test72: fix mock bdev functions

The minixfs library only ever submits vector elements (and reads) of
the system page size. The test implementation was expecting vector
elements (and reads) of the file system block size. The resulting
mismatch caused I/O to fail in various ways, even though this did not
have an effect on the actual test.

Change-Id: I02f4a3efcd4a32916435d82c7d5798e6b78f0a27

minix/tests/test72.c

@@ -116,35 +116,27 @@ static void allocate(int b)
 ssize_t
 bdev_gather(dev_t dev, u64_t pos, iovec_t *vec, int count, int flags)
 {
-	int i;
+	int i, block;
+	size_t size, block_off;
 	ssize_t tot = 0;
 	assert(dev == MYDEV);
 	assert(curblocksize > 0);
 	assert(!(pos % curblocksize));
 	for(i = 0; i < count; i++) {
-		int subpages, block, block_off;
 		char *data = (char *) vec[i].iov_addr;
-		assert(!(pos % curblocksize));
 		block = pos / curblocksize;
-		block_off = pos % curblocksize;
+		block_off = (size_t)(pos % curblocksize);
-		assert(!(vec[i].iov_size % PAGE_SIZE));
+		size = vec[i].iov_size;
-		subpages = vec[i].iov_size / PAGE_SIZE;
+		assert(size == PAGE_SIZE);
-		while(subpages > 0) {
 		assert(block >= 0);
 		assert(block < MAXBLOCKS);
-			assert(block_off >= 0);
+		assert(block_off + size <= curblocksize);
-			assert(block_off < curblocksize);
 		if(!writtenblocks[block]) {
 			allocate(block);
 		}
-			memcpy(data, writtenblocks[block] + block_off,
+		memcpy(data, writtenblocks[block] + block_off, size);
-				PAGE_SIZE);
+		pos += size;
-			block++;
+		tot += size;
-			subpages--;
-			data += PAGE_SIZE;
-			tot += PAGE_SIZE;
-			block_off += PAGE_SIZE;
-		}
 	}
 
 	return tot;
@@ -154,29 +146,26 @@ ssize_t
 bdev_scatter(dev_t dev, u64_t pos, iovec_t *vec, int count, int flags)
 {
 	int i, block;
+	size_t size, block_off;
 	ssize_t tot = 0;
 	assert(dev == MYDEV);
 	assert(curblocksize > 0);
 	assert(!(pos % curblocksize));
-	block = pos / curblocksize;
 	for(i = 0; i < count; i++) {
-		int subblocks;
 		char *data = (char *) vec[i].iov_addr;
-		assert(vec[i].iov_size > 0);
+		block = pos / curblocksize;
-		assert(!(vec[i].iov_size % PAGE_SIZE));
+		block_off = (size_t)(pos % curblocksize);
-		subblocks = vec[i].iov_size / curblocksize;
+		size = vec[i].iov_size;
-		while(subblocks > 0) {
+		assert(size == PAGE_SIZE);
 		assert(block >= 0);
 		assert(block < MAXBLOCKS);
+		assert(block_off + size <= curblocksize);
 		if(!writtenblocks[block]) {
 			allocate(block);
 		}
-			memcpy(writtenblocks[block], data, curblocksize);
+		memcpy(writtenblocks[block] + block_off, data, size);
-			block++;
+		pos += size;
-			subblocks--;
+		tot += size;
-			data += curblocksize;
-			tot += curblocksize;
-		}
 	}
 
 	return tot;
@@ -186,31 +175,23 @@ ssize_t
 bdev_read(dev_t dev, u64_t pos, char *data, size_t count, int flags)
 {
 	int block;
-	ssize_t tot = 0;
-	int subblocks;
 
 	assert(dev == MYDEV);
 	assert(curblocksize > 0);
 	assert(!(pos % curblocksize));
 	assert(count > 0);
 	assert(!(count % curblocksize));
+	assert(count == PAGE_SIZE);
+	assert(curblocksize == PAGE_SIZE);
 
 	block = pos / curblocksize;
-	subblocks = count / curblocksize;
-	while(subblocks > 0) {
 	assert(block >= 0);
 	assert(block < MAXBLOCKS);
 	if(!writtenblocks[block]) {
 		allocate(block);
 	}
 	memcpy(data, writtenblocks[block], curblocksize);
-		block++;
+	return count;
-		subblocks--;
-		data += curblocksize;
-		tot += curblocksize;
-	}
-
-	return tot;
 }
 
 /* Fake some libsys functions */