diff --git a/common/channel.cc b/common/channel.cc
index d72ebd7..af3b95f 100644
--- a/common/channel.cc
+++ b/common/channel.cc
@@ -83,6 +83,25 @@ static void UnmapMemory(void *p, size_t size, const char *purpose) {
 
   mapped_regions->erase(p);
 #endif
+}
+
+template <typename BufferSetIter>
+static void UnmapBuffers(BufferSetIter first, BufferSetIter last, int num_slots) {
+  // Unmap any previously mapped buffers.
+  for (; first < last; ++first) {
+    int64_t buffers_size =
+        sizeof(BufferHeader) +
+        num_slots *
+            (Aligned<32>(first->slot_size) + sizeof(MessagePrefix));
+    if (buffers_size > 0 && first->buffer != nullptr) {
+      UnmapMemory(first->buffer, buffers_size, "buffers");
+      first->buffer = nullptr;
+      first->slot_size = 0;
+    }
+  }
+
+
+
 }
 
 static absl::StatusOr<void *> CreateSharedMemory(int id, const char *suffix,
@@ -319,15 +338,7 @@ absl::Status Channel::Map(SharedMemoryFds fds,
         UnmapMemory(scb_, sizeof(SystemControlBlock), "SCB");
         UnmapMemory(ccb_, ccb_size, "CCB");
         // Unmap any previously mapped buffers.
-        for (int i = 0; i < index; i++) {
-          int64_t buffers_size =
-              sizeof(BufferHeader) +
-              num_slots_ *
-                  (Aligned<32>(buffers_[i].slot_size) + sizeof(MessagePrefix));
-          if (buffers_size > 0 && buffers_[i].buffer != nullptr) {
-            UnmapMemory(buffers_[i].buffer, buffers_size, "buffers");
-          }
-        }
+        UnmapBuffers(buffers_.begin(), buffers_.begin() + index, num_slots_);
         return absl::InternalError(absl::StrFormat(
             "Failed to map channel buffers: %s", strerror(errno)));
       }
@@ -411,15 +422,7 @@ absl::Status Channel::MapNewBuffers(std::vector<SlotBuffer> buffers) {
 
       if (mem == MAP_FAILED) {
         // Unmap any newly mapped buffers.
-        for (size_t i = start; i < buffers_.size(); i++) {
-          int64_t buffers_size =
-              sizeof(BufferHeader) +
-              num_slots_ *
-                  (Aligned<32>(buffers_[i].slot_size) + sizeof(MessagePrefix));
-          if (buffers_size > 0 && buffers_[i].buffer != nullptr) {
-            UnmapMemory(buffers_[i].buffer, buffers_size, "buffers");
-          }
-        }
+        UnmapBuffers(buffers_.begin() + start, buffers_.end(), num_slots_);
         return absl::InternalError(absl::StrFormat(
             "Failed to map new channel buffers: %s", strerror(errno)));
       }
diff --git a/manual_tests/perf_subspace.cc b/manual_tests/perf_subspace.cc
index d824f61..75609bd 100644
--- a/manual_tests/perf_subspace.cc
+++ b/manual_tests/perf_subspace.cc
@@ -17,10 +17,10 @@ ABSL_FLAG(int, num_slots, 500, "Number of slots in channel");
 
 void PubCoroutine(co::Coroutine *c) {
   subspace::Client client(c);
-  absl::Status s = client.Init(absl::GetFlag(FLAGS_socket));
-  if (!s.ok()) {
+  absl::Status init_status = client.Init(absl::GetFlag(FLAGS_socket));
+  if (!init_status.ok()) {
     fprintf(stderr, "Can't connect to Subspace server: %s\n",
-            s.ToString().c_str());
+            init_status.ToString().c_str());
     exit(1);
   }
   int num_slots = absl::GetFlag(FLAGS_num_slots);
@@ -46,9 +46,9 @@ void PubCoroutine(co::Coroutine *c) {
       }
       if (*buffer == nullptr) {
         // Wait for publisher trigger.
-        absl::Status s = pub->Wait();
-        if (!s.ok()) {
-          fprintf(stderr, "Can't wait for publisher: %s", s.ToString().c_str());
+        absl::Status wait_status = pub->Wait();
+        if (!wait_status.ok()) {
+          fprintf(stderr, "Can't wait for publisher: %s", wait_status.ToString().c_str());
           exit(1);
         }
         continue;
@@ -66,10 +66,10 @@ void PubCoroutine(co::Coroutine *c) {
 
 void SubCoroutine(co::Coroutine *c) {
   subspace::Client client(c);
-  absl::Status s = client.Init(absl::GetFlag(FLAGS_socket));
-  if (!s.ok()) {
+  absl::Status init_status = client.Init(absl::GetFlag(FLAGS_socket));
+  if (!init_status.ok()) {
     fprintf(stderr, "Can't connect to Subspace server: %s\n",
-            s.ToString().c_str());
+            init_status.ToString().c_str());
     exit(1);
   }
   int slot_size = absl::GetFlag(FLAGS_slot_size);
@@ -97,8 +97,8 @@ void SubCoroutine(co::Coroutine *c) {
     if (start != 0) {
       wait_start = toolbelt::Now();
     }
-    if (absl::Status s = sub->Wait(); !s.ok()) {
-      fprintf(stderr, "Can't wait for subscriber: %s\n", s.ToString().c_str());
+    if (absl::Status wait_status = sub->Wait(); !wait_status.ok()) {
+      fprintf(stderr, "Can't wait for subscriber: %s\n", wait_status.ToString().c_str());
       exit(1);
     }
     if (wait_start != 0) {
diff --git a/manual_tests/perf_subspace_pub.cc b/manual_tests/perf_subspace_pub.cc
index 67f3e08..689f5d9 100644
--- a/manual_tests/perf_subspace_pub.cc
+++ b/manual_tests/perf_subspace_pub.cc
@@ -20,9 +20,9 @@ int main(int argc, char **argv) {
   signal(SIGPIPE, SIG_IGN);
 
   subspace::Client client;
-  absl::Status s = client.Init(absl::GetFlag(FLAGS_socket));
-  if (!s.ok()) {
-    fprintf(stderr, "Can't connect to Subspace server: %s\n", s.ToString().c_str());
+  absl::Status init_status = client.Init(absl::GetFlag(FLAGS_socket));
+  if (!init_status.ok()) {
+    fprintf(stderr, "Can't connect to Subspace server: %s\n", init_status.ToString().c_str());
     exit(1);
   }
   bool reliable = absl::GetFlag(FLAGS_reliable);
@@ -49,9 +49,9 @@ int main(int argc, char **argv) {
       }
       if (*buffer == nullptr) {
         // Wait for publisher trigger.
-        absl::Status s = pub->Wait();
-        if (!s.ok()) {
-          fprintf(stderr, "Can't wait for publisher: %s", s.ToString().c_str());
+        absl::Status wait_status = pub->Wait();
+        if (!wait_status.ok()) {
+          fprintf(stderr, "Can't wait for publisher: %s", wait_status.ToString().c_str());
           exit(1);
         }
         continue;
diff --git a/manual_tests/perf_subspace_sub.cc b/manual_tests/perf_subspace_sub.cc
index 837632e..392c8fc 100644
--- a/manual_tests/perf_subspace_sub.cc
+++ b/manual_tests/perf_subspace_sub.cc
@@ -21,10 +21,10 @@ int main(int argc, char **argv) {
   signal(SIGPIPE, SIG_IGN);
 
   subspace::Client client;
-  absl::Status s = client.Init(absl::GetFlag(FLAGS_socket));
-  if (!s.ok()) {
+  absl::Status init_status = client.Init(absl::GetFlag(FLAGS_socket));
+  if (!init_status.ok()) {
     fprintf(stderr, "Can't connect to Subspace server: %s\n",
-            s.ToString().c_str());
+            init_status.ToString().c_str());
     exit(1);
   }
   bool reliable = absl::GetFlag(FLAGS_reliable);
@@ -54,8 +54,8 @@ int main(int argc, char **argv) {
     if (start != 0) {
       wait_start = toolbelt::Now();
     }
-    if (absl::Status s = sub->Wait(); !s.ok()) {
-      fprintf(stderr, "Can't wait for subscriber: %s\n", s.ToString().c_str());
+    if (absl::Status wait_status = sub->Wait(); !wait_status.ok()) {
+      fprintf(stderr, "Can't wait for subscriber: %s\n", wait_status.ToString().c_str());
       exit(1);
     }
     if (wait_start != 0) {
diff --git a/manual_tests/pub.cc b/manual_tests/pub.cc
index 4715cec..e69fc22 100644
--- a/manual_tests/pub.cc
+++ b/manual_tests/pub.cc
@@ -18,10 +18,10 @@ int main(int argc, char **argv) {
   absl::ParseCommandLine(argc, argv);
 
   subspace::Client client;
-  absl::Status s = client.Init(absl::GetFlag(FLAGS_socket));
-  if (!s.ok()) {
+  absl::Status init_status = client.Init(absl::GetFlag(FLAGS_socket));
+  if (!init_status.ok()) {
     fprintf(stderr, "Can't connect to Subspace server: %s\n",
-            s.ToString().c_str());
+            init_status.ToString().c_str());
     exit(1);
   }
   bool reliable = absl::GetFlag(FLAGS_reliable);
@@ -63,10 +63,10 @@ int main(int argc, char **argv) {
         }
         if (*buffer == nullptr) {
           // Wait for publisher trigger.
-          absl::Status s = pub->Wait();
-          if (!s.ok()) {
+          absl::Status wait_status = pub->Wait();
+          if (!wait_status.ok()) {
             fprintf(stderr, "Can't wait for publisher: %s",
-                    s.ToString().c_str());
+                    wait_status.ToString().c_str());
             exit(1);
           }
           continue;
diff --git a/manual_tests/sub.cc b/manual_tests/sub.cc
index 7b266a4..2dab9f7 100644
--- a/manual_tests/sub.cc
+++ b/manual_tests/sub.cc
@@ -18,9 +18,9 @@ int main(int argc, char **argv) {
 
   subspace::Client client;
 
-  absl::Status s = client.Init(absl::GetFlag(FLAGS_socket));
-  if (!s.ok()) {
-    fprintf(stderr, "Can't connect to Subspace server: %s\n", s.ToString().c_str());
+  absl::Status init_status = client.Init(absl::GetFlag(FLAGS_socket));
+  if (!init_status.ok()) {
+    fprintf(stderr, "Can't connect to Subspace server: %s\n", init_status.ToString().c_str());
     exit(1);
   }
   bool reliable = absl::GetFlag(FLAGS_reliable);
@@ -39,8 +39,8 @@ int main(int argc, char **argv) {
       });
 
   for (;;) {
-    if (absl::Status s = sub->Wait(); !s.ok()) {
-      fprintf(stderr, "Can't wait for subscriber: %s\n", s.ToString().c_str());
+    if (absl::Status wait_status = sub->Wait(); !wait_status.ok()) {
+      fprintf(stderr, "Can't wait for subscriber: %s\n", wait_status.ToString().c_str());
       exit(1);
     }
     for (;;) {
diff --git a/server/server.cc b/server/server.cc
index 5b6fa6b..0da2313 100644
--- a/server/server.cc
+++ b/server/server.cc
@@ -895,12 +895,12 @@ void Server::BridgeReceiverCoroutine(std::string channel_name,
     }
     prefix->flags |= kMessageBridged;
 
-    absl::StatusOr<const Message> s =
+    absl::StatusOr<const Message> pub_msg =
         pub->PublishMessageInternal(*n, /*omit_prefix=*/true);
-    if (!s.ok()) {
+    if (!pub_msg.ok()) {
       logger_.Log(toolbelt::LogLevel::kError,
                   "Failed to publish bridge message for %s: %s",
-                  channel_name.c_str(), s.status().ToString().c_str());
+                  channel_name.c_str(), pub_msg.status().ToString().c_str());
     }
   }