Re: [PATCH 2/4] btrfs: Adjust 32 checks for null pointers

Timofey Titovets
2017-08-21T10:44:22Z

That's will work, but that's don't improve anything.

Reviewed-by: Timofey Titovets <nefelim4ag@gmail.com>

2017-08-20 23:18 GMT+03:00 SF Markus Elfring <elfring@users.sourceforge.net>:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Sun, 20 Aug 2017 21:36:31 +0200
> MIME-Version: 1.0
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: 8bit
>
> The script “checkpatch.pl” pointed information out like the following.
>
> Comparison to NULL could be written …
>
> Thus fix the affected source code places.
>
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
> fs/btrfs/ctree.c | 4 ++--
> fs/btrfs/extent-tree.c | 2 +-
> fs/btrfs/extent_io.c | 2 +-
> fs/btrfs/inode.c | 4 ++--
> fs/btrfs/lzo.c | 4 ++--
> fs/btrfs/qgroup.c | 6 +++---
> fs/btrfs/reada.c | 4 ++--
> fs/btrfs/scrub.c | 12 ++++++------
> fs/btrfs/transaction.c | 2 +-
> fs/btrfs/tree-log.c | 4 ++--
> fs/btrfs/volumes.c | 14 +++++++-------
> fs/btrfs/xattr.c | 2 +-
> fs/btrfs/zlib.c | 4 ++--
> 13 files changed, 32 insertions(+), 32 deletions(-)
>
> diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
> index 6d49db7d86be..b89c101ef45e 100644
> --- a/fs/btrfs/ctree.c
> +++ b/fs/btrfs/ctree.c
> @@ -2686,7 +2686,7 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
>
> lowest_level = p->lowest_level;
> WARN_ON(lowest_level && ins_len > 0);
> - WARN_ON(p->nodes[0] != NULL);
> + WARN_ON(p->nodes[0]);
> BUG_ON(!cow && ins_len);
>
> if (ins_len < 0) {
> @@ -2965,7 +2965,7 @@ int btrfs_search_old_slot(struct btrfs_root *root, const struct btrfs_key *key,
> int prev_cmp = -1;
>
> lowest_level = p->lowest_level;
> - WARN_ON(p->nodes[0] != NULL);
> + WARN_ON(p->nodes[0]);
>
> if (p->search_commit_root) {
> BUG_ON(time_seq);
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 116c5615d6c2..240dccf8d41c 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -9774,7 +9774,7 @@ void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
> block_group->iref = 0;
> block_group->inode = NULL;
> spin_unlock(&block_group->lock);
> - ASSERT(block_group->io_ctl.inode == NULL);
> + ASSERT(!block_group->io_ctl.inode);
> iput(inode);
> last = block_group->key.objectid + block_group->key.offset;
> btrfs_put_block_group(block_group);
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index ea4947c97505..7fd39a1ec7d6 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -4793,7 +4793,7 @@ struct extent_buffer *btrfs_clone_extent_buffer(struct extent_buffer *src)
> unsigned long num_pages = num_extent_pages(src->start, src->len);
>
> new = __alloc_extent_buffer(src->fs_info, src->start, src->len);
> - if (new == NULL)
> + if (!new)
> return NULL;
>
> for (i = 0; i < num_pages; i++) {
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 4cb399854f0e..508057ec2534 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -7599,7 +7599,7 @@ bool btrfs_page_exists_in_range(struct inode *inode, loff_t start, loff_t end)
> * found idx is less than or equal to the end idx then we know that
> * a page exists. If no pages are found or if those pages are
> * outside of the range then we're fine (yay!) */
> - while (page == NULL &&
> + while (!page &&
> radix_tree_gang_lookup_slot(root, &pagep, NULL, start_idx, 1)) {
> page = radix_tree_deref_slot(pagep);
> if (unlikely(!page))
> @@ -9588,7 +9588,7 @@ int btrfs_drop_inode(struct inode *inode)
> {
> struct btrfs_root *root = BTRFS_I(inode)->root;
>
> - if (root == NULL)
> + if (!root)
> return 1;
>
> /* the snap/subvol tree is on deleting */
> diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c
> index d433e75d489a..29452a0fec91 100644
> --- a/fs/btrfs/lzo.c
> +++ b/fs/btrfs/lzo.c
> @@ -125,7 +125,7 @@ static int lzo_compress_pages(struct list_head *ws,
> * the first 4 bytes
> */
> out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
> - if (out_page == NULL) {
> + if (!out_page) {
> ret = -ENOMEM;
> goto out;
> }
> @@ -195,7 +195,7 @@ static int lzo_compress_pages(struct list_head *ws,
> }
>
> out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
> - if (out_page == NULL) {
> + if (!out_page) {
> ret = -ENOMEM;
> goto out;
> }
> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
> index ddc37c537058..1a29f333f54c 100644
> --- a/fs/btrfs/qgroup.c
> +++ b/fs/btrfs/qgroup.c
> @@ -1468,7 +1468,7 @@ int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans,
> if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)
> || bytenr == 0 || num_bytes == 0)
> return 0;
> - if (WARN_ON(trans == NULL))
> + if (WARN_ON(!trans))
> return -EINVAL;
> record = kmalloc(sizeof(*record), gfp_flag);
> if (!record)
> @@ -1604,7 +1604,7 @@ int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
> struct btrfs_path *path = NULL;
>
> BUG_ON(root_level < 0 || root_level >= BTRFS_MAX_LEVEL);
> - BUG_ON(root_eb == NULL);
> + BUG_ON(!root_eb);
>
> if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
> return 0;
> @@ -1640,7 +1640,7 @@ int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
> walk_down:
> level = root_level;
> while (level >= 0) {
> - if (path->nodes[level] == NULL) {
> + if (!path->nodes[level]) {
> int parent_slot;
> u64 child_gen;
> u64 child_bytenr;
> diff --git a/fs/btrfs/reada.c b/fs/btrfs/reada.c
> index ab852b8e3e37..71b96c2dadbf 100644
> --- a/fs/btrfs/reada.c
> +++ b/fs/btrfs/reada.c
> @@ -445,7 +445,7 @@ static struct reada_extent *reada_find_extent(struct btrfs_fs_info *fs_info,
> if (ret) {
> while (--nzones >= 0) {
> dev = re->zones[nzones]->device;
> - BUG_ON(dev == NULL);
> + BUG_ON(!dev);
> /* ignore whether the entry was inserted */
> radix_tree_delete(&dev->reada_extents, index);
> }
> @@ -661,7 +661,7 @@ static int reada_start_machine_dev(struct btrfs_device *dev)
> int i;
>
> spin_lock(&fs_info->reada_lock);
> - if (dev->reada_curr_zone == NULL) {
> + if (!dev->reada_curr_zone) {
> ret = reada_pick_zone(dev);
> if (!ret) {
> spin_unlock(&fs_info->reada_lock);
> diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
> index f49b94ab3d2a..a36491587d13 100644
> --- a/fs/btrfs/scrub.c
> +++ b/fs/btrfs/scrub.c
> @@ -710,7 +710,7 @@ struct scrub_ctx *scrub_setup_ctx(struct btrfs_device *dev, int is_dev_replace)
> spin_lock_init(&sctx->stat_lock);
> init_waitqueue_head(&sctx->list_wait);
>
> - WARN_ON(sctx->wr_curr_bio != NULL);
> + WARN_ON(sctx->wr_curr_bio);
> mutex_init(&sctx->wr_lock);
> sctx->wr_curr_bio = NULL;
> if (is_dev_replace) {
> @@ -1730,7 +1730,7 @@ static void scrub_recheck_block(struct btrfs_fs_info *fs_info,
> struct bio *bio;
> struct scrub_page *page = sblock->pagev[page_num];
>
> - if (page->dev->bdev == NULL) {
> + if (!page->dev->bdev) {
> page->io_error = 1;
> sblock->no_io_error_seen = 0;
> continue;
> @@ -1812,8 +1812,8 @@ static int scrub_repair_page_from_good_copy(struct scrub_block *sblock_bad,
> struct scrub_page *page_good = sblock_good->pagev[page_num];
> struct btrfs_fs_info *fs_info = sblock_bad->sctx->fs_info;
>
> - BUG_ON(page_bad->page == NULL);
> - BUG_ON(page_good->page == NULL);
> + BUG_ON(!page_bad->page);
> + BUG_ON(!page_good->page);
> if (force_write || sblock_bad->header_error ||
> sblock_bad->checksum_error || page_bad->io_error) {
> struct bio *bio;
> @@ -1877,7 +1877,7 @@ static int scrub_write_page_to_dev_replace(struct scrub_block *sblock,
> {
> struct scrub_page *spage = sblock->pagev[page_num];
>
> - BUG_ON(spage->page == NULL);
> + BUG_ON(!spage->page);
> if (spage->io_error) {
> void *mapped_buffer = kmap_atomic(spage->page);
>
> @@ -4263,7 +4263,7 @@ int btrfs_scrub_cancel_dev(struct btrfs_fs_info *fs_info,
> while (dev->scrub_device) {
> mutex_unlock(&fs_info->scrub_lock);
> wait_event(fs_info->scrub_pause_wait,
> - dev->scrub_device == NULL);
> + !dev->scrub_device);
> mutex_lock(&fs_info->scrub_lock);
> }
> mutex_unlock(&fs_info->scrub_lock);
> diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
> index f615d59b0489..01d6c93caae6 100644
> --- a/fs/btrfs/transaction.c
> +++ b/fs/btrfs/transaction.c
> @@ -1508,7 +1508,7 @@ static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
> btrfs_ino(BTRFS_I(parent_inode)),
> dentry->d_name.name,
> dentry->d_name.len, 0);
> - if (dir_item != NULL && !IS_ERR(dir_item)) {
> + if (dir_item && !IS_ERR(dir_item)) {
> pending->error = -EEXIST;
> goto dir_item_existed;
> } else if (IS_ERR(dir_item)) {
> diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> index 3a11ae63676e..34692772cbcf 100644
> --- a/fs/btrfs/tree-log.c
> +++ b/fs/btrfs/tree-log.c
> @@ -1189,7 +1189,7 @@ static int extref_get_fields(struct extent_buffer *eb, int slot,
> return -EIO;
>
> *name = kmalloc(*namelen, GFP_NOFS);
> - if (*name == NULL)
> + if (!*name)
> return -ENOMEM;
>
> read_extent_buffer(eb, *name, (unsigned long)&extref->name,
> @@ -1216,7 +1216,7 @@ static int ref_get_fields(struct extent_buffer *eb, int slot,
> return -EIO;
>
> *name = kmalloc(*namelen, GFP_NOFS);
> - if (*name == NULL)
> + if (!*name)
> return -ENOMEM;
>
> read_extent_buffer(eb, *name, (unsigned long)(ref + 1), *namelen);
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index 12bd04a4104f..dfe54b5c6884 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -409,8 +409,8 @@ static noinline void run_scheduled_bios(struct btrfs_device *device)
> * device->running_pending is used to synchronize with the
> * schedule_bio code.
> */
> - if (device->pending_sync_bios.head == NULL &&
> - device->pending_bios.head == NULL) {
> + if (!device->pending_sync_bios.head &&
> + !device->pending_bios.head) {
> again = 0;
> device->running_pending = 0;
> } else {
> @@ -5439,7 +5439,7 @@ static int get_extra_mirror_from_replace(struct btrfs_fs_info *fs_info,
> ret = __btrfs_map_block(fs_info, BTRFS_MAP_GET_READ_MIRRORS,
> logical, &length, &bbio, 0, 0);
> if (ret) {
> - ASSERT(bbio == NULL);
> + ASSERT(!bbio);
> return ret;
> }
>
> @@ -5688,7 +5688,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
> btrfs_dev_replace_set_lock_blocking(dev_replace);
>
> if (dev_replace_is_ongoing && mirror_num == map->num_stripes + 1 &&
> - !need_full_stripe(op) && dev_replace->tgtdev != NULL) {
> + !need_full_stripe(op) && dev_replace->tgtdev) {
> ret = get_extra_mirror_from_replace(fs_info, logical, *length,
> dev_replace->srcdev->devid,
> &mirror_num,
> @@ -5804,7 +5804,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
> }
>
> num_alloc_stripes = num_stripes;
> - if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL) {
> + if (dev_replace_is_ongoing && dev_replace->tgtdev) {
> if (op == BTRFS_MAP_WRITE)
> num_alloc_stripes <<= 1;
> if (op == BTRFS_MAP_GET_READ_MIRRORS)
> @@ -5817,7 +5817,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
> ret = -ENOMEM;
> goto out;
> }
> - if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL)
> + if (dev_replace_is_ongoing && dev_replace->tgtdev)
> bbio->tgtdev_map = (int *)(bbio->stripes + num_alloc_stripes);
>
> /* build raid_map */
> @@ -5863,7 +5863,7 @@ static int __btrfs_map_block(struct btrfs_fs_info *fs_info,
> if (bbio->raid_map)
> sort_parity_stripes(bbio, num_stripes);
>
> - if (dev_replace_is_ongoing && dev_replace->tgtdev != NULL &&
> + if (dev_replace_is_ongoing && dev_replace->tgtdev &&
> need_full_stripe(op)) {
> handle_ops_on_dev_replace(op, &bbio, dev_replace, &num_stripes,
> &max_errors);
> diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
> index 2c7e53f9ff1b..0c0972aee7e8 100644
> --- a/fs/btrfs/xattr.c
> +++ b/fs/btrfs/xattr.c
> @@ -444,7 +444,7 @@ static int btrfs_initxattrs(struct inode *inode,
> char *name;
> int err = 0;
>
> - for (xattr = xattr_array; xattr->name != NULL; xattr++) {
> + for (xattr = xattr_array; xattr->name; xattr++) {
> name = kmalloc(XATTR_SECURITY_PREFIX_LEN +
> strlen(xattr->name) + 1, GFP_KERNEL);
> if (!name) {
> diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
> index c248f9286366..3bbe6904193a 100644
> --- a/fs/btrfs/zlib.c
> +++ b/fs/btrfs/zlib.c
> @@ -109,7 +109,7 @@ static int zlib_compress_pages(struct list_head *ws,
> data_in = kmap(in_page);
>
> out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
> - if (out_page == NULL) {
> + if (!out_page) {
> ret = -ENOMEM;
> goto out;
> }
> @@ -151,7 +151,7 @@ static int zlib_compress_pages(struct list_head *ws,
> goto out;
> }
> out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
> - if (out_page == NULL) {
> + if (!out_page) {
> ret = -ENOMEM;
> goto out;
> }
> --
> 2.14.0
>
> --
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--
Have a nice day,
Timofey.