From 82e12fe9244ff653f703722a8937b595e10e71f4 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Tue, 16 Jun 2009 11:03:07 +1000 Subject: nfsd: don't take nfsd_mutex twice when setting number of threads. Currently when we write a number to 'threads' in nfsdfs, we take the nfsd_mutex, update the number of threads, then take the mutex again to read the number of threads. Mostly this isn't a big deal. However if we are write '0', and portmap happens to be dead, then we can get unpredictable behaviour. If the nfsd threads all got killed quickly and the last thread is waiting for portmap to respond, then the second time we take the mutex we will block waiting for the last thread. However if the nfsd threads didn't die quite that fast, then there will be no contention when we try to take the mutex again. Unpredictability isn't fun, and waiting for the last thread to exit is pointless, so avoid taking the lock twice. To achieve this, get nfsd_svc return a non-negative number of active threads when not returning a negative error. Signed-off-by: NeilBrown --- fs/nfsd/nfssvc.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'fs/nfsd/nfssvc.c') diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c index cbba4a935786..209eaa0885d1 100644 --- a/fs/nfsd/nfssvc.c +++ b/fs/nfsd/nfssvc.c @@ -413,6 +413,12 @@ nfsd_svc(unsigned short port, int nrservs) goto failure; error = svc_set_num_threads(nfsd_serv, NULL, nrservs); + if (error == 0) + /* We are holding a reference to nfsd_serv which + * we don't want to count in the return value, + * so subtract 1 + */ + error = nfsd_serv->sv_nrthreads - 1; failure: svc_destroy(nfsd_serv); /* Release server */ out: -- cgit v1.2.1