From b27b22a68c095daaa2a7f32a4b6cac3659cbb10e Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Fri, 28 Jan 2022 15:05:59 +0100
Subject: [PATCH] Kernel: Allocate entire SelectBlocker::FDVector at once

Use try_ensure_capacity() + unchecked_append() instead of repeatedly
doing try_append().
---
 Kernel/Syscalls/poll.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Kernel/Syscalls/poll.cpp b/Kernel/Syscalls/poll.cpp
index 8c63ee51c2..3619b7bb10 100644
--- a/Kernel/Syscalls/poll.cpp
+++ b/Kernel/Syscalls/poll.cpp
@@ -45,6 +45,8 @@ ErrorOr<FlatPtr> Process::sys$poll(Userspace<const Syscall::SC_poll_params*> use
     }
 
     Thread::SelectBlocker::FDVector fds_info;
+    TRY(fds_info.try_ensure_capacity(params.nfds));
+
     for (size_t i = 0; i < params.nfds; i++) {
         auto& pfd = fds_copy[i];
         auto description = TRY(fds().open_file_description(pfd.fd));
@@ -57,7 +59,7 @@ ErrorOr<FlatPtr> Process::sys$poll(Userspace<const Syscall::SC_poll_params*> use
             block_flags |= BlockFlags::ReadPriority;
         if (pfd.events & POLLWRBAND)
             block_flags |= BlockFlags::WritePriority;
-        TRY(fds_info.try_append({ move(description), block_flags }));
+        fds_info.unchecked_append({ move(description), block_flags });
     }
 
     auto* current_thread = Thread::current();