demos/janitorings/is_power_of_2.cocci

   1 // From: vignesh babu <vignesh.babu@wipro.com>
   2 // Subject: [KJ] [PATCH]is_power_of_2-ntfs
   3 // To: aia21@cantab.net
   4 // Cc: linux-ntfs-dev@lists.sourceforge.net,
   5 //         Kernel Janitors List <kernel-janitors@lists.osdl.org>,
   6 //         linux-kernel <linux-kernel@vger.kernel.org>
   7 // Date: Thu, 14 Jun 2007 13:39:04 +0530
   8 // Organization: WIPRO Technologies
   9 // Reply-To: vignesh.babu@wipro.com
  10 //
  11 //
  12 // Replacing (n & (n-1)) in the context of power of 2 checks
  13 // with is_power_of_2
  14 //
  15 // Signed-off-by: vignesh babu <vignesh.babu@wipro.com>
  16 // ---
  17 // diff --git a/fs/ntfs/inode.c b/fs/ntfs/inode.c
  18 // index b532a73..8152f79 100644
  19 // --- a/fs/ntfs/inode.c
  20 // +++ b/fs/ntfs/inode.c
  21 // @@ -27,6 +27,7 @@
  22 //  #include <linux/pagemap.h>
  23 //  #include <linux/quotaops.h>
  24 //  #include <linux/slab.h>
  25 // +#include <linux/log2.h>
  26 //
  27 //  #include "aops.h"
  28 //  #include "attrib.h"
  29 // @@ -1574,7 +1575,7 @@ static int ntfs_read_locked_index_inode(struct inode *base_vi, struct inode *vi)
  30 //      ntfs_debug("Index collation rule is 0x%x.",
  31 //                      le32_to_cpu(ir->collation_rule));
  32 //      ni->itype.index.block_size = le32_to_cpu(ir->index_block_size);
  33 // -    if (ni->itype.index.block_size & (ni->itype.index.block_size - 1)) {
  34 // +    if (!is_power_of_2(ni->itype.index.block_size)) {
  35 //              ntfs_error(vi->i_sb, "Index block size (%u) is not a power of "
  36 //                              "two.", ni->itype.index.block_size);
  37
  38
  39 // how deal with extra '()'
  40
  41 // -            while ((big_pow2 & (big_pow2 - 1)) != 0)
  42 // +            while (!is_power_of_2(big_pow2))
  43 //
  44 //
  45 // -    if (ubi->min_io_size == 0 ||
  46 // -        (ubi->min_io_size & (ubi->min_io_size - 1))) {
  47 // +    if (!is_power_of_2(ubi->min_io_size)) {
  48 //
  49 // -            if ((arg & (arg-1)) != 0 || arg < 1) {
  50 // +            if (!is_power_of_2(arg)) {
  51 //
  52 //
  53 // // do something general for those != 0 ? always redundant ?
  54 // -    if (bsize < 512 || bsize > 4096 || (bsize & (bsize - 1)) != 0)
  55 // +    if (bsize < 512 || bsize > 4096 || !is_power_of_2(bsize))
  56 //
  57 // -            if (!bits || (bits & (bits - 1)))
  58 // +            if (!is_power_of_2(bits))
  59 //
  60 //
  61 // -    J_ASSERT ((hash_size & (hash_size-1)) == 0);
  62 // +    J_ASSERT (is_power_of_2(hash_size));
  63 //
  64 // -            if ((new_size & (new_size - 1)) != 0) {
  65 // +            if (!is_power_of_2(new_size)){
  66 //
  67 //  #include "xfs_quota.h"
  68 //  #include "xfs_acl.h"
  69 //
  70 // +#include <linux/log2.h>
  71 //
  72 //
  73 // -    return !(size % (PAGE_SIZE >> 9) || (size & (size - 1)) ||
  74 // +    return !(size % (PAGE_SIZE >> 9) || !is_power_of_2(size) ||
  75
  76
  77
  78 // script found on KJ:
  79 // grep -e "([^\(\)]+) ?\& ?\(\1 ?- ?1\)"
  80
  81
  82 @ rule1 @
  83 expression n;
  84 @@
  85
  86 - n & (n-1)
  87 + !is_power_of_2(n)
  88
  89 @ rule2 depends on rule1 @
  90 @@
  91
  92   #include <linux/...>
  93 + #include <linux/log2.h>