From: Shyam Prasad N <sprasad@xxxxxxxxxxxxx>
parse_server_interfaces should be in complete charge of maintaining
the iface_list linked list. Today, iface entries are removed
from the list only when the last refcount is dropped.
i.e. in release_iface. However, this can result in undercounting
of refcount if the server stops advertising interfaces (which
Azure SMB server does).
This change puts parse_server_interfaces in full charge of
maintaining the iface_list. So if an empty list is returned
by the server, the entries in the list will immediately be
removed. This way, a following call to the same function will
not find entries in the list.
Fixes: aa45dadd34e4 ("cifs: change iface_list from array to sorted linked list")
Signed-off-by: Shyam Prasad N <sprasad@xxxxxxxxxxxxx>
---
fs/smb/client/cifsglob.h | 1 -
fs/smb/client/smb2ops.c | 27 +++++++++++++++++----------
2 files changed, 17 insertions(+), 11 deletions(-)
diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index ba80c854c9ca..f840756e0169 100644
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -1014,7 +1014,6 @@ release_iface(struct kref *ref)
struct cifs_server_iface *iface = container_of(ref,
struct cifs_server_iface,
refcount);
- list_del_init(&iface->iface_head);
kfree(iface);
}
diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
index 104c58df0368..b813485c0e86 100644
--- a/fs/smb/client/smb2ops.c
+++ b/fs/smb/client/smb2ops.c
@@ -595,16 +595,12 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf,
}
/*
- * Go through iface_list and do kref_put to remove
- * any unused ifaces. ifaces in use will be removed
- * when the last user calls a kref_put on it
+ * Go through iface_list and mark them as inactive
*/
list_for_each_entry_safe(iface, niface, &ses->iface_list,
- iface_head) {
+ iface_head)
iface->is_active = 0;
- kref_put(&iface->refcount, release_iface);
- ses->iface_count--;
- }
+
spin_unlock(&ses->iface_lock);
/*
@@ -678,10 +674,7 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf,
iface_head) {
ret = iface_cmp(iface, &tmp_iface);
if (!ret) {
- /* just get a ref so that it doesn't get picked/freed */
iface->is_active = 1;
- kref_get(&iface->refcount);
- ses->iface_count++;
spin_unlock(&ses->iface_lock);
goto next_iface;
} else if (ret < 0) {
@@ -748,6 +741,20 @@ parse_server_interfaces(struct network_interface_info_ioctl_rsp *buf,
}
out:
+ /*
+ * Go through the list again and put the inactive entries
+ */
+ spin_lock(&ses->iface_lock);
+ list_for_each_entry_safe(iface, niface, &ses->iface_list,
+ iface_head) {
+ if (!iface->is_active) {
+ list_del(&iface->iface_head);
+ kref_put(&iface->refcount, release_iface);
+ ses->iface_count--;
+ }
+ }
+ spin_unlock(&ses->iface_lock);
+
return rc;
}
--
2.34.1
