[LTP] [PATCH 1/3] libswap: add two method to create swapfile

[Li Wang]

This introduces new functionality to the libswap library by adding
two methods for creating a swapfile: SWAPFILE_BY_SIZE and SWAPFILE_BY_BLOCKS.
The make_swapfile function is updated to accept an additional enum
swapfile_method parameter to specify the creation method.

Two macros, MAKE_SWAPFILE_SIZE and MAKE_SWAPFILE_BLKS, are defined
to simplify the interface for creating swapfiles by size and by
blocks respectively.
---
 include/libswap.h         | 16 ++++++++++++++--
 libs/libltpswap/libswap.c | 30 ++++++++++++++++++++++--------
 2 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/include/libswap.h b/include/libswap.h
index 8c75e20ae..1dee907f0 100644
--- a/include/libswap.h
+++ b/include/libswap.h
@@ -11,10 +11,22 @@
 #ifndef __LIBSWAP_H__
 #define __LIBSWAP_H__
 
+enum swapfile_method {
+    SWAPFILE_BY_SIZE,
+    SWAPFILE_BY_BLOCKS
+};
+
 /*
- * Make a swap file
+ * Create a swapfile of a specified size or number of blocks.
  */
-int make_swapfile(const char *swapfile, int blocks, int safe);
+int make_swapfile(const char *swapfile, unsigned int num,
+			int safe, enum swapfile_method method);
+
+#define MAKE_SWAPFILE_SIZE(swapfile, size, safe) \
+    make_swapfile(swapfile, size, safe, SWAPFILE_BY_SIZE)
+
+#define MAKE_SWAPFILE_BLKS(swapfile, blocks, safe) \
+    make_swapfile(swapfile, blocks, safe, SWAPFILE_BY_BLOCKS)
 
 /*
  * Check swapon/swapoff support status of filesystems or files
diff --git a/libs/libltpswap/libswap.c b/libs/libltpswap/libswap.c
index a26ea25e4..6a0f24ed2 100644
--- a/libs/libltpswap/libswap.c
+++ b/libs/libltpswap/libswap.c
@@ -133,23 +133,37 @@ out:
 	return contiguous;
 }
 
-int make_swapfile(const char *swapfile, int blocks, int safe)
+int make_swapfile(const char *swapfile, unsigned int num, int safe, enum swapfile_method method)
 {
 	struct statvfs fs_info;
 	unsigned long blk_size, bs;
 	size_t pg_size = sysconf(_SC_PAGESIZE);
 	char mnt_path[100];
+	unsigned int blocks;
 
 	if (statvfs(".", &fs_info) == -1)
 		return -1;
 
 	blk_size = fs_info.f_bsize;
 
-	/* To guarantee at least one page can be swapped out */
-	if (blk_size * blocks < pg_size)
-		bs = pg_size;
-	else
-		bs = blk_size;
+	switch (method) {
+	case SWAPFILE_BY_BLOCKS:
+		blocks = num;
+		if (blk_size * blocks < pg_size)
+			bs = pg_size;
+		else
+			bs = blk_size;
+	break;
+	case SWAPFILE_BY_SIZE:
+		if (num * 1024 * 1024 < pg_size)
+			bs = pg_size;
+		else
+			bs = blk_size;
+		blocks = (num * 1024 * 1024) / blk_size;
+	break;
+	default:
+		return -1;
+	}
 
 	if (sscanf(swapfile, "%[^/]", mnt_path) != 1)
 		tst_brk(TBROK, "sscanf failed");
@@ -175,13 +189,13 @@ int make_swapfile(const char *swapfile, int blocks, int safe)
 	argv[2] = NULL;
 
 	return tst_cmd(argv, "/dev/null", "/dev/null", safe ?
-				   TST_CMD_PASS_RETVAL | TST_CMD_TCONF_ON_MISSING : 0);
+			TST_CMD_PASS_RETVAL | TST_CMD_TCONF_ON_MISSING : 0);
 }
 
 bool is_swap_supported(const char *filename)
 {
 	int i, sw_support = 0;
-	int ret = make_swapfile(filename, 10, 1);
+	int ret = MAKE_SWAPFILE_BLKS(filename, 10, 1);
 	int fi_contiguous = file_is_contiguous(filename);
 	long fs_type = tst_fs_type(filename);
 	const char *fstype = tst_fs_type_name(fs_type);
-- 
2.40.1