[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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