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Subject[PATCH 5/6] xenbus: process be_watch events in xenwatch multithreading
Date
This is the 5th patch of a (6-patch) patch set.

With this patch, watch event in relative path pattern
'backend/<pvdev>/<domid>i/...' can be processed in per-domU xenwatch
thread.

Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
---
drivers/xen/xenbus/xenbus_probe.c | 2 +-
drivers/xen/xenbus/xenbus_probe_backend.c | 32 +++++++++++++++++++++++++++++++
include/xen/xenbus.h | 2 ++
3 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index ba0644c..aa1b15a 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -552,7 +552,7 @@ int xenbus_probe_devices(struct xen_bus_type *bus)
}
EXPORT_SYMBOL_GPL(xenbus_probe_devices);

-static unsigned int char_count(const char *str, char c)
+unsigned int char_count(const char *str, char c)
{
unsigned int i, ret = 0;

diff --git a/drivers/xen/xenbus/xenbus_probe_backend.c b/drivers/xen/xenbus/xenbus_probe_backend.c
index b0bed4f..50df86a 100644
--- a/drivers/xen/xenbus/xenbus_probe_backend.c
+++ b/drivers/xen/xenbus/xenbus_probe_backend.c
@@ -211,9 +211,41 @@ static void backend_changed(struct xenbus_watch *watch,
xenbus_dev_changed(path, &xenbus_backend);
}

+static domid_t path_to_domid(const char *path)
+{
+ const char *p = path;
+ domid_t domid = 0;
+
+ while (*p) {
+ if (*p < '0' || *p > '9')
+ break;
+ domid = (domid << 3) + (domid << 1) + (*p - '0');
+ p++;
+ }
+
+ return domid;
+}
+
+/* path: backend/<pvdev>/<domid>/... */
+static domid_t be_get_domid(struct xenbus_watch *watch,
+ const char *path,
+ const char *token)
+{
+ const char *p = path;
+
+ if (char_count(path, '/') < 2)
+ return 0;
+
+ p = strchr(p, '/') + 1;
+ p = strchr(p, '/') + 1;
+
+ return path_to_domid(p);
+}
+
static struct xenbus_watch be_watch = {
.node = "backend",
.callback = backend_changed,
+ .get_domid = be_get_domid,
};

static int read_frontend_details(struct xenbus_device *xendev)
diff --git a/include/xen/xenbus.h b/include/xen/xenbus.h
index 4ac2cee..79d784e 100644
--- a/include/xen/xenbus.h
+++ b/include/xen/xenbus.h
@@ -241,6 +241,8 @@ extern const struct file_operations xen_xenbus_fops;
extern struct xenstore_domain_interface *xen_store_interface;
extern int xen_store_evtchn;

+unsigned int char_count(const char *str, char c);
+
void mtwatch_create_domain(domid_t domid);
void mtwatch_put_domain(domid_t domid);

--
2.7.4
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