Commit d5751469 authored by Pavel Shilovsky's avatar Pavel Shilovsky Committed by Steve French
Browse files

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: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarPavel Shilovsky <piastry@etersoft.ru>
Signed-off-by: default avatarSteve French <sfrench@us.ibm.com>
parent b0f8ef20

fs/cifs/file.c

+56 −13
Original line number Diff line number Diff line
@@ -920,16 +920,26 @@ cifs_push_mandatory_locks(struct cifsFileInfo *cfile) 
	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 @@ cifs_push_posix_locks(struct cifsFileInfo *cfile) 
		return rc;

	}



	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 @@ cifs_push_posix_locks(struct cifsFileInfo *cfile) 
		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