[linux-cifs-client] [PATCH 1/5] cifs: protect GlobalOplock_Q with its own spinlock
Shirish Pargaonkar
shirishpargaonkar at gmail.com
Fri Aug 28 11:38:39 MDT 2009
On Tue, Aug 18, 2009 at 1:06 PM, Jeff Layton<jlayton at redhat.com> wrote:
> 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: Jeff Layton <jlayton at redhat.com>
> ---
> fs/cifs/cifsfs.c | 13 +++++++------
> fs/cifs/cifsglob.h | 6 +++++-
> fs/cifs/transport.c | 17 ++++++++---------
> 3 files changed, 20 insertions(+), 16 deletions(-)
>
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index b750aa5..3610e99 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -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;
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 6084d63..f100399 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -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;
> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> index 0ad3e2d..1da4ab2 100644
> --- a/fs/cifs/transport.c
> +++ b/fs/cifs/transport.c
> @@ -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
> --
> 1.6.0.6
>
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>
Acked-by: Shirish Pargaonkar <shirishpargaonkar at gmail.com>
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