[PATCH V2 2/6] stm class: adds a loop to extract the first valid STM device name

[Chunyan Zhang]

The node name of STM master management policy is a concatenation of an
STM device name to which this policy applies and following an arbitrary
string, these two strings are concatenated with a dot.

This patch adds a loop for extracting the STM device name when an
arbitrary number of dot(s) are found in this STM device name.

Signed-off-by: Chunyan Zhang <zhang.chun...@linaro.org>
---
 drivers/hwtracing/stm/policy.c | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/drivers/hwtracing/stm/policy.c b/drivers/hwtracing/stm/policy.c
index 11ab6d0..691686e 100644
--- a/drivers/hwtracing/stm/policy.c
+++ b/drivers/hwtracing/stm/policy.c
@@ -321,21 +321,26 @@ stp_policies_make(struct config_group *group, const char 
*name)
        /*
         * node must look like <device_name>.<policy_name>, where
         * <device_name> is the name of an existing stm device and
-        * <policy_name> is an arbitrary string
+        * <policy_name> is an arbitrary string, when an arbitrary
+        * number of dot(s) are found in the <device_name>, the
+        * first matched STM device name would be extracted.
         */
-       p = strchr(devname, '.');
-       if (!p) {
-               kfree(devname);
-               return ERR_PTR(-EINVAL);
-       }
+       for (p = devname; ; p++) {
+               p = strchr(p, '.');
+               if (!p) {
+                       kfree(devname);
+                       return ERR_PTR(-EINVAL);
+               }
 
-       *p++ = '\0';
+               *p = '\0';
 
-       stm = stm_find_device(devname);
-       kfree(devname);
+               stm = stm_find_device(devname);
+               if (stm)
+                       break;
+               *p = '.';
+       };
 
-       if (!stm)
-               return ERR_PTR(-ENODEV);
+       kfree(devname);
 
        mutex_lock(&stm->policy_mutex);
        if (stm->policy) {
-- 
1.9.1