434,47 @@ static void make_response(blkif_t *blkif
{
blkif_response_t *resp;
unsigned long flags;
- blkif_back_ring_t *blk_ring = &blkif->blk_ring;
+ blkif_v1_back_ring_t *blk_v1_ring = NULL;
+ blkif_v2_back_ring_t *blk_v2_ring = NULL;
int more_to_do = 0;
int notify;
+
spin_lock_irqsave(&blkif->blk_ring_lock, flags);
- /* Place on the response ring for the relevant domain. */
- resp = RING_GET_RESPONSE(blk_ring, blk_ring->rsp_prod_pvt);
+ /* Place on the response ring for the relevant domain. */
+ if (1 == blkif->blk_protocol) {
+ blk_v1_ring = &blkif->blk_v1_ring;
+ resp = RING_GET_RESPONSE(blk_v1_ring,
blk_v1_ring->rsp_prod_pvt);
+ } else {
+ blk_v2_ring = &blkif->blk_v2_ring;
+ resp = RING_GET_RESPONSE(blk_v2_ring,
blk_v2_ring->rsp_prod_pvt);
+ }
resp->id = id;
resp->operation = op;
resp->status = st;
- blk_ring->rsp_prod_pvt++;
- RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(blk_ring, notify);
-
- if (blk_ring->rsp_prod_pvt == blk_ring->req_cons) {
- /*
- * Tail check for pending requests. Allows frontend to avoid
- * notifications if requests are already in flight (lower
- * overheads and promotes batching).
- */
- RING_FINAL_CHECK_FOR_REQUESTS(blk_ring, more_to_do);
- } else if (RING_HAS_UNCONSUMED_REQUESTS(blk_ring)) {
- more_to_do = 1;
+ if (1 == blkif->blk_protocol) {
+ blk_v1_ring->rsp_prod_pvt++;
+ RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(blk_v1_ring, notify);
+ if (blk_v1_ring->rsp_prod_pvt == blk_v1_ring->req_cons) {
+ /*
+ * Tail check for pending requests. Allows frontend to
avoid
+ * notifications if requests are already in flight
(lower
+ * overheads and promotes batching).
+ */
+ RING_FINAL_CHECK_FOR_REQUESTS(blk_v1_ring, more_to_do);
+ } else if (RING_HAS_UNCONSUMED_REQUESTS(blk_v1_ring)) {
+ more_to_do = 1;
+ }
+ } else {
+ blk_v2_ring->rsp_prod_pvt++;
+ RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(blk_v2_ring, notify);
+ if (blk_v2_ring->rsp_prod_pvt == blk_v2_ring->req_cons) {
+ RING_FINAL_CHECK_FOR_REQUESTS(blk_v2_ring, more_to_do);
+ } else if (RING_HAS_UNCONSUMED_REQUESTS(blk_v2_ring)) {
+ more_to_do = 1;
+ }
+ }
- }
spin_unlock_irqrestore(&blkif->blk_ring_lock, flags);
if (more_to_do)
blkif_notify_work(blkif);
Index:
build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blktap/common.h
===================================================================
---
build-64-release304-12901.orig/linux-2.6-xen-sparse/drivers/xen/blktap/common.h
+++ build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blktap/common.h
@@ -59,7 +59,9 @@ typedef struct blkif_st {
unsigned int evtchn;
unsigned int irq;
/* Comms information. */
- blkif_back_ring_t blk_ring;
+ int blk_protocol;
+ blkif_v1_back_ring_t blk_v1_ring;
+ blkif_v2_back_ring_t blk_v2_ring;
struct vm_struct *blk_ring_area;
/* Back pointer to the backend_info. */
struct backend_info *be;
Index:
build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blktap/interface.c
===================================================================
---
build-64-release304-12901.orig/linux-2.6-xen-sparse/drivers/xen/blktap/interface.c
+++
build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blktap/interface.c
@@ -96,7 +96,8 @@ static void unmap_frontend_page(blkif_t
int tap_blkif_map(blkif_t *blkif, unsigned long shared_page,
unsigned int evtchn)
{
- blkif_sring_t *sring;
+ blkif_v1_sring_t *sring_v1;
+ blkif_v2_sring_t *sring_v2;
int err;
struct evtchn_bind_interdomain bind_interdomain;
@@ -126,8 +127,13 @@ int tap_blkif_map(blkif_t *blkif, unsign
blkif->evtchn = bind_interdomain.local_port;
- sring = (blkif_sring_t *)blkif->blk_ring_area->addr;
- BACK_RING_INIT(&blkif->blk_ring, sring, PAGE_SIZE);
+ if (1 == blkif->blk_protocol) {
+ sring_v1 = (blkif_v1_sring_t *)blkif->blk_ring_area->addr;
+ BACK_RING_INIT(&blkif->blk_v1_ring, sring_v1, PAGE_SIZE);
+ } else {
+ sring_v2 = (blkif_v2_sring_t *)blkif->blk_ring_area->addr;
+ BACK_RING_INIT(&blkif->blk_v2_ring, sring_v2, PAGE_SIZE);
+ }
blkif->irq = bind_evtchn_to_irqhandler(
blkif->evtchn, tap_blkif_be_int, 0, "blkif-backend", blkif);
@@ -141,10 +147,11 @@ void tap_blkif_unmap(blkif_t *blkif)
unbind_from_irqhandler(blkif->irq, blkif);
blkif->irq = 0;
}
- if (blkif->blk_ring.sring) {
+ if (blkif->blk_v1_ring.sring || blkif->blk_v2_ring.sring) {
unmap_frontend_page(blkif);
free_vm_area(blkif->blk_ring_area);
- blkif->blk_ring.sring = NULL;
+ blkif->blk_v1_ring.sring = NULL;
+ blkif->blk_v2_ring.sring = NULL;
}
}
Index:
build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c
===================================================================
---
build-64-release304-12901.orig/linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c
+++ build-64-release304-12901/linux-2.6-xen-sparse/drivers/xen/blktap/xenbus.c
@@ -316,6 +316,7 @@ static int connect_ring(struct backend_i
struct xenbus_device *dev = be->dev;
unsigned long ring_ref;
unsigned int evtchn;
+ unsigned int protocol;
int err;
DPRINTK("%s\n", dev->otherend);
@@ -329,6 +330,19 @@ static int connect_ring(struct backend_i
return err;
}
+ err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
+ "%u", &protocol, NULL);
+ if (err)
+ protocol = BLKIF_NATIVE_PROTOCOL;
+ if (protocol < 1 || protocol > 2) {
+ xenbus_dev_fatal(dev, err, "unknown fe protocol %d", protocol);
+ return -1;
+ }
+ be->blkif->blk_protocol = protocol;
+
+ printk("blktap: ring-ref %ld, event-channel %d, protocol %d\n",
+ ring_ref, evtchn, protocol);
+
/* Map the shared frame, irq etc. */
err = tap_blkif_map(be->blkif, ring_ref, evtchn);
if (err) {
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