All of lore.kernel.org
 help / color / mirror / Atom feed
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Chris Mason <clm@fb.com>, Qu Wenruo <wqu@suse.com>
Cc: Josef Bacik <josef@toxicpanda.com>,
	David Sterba <dsterba@suse.com>,
	linux-btrfs@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH] btrfs: clean up NULL checks in qgroup_unreserve_range()
Date: Fri, 23 Oct 2020 14:26:33 +0300	[thread overview]
Message-ID: <20201023112633.GE282278@mwanda> (raw)

Smatch complains that this code dereferences "entry" before checking
whether it's NULL on the next line.  Fortunately, rb_entry() will never
return NULL so it doesn't cause a problem.  We can clean up the NULL
checking a bit to silence the warning and make the code more clear.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
My patch does not change run-time, but it's possible that the original
code was buggy and I missed it.

 fs/btrfs/qgroup.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 580899bdb991..a7ae2f18f486 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -3417,24 +3417,20 @@ static int qgroup_unreserve_range(struct btrfs_inode *inode,
 {
 	struct rb_node *node;
 	struct rb_node *next;
-	struct ulist_node *entry = NULL;
+	struct ulist_node *entry;
 	int ret = 0;
 
 	node = reserved->range_changed.root.rb_node;
+	if (!node)
+		return 0;
 	while (node) {
 		entry = rb_entry(node, struct ulist_node, rb_node);
 		if (entry->val < start)
 			node = node->rb_right;
-		else if (entry)
-			node = node->rb_left;
 		else
-			break;
+			node = node->rb_left;
 	}
 
-	/* Empty changeset */
-	if (!entry)
-		return 0;
-
 	if (entry->val > start && rb_prev(&entry->rb_node))
 		entry = rb_entry(rb_prev(&entry->rb_node), struct ulist_node,
 				 rb_node);
-- 
2.28.0


WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Chris Mason <clm@fb.com>, Qu Wenruo <wqu@suse.com>
Cc: Josef Bacik <josef@toxicpanda.com>,
	David Sterba <dsterba@suse.com>,
	linux-btrfs@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [PATCH] btrfs: clean up NULL checks in qgroup_unreserve_range()
Date: Fri, 23 Oct 2020 11:26:33 +0000	[thread overview]
Message-ID: <20201023112633.GE282278@mwanda> (raw)

Smatch complains that this code dereferences "entry" before checking
whether it's NULL on the next line.  Fortunately, rb_entry() will never
return NULL so it doesn't cause a problem.  We can clean up the NULL
checking a bit to silence the warning and make the code more clear.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
My patch does not change run-time, but it's possible that the original
code was buggy and I missed it.

 fs/btrfs/qgroup.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 580899bdb991..a7ae2f18f486 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -3417,24 +3417,20 @@ static int qgroup_unreserve_range(struct btrfs_inode *inode,
 {
 	struct rb_node *node;
 	struct rb_node *next;
-	struct ulist_node *entry = NULL;
+	struct ulist_node *entry;
 	int ret = 0;
 
 	node = reserved->range_changed.root.rb_node;
+	if (!node)
+		return 0;
 	while (node) {
 		entry = rb_entry(node, struct ulist_node, rb_node);
 		if (entry->val < start)
 			node = node->rb_right;
-		else if (entry)
-			node = node->rb_left;
 		else
-			break;
+			node = node->rb_left;
 	}
 
-	/* Empty changeset */
-	if (!entry)
-		return 0;
-
 	if (entry->val > start && rb_prev(&entry->rb_node))
 		entry = rb_entry(rb_prev(&entry->rb_node), struct ulist_node,
 				 rb_node);
-- 
2.28.0

             reply	other threads:[~2020-10-23 11:26 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-23 11:26 Dan Carpenter [this message]
2020-10-23 11:26 ` [PATCH] btrfs: clean up NULL checks in qgroup_unreserve_range() Dan Carpenter
2020-10-23 11:39 ` Qu Wenruo
2020-10-23 11:39   ` Qu Wenruo
2020-10-29 20:51 ` David Sterba
2020-10-29 20:51   ` David Sterba

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201023112633.GE282278@mwanda \
    --to=dan.carpenter@oracle.com \
    --cc=clm@fb.com \
    --cc=dsterba@suse.com \
    --cc=josef@toxicpanda.com \
    --cc=kernel-janitors@vger.kernel.org \
    --cc=linux-btrfs@vger.kernel.org \
    --cc=wqu@suse.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.