kexec: Use min() and min_t() to simplify logic

Simplify the logic of variable assignments.

[akpm@linux-foundation.org: replace min_t with min, remove unneeded casts]
Signed-off-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: NSimon Horman <horms@verge.net.au>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kernel/kexec.c

@@ -819,13 +819,9 @@ static int kimage_load_normal_segment(struct kimage *image,
 		/* Start with a clear page */
 		clear_page(ptr);
 		ptr += maddr & ~PAGE_MASK;
-		mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
-		if (mchunk > mbytes)
-			mchunk = mbytes;
-
-		uchunk = mchunk;
-		if (uchunk > ubytes)
-			uchunk = ubytes;
+		mchunk = min_t(size_t, mbytes,
+				PAGE_SIZE - (maddr & ~PAGE_MASK));
+		uchunk = min(ubytes, mchunk);
 
 		result = copy_from_user(ptr, buf, uchunk);
 		kunmap(page);
@@ -871,13 +867,10 @@ static int kimage_load_crash_segment(struct kimage *image,
 		}
 		ptr = kmap(page);
 		ptr += maddr & ~PAGE_MASK;
-		mchunk = PAGE_SIZE - (maddr & ~PAGE_MASK);
-		if (mchunk > mbytes)
-			mchunk = mbytes;
-
-		uchunk = mchunk;
-		if (uchunk > ubytes) {
-			uchunk = ubytes;
+		mchunk = min_t(size_t, mbytes,
+				PAGE_SIZE - (maddr & ~PAGE_MASK));
+		uchunk = min(ubytes, mchunk);
+		if (mchunk > uchunk) {
 			/* Zero the trailing part of the page */
 			memset(ptr + uchunk, 0, mchunk - uchunk);
 		}
@@ -1546,8 +1539,7 @@ void vmcoreinfo_append_str(const char *fmt, ...)
 	r = vsnprintf(buf, sizeof(buf), fmt, args);
 	va_end(args);
 
-	if (r + vmcoreinfo_size > vmcoreinfo_max_size)
-		r = vmcoreinfo_max_size - vmcoreinfo_size;
+	r = min(r, vmcoreinfo_max_size - vmcoreinfo_size);
 
 	memcpy(&vmcoreinfo_data[vmcoreinfo_size], buf, r);