[Xen-devel] [RFC][PATCH 10/13] Kemari: XenbusStateAttached handler for blkback

[Yoshiaki Tamura <tamura.yoshiaki@xxxxxxxxxxxxx>]

References: <49B86208.2020205@xxxxxxxxxxxxx>
In-Reply-To: <49B86208.2020205@xxxxxxxxxxxxx>
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This is an updated version of the following patch.  No major changes.

http://lists.xensource.com/archives/html/xen-devel/2009-03/msg00379.html

Signed-off-by: Yoshi Tamura <tamura.yoshiaki@xxxxxxxxxxxxx>
Signed-off-by: Yoshisato Yanagisawa <yanagisawa.yoshisato@xxxxxxxxxxxxx>
---
 drivers/xen/blkback/common.h    |    2 +
 drivers/xen/blkback/interface.c |   41 +++++++++++++++++++++++++++
 drivers/xen/blkback/xenbus.c    |   59 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 102 insertions(+)

diff -r 0430b1dbfb3a -r e183d2114ea1 drivers/xen/blkback/common.h
--- a/drivers/xen/blkback/common.h      Fri Mar 06 12:51:33 2009 +0000
+++ b/drivers/xen/blkback/common.h      Tue Mar 10 15:40:44 2009 +0900
@@ -100,6 +100,8 @@ void blkif_disconnect(blkif_t *blkif);
 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_attach(blkif_t *blkif, unsigned long shared_page,
+                 unsigned int evtchn);

 #define blkif_get(_b) (atomic_inc(&(_b)->refcnt))
 #define blkif_put(_b)                                  \
diff -r 0430b1dbfb3a -r e183d2114ea1 drivers/xen/blkback/interface.c
--- a/drivers/xen/blkback/interface.c   Fri Mar 06 12:51:33 2009 +0000
+++ b/drivers/xen/blkback/interface.c   Tue Mar 10 15:40:44 2009 +0900
@@ -144,6 +144,47 @@ int blkif_map(blkif_t *blkif, unsigned l
        return 0;
 }

+int blkif_attach(blkif_t *blkif, unsigned long shared_page,
+                unsigned int evtchn)
+{
+       /* Sorry! Only 32bit curretly. */
+       blkif_x86_32_sring_t *sring_x86_32;
+       int err;
+
+       /* Already connected through? */
+       if (blkif->irq)
+               return 0;
+
+       if ( (blkif->blk_ring_area = alloc_vm_area(PAGE_SIZE)) == NULL )
+               return -ENOMEM;
+
+       err = map_frontend_page(blkif, shared_page);
+       if (err) {
+               free_vm_area(blkif->blk_ring_area);
+               return err;
+       }
+
+       sring_x86_32 =
+               (blkif_x86_32_sring_t *)blkif->blk_ring_area->addr;
+       BACK_RING_ATTACH(&blkif->blk_rings.x86_32,
+                        sring_x86_32, PAGE_SIZE);
+
+       err = bind_interdomain_evtchn_to_irqhandler(
+               blkif->domid, evtchn, blkif_be_int, 0, "blkif-backend", blkif);
+       if (err < 0)
+       {
+               unmap_frontend_page(blkif);
+               free_vm_area(blkif->blk_ring_area);
+               blkif->blk_rings.common.sring = NULL;
+               return err;
+       }
+       blkif->irq = err;
+
+       blkif->blk_rings.x86_32.req_cons = blkif->blk_rings.x86_32.rsp_prod_pvt;
+
+       return 0;
+}
+
 void blkif_disconnect(blkif_t *blkif)
 {
        if (blkif->xenblkd) {
diff -r 0430b1dbfb3a -r e183d2114ea1 drivers/xen/blkback/xenbus.c
--- a/drivers/xen/blkback/xenbus.c      Fri Mar 06 12:51:33 2009 +0000
+++ b/drivers/xen/blkback/xenbus.c      Tue Mar 10 15:40:44 2009 +0900
@@ -39,6 +39,7 @@ struct backend_info

 static void connect(struct backend_info *);
 static int connect_ring(struct backend_info *);
+static int attach_ring(struct backend_info *);
 static void backend_changed(struct xenbus_watch *, const char **,
                            unsigned int);

@@ -376,6 +377,16 @@ static void frontend_changed(struct xenb
                update_blkif_status(be->blkif);
                break;

+       case XenbusStateAttached:
+               if (dev->state == XenbusStateAttached)
+                       break;
+
+               err = attach_ring(be);
+               if (err)
+                       break;
+               update_blkif_status(be->blkif);
+               break;
+
        case XenbusStateClosing:
                blkif_disconnect(be->blkif);
                xenbus_switch_state(dev, XenbusStateClosing);
@@ -515,6 +526,54 @@ static int connect_ring(struct backend_i
        return 0;
 }

+static int attach_ring(struct backend_info *be)
+{
+       struct xenbus_device *dev = be->dev;
+       unsigned long ring_ref;
+       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",
+                                                dev->otherend);
+               return err;
+       }
+
+       be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
+       err = xenbus_gather(XBT_NIL, dev->otherend, "protocol",
+                           "%63s", protocol, NULL);
+       if (err)
+               strcpy(protocol, "unspecified, assuming native");
+       else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE))
+               be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
+       else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32))
+               be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_32;
+       else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64))
+               be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64;
+       else {
+               xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
+               return -1;
+       }
+       printk(KERN_INFO
+              "blkback: 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 = blkif_attach(be->blkif, ring_ref, evtchn);
+       if (err) {
+               xenbus_dev_fatal(dev, err, "mapping ring-ref %lu port %u",
+                                ring_ref, evtchn);
+               return err;
+       }
+
+       return 0;
+}

 /* ** Driver Registration ** */




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