fs/proc/vmcore.c: put if tests in the top of the while loop to reduce duplication

In read_vmcore() two `if' tests are duplicated.  Change the position of
them could reduce the duplication.  This change does not affect the
behaviour of the function.

[akpm@linux-foundation.org: avoid `if (foo = bar)' thing, use min_t()]
[akpm@linux-foundation.org: s/max_t/min_t/]
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/vmcore.c

@@ -176,15 +176,15 @@ static ssize_t read_vmcore(struct file *file, char __user *buffer,
 	start = map_offset_to_paddr(*fpos, &vmcore_list, &curr_m);
 	if (!curr_m)
         	return -EINVAL;
-	if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
-		tsz = buflen;
-
-	/* Calculate left bytes in current memory segment. */
-	nr_bytes = (curr_m->size - (start - curr_m->paddr));
-	if (tsz > nr_bytes)
-		tsz = nr_bytes;
 
 	while (buflen) {
+		tsz = min_t(size_t, buflen, PAGE_SIZE - (start & ~PAGE_MASK));
+
+		/* Calculate left bytes in current memory segment. */
+		nr_bytes = (curr_m->size - (start - curr_m->paddr));
+		if (tsz > nr_bytes)
+			tsz = nr_bytes;
+
 		tmp = read_from_oldmem(buffer, tsz, &start, 1);
 		if (tmp < 0)
 			return tmp;
@@ -199,12 +199,6 @@ static ssize_t read_vmcore(struct file *file, char __user *buffer,
 						struct vmcore, list);
 			start = curr_m->paddr;
 		}
-		if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
-			tsz = buflen;
-		/* Calculate left bytes in current memory segment. */
-		nr_bytes = (curr_m->size - (start - curr_m->paddr));
-		if (tsz > nr_bytes)
-			tsz = nr_bytes;
 	}
 	return acc;
 }