Next record calucaltion can be reduced to a much more tivial ALIGN
operation as follows:
1. Splitting 5 into 2 + 3 we get
next = ((be16_to_cpu(rec->len) + 2 + 3) & ~3) - 2 (1)
2. Using ALIGN macro we reduce (1) to:
ALIGN(be16_to_cpu(rec->len) + 2, 4) - 2 (2)
3. Subsituting 'next' in original next record calucation we get:
(void *)&rec->data[ALIGN(be16_to_cpu(rec->len) + 2, 4) - 2] (3)
4. Converting array index to pointer arithmetic we convert (3) into:
(void *)rec + sizeof(*rec) +
ALIGN(be16_to_cpu(rec->len) + 2, 4) - 2 (4)
5. Subsituting sizeof(*rec) with its value, 6, and substracting 2,
in (4) we get:
(void *)rec + ALIGN(be16_to_cpu(rec->len) + 2, 4) + 4 (5)
6. Since ALIGN(X, 4) + 4 == ALIGN(X + 4, 4), (5) can be converted to:
(void *)rec + ALIGN(be16_to_cpu(rec->len) + 6, 4) (6)
5. Subsituting 6 in (6) to sizeof(*rec) we get:
(void *)rec + ALIGN(be16_to_cpu(rec->len) + sizeof(*rec), 4) (7)
Using expression (7) should make it more clear that next record is
located by adding full size of the current record (payload + auxiliary
data) aligned to 4 bytes, to the location of the current one. No
functional change intended.
Cc: Chris Healy <cphealy@gmail.com>
Cc: Kyle McMartin <kyle@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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