[PATCH v2 2/4] fs/ceph: add helper function ceph_cap_is_removed()

[Max Kellermann <max.kellermann@ionos.com>]

Having it as a wrapper allows replacing the implementation, which the
next patch will do.

Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
---
 fs/ceph/caps.c       |  6 ++----
 fs/ceph/mds_client.c |  2 +-
 fs/ceph/super.h      | 14 ++++++++++++++
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index c1213d72645e..f6f3e817b712 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1128,8 +1128,7 @@ static void __ceph_remove_cap(struct ceph_cap *cap, bool queue_release)
 	struct ceph_mds_client *mdsc;
 	int removed = 0;
 
-	/* 'ci' being NULL means the remove have already occurred */
-	if (!ci) {
+	if (ceph_cap_is_removed(cap)) {
 		doutc(cl, "inode is NULL\n");
 		return;
 	}
@@ -1201,8 +1200,7 @@ void ceph_remove_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
 	struct ceph_inode_info *ci = cap->ci;
 	struct ceph_fs_client *fsc;
 
-	/* 'ci' being NULL means the remove have already occurred */
-	if (!ci) {
+	if (ceph_cap_is_removed(cap)) {
 		doutc(mdsc->fsc->client, "inode is NULL\n");
 		return;
 	}
diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 853bf698b356..019f5e60ff82 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -1902,7 +1902,7 @@ int ceph_iterate_session_caps(struct ceph_mds_session *session,
 
 		spin_lock(&session->s_cap_lock);
 		p = p->next;
-		if (!cap->ci) {
+		if (ceph_cap_is_removed(cap)) {
 			doutc(cl, "finishing cap %p removal\n", cap);
 			BUG_ON(cap->session != session);
 			cap->session = NULL;
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index b878f14ca959..628d153601a5 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -1269,6 +1269,20 @@ extern void ceph_add_cap(struct inode *inode,
 			 unsigned issued, unsigned wanted,
 			 unsigned cap, unsigned seq, u64 realmino, int flags,
 			 struct ceph_cap **new_cap);
+
+/**
+ * Determine whether __ceph_remove_cap() has been called on this #cap
+ * (but the object has not yet been freed because it is protected by
+ * `ceph_mds_session.s_cap_iterator`).
+ *
+ * Caller must lock either `ceph_inode_info.i_ceph_lock` or
+ * `ceph_mds_session.s_cap_lock`.
+ */
+static inline bool ceph_cap_is_removed(const struct ceph_cap *cap)
+{
+	return !cap->ci;
+}
+
 extern void ceph_remove_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
 			    bool queue_release);
 extern void __ceph_remove_caps(struct ceph_inode_info *ci);
-- 
2.47.3