Fix comments

Author: tiif

tests/fail-dep/libc/libc_eventfd_write_block.rs

@@ -1,7 +1,8 @@
 //@ignore-target-windows: No eventfd on Windows
 //@ignore-target-apple: No eventfd in macos
 fn main() {
-    // eventfd write will block when we try to add until it exceed u64::MAX - 1.
+    // eventfd write will block when EFD_NONBLOCK flag is clear
+    // and the addition caused counter to exceed u64::MAX - 1.
     // This will pass when blocking is implemented.
     let flags = libc::EFD_CLOEXEC;
     let fd = unsafe { libc::eventfd(0, flags) };

tests/pass-dep/libc/libc-eventfd.rs

@@ -103,7 +103,7 @@ fn test_race() {
         let res: i32 = unsafe {
             libc::read(fd, buf.as_mut_ptr().cast(), buf.len() as libc::size_t).try_into().unwrap()
         };
-        // read returns number of bytes has been read, which is always 8
+        // read returns number of bytes has been read, which is always 8.
         assert_eq!(res, 8);
         let counter: u64;
         if cfg!(target_endian = "big") {
@@ -113,10 +113,8 @@ fn test_race() {
             counter = u64::from_le_bytes(buf);
         }
         assert_eq!(counter, 1);
-        // Read from the static mutable variable
         unsafe { assert_eq!(VAL, 1) };
     });
-    // Write to the static mutable variable
     unsafe { VAL = 1 };
     let data: [u8; 8];
     if cfg!(target_endian = "big") {
@@ -127,7 +125,7 @@ fn test_race() {
     }
     let res: i64 =
         unsafe { libc::write(fd, data.as_ptr() as *const libc::c_void, 8).try_into().unwrap() };
-    // write return number of bytes written, which is always 8
+    // write returns number of bytes written, which is always 8.
     assert_eq!(res, 8);
     thread::yield_now();
     thread1.join().unwrap();