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Commit 1b49c556 authored by Jeff Layton's avatar Jeff Layton Committed by Steve French
Browse files

cifs: protect GlobalOplock_Q with its own spinlock 



Right now, the GlobalOplock_Q is protected by the GlobalMid_Lock. That
lock is also used for completely unrelated purposes (mostly for managing
the global mid queue). Give the list its own dedicated spinlock
(cifs_oplock_lock) and rename the list to cifs_oplock_list to
eliminate the camel-case.

Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarSteve French <sfrench@us.ibm.com>
parent 8e047d09

fs/cifs/cifsfs.c

+7 −6
Original line number Diff line number Diff line
@@ -986,19 +986,19 @@ static int cifs_oplock_thread(void *dummyarg) 
		if (try_to_freeze())

			continue;



		spin_lock(&GlobalMid_Lock);

		if (list_empty(&GlobalOplock_Q)) {

			spin_unlock(&GlobalMid_Lock);

		spin_lock(&cifs_oplock_lock);

		if (list_empty(&cifs_oplock_list)) {

			spin_unlock(&cifs_oplock_lock);

			set_current_state(TASK_INTERRUPTIBLE);

			schedule_timeout(39*HZ);

		} else {

			oplock_item = list_entry(GlobalOplock_Q.next,

			oplock_item = list_entry(cifs_oplock_list.next,

						struct oplock_q_entry, qhead);

			cFYI(1, ("found oplock item to write out"));

			pTcon = oplock_item->tcon;

			inode = oplock_item->pinode;

			netfid = oplock_item->netfid;

			spin_unlock(&GlobalMid_Lock);

			spin_unlock(&cifs_oplock_lock);

			DeleteOplockQEntry(oplock_item);

			/* can not grab inode sem here since it would

				deadlock when oplock received on delete
@@ -1055,7 +1055,7 @@ init_cifs(void) 
	int rc = 0;

	cifs_proc_init();

	INIT_LIST_HEAD(&cifs_tcp_ses_list);

	INIT_LIST_HEAD(&GlobalOplock_Q);

	INIT_LIST_HEAD(&cifs_oplock_list);

#ifdef CONFIG_CIFS_EXPERIMENTAL

	INIT_LIST_HEAD(&GlobalDnotifyReqList);

	INIT_LIST_HEAD(&GlobalDnotifyRsp_Q);
@@ -1084,6 +1084,7 @@ init_cifs(void) 
	rwlock_init(&GlobalSMBSeslock);

	rwlock_init(&cifs_tcp_ses_lock);

	spin_lock_init(&GlobalMid_Lock);

	spin_lock_init(&cifs_oplock_lock);



	if (cifs_max_pending < 2) {

		cifs_max_pending = 2;

fs/cifs/cifsglob.h

+5 −1
Original line number Diff line number Diff line
@@ -656,7 +656,11 @@ GLOBAL_EXTERN rwlock_t cifs_tcp_ses_lock; 
 */

GLOBAL_EXTERN rwlock_t GlobalSMBSeslock;



GLOBAL_EXTERN struct list_head GlobalOplock_Q;

/* Global list of oplocks */

GLOBAL_EXTERN struct list_head cifs_oplock_list;



/* Protects the cifs_oplock_list */

GLOBAL_EXTERN spinlock_t cifs_oplock_lock;



/* Outstanding dir notify requests */

GLOBAL_EXTERN struct list_head GlobalDnotifyReqList;

fs/cifs/transport.c

+8 −9
Original line number Diff line number Diff line
@@ -119,20 +119,19 @@ AllocOplockQEntry(struct inode *pinode, __u16 fid, struct cifsTconInfo *tcon) 
		temp->pinode = pinode;

		temp->tcon = tcon;

		temp->netfid = fid;

		spin_lock(&GlobalMid_Lock);

		list_add_tail(&temp->qhead, &GlobalOplock_Q);

		spin_unlock(&GlobalMid_Lock);

		spin_lock(&cifs_oplock_lock);

		list_add_tail(&temp->qhead, &cifs_oplock_list);

		spin_unlock(&cifs_oplock_lock);

	}

	return temp;



}



void DeleteOplockQEntry(struct oplock_q_entry *oplockEntry)

{

	spin_lock(&GlobalMid_Lock);

	spin_lock(&cifs_oplock_lock);

    /* should we check if list empty first? */

	list_del(&oplockEntry->qhead);

	spin_unlock(&GlobalMid_Lock);

	spin_unlock(&cifs_oplock_lock);

	kmem_cache_free(cifs_oplock_cachep, oplockEntry);

}
@@ -144,14 +143,14 @@ void DeleteTconOplockQEntries(struct cifsTconInfo *tcon) 
	if (tcon == NULL)

		return;



	spin_lock(&GlobalMid_Lock);

	list_for_each_entry(temp, &GlobalOplock_Q, qhead) {

	spin_lock(&cifs_oplock_lock);

	list_for_each_entry(temp, &cifs_oplock_list, qhead) {

		if ((temp->tcon) && (temp->tcon == tcon)) {

			list_del(&temp->qhead);

			kmem_cache_free(cifs_oplock_cachep, temp);

		}

	}

	spin_unlock(&GlobalMid_Lock);

	spin_unlock(&cifs_oplock_lock);

}



static int