[PATCH 3/6 linux-next] ext4: create EXT4_MAX_BLOCKS() macro

[Fabian Frederick]

Create a macro to calculate length + offset -> maximum blocks
This adds more readability.

Signed-off-by: Fabian Frederick <f...@skynet.be>
---
 fs/ext4/ext4.h    |  3 +++
 fs/ext4/extents.c | 15 +++------------
 fs/ext4/file.c    |  3 +--
 3 files changed, 7 insertions(+), 14 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index ea31931..6e98f3f 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -262,6 +262,9 @@ struct ext4_io_submit {
                                 (s)->s_first_ino)
 #endif
 #define EXT4_BLOCK_ALIGN(size, blkbits)                ALIGN((size), (1 << 
(blkbits)))
+#define EXT4_MAX_BLOCKS(size, offset, blkbits) \
+       ((EXT4_BLOCK_ALIGN(size + offset, blkbits) >> blkbits) - (offset >> \
+                                                                 blkbits))
 
 /* Translate a block number to a cluster number */
 #define EXT4_B2C(sbi, blk)     ((blk) >> (sbi)->s_cluster_bits)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 4f1cca8..ac54907 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4960,13 +4960,8 @@ long ext4_fallocate(struct file *file, int mode, loff_t 
offset, loff_t len)
 
        trace_ext4_fallocate_enter(inode, offset, len, mode);
        lblk = offset >> blkbits;
-       /*
-        * We can't just convert len to max_blocks because
-        * If blocksize = 4096 offset = 3072 and len = 2048
-        */
-       max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
-               - lblk;
 
+       max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
        flags = EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT;
        if (mode & FALLOC_FL_KEEP_SIZE)
                flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
@@ -5029,12 +5024,8 @@ int ext4_convert_unwritten_extents(handle_t *handle, 
struct inode *inode,
        unsigned int credits, blkbits = inode->i_blkbits;
 
        map.m_lblk = offset >> blkbits;
-       /*
-        * We can't just convert len to max_blocks because
-        * If blocksize = 4096 offset = 3072 and len = 2048
-        */
-       max_blocks = ((EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits) -
-                     map.m_lblk);
+       max_blocks = EXT4_MAX_BLOCKS(len, offset, blkbits);
+
        /*
         * This is somewhat ugly but the idea is clear: When transaction is
         * reserved, everything goes into it. Otherwise we rather start several
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 261ac37..34acda7 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -144,8 +144,7 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter 
*from)
                        int err, len;
 
                        map.m_lblk = pos >> blkbits;
-                       map.m_len = (EXT4_BLOCK_ALIGN(pos + length, blkbits) >> 
blkbits)
-                               - map.m_lblk;
+                       map.m_len = EXT4_MAX_BLOCKS(length, pos, blkbits);
                        len = map.m_len;
 
                        err = ext4_map_blocks(NULL, inode, &map, 0);
-- 
2.8.1