linux-kernel - [PATCH 2/2] ceph: replace usage of found with dedicated list iterator variable

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Date:   Thu, 31 Mar 2022 23:53:29 +0200
From:   Jakob Koschel <jakobkoschel@...il.com>
To:     Jeff Layton <jlayton@...nel.org>
Cc:     Ilya Dryomov <idryomov@...il.com>, ceph-devel@...r.kernel.org,
        linux-kernel@...r.kernel.org, Mike Rapoport <rppt@...nel.org>,
        "Brian Johannesmeyer" <bjohannesmeyer@...il.com>,
        Cristiano Giuffrida <c.giuffrida@...nl>,
        "Bos, H.J." <h.j.bos@...nl>, Jakob Koschel <jakobkoschel@...il.com>
Subject: [PATCH 2/2] ceph: replace usage of found with dedicated list iterator variable

To move the list iterator variable into the list_for_each_entry_*()
macro in the future it should be avoided to use the list iterator
variable after the loop body.

To *never* use the list iterator variable after the loop it was
concluded to use a separate iterator variable instead of a
found boolean [1].

This removes the need to use a found variable and simply checking if
the variable was set, can determine if the break/goto was hit.

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1]
Signed-off-by: Jakob Koschel <jakobkoschel@...il.com>
---
 fs/ceph/caps.c | 32 +++++++++++++++-----------------
 1 file changed, 15 insertions(+), 17 deletions(-)

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 519750bc5a1a..70f9c5ffa9b7 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -3179,10 +3179,9 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
 				struct ceph_snap_context *snapc)
 {
 	struct inode *inode = &ci->vfs_inode;
-	struct ceph_cap_snap *capsnap = NULL;
+	struct ceph_cap_snap *capsnap = NULL, *iter;
 	int put = 0;
 	bool last = false;
-	bool found = false;
 	bool flush_snaps = false;
 	bool complete_capsnap = false;
 
@@ -3209,14 +3208,14 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
 		     ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
 		     last ? " LAST" : "");
 	} else {
-		list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
-			if (capsnap->context == snapc) {
-				found = true;
+		list_for_each_entry(iter, &ci->i_cap_snaps, ci_item) {
+			if (iter->context == snapc) {
+				capsnap = iter;
 				break;
 			}
 		}
 
-		if (!found) {
+		if (!capsnap) {
 			/*
 			 * The capsnap should already be removed when removing
 			 * auth cap in the case of a forced unmount.
@@ -3766,8 +3765,7 @@ static void handle_cap_flushsnap_ack(struct inode *inode, u64 flush_tid,
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
 	u64 follows = le64_to_cpu(m->snap_follows);
-	struct ceph_cap_snap *capsnap;
-	bool flushed = false;
+	struct ceph_cap_snap *capsnap = NULL, *iter;
 	bool wake_ci = false;
 	bool wake_mdsc = false;
 
@@ -3775,26 +3773,26 @@ static void handle_cap_flushsnap_ack(struct inode *inode, u64 flush_tid,
 	     inode, ci, session->s_mds, follows);
 
 	spin_lock(&ci->i_ceph_lock);
-	list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
-		if (capsnap->follows == follows) {
-			if (capsnap->cap_flush.tid != flush_tid) {
+	list_for_each_entry(iter, &ci->i_cap_snaps, ci_item) {
+		if (iter->follows == follows) {
+			if (iter->cap_flush.tid != flush_tid) {
 				dout(" cap_snap %p follows %lld tid %lld !="
-				     " %lld\n", capsnap, follows,
-				     flush_tid, capsnap->cap_flush.tid);
+				     " %lld\n", iter, follows,
+				     flush_tid, iter->cap_flush.tid);
 				break;
 			}
-			flushed = true;
+			capsnap = iter;
 			break;
 		} else {
 			dout(" skipping cap_snap %p follows %lld\n",
-			     capsnap, capsnap->follows);
+			     iter, iter->follows);
 		}
 	}
-	if (flushed)
+	if (capsnap)
 		ceph_remove_capsnap(inode, capsnap, &wake_ci, &wake_mdsc);
 	spin_unlock(&ci->i_ceph_lock);
 
-	if (flushed) {
+	if (capsnap) {
 		ceph_put_snap_context(capsnap->context);
 		ceph_put_cap_snap(capsnap);
 		if (wake_ci)
-- 
2.25.1