--- linux/fs/pipe.c	2018/04/24 18:00:41	1.1.1.1
+++ linux/fs/pipe.c	2018/04/24 18:00:53	1.1.1.2
@@ -1,3 +1,9 @@
+/*
+ *  linux/fs/pipe.c
+ *
+ *  (C) 1991  Linus Torvalds
+ */
+
 #include <signal.h>
 
 #include <linux/sched.h>
@@ -6,47 +12,60 @@
 
 int read_pipe(struct m_inode * inode, char * buf, int count)
 {
-	char * b=buf;
+	int chars, size, read = 0;
 
-	while (PIPE_EMPTY(*inode)) {
-		wake_up(&inode->i_wait);
-		if (inode->i_count != 2) /* are there any writers left? */
-			return 0;
-		sleep_on(&inode->i_wait);
-	}
-	while (count>0 && !(PIPE_EMPTY(*inode))) {
-		count --;
-		put_fs_byte(((char *)inode->i_size)[PIPE_TAIL(*inode)],b++);
-		INC_PIPE( PIPE_TAIL(*inode) );
+	while (count>0) {
+		while (!(size=PIPE_SIZE(*inode))) {
+			wake_up(&inode->i_wait);
+			if (inode->i_count != 2) /* are there any writers? */
+				return read;
+			sleep_on(&inode->i_wait);
+		}
+		chars = PAGE_SIZE-PIPE_TAIL(*inode);
+		if (chars > count)
+			chars = count;
+		if (chars > size)
+			chars = size;
+		count -= chars;
+		read += chars;
+		size = PIPE_TAIL(*inode);
+		PIPE_TAIL(*inode) += chars;
+		PIPE_TAIL(*inode) &= (PAGE_SIZE-1);
+		while (chars-->0)
+			put_fs_byte(((char *)inode->i_size)[size++],buf++);
 	}
 	wake_up(&inode->i_wait);
-	return b-buf;
+	return read;
 }
 	
 int write_pipe(struct m_inode * inode, char * buf, int count)
 {
-	char * b=buf;
+	int chars, size, written = 0;
 
-	wake_up(&inode->i_wait);
-	if (inode->i_count != 2) { /* no readers */
-		current->signal |= (1<<(SIGPIPE-1));
-		return -1;
-	}
-	while (count-->0) {
-		while (PIPE_FULL(*inode)) {
+	while (count>0) {
+		while (!(size=(PAGE_SIZE-1)-PIPE_SIZE(*inode))) {
 			wake_up(&inode->i_wait);
-			if (inode->i_count != 2) {
+			if (inode->i_count != 2) { /* no readers */
 				current->signal |= (1<<(SIGPIPE-1));
-				return b-buf;
+				return written?written:-1;
 			}
 			sleep_on(&inode->i_wait);
 		}
-		((char *)inode->i_size)[PIPE_HEAD(*inode)] = get_fs_byte(b++);
-		INC_PIPE( PIPE_HEAD(*inode) );
-		wake_up(&inode->i_wait);
+		chars = PAGE_SIZE-PIPE_HEAD(*inode);
+		if (chars > count)
+			chars = count;
+		if (chars > size)
+			chars = size;
+		count -= chars;
+		written += chars;
+		size = PIPE_HEAD(*inode);
+		PIPE_HEAD(*inode) += chars;
+		PIPE_HEAD(*inode) &= (PAGE_SIZE-1);
+		while (chars-->0)
+			((char *)inode->i_size)[size++]=get_fs_byte(buf++);
 	}
 	wake_up(&inode->i_wait);
-	return b-buf;
+	return written;
 }
 
 int sys_pipe(unsigned long * fildes)