From 54666dffa80b1f9a9f38e9d627b0bb4be62ef6d8 Mon Sep 17 00:00:00 2001
From: Pawel Biernacki <kaktus@FreeBSD.org>
Date: Mon, 30 Dec 2019 18:11:06 +0000
Subject: [PATCH] linux(4): implement copy_file_range(2)

copy_file_range(2) is implemented natively since r350315, make it available
for Linux binaries too.

Reviewed by:	kib (mentor), trasz (previous version)
Approved by:	kib (mentor)
Differential Revision:	https://reviews.freebsd.org/D22959
---
 sys/amd64/linux/linux_dummy.c     |  2 --
 sys/amd64/linux32/linux32_dummy.c |  2 --
 sys/arm64/linux/linux_dummy.c     |  2 --
 sys/compat/linux/linux_file.c     | 41 +++++++++++++++++++++++++++++++
 sys/i386/linux/linux_dummy.c      |  2 --
 5 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/sys/amd64/linux/linux_dummy.c b/sys/amd64/linux/linux_dummy.c
index 9691fa43729..2b7e988d754 100644
--- a/sys/amd64/linux/linux_dummy.c
+++ b/sys/amd64/linux/linux_dummy.c
@@ -144,8 +144,6 @@ DUMMY(userfaultfd);
 DUMMY(membarrier);
 /* Linux 4.4: */
 DUMMY(mlock2);
-/* Linux 4.5: */
-DUMMY(copy_file_range);
 /* Linux 4.6: */
 DUMMY(preadv2);
 DUMMY(pwritev2);
diff --git a/sys/amd64/linux32/linux32_dummy.c b/sys/amd64/linux32/linux32_dummy.c
index 05cd0b41e90..3787951b910 100644
--- a/sys/amd64/linux32/linux32_dummy.c
+++ b/sys/amd64/linux32/linux32_dummy.c
@@ -148,8 +148,6 @@ DUMMY(userfaultfd);
 DUMMY(membarrier);
 /* Linux 4.4: */
 DUMMY(mlock2);
-/* Linux 4.5: */
-DUMMY(copy_file_range);
 /* Linux 4.6: */
 DUMMY(preadv2);
 DUMMY(pwritev2);
diff --git a/sys/arm64/linux/linux_dummy.c b/sys/arm64/linux/linux_dummy.c
index ab8566623df..0cfe3669da7 100644
--- a/sys/arm64/linux/linux_dummy.c
+++ b/sys/arm64/linux/linux_dummy.c
@@ -142,8 +142,6 @@ DUMMY(userfaultfd);
 DUMMY(membarrier);
 /* Linux 4.4: */
 DUMMY(mlock2);
-/* Linux 4.5: */
-DUMMY(copy_file_range);
 /* Linux 4.6: */
 DUMMY(preadv2);
 DUMMY(pwritev2);
diff --git a/sys/compat/linux/linux_file.c b/sys/compat/linux/linux_file.c
index d48132440db..565fc562fdf 100644
--- a/sys/compat/linux/linux_file.c
+++ b/sys/compat/linux/linux_file.c
@@ -1565,3 +1565,44 @@ linux_fallocate(struct thread *td, struct linux_fallocate_args *args)
 	return (kern_posix_fallocate(td, args->fd, args->offset,
 	    args->len));
 }
+
+int
+linux_copy_file_range(struct thread *td, struct linux_copy_file_range_args
+    *args)
+{
+	l_loff_t inoff, outoff, *inoffp, *outoffp;
+	int error, flags;
+
+	/*
+	 * copy_file_range(2) on Linux doesn't define any flags (yet), so is
+	 * the native implementation.  Enforce it.
+	 */
+	if (args->flags != 0) {
+		linux_msg(td, "copy_file_range unsupported flags 0x%x",
+		    args->flags);
+		return (EINVAL);
+	}
+	flags = 0;
+	inoffp = outoffp = NULL;
+	if (args->off_in != NULL) {
+		error = copyin(args->off_in, &inoff, sizeof(l_loff_t));
+		if (error != 0)
+			return (error);
+		inoffp = &inoff;
+	}
+	if (args->off_out != NULL) {
+		error = copyin(args->off_out, &outoff, sizeof(l_loff_t));
+		if (error != 0)
+			return (error);
+		outoffp = &outoff;
+	}
+
+	error = kern_copy_file_range(td, args->fd_in, inoffp, args->fd_out,
+	    outoffp, args->len, flags);
+	if (error == 0 && args->off_in != NULL)
+		error = copyout(inoffp, args->off_in, sizeof(l_loff_t));
+	if (error == 0 && args->off_out != NULL)
+		error = copyout(outoffp, args->off_out, sizeof(l_loff_t));
+	return (error);
+}
+
diff --git a/sys/i386/linux/linux_dummy.c b/sys/i386/linux/linux_dummy.c
index 16136dc34d7..ed61654355e 100644
--- a/sys/i386/linux/linux_dummy.c
+++ b/sys/i386/linux/linux_dummy.c
@@ -144,8 +144,6 @@ DUMMY(userfaultfd);
 DUMMY(membarrier);
 /* Linux 4.4: */
 DUMMY(mlock2);
-/* Linux 4.5: */
-DUMMY(copy_file_range);
 /* Linux 4.6: */
 DUMMY(preadv2);
 DUMMY(pwritev2);