CIFS: Do not kmalloc under the flocks spinlock
Reorganize the code to make the memory already allocated before
spinlock'ed loop.
Cc: stable@vger.kernel.org
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 4dd9283..5e64748 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -920,16 +920,26 @@
for (lockp = &inode->i_flock; *lockp != NULL; \
lockp = &(*lockp)->fl_next)
+struct lock_to_push {
+ struct list_head llist;
+ __u64 offset;
+ __u64 length;
+ __u32 pid;
+ __u16 netfid;
+ __u8 type;
+};
+
static int
cifs_push_posix_locks(struct cifsFileInfo *cfile)
{
struct cifsInodeInfo *cinode = CIFS_I(cfile->dentry->d_inode);
struct cifs_tcon *tcon = tlink_tcon(cfile->tlink);
struct file_lock *flock, **before;
- struct cifsLockInfo *lck, *tmp;
+ unsigned int count = 0, i = 0;
int rc = 0, xid, type;
+ struct list_head locks_to_send, *el;
+ struct lock_to_push *lck, *tmp;
__u64 length;
- struct list_head locks_to_send;
xid = GetXid();
@@ -940,29 +950,55 @@
return rc;
}
- INIT_LIST_HEAD(&locks_to_send);
-
lock_flocks();
cifs_for_each_lock(cfile->dentry->d_inode, before) {
+ if ((*before)->fl_flags & FL_POSIX)
+ count++;
+ }
+ unlock_flocks();
+
+ INIT_LIST_HEAD(&locks_to_send);
+
+ /*
+ * Allocating count locks is enough because no locks can be added to
+ * the list while we are holding cinode->lock_mutex that protects
+ * locking operations of this inode.
+ */
+ for (; i < count; i++) {
+ lck = kmalloc(sizeof(struct lock_to_push), GFP_KERNEL);
+ if (!lck) {
+ rc = -ENOMEM;
+ goto err_out;
+ }
+ list_add_tail(&lck->llist, &locks_to_send);
+ }
+
+ i = 0;
+ el = locks_to_send.next;
+ lock_flocks();
+ cifs_for_each_lock(cfile->dentry->d_inode, before) {
+ if (el == &locks_to_send) {
+ /* something is really wrong */
+ cERROR(1, "Can't push all brlocks!");
+ break;
+ }
flock = *before;
+ if ((flock->fl_flags & FL_POSIX) == 0)
+ continue;
length = 1 + flock->fl_end - flock->fl_start;
if (flock->fl_type == F_RDLCK || flock->fl_type == F_SHLCK)
type = CIFS_RDLCK;
else
type = CIFS_WRLCK;
-
- lck = cifs_lock_init(flock->fl_start, length, type,
- cfile->netfid);
- if (!lck) {
- rc = -ENOMEM;
- goto send_locks;
- }
+ lck = list_entry(el, struct lock_to_push, llist);
lck->pid = flock->fl_pid;
-
- list_add_tail(&lck->llist, &locks_to_send);
+ lck->netfid = cfile->netfid;
+ lck->length = length;
+ lck->type = type;
+ lck->offset = flock->fl_start;
+ i++;
+ el = el->next;
}
-
-send_locks:
unlock_flocks();
list_for_each_entry_safe(lck, tmp, &locks_to_send, llist) {
@@ -979,11 +1015,18 @@
kfree(lck);
}
+out:
cinode->can_cache_brlcks = false;
mutex_unlock(&cinode->lock_mutex);
FreeXid(xid);
return rc;
+err_out:
+ list_for_each_entry_safe(lck, tmp, &locks_to_send, llist) {
+ list_del(&lck->llist);
+ kfree(lck);
+ }
+ goto out;
}
static int