From e9666bf645105d08bcb6dffd5c36d02f817841b7 Mon Sep 17 00:00:00 2001
From: Mark Johnston <markj@FreeBSD.org>
Date: Fri, 18 Aug 2017 04:07:25 +0000
Subject: [PATCH] Remove some unneeded subroutines for padding writes to dump
 devices.

Right now we only need to pad when writing kernel dump headers, so
flatten three related subroutines into one. The encrypted kernel dump
code already writes out its key in a dumper.blocksize-sized block.

No functional change intended.

Reviewed by:	cem, def
Sponsored by:	Dell EMC Isilon
Differential Revision:	https://reviews.freebsd.org/D11647
---
 sys/kern/kern_shutdown.c | 56 +++++++++++-----------------------------
 1 file changed, 15 insertions(+), 41 deletions(-)

diff --git a/sys/kern/kern_shutdown.c b/sys/kern/kern_shutdown.c
index 7ba399ae7e8a..168da47170af 100644
--- a/sys/kern/kern_shutdown.c
+++ b/sys/kern/kern_shutdown.c
@@ -1151,52 +1151,26 @@ dump_write(struct dumperinfo *di, void *virtual, vm_offset_t physical,
 	return (dump_raw_write(di, virtual, physical, offset, length));
 }
 
-static int
-dump_pad(struct dumperinfo *di, void *virtual, size_t length, void **buf,
-    size_t *size)
-{
-
-	if (length > di->blocksize)
-		return (ENOMEM);
-
-	*size = di->blocksize;
-	if (length == di->blocksize) {
-		*buf = virtual;
-	} else {
-		*buf = di->blockbuf;
-		memcpy(*buf, virtual, length);
-		memset((uint8_t *)*buf + length, 0, di->blocksize - length);
-	}
-
-	return (0);
-}
-
-static int
-dump_raw_write_pad(struct dumperinfo *di, void *virtual, vm_offset_t physical,
-    off_t offset, size_t length, size_t *size)
-{
-	void *buf;
-	int error;
-
-	error = dump_pad(di, virtual, length, &buf, size);
-	if (error != 0)
-		return (error);
-
-	return (dump_raw_write(di, buf, physical, offset, *size));
-}
-
 static int
 dump_write_header(struct dumperinfo *di, struct kerneldumpheader *kdh,
     vm_offset_t physical, off_t offset)
 {
-	size_t size;
-	int ret;
+	void *buf;
+	size_t hdrsz;
 
-	ret = dump_raw_write_pad(di, kdh, physical, offset, sizeof(*kdh),
-	    &size);
-	if (ret == 0 && size != di->blocksize)
-		ret = EINVAL;
-	return (ret);
+	hdrsz = sizeof(*kdh);
+	if (hdrsz > di->blocksize)
+		return (ENOMEM);
+
+	if (hdrsz == di->blocksize)
+		buf = kdh;
+	else {
+		buf = di->blockbuf;
+		memset(buf, 0, di->blocksize);
+		memcpy(buf, kdh, hdrsz);
+	}
+
+	return (dump_raw_write(di, buf, physical, offset, di->blocksize));
 }
 
 /*