diff --git a/src/basic/hashmap.c b/src/basic/hashmap.c
index 018ef5e7d8..eba56add1f 100644
--- a/src/basic/hashmap.c
+++ b/src/basic/hashmap.c
@@ -1543,47 +1543,9 @@ static unsigned find_first_entry(HashmapBase *h) {
         return hashmap_iterate_entry(h, &i);
 }
 
-void *internal_hashmap_first(HashmapBase *h) {
-        unsigned idx;
-
-        idx = find_first_entry(h);
-        if (idx == IDX_NIL)
-                return NULL;
-
-        return entry_value(h, bucket_at(h, idx));
-}
-
-void *internal_hashmap_first_key(HashmapBase *h) {
+void *internal_hashmap_first_key_and_value(HashmapBase *h, bool remove, void **ret_key) {
         struct hashmap_base_entry *e;
-        unsigned idx;
-
-        idx = find_first_entry(h);
-        if (idx == IDX_NIL)
-                return NULL;
-
-        e = bucket_at(h, idx);
-        return (void*) e->key;
-}
-
-void *internal_hashmap_steal_first(HashmapBase *h) {
-        struct hashmap_base_entry *e;
-        void *data;
-        unsigned idx;
-
-        idx = find_first_entry(h);
-        if (idx == IDX_NIL)
-                return NULL;
-
-        e = bucket_at(h, idx);
-        data = entry_value(h, e);
-        remove_entry(h, idx);
-
-        return data;
-}
-
-void *internal_hashmap_steal_first_key(HashmapBase *h) {
-        struct hashmap_base_entry *e;
-        void *key;
+        void *key, *data;
         unsigned idx;
 
         idx = find_first_entry(h);
@@ -1592,9 +1554,15 @@ void *internal_hashmap_steal_first_key(HashmapBase *h) {
 
         e = bucket_at(h, idx);
         key = (void*) e->key;
-        remove_entry(h, idx);
+        data = entry_value(h, e);
 
-        return key;
+        if (remove)
+                remove_entry(h, idx);
+
+        if (ret_key)
+                *ret_key = key;
+
+        return data;
 }
 
 unsigned internal_hashmap_size(HashmapBase *h) {
diff --git a/src/basic/hashmap.h b/src/basic/hashmap.h
index b771ceccdc..bb2a5c76ec 100644
--- a/src/basic/hashmap.h
+++ b/src/basic/hashmap.h
@@ -290,36 +290,51 @@ static inline void ordered_hashmap_clear_free_free(OrderedHashmap *h) {
  * the first entry is O(1).
  */
 
-void *internal_hashmap_steal_first(HashmapBase *h);
+void *internal_hashmap_first_key_and_value(HashmapBase *h, bool remove, void **ret_key);
+static inline void *hashmap_steal_first_key_and_value(Hashmap *h, void **ret) {
+        return internal_hashmap_first_key_and_value(HASHMAP_BASE(h), true, ret);
+}
+static inline void *ordered_hashmap_steal_first_key_and_value(OrderedHashmap *h, void **ret) {
+        return internal_hashmap_first_key_and_value(HASHMAP_BASE(h), true, ret);
+}
+static inline void *hashmap_first_key_and_value(Hashmap *h, void **ret) {
+        return internal_hashmap_first_key_and_value(HASHMAP_BASE(h), false, ret);
+}
+static inline void *ordered_hashmap_first_key_and_value(OrderedHashmap *h, void **ret) {
+        return internal_hashmap_first_key_and_value(HASHMAP_BASE(h), false, ret);
+}
+
+
 static inline void *hashmap_steal_first(Hashmap *h) {
-        return internal_hashmap_steal_first(HASHMAP_BASE(h));
+        return internal_hashmap_first_key_and_value(HASHMAP_BASE(h), true, NULL);
 }
 static inline void *ordered_hashmap_steal_first(OrderedHashmap *h) {
-        return internal_hashmap_steal_first(HASHMAP_BASE(h));
+        return internal_hashmap_first_key_and_value(HASHMAP_BASE(h), true, NULL);
 }
-
-void *internal_hashmap_steal_first_key(HashmapBase *h);
-static inline void *hashmap_steal_first_key(Hashmap *h) {
-        return internal_hashmap_steal_first_key(HASHMAP_BASE(h));
-}
-static inline void *ordered_hashmap_steal_first_key(OrderedHashmap *h) {
-        return internal_hashmap_steal_first_key(HASHMAP_BASE(h));
-}
-
-void *internal_hashmap_first_key(HashmapBase *h) _pure_;
-static inline void *hashmap_first_key(Hashmap *h) {
-        return internal_hashmap_first_key(HASHMAP_BASE(h));
-}
-static inline void *ordered_hashmap_first_key(OrderedHashmap *h) {
-        return internal_hashmap_first_key(HASHMAP_BASE(h));
-}
-
-void *internal_hashmap_first(HashmapBase *h) _pure_;
 static inline void *hashmap_first(Hashmap *h) {
-        return internal_hashmap_first(HASHMAP_BASE(h));
+        return internal_hashmap_first_key_and_value(HASHMAP_BASE(h), false, NULL);
 }
 static inline void *ordered_hashmap_first(OrderedHashmap *h) {
-        return internal_hashmap_first(HASHMAP_BASE(h));
+        return internal_hashmap_first_key_and_value(HASHMAP_BASE(h), false, NULL);
+}
+
+static inline void *internal_hashmap_first_key(HashmapBase *h, bool remove) {
+        void *key = NULL;
+
+        (void) internal_hashmap_first_key_and_value(HASHMAP_BASE(h), remove, &key);
+        return key;
+}
+static inline void *hashmap_steal_first_key(Hashmap *h) {
+        return internal_hashmap_first_key(HASHMAP_BASE(h), true);
+}
+static inline void *ordered_hashmap_steal_first_key(OrderedHashmap *h) {
+        return internal_hashmap_first_key(HASHMAP_BASE(h), true);
+}
+static inline void *hashmap_first_key(Hashmap *h) {
+        return internal_hashmap_first_key(HASHMAP_BASE(h), false);
+}
+static inline void *ordered_hashmap_first_key(OrderedHashmap *h) {
+        return internal_hashmap_first_key(HASHMAP_BASE(h), false);
 }
 
 #define hashmap_clear_with_destructor(_s, _f)                   \
diff --git a/src/basic/set.h b/src/basic/set.h
index 664713810d..0d99d5550d 100644
--- a/src/basic/set.h
+++ b/src/basic/set.h
@@ -86,7 +86,7 @@ static inline void set_clear_free(Set *s) {
 /* no set_clear_free_free */
 
 static inline void *set_steal_first(Set *s) {
-        return internal_hashmap_steal_first(HASHMAP_BASE(s));
+        return internal_hashmap_first_key_and_value(HASHMAP_BASE(s), true, NULL);
 }
 
 #define set_clear_with_destructor(_s, _f)               \
@@ -105,7 +105,7 @@ static inline void *set_steal_first(Set *s) {
 /* no set_first_key */
 
 static inline void *set_first(Set *s) {
-        return internal_hashmap_first(HASHMAP_BASE(s));
+        return internal_hashmap_first_key_and_value(HASHMAP_BASE(s), false, NULL);
 }
 
 /* no set_next */
diff --git a/src/libsystemd/sd-device/device-enumerator.c b/src/libsystemd/sd-device/device-enumerator.c
index c7e5bf4431..3ae283e93c 100644
--- a/src/libsystemd/sd-device/device-enumerator.c
+++ b/src/libsystemd/sd-device/device-enumerator.c
@@ -792,6 +792,33 @@ static int enumerator_scan_devices_all(sd_device_enumerator *enumerator) {
         return r;
 }
 
+static void device_enumerator_dedup_devices(sd_device_enumerator *enumerator) {
+        sd_device **a, **b, **end;
+
+        assert(enumerator);
+
+        if (enumerator->n_devices <= 1)
+                return;
+
+        a = enumerator->devices + 1;
+        b = enumerator->devices;
+        end = enumerator->devices + enumerator->n_devices;
+
+        for (; a < end; a++) {
+                const char *devpath_a, *devpath_b;
+
+                assert_se(sd_device_get_devpath(*a, &devpath_a) >= 0);
+                assert_se(sd_device_get_devpath(*b, &devpath_b) >= 0);
+
+                if (path_equal(devpath_a, devpath_b))
+                        sd_device_unref(*a);
+                else
+                        *(++b) = *a;
+        }
+
+        enumerator->n_devices = b - enumerator->devices + 1;
+}
+
 int device_enumerator_scan_devices(sd_device_enumerator *enumerator) {
         int r = 0, k;
         size_t i;
@@ -822,6 +849,7 @@ int device_enumerator_scan_devices(sd_device_enumerator *enumerator) {
         }
 
         typesafe_qsort(enumerator->devices, enumerator->n_devices, device_compare);
+        device_enumerator_dedup_devices(enumerator);
 
         enumerator->scan_uptodate = true;
         enumerator->type = DEVICE_ENUMERATION_TYPE_DEVICES;
@@ -906,6 +934,7 @@ int device_enumerator_scan_subsystems(sd_device_enumerator *enumerator) {
         }
 
         typesafe_qsort(enumerator->devices, enumerator->n_devices, device_compare);
+        device_enumerator_dedup_devices(enumerator);
 
         enumerator->scan_uptodate = true;
         enumerator->type = DEVICE_ENUMERATION_TYPE_SUBSYSTEMS;
diff --git a/src/libsystemd/sd-device/test-sd-device.c b/src/libsystemd/sd-device/test-sd-device.c
index fc2d02b4b3..e2701e0e24 100644
--- a/src/libsystemd/sd-device/test-sd-device.c
+++ b/src/libsystemd/sd-device/test-sd-device.c
@@ -3,6 +3,7 @@
 #include "device-enumerator-private.h"
 #include "device-private.h"
 #include "device-util.h"
+#include "hashmap.h"
 #include "string-util.h"
 #include "tests.h"
 #include "util.h"
@@ -63,9 +64,73 @@ static void test_sd_device_basic(void) {
         }
 }
 
+static void test_sd_device_enumerator_filter_subsystem_one(const char *subsystem, Hashmap *h) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        sd_device *d, *t;
+
+        assert_se(sd_device_enumerator_new(&e) >= 0);
+        assert_se(sd_device_enumerator_add_match_subsystem(e, subsystem, true) >= 0);
+
+        FOREACH_DEVICE(e, d) {
+                const char *syspath;
+
+                assert_se(sd_device_get_syspath(d, &syspath) >= 0);
+                assert_se(t = hashmap_remove(h, syspath));
+                assert_se(!sd_device_unref(t));
+
+                log_debug("Removed subsystem:%s syspath:%s", subsystem, syspath);
+        }
+
+        assert_se(hashmap_isempty(h));
+}
+
+static void test_sd_device_enumerator_filter_subsystem(void) {
+        _cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
+        _cleanup_(hashmap_freep) Hashmap *subsystems;
+        sd_device *d;
+        Hashmap *h;
+        char *s;
+
+        assert_se(subsystems = hashmap_new(&string_hash_ops));
+        assert_se(sd_device_enumerator_new(&e) >= 0);
+
+        FOREACH_DEVICE(e, d) {
+                const char *syspath, *subsystem;
+                int r;
+
+                assert_se(sd_device_get_syspath(d, &syspath) >= 0);
+
+                r = sd_device_get_subsystem(d, &subsystem);
+                assert_se(r >= 0 || r == -ENOENT);
+                if (r < 0)
+                        continue;
+
+                h = hashmap_get(subsystems, subsystem);
+                if (!h) {
+                        char *str;
+                        assert_se(str = strdup(subsystem));
+                        assert_se(h = hashmap_new(&string_hash_ops));
+                        assert_se(hashmap_put(subsystems, str, h) >= 0);
+                }
+
+                assert_se(hashmap_put(h, syspath, d) >= 0);
+                assert_se(sd_device_ref(d));
+
+                log_debug("Added subsystem:%s syspath:%s", subsystem, syspath);
+        }
+
+        while ((h = hashmap_steal_first_key_and_value(subsystems, (void**) &s))) {
+                test_sd_device_enumerator_filter_subsystem_one(s, h);
+                hashmap_free(h);
+                free(s);
+        }
+}
+
 int main(int argc, char **argv) {
         test_setup_logging(LOG_INFO);
 
         test_sd_device_basic();
+        test_sd_device_enumerator_filter_subsystem();
+
         return 0;
 }