internal/poll: improve Splice comments
Clarify the behavior of splice on older kernels, merge comments so
control flow becomes more obvious, as discussed in CL 133575.
Change-Id: I95855991bd0b1fa1c78a900b39c4382f65d83468
Reviewed-on: https://go-review.googlesource.com/135436
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/src/internal/poll/splice_linux.go b/src/internal/poll/splice_linux.go
index 9ba94d6..4f97298 100644
--- a/src/internal/poll/splice_linux.go
+++ b/src/internal/poll/splice_linux.go
@@ -39,15 +39,18 @@
max = int(remain)
}
inPipe, err = spliceDrain(pwfd, src, max)
- // the operation is considered handled if splice returns no error, or
- // an error other than EINVAL. An EINVAL means the kernel does not
- // support splice for the socket type of dst and/or src. The failed
- // syscall does not consume any data so it is safe to fall back to a
- // generic copy.
- handled = handled || (err != syscall.EINVAL)
+ // The operation is considered handled if splice returns no
+ // error, or an error other than EINVAL. An EINVAL means the
+ // kernel does not support splice for the socket type of src.
+ // The failed syscall does not consume any data so it is safe
+ // to fall back to a generic copy.
+ //
// spliceDrain should never return EAGAIN, so if err != nil,
- // Splice cannot continue. If inPipe == 0 && err == nil,
- // src is at EOF, and the transfer is complete.
+ // Splice cannot continue.
+ //
+ // If inPipe == 0 && err == nil, src is at EOF, and the
+ // transfer is complete.
+ handled = handled || (err != syscall.EINVAL)
if err != nil || (inPipe == 0 && err == nil) {
break
}
