udev/net: several cleanups for config_parse_rps_cpu_mask()

- Previously, `LinkConfig.rps_cpu_mask == NULL` indicates setting RPS
  will be skipped, but now make the condition is changed to
  `LinkConfig.rps_cpu_mask.set == NULL`. Then, we can avoid allocating
  CPUSet when something configured.
- When "disable" or "all", now allocate a temporal object, and then
  replace with it.

No functional change, just refactoring.

src/udev/net/link-config.c

@@ -12,7 +12,6 @@
 #include "condition.h"
 #include "conf-files.h"
 #include "conf-parser.h"
-#include "cpu-set-util.h"
 #include "creds-util.h"
 #include "device-private.h"
 #include "device-util.h"
@@ -78,7 +77,7 @@ static LinkConfig* link_config_free(LinkConfig *config) {
         free(config->alias);
         free(config->wol_password_file);
         erase_and_free(config->wol_password);
-        cpu_set_free(config->rps_cpu_mask);
+        cpu_set_done(&config->rps_cpu_mask);
 
         ordered_hashmap_free(config->sr_iov_by_section);
 
@@ -954,10 +953,10 @@ static int link_apply_rps_cpu_mask(Link *link) {
         }
 
         /* Skip if the config is not specified. */
-        if (!config->rps_cpu_mask)
+        if (!config->rps_cpu_mask.set)
                 return 0;
 
-        mask_str = cpu_set_to_mask_string(config->rps_cpu_mask);
+        mask_str = cpu_set_to_mask_string(&config->rps_cpu_mask);
         if (!mask_str)
                 return log_oom();
 
@@ -1369,8 +1368,7 @@ int config_parse_rps_cpu_mask(
                 void *data,
                 void *userdata) {
 
-        _cleanup_(cpu_set_freep) CPUSet *allocated = NULL;
-        CPUSet *mask, **rps_cpu_mask = ASSERT_PTR(data);
+        CPUSet *mask = ASSERT_PTR(data);
         int r;
 
         assert(filename);
@@ -1378,38 +1376,36 @@ int config_parse_rps_cpu_mask(
         assert(rvalue);
 
         if (isempty(rvalue)) {
-                *rps_cpu_mask = cpu_set_free(*rps_cpu_mask);
+                cpu_set_done(mask);
                 return 0;
         }
 
-        if (*rps_cpu_mask)
-                mask = *rps_cpu_mask;
-        else {
-                allocated = new0(CPUSet, 1);
-                if (!allocated)
+        if (streq(rvalue, "disable")) {
+                _cleanup_(cpu_set_done) CPUSet c = {};
+
+                r = cpu_set_realloc(&c, 1);
+                if (r < 0)
                         return log_oom();
 
-                mask = allocated;
+                return cpu_set_done_and_replace(*mask, c);
         }
 
-        if (streq(rvalue, "disable"))
-                cpu_set_done(mask);
+        if (streq(rvalue, "all")) {
+                _cleanup_(cpu_set_done) CPUSet c = {};
 
-        else if (streq(rvalue, "all")) {
-                r = cpu_set_add_all(mask);
+                r = cpu_set_add_all(&c);
                 if (r < 0) {
                         log_syntax(unit, LOG_WARNING, filename, line, r,
                                    "Failed to create CPU affinity mask representing \"all\" cpus, ignoring: %m");
                         return 0;
                 }
-        } else {
-                r = parse_cpu_set_extend(rvalue, mask, /* warn= */ true, unit, filename, line, lvalue);
-                if (r < 0)
-                        return 0;
+
+                return cpu_set_done_and_replace(*mask, c);
         }
 
-        if (allocated)
-                *rps_cpu_mask = TAKE_PTR(allocated);
+        r = parse_cpu_set_extend(rvalue, mask, /* warn= */ true, unit, filename, line, lvalue);
+        if (r < 0)
+                return 0;
 
         return 0;
 }

src/udev/net/link-config.h

@@ -3,6 +3,7 @@
 
 #include "sd-device.h"
 
+#include "cpu-set-util.h"
 #include "ether-addr-util.h"
 #include "ethtool-util.h"
 #include "forward.h"
@@ -110,7 +111,7 @@ struct LinkConfig {
         uint32_t eee_advertise[N_ADVERTISE];
 
         /* Rx RPS CPU mask */
-        CPUSet *rps_cpu_mask;
+        CPUSet rps_cpu_mask;
 
         /* SR-IOV */
         uint32_t sr_iov_num_vfs;