Btrfs: use linux/sizes.h to represent constants

We use many constants to represent size and offset value.  And to make
code readable we use '256 * 1024 * 1024' instead of '268435456' to
represent '256MB'.  However we can make far more readable with 'SZ_256MB'
which is defined in the 'linux/sizes.h'.

So this patch replaces 'xxx * 1024 * 1024' kind of expression with
single 'SZ_xxxMB' if 'xxx' is a power of 2 then 'xxx * SZ_1M' if 'xxx' is
not a power of 2. And I haven't touched to '4096' & '8192' because it's
more intuitive than 'SZ_4KB' & 'SZ_8KB'.

Signed-off-by: Byongho Lee <bhlee.kernel@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 3b39cd8..a379ff6 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -414,15 +414,15 @@
 	unsigned long nr_pages_ret = 0;
 	unsigned long total_compressed = 0;
 	unsigned long total_in = 0;
-	unsigned long max_compressed = 128 * 1024;
-	unsigned long max_uncompressed = 128 * 1024;
+	unsigned long max_compressed = SZ_128K;
+	unsigned long max_uncompressed = SZ_128K;
 	int i;
 	int will_compress;
 	int compress_type = root->fs_info->compress_type;
 	int redirty = 0;
 
 	/* if this is a small write inside eof, kick off a defrag */
-	if ((end - start + 1) < 16 * 1024 &&
+	if ((end - start + 1) < SZ_16K &&
 	    (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 		btrfs_add_inode_defrag(NULL, inode);
 
@@ -430,7 +430,7 @@
 again:
 	will_compress = 0;
 	nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
-	nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
+	nr_pages = min_t(unsigned long, nr_pages, SZ_128K / PAGE_CACHE_SIZE);
 
 	/*
 	 * we don't want to send crud past the end of i_size through
@@ -944,7 +944,7 @@
 	disk_num_bytes = num_bytes;
 
 	/* if this is a small write inside eof, kick off defrag */
-	if (num_bytes < 64 * 1024 &&
+	if (num_bytes < SZ_64K &&
 	    (start > 0 || end + 1 < BTRFS_I(inode)->disk_i_size))
 		btrfs_add_inode_defrag(NULL, inode);
 
@@ -1107,7 +1107,7 @@
 	 * atomic_sub_return implies a barrier for waitqueue_active
 	 */
 	if (atomic_sub_return(nr_pages, &root->fs_info->async_delalloc_pages) <
-	    5 * 1024 * 1024 &&
+	    5 * SZ_1M &&
 	    waitqueue_active(&root->fs_info->async_submit_wait))
 		wake_up(&root->fs_info->async_submit_wait);
 
@@ -1132,7 +1132,7 @@
 	struct btrfs_root *root = BTRFS_I(inode)->root;
 	unsigned long nr_pages;
 	u64 cur_end;
-	int limit = 10 * 1024 * 1024;
+	int limit = 10 * SZ_1M;
 
 	clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
 			 1, 0, NULL, GFP_NOFS);
@@ -1148,7 +1148,7 @@
 		    !btrfs_test_opt(root, FORCE_COMPRESS))
 			cur_end = end;
 		else
-			cur_end = min(end, start + 512 * 1024 - 1);
+			cur_end = min(end, start + SZ_512K - 1);
 
 		async_cow->end = cur_end;
 		INIT_LIST_HEAD(&async_cow->extents);
@@ -4348,7 +4348,7 @@
 	 * up a huge file in a single leaf.  Most of the time that
 	 * bytes_deleted is > 0, it will be huge by the time we get here
 	 */
-	if (be_nice && bytes_deleted > 32 * 1024 * 1024) {
+	if (be_nice && bytes_deleted > SZ_32M) {
 		if (btrfs_should_end_transaction(trans, root)) {
 			err = -EAGAIN;
 			goto error;
@@ -4591,7 +4591,7 @@
 
 	btrfs_free_path(path);
 
-	if (be_nice && bytes_deleted > 32 * 1024 * 1024) {
+	if (be_nice && bytes_deleted > SZ_32M) {
 		unsigned long updates = trans->delayed_ref_updates;
 		if (updates) {
 			trans->delayed_ref_updates = 0;
@@ -9757,7 +9757,7 @@
 			}
 		}
 
-		cur_bytes = min(num_bytes, 256ULL * 1024 * 1024);
+		cur_bytes = min_t(u64, num_bytes, SZ_256M);
 		cur_bytes = max(cur_bytes, min_size);
 		/*
 		 * If we are severely fragmented we could end up with really