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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [MINI-OS PATCH 15/19] 9pfs: refactor init_9pfront()
Move the Xenstore and backend interface related handling into a
sub-function in order to prepare supporting reconnecting to an active
9pfs device after kexec.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
9pfront.c | 136 ++++++++++++++++++++++++++++++++++--------------------
1 file changed, 86 insertions(+), 50 deletions(-)
diff --git a/9pfront.c b/9pfront.c
index 2bfc49b1..8da2f726 100644
--- a/9pfront.c
+++ b/9pfront.c
@@ -1097,68 +1097,65 @@ static void free_9pfront(struct dev_9pfs *dev)
free(dev);
}
-void *init_9pfront(unsigned int id, const char *mnt)
+static bool issue_err(struct dev_9pfs *dev, char *msg, char *reason)
+{
+ if ( msg )
+ {
+ printk("9pfsfront add %u failed, error %s accessing Xenstore\n",
+ dev->id, msg);
+ free(msg);
+ }
+ else
+ printk("9pfsfront add %u failed, %s\n", dev->id, reason);
+
+ return false;
+}
+
+static bool read_config_xs(struct dev_9pfs *dev)
{
- struct dev_9pfs *dev;
char *msg;
char *reason = "";
- xenbus_transaction_t xbt;
- int retry = 1;
XenbusState state;
- unsigned int i;
- void *addr;
+ xenbus_transaction_t xbt;
char *version;
char *v;
-
- printk("9pfsfront add %u, for mount at %s\n", id, mnt);
- dev = malloc(sizeof(*dev));
- memset(dev, 0, sizeof(*dev));
- snprintf(dev->nodename, sizeof(dev->nodename), "device/9pfs/%u", id);
- dev->id = id;
- init_waitqueue_head(&dev->waitq);
- init_SEMAPHORE(&dev->ring_out_sem, 1);
- init_SEMAPHORE(&dev->ring_in_sem, 1);
- dev->fid_mask = ~0ULL;
-
- for ( i = 0; i < N_REQS; i++ )
- {
- dev->req[i].id = i;
- dev->req[i].next_free = i + 1;
- }
- dev->free_reqs = 0;
+ void *addr;
+ unsigned int i;
+ int retry = 1;
msg = xenbus_read_unsigned(XBT_NIL, dev->nodename, "backend-id",
&dev->dom);
if ( msg )
- goto err;
+ return issue_err(dev, msg, reason);
msg = xenbus_read_string(XBT_NIL, dev->nodename, "backend", &dev->backend);
if ( msg )
- goto err;
+ return issue_err(dev, msg, reason);
msg = xenbus_read_string(XBT_NIL, dev->nodename, "tag", &dev->tag);
if ( msg )
- goto err;
+ return issue_err(dev, msg, reason);
snprintf(dev->bepath, sizeof(dev->bepath), "%s/state", dev->backend);
free(xenbus_watch_path_token(XBT_NIL, dev->bepath, dev->bepath,
&dev->events));
+
state = xenbus_read_integer(dev->bepath);
while ( msg == NULL && state < XenbusStateInitWait )
msg = xenbus_wait_for_state_change(dev->bepath, &state, &dev->events);
if ( msg || state != XenbusStateInitWait )
{
reason = "illegal backend state";
- goto err;
+ return issue_err(dev, msg, reason);
}
msg = xenbus_read_unsigned(XBT_NIL, dev->backend, "max-ring-page-order",
&dev->ring_order);
if ( msg )
- goto err;
+ return issue_err(dev, msg, reason);
if ( dev->ring_order > DEFAULT_9PFS_RING_ORDER )
dev->ring_order = DEFAULT_9PFS_RING_ORDER;
msg = xenbus_read_string(XBT_NIL, dev->backend, "versions", &version);
if ( msg )
- goto err;
+ return issue_err(dev, msg, reason);
for ( v = version; *v; v++ )
{
if ( strtoul(v, &v, 10) == 1 && (*v == ',' || *v == 0) )
@@ -1170,25 +1167,36 @@ void *init_9pfront(unsigned int id, const char *mnt)
{
reason = "backend published illegal version string";
free(version);
- goto err;
+ return issue_err(dev, msg, reason);
}
}
free(version);
if ( v )
{
reason = "backend doesn't support version 1";
- goto err;
+ return issue_err(dev, msg, reason);
}
- dev->ring_ref = gnttab_alloc_and_grant((void **)&dev->intf);
+ dev->intf = (void *)alloc_page();
+ if ( !dev->intf )
+ {
+ reason = "couldn't allocate shared interface page";
+ return issue_err(dev, msg, reason);
+ }
memset(dev->intf, 0, PAGE_SIZE);
+ dev->ring_ref = gnttab_grant_access(dev->dom, virt_to_mfn(dev->intf), 0);
if ( evtchn_alloc_unbound(dev->dom, intr_9pfs, dev, &dev->evtchn) )
{
reason = "no event channel";
- goto err;
+ return issue_err(dev, msg, reason);
}
dev->intf->ring_order = dev->ring_order;
dev->data.in = (void *)alloc_pages(dev->ring_order);
+ if ( !dev->data.in )
+ {
+ reason = "couldn't allocate ring pages";
+ return issue_err(dev, msg, reason);
+ }
dev->data.out = dev->data.in + XEN_FLEX_RING_SIZE(dev->ring_order);
for ( i = 0; i < (1 << dev->ring_order); i++ )
{
@@ -1204,30 +1212,35 @@ void *init_9pfront(unsigned int id, const char *mnt)
free(msg);
msg = NULL;
reason = "starting transaction";
- goto err;
+ return issue_err(dev, msg, reason);
}
msg = xenbus_printf(xbt, dev->nodename, "version", "%u", 1);
if ( msg )
- goto err_tr;
+ break;
msg = xenbus_printf(xbt, dev->nodename, "num-rings", "%u", 1);
if ( msg )
- goto err_tr;
+ break;
msg = xenbus_printf(xbt, dev->nodename, "ring-ref0", "%u",
dev->ring_ref);
if ( msg )
- goto err_tr;
+ break;
msg = xenbus_printf(xbt, dev->nodename, "event-channel-0", "%u",
dev->evtchn);
if ( msg )
- goto err_tr;
+ break;
msg = xenbus_printf(xbt, dev->nodename, "state", "%u",
XenbusStateInitialised);
if ( msg )
- goto err_tr;
+ break;
free(xenbus_transaction_end(xbt, 0, &retry));
}
+ if ( msg )
+ {
+ free(xenbus_transaction_end(xbt, 1, &retry));
+ return issue_err(dev, msg, reason);
+ }
state = xenbus_read_integer(dev->bepath);
while ( msg == NULL && state < XenbusStateConnected )
@@ -1235,13 +1248,42 @@ void *init_9pfront(unsigned int id, const char *mnt)
if ( msg || state != XenbusStateConnected )
{
reason = "illegal backend state";
- goto err;
+ return issue_err(dev, msg, reason);
}
msg = xenbus_printf(XBT_NIL, dev->nodename, "state", "%u",
XenbusStateConnected);
if ( msg )
- goto err;
+ return issue_err(dev, msg, reason);
+
+ return true;
+}
+
+void *init_9pfront(unsigned int id, const char *mnt)
+{
+ struct dev_9pfs *dev;
+ char *reason = "";
+ unsigned int i;
+
+ printk("9pfsfront add %u, for mount at %s\n", id, mnt);
+ dev = malloc(sizeof(*dev));
+ memset(dev, 0, sizeof(*dev));
+ snprintf(dev->nodename, sizeof(dev->nodename), "device/9pfs/%u", id);
+ dev->id = id;
+ init_waitqueue_head(&dev->waitq);
+ init_SEMAPHORE(&dev->ring_out_sem, 1);
+ init_SEMAPHORE(&dev->ring_in_sem, 1);
+ dev->fid_mask = ~0ULL;
+
+ for ( i = 0; i < N_REQS; i++ )
+ {
+ dev->req[i].id = i;
+ dev->req[i].next_free = i + 1;
+ }
+ dev->free_reqs = 0;
+
+ if ( !read_config_xs(dev) )
+ goto err_out;
unmask_evtchn(dev->evtchn);
@@ -1260,17 +1302,11 @@ void *init_9pfront(unsigned int id, const char *mnt)
return dev;
- err_tr:
- free(xenbus_transaction_end(xbt, 1, &retry));
-
err:
- if ( msg )
- printk("9pfsfront add %u failed, error %s accessing Xenstore\n",
- id, msg);
- else
- printk("9pfsfront add %u failed, %s\n", id, reason);
+ printk("9pfsfront add %u failed, %s\n", id, reason);
+
+ err_out:
free_9pfront(dev);
- free(msg);
return NULL;
}
EXPORT_SYMBOL(init_9pfront);
--
2.43.0
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