| Message ID | CADug+U6-=+_Xy41Lw3hnOqSR84Bo7MjKDL_PykiZVdUx=b8tAA@mail.gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Dec 26, 2012 at 05:09:07PM +0200, Andriy Skulysh wrote: > There is a race in enqueueing thread to a pool and > waking up a thread. > lockd doesn't wake up on reception of lock granted callback > if svc_wake_up() is called before lockd's thread is added > to a pool. > > Signed-off-by: Andriy Skulysh <Andriy_Skulysh@xyratex.com> > --- > include/linux/sunrpc/svc.h | 1 + > net/sunrpc/svc_xprt.c | 9 ++++++++- > 2 files changed, 9 insertions(+), 1 deletions(-) > > diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h > index 676ddf5..1f0216b 100644 > --- a/include/linux/sunrpc/svc.h > +++ b/include/linux/sunrpc/svc.h > @@ -50,6 +50,7 @@ struct svc_pool { > unsigned int sp_nrthreads; /* # of threads in pool */ > struct list_head sp_all_threads; /* all server threads */ > struct svc_pool_stats sp_stats; /* statistics on pool operation */ > + int sp_task_pending;/* has pending task */ > } ____cacheline_aligned_in_smp; > > /* > diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c > index b8e47fa..c7ab6f5 100644 > --- a/net/sunrpc/svc_xprt.c > +++ b/net/sunrpc/svc_xprt.c > @@ -499,7 +499,8 @@ void svc_wake_up(struct svc_serv *serv) > rqstp->rq_xprt = NULL; > */ > wake_up(&rqstp->rq_wait); > - } > + } else > + pool->sp_task_pending = 1; > spin_unlock_bh(&pool->sp_lock); > } > } > @@ -634,7 +635,13 @@ struct svc_xprt *svc_get_next_xprt(struct > svc_rqst *rqstp, long timeout) > * long for cache updates. > */ > rqstp->rq_chandle.thread_wait = 1*HZ; > + pool->sp_task_pending = 0; > } else { > + if (pool->sp_task_pending) { > + pool->sp_task_pending = 0; > + spin_unlock_bh(&pool->sp_lock); > + return -EAGAIN; That should be ERR_PTR(-EAGAIN). Other than this this looks right to me.... Out of curiosity: how did you run across this problem, and how did you test the fix? --b. > + } > /* No data pending. Go to sleep */ > svc_thread_enqueue(pool, rqstp); > > -- > 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h index 676ddf5..1f0216b 100644 --- a/include/linux/sunrpc/svc.h +++ b/include/linux/sunrpc/svc.h @@ -50,6 +50,7 @@ struct svc_pool { unsigned int sp_nrthreads; /* # of threads in pool */ struct list_head sp_all_threads; /* all server threads */ struct svc_pool_stats sp_stats; /* statistics on pool operation */ + int sp_task_pending;/* has pending task */ } ____cacheline_aligned_in_smp; /* diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index b8e47fa..c7ab6f5 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -499,7 +499,8 @@ void svc_wake_up(struct svc_serv *serv) rqstp->rq_xprt = NULL; */ wake_up(&rqstp->rq_wait); - } + } else + pool->sp_task_pending = 1; spin_unlock_bh(&pool->sp_lock); } } @@ -634,7 +635,13 @@ struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout) * long for cache updates. */ rqstp->rq_chandle.thread_wait = 1*HZ; + pool->sp_task_pending = 0; } else { + if (pool->sp_task_pending) { + pool->sp_task_pending = 0; + spin_unlock_bh(&pool->sp_lock); + return -EAGAIN; + } /* No data pending. Go to sleep */ svc_thread_enqueue(pool, rqstp);
There is a race in enqueueing thread to a pool and waking up a thread. lockd doesn't wake up on reception of lock granted callback if svc_wake_up() is called before lockd's thread is added to a pool. Signed-off-by: Andriy Skulysh <Andriy_Skulysh@xyratex.com> --- include/linux/sunrpc/svc.h | 1 + net/sunrpc/svc_xprt.c | 9 ++++++++- 2 files changed, 9 insertions(+), 1 deletions(-)