diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-03-12 15:06:54 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-03-12 15:06:54 -0700 |
commit | ebc551f2b8f905eca0e25c476c1e5c098cd92103 (patch) | |
tree | 30438c51fc573494337b50267956d29cf77f72ff /net/sunrpc/svc_xprt.c | |
parent | a5adcfcad55d5f034b33f79f1a873229d1e77b24 (diff) | |
parent | f875a792abe933d0b4553ab6e29c624b58932e41 (diff) |
Merge tag 'nfsd-5.1' of git://linux-nfs.org/~bfields/linux
Pull NFS server updates from Bruce Fields:
"Miscellaneous NFS server fixes.
Probably the most visible bug is one that could artificially limit
NFSv4.1 performance by limiting the number of oustanding rpcs from a
single client.
Neil Brown also gets a special mention for fixing a 14.5-year-old
memory-corruption bug in the encoding of NFSv3 readdir responses"
* tag 'nfsd-5.1' of git://linux-nfs.org/~bfields/linux:
nfsd: allow nfsv3 readdir request to be larger.
nfsd: fix wrong check in write_v4_end_grace()
nfsd: fix memory corruption caused by readdir
nfsd: fix performance-limiting session calculation
svcrpc: fix UDP on servers with lots of threads
svcrdma: Remove syslog warnings in work completion handlers
svcrdma: Squelch compiler warning when SUNRPC_DEBUG is disabled
svcrdma: Use struct_size() in kmalloc()
svcrpc: fix unlikely races preventing queueing of sockets
svcrpc: svc_xprt_has_something_to_do seems a little long
SUNRPC: Don't allow compiler optimisation of svc_xprt_release_slot()
nfsd: fix an IS_ERR() vs NULL check
Diffstat (limited to 'net/sunrpc/svc_xprt.c')
-rw-r--r-- | net/sunrpc/svc_xprt.c | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c index 4eb8fbf2508d..61530b1b7754 100644 --- a/net/sunrpc/svc_xprt.c +++ b/net/sunrpc/svc_xprt.c @@ -357,15 +357,29 @@ static void svc_xprt_release_slot(struct svc_rqst *rqstp) struct svc_xprt *xprt = rqstp->rq_xprt; if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) { atomic_dec(&xprt->xpt_nr_rqsts); + smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */ svc_xprt_enqueue(xprt); } } -static bool svc_xprt_has_something_to_do(struct svc_xprt *xprt) +static bool svc_xprt_ready(struct svc_xprt *xprt) { - if (xprt->xpt_flags & ((1<<XPT_CONN)|(1<<XPT_CLOSE))) + unsigned long xpt_flags; + + /* + * If another cpu has recently updated xpt_flags, + * sk_sock->flags, xpt_reserved, or xpt_nr_rqsts, we need to + * know about it; otherwise it's possible that both that cpu and + * this one could call svc_xprt_enqueue() without either + * svc_xprt_enqueue() recognizing that the conditions below + * are satisfied, and we could stall indefinitely: + */ + smp_rmb(); + xpt_flags = READ_ONCE(xprt->xpt_flags); + + if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE))) return true; - if (xprt->xpt_flags & ((1<<XPT_DATA)|(1<<XPT_DEFERRED))) { + if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) { if (xprt->xpt_ops->xpo_has_wspace(xprt) && svc_xprt_slots_in_range(xprt)) return true; @@ -381,7 +395,7 @@ void svc_xprt_do_enqueue(struct svc_xprt *xprt) struct svc_rqst *rqstp = NULL; int cpu; - if (!svc_xprt_has_something_to_do(xprt)) + if (!svc_xprt_ready(xprt)) return; /* Mark transport as busy. It will remain in this state until @@ -475,7 +489,7 @@ void svc_reserve(struct svc_rqst *rqstp, int space) if (xprt && space < rqstp->rq_reserved) { atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved); rqstp->rq_reserved = space; - + smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */ svc_xprt_enqueue(xprt); } } |