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authorJuergen Gross <jgross@suse.com>2016-12-22 08:19:47 +0100
committerJuergen Gross <jgross@suse.com>2016-12-23 20:06:23 +0100
commit9a6161fe73bdd3ae4a1e18421b0b20cb7141f680 (patch)
treeb992ad5f49bc787ca28e278227c55661885efb1b /drivers/xen
parent639b08810d6ad74ded2c5f6e233c4fcb9d147168 (diff)
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xen: return xenstore command failures via response instead of rc
When the xenbus driver does some special handling for a Xenstore command any error condition related to the command should be returned via an error response instead of letting the related write operation fail. Otherwise the user land handler might take wrong decisions assuming the connection to Xenstore is broken. While at it try to return the same error values xenstored would return for those cases. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/xenbus/xenbus_dev_frontend.c47
1 files changed, 27 insertions, 20 deletions
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index a06828124b70..79130b310247 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -302,6 +302,29 @@ static void watch_fired(struct xenbus_watch *watch,
mutex_unlock(&adap->dev_data->reply_mutex);
}
+static int xenbus_command_reply(struct xenbus_file_priv *u,
+ unsigned int msg_type, const char *reply)
+{
+ struct {
+ struct xsd_sockmsg hdr;
+ const char body[16];
+ } msg;
+ int rc;
+
+ msg.hdr = u->u.msg;
+ msg.hdr.type = msg_type;
+ msg.hdr.len = strlen(reply) + 1;
+ if (msg.hdr.len > sizeof(msg.body))
+ return -E2BIG;
+
+ mutex_lock(&u->reply_mutex);
+ rc = queue_reply(&u->read_buffers, &msg, sizeof(msg.hdr) + msg.hdr.len);
+ wake_up(&u->read_waitq);
+ mutex_unlock(&u->reply_mutex);
+
+ return rc;
+}
+
static int xenbus_write_transaction(unsigned msg_type,
struct xenbus_file_priv *u)
{
@@ -321,7 +344,7 @@ static int xenbus_write_transaction(unsigned msg_type,
if (trans->handle.id == u->u.msg.tx_id)
break;
if (&trans->list == &u->transactions)
- return -ESRCH;
+ return xenbus_command_reply(u, XS_ERROR, "ENOENT");
}
reply = xenbus_dev_request_and_reply(&u->u.msg);
@@ -372,12 +395,12 @@ static int xenbus_write_watch(unsigned msg_type, struct xenbus_file_priv *u)
path = u->u.buffer + sizeof(u->u.msg);
token = memchr(path, 0, u->u.msg.len);
if (token == NULL) {
- rc = -EILSEQ;
+ rc = xenbus_command_reply(u, XS_ERROR, "EINVAL");
goto out;
}
token++;
if (memchr(token, 0, u->u.msg.len - (token - path)) == NULL) {
- rc = -EILSEQ;
+ rc = xenbus_command_reply(u, XS_ERROR, "EINVAL");
goto out;
}
@@ -411,23 +434,7 @@ static int xenbus_write_watch(unsigned msg_type, struct xenbus_file_priv *u)
}
/* Success. Synthesize a reply to say all is OK. */
- {
- struct {
- struct xsd_sockmsg hdr;
- char body[3];
- } __packed reply = {
- {
- .type = msg_type,
- .len = sizeof(reply.body)
- },
- "OK"
- };
-
- mutex_lock(&u->reply_mutex);
- rc = queue_reply(&u->read_buffers, &reply, sizeof(reply));
- wake_up(&u->read_waitq);
- mutex_unlock(&u->reply_mutex);
- }
+ rc = xenbus_command_reply(u, msg_type, "OK");
out:
return rc;