| Message ID | 1511954146-11793-2-git-send-email-elena.reshetova@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Nov 29, 2017 at 01:15:43PM +0200, Elena Reshetova wrote: > atomic_t variables are currently used to implement reference > counters with the following properties: > - counter is initialized to 1 using atomic_set() > - a resource is freed upon counter reaching zero > - once counter reaches zero, its further > increments aren't allowed > - counter schema uses basic atomic operations > (set, inc, inc_not_zero, dec_and_test, etc.) Whoops, I forgot that this doesn't apply to h_count. Well, it's confusing, because h_count is actually used in two different ways: depending on whether a nlm_host represents a client or server, it may have the above properties or not. Inclined to drop this patch for now. --b. > > Such atomic variables should be converted to a newly provided > refcount_t type and API that prevents accidental counter overflows > and underflows. This is important since overflows and underflows > can lead to use-after-free situation and be exploitable. > > The variable nlm_host.h_count is used as pure reference counter. > Convert it to refcount_t and fix up the operations. > > **Important note for maintainers: > > Some functions from refcount_t API defined in lib/refcount.c > have different memory ordering guarantees than their atomic > counterparts. > The full comparison can be seen in > https://lkml.org/lkml/2017/11/15/57 and it is hopefully soon > in state to be merged to the documentation tree. > Normally the differences should not matter since refcount_t provides > enough guarantees to satisfy the refcounting use cases, but in > some rare cases it might matter. > Please double check that you don't have some undocumented > memory guarantees for this variable usage. > > For the nlm_host.h_count it might make a difference > in following places: > - nlmsvc_release_host(): decrement in refcount_dec() > provides RELEASE ordering, while original atomic_dec() > was fully unordered. Since the change is for better, it > should not matter. > - nlmclnt_release_host(): decrement in refcount_dec_and_test() only > provides RELEASE ordering and control dependency on success > vs. fully ordered atomic counterpart. It doesn't seem to > matter in this case since object freeing happens under mutex > lock anyway. > > Suggested-by: Kees Cook <keescook@chromium.org> > Reviewed-by: David Windsor <dwindsor@gmail.com> > Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> > Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> > --- > fs/lockd/host.c | 14 +++++++------- > include/linux/lockd/lockd.h | 3 ++- > 2 files changed, 9 insertions(+), 8 deletions(-) > > diff --git a/fs/lockd/host.c b/fs/lockd/host.c > index 826a891..11b6832 100644 > --- a/fs/lockd/host.c > +++ b/fs/lockd/host.c > @@ -151,7 +151,7 @@ static struct nlm_host *nlm_alloc_host(struct nlm_lookup_host_info *ni, > host->h_state = 0; > host->h_nsmstate = 0; > host->h_pidcount = 0; > - atomic_set(&host->h_count, 1); > + refcount_set(&host->h_count, 1); > mutex_init(&host->h_mutex); > host->h_nextrebind = now + NLM_HOST_REBIND; > host->h_expires = now + NLM_HOST_EXPIRE; > @@ -290,7 +290,7 @@ void nlmclnt_release_host(struct nlm_host *host) > > WARN_ON_ONCE(host->h_server); > > - if (atomic_dec_and_test(&host->h_count)) { > + if (refcount_dec_and_test(&host->h_count)) { > WARN_ON_ONCE(!list_empty(&host->h_lockowners)); > WARN_ON_ONCE(!list_empty(&host->h_granted)); > WARN_ON_ONCE(!list_empty(&host->h_reclaim)); > @@ -410,7 +410,7 @@ void nlmsvc_release_host(struct nlm_host *host) > dprintk("lockd: release server host %s\n", host->h_name); > > WARN_ON_ONCE(!host->h_server); > - atomic_dec(&host->h_count); > + refcount_dec(&host->h_count); > } > > /* > @@ -504,7 +504,7 @@ struct nlm_host * nlm_get_host(struct nlm_host *host) > { > if (host) { > dprintk("lockd: get host %s\n", host->h_name); > - atomic_inc(&host->h_count); > + refcount_inc(&host->h_count); > host->h_expires = jiffies + NLM_HOST_EXPIRE; > } > return host; > @@ -593,7 +593,7 @@ static void nlm_complain_hosts(struct net *net) > if (net && host->net != net) > continue; > dprintk(" %s (cnt %d use %d exp %ld net %x)\n", > - host->h_name, atomic_read(&host->h_count), > + host->h_name, refcount_read(&host->h_count), > host->h_inuse, host->h_expires, host->net->ns.inum); > } > } > @@ -662,11 +662,11 @@ nlm_gc_hosts(struct net *net) > for_each_host_safe(host, next, chain, nlm_server_hosts) { > if (net && host->net != net) > continue; > - if (atomic_read(&host->h_count) || host->h_inuse > + if (refcount_read(&host->h_count) || host->h_inuse > || time_before(jiffies, host->h_expires)) { > dprintk("nlm_gc_hosts skipping %s " > "(cnt %d use %d exp %ld net %x)\n", > - host->h_name, atomic_read(&host->h_count), > + host->h_name, refcount_read(&host->h_count), > host->h_inuse, host->h_expires, > host->net->ns.inum); > continue; > diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h > index d7d313f..39dfeea 100644 > --- a/include/linux/lockd/lockd.h > +++ b/include/linux/lockd/lockd.h > @@ -17,6 +17,7 @@ > #include <net/ipv6.h> > #include <linux/fs.h> > #include <linux/kref.h> > +#include <linux/refcount.h> > #include <linux/utsname.h> > #include <linux/lockd/bind.h> > #include <linux/lockd/xdr.h> > @@ -58,7 +59,7 @@ struct nlm_host { > u32 h_state; /* pseudo-state counter */ > u32 h_nsmstate; /* true remote NSM state */ > u32 h_pidcount; /* Pseudopids */ > - atomic_t h_count; /* reference count */ > + refcount_t h_count; /* reference count */ > struct mutex h_mutex; /* mutex for pmap binding */ > unsigned long h_nextrebind; /* next portmap call */ > unsigned long h_expires; /* eligible for GC */ > -- > 2.7.4 -- 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
On Wed, Nov 29, 2017 at 01:15:43PM +0200, Elena Reshetova wrote: > atomic_t variables are currently used to implement reference > counters with the following properties: > - counter is initialized to 1 using atomic_set() > - a resource is freed upon counter reaching zero > - once counter reaches zero, its further > increments aren't allowed > - counter schema uses basic atomic operations > (set, inc, inc_not_zero, dec_and_test, etc.) >Whoops, I forgot that this doesn't apply to h_count. >Well, it's confusing, because h_count is actually used in two different >ways: depending on whether a nlm_host represents a client or server, it >may have the above properties or not. So, what happens when it is not having the above properties? Is the object being reused or? I am just trying to understand if there is a way to fix this patch to work for the case or is the drop is the only correct way to go. Best Regards, Elena. >Inclined to drop this patch for now. --b. > > Such atomic variables should be converted to a newly provided > refcount_t type and API that prevents accidental counter overflows > and underflows. This is important since overflows and underflows > can lead to use-after-free situation and be exploitable. > > The variable nlm_host.h_count is used as pure reference counter. > Convert it to refcount_t and fix up the operations. > > **Important note for maintainers: > > Some functions from refcount_t API defined in lib/refcount.c > have different memory ordering guarantees than their atomic > counterparts. > The full comparison can be seen in > https://lkml.org/lkml/2017/11/15/57 and it is hopefully soon > in state to be merged to the documentation tree. > Normally the differences should not matter since refcount_t provides > enough guarantees to satisfy the refcounting use cases, but in > some rare cases it might matter. > Please double check that you don't have some undocumented > memory guarantees for this variable usage. > > For the nlm_host.h_count it might make a difference > in following places: > - nlmsvc_release_host(): decrement in refcount_dec() > provides RELEASE ordering, while original atomic_dec() > was fully unordered. Since the change is for better, it > should not matter. > - nlmclnt_release_host(): decrement in refcount_dec_and_test() only > provides RELEASE ordering and control dependency on success > vs. fully ordered atomic counterpart. It doesn't seem to > matter in this case since object freeing happens under mutex > lock anyway. > > Suggested-by: Kees Cook <keescook@chromium.org> > Reviewed-by: David Windsor <dwindsor@gmail.com> > Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> > Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> > --- > fs/lockd/host.c | 14 +++++++------- > include/linux/lockd/lockd.h | 3 ++- > 2 files changed, 9 insertions(+), 8 deletions(-) > > diff --git a/fs/lockd/host.c b/fs/lockd/host.c > index 826a891..11b6832 100644 > --- a/fs/lockd/host.c > +++ b/fs/lockd/host.c > @@ -151,7 +151,7 @@ static struct nlm_host *nlm_alloc_host(struct nlm_lookup_host_info *ni, > host->h_state = 0; > host->h_nsmstate = 0; > host->h_pidcount = 0; > - atomic_set(&host->h_count, 1); > + refcount_set(&host->h_count, 1); > mutex_init(&host->h_mutex); > host->h_nextrebind = now + NLM_HOST_REBIND; > host->h_expires = now + NLM_HOST_EXPIRE; > @@ -290,7 +290,7 @@ void nlmclnt_release_host(struct nlm_host *host) > > WARN_ON_ONCE(host->h_server); > > - if (atomic_dec_and_test(&host->h_count)) { > + if (refcount_dec_and_test(&host->h_count)) { > WARN_ON_ONCE(!list_empty(&host->h_lockowners)); > WARN_ON_ONCE(!list_empty(&host->h_granted)); > WARN_ON_ONCE(!list_empty(&host->h_reclaim)); > @@ -410,7 +410,7 @@ void nlmsvc_release_host(struct nlm_host *host) > dprintk("lockd: release server host %s\n", host->h_name); > > WARN_ON_ONCE(!host->h_server); > - atomic_dec(&host->h_count); > + refcount_dec(&host->h_count); > } > > /* > @@ -504,7 +504,7 @@ struct nlm_host * nlm_get_host(struct nlm_host *host) > { > if (host) { > dprintk("lockd: get host %s\n", host->h_name); > - atomic_inc(&host->h_count); > + refcount_inc(&host->h_count); > host->h_expires = jiffies + NLM_HOST_EXPIRE; > } > return host; > @@ -593,7 +593,7 @@ static void nlm_complain_hosts(struct net *net) > if (net && host->net != net) > continue; > dprintk(" %s (cnt %d use %d exp %ld net %x)\n", > - host->h_name, atomic_read(&host->h_count), > + host->h_name, refcount_read(&host->h_count), > host->h_inuse, host->h_expires, host->net->ns.inum); > } > } > @@ -662,11 +662,11 @@ nlm_gc_hosts(struct net *net) > for_each_host_safe(host, next, chain, nlm_server_hosts) { > if (net && host->net != net) > continue; > - if (atomic_read(&host->h_count) || host->h_inuse > + if (refcount_read(&host->h_count) || host->h_inuse > || time_before(jiffies, host->h_expires)) { > dprintk("nlm_gc_hosts skipping %s " > "(cnt %d use %d exp %ld net %x)\n", > - host->h_name, atomic_read(&host->h_count), > + host->h_name, refcount_read(&host->h_count), > host->h_inuse, host->h_expires, > host->net->ns.inum); > continue; > diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h > index d7d313f..39dfeea 100644 > --- a/include/linux/lockd/lockd.h > +++ b/include/linux/lockd/lockd.h > @@ -17,6 +17,7 @@ > #include <net/ipv6.h> > #include <linux/fs.h> > #include <linux/kref.h> > +#include <linux/refcount.h> > #include <linux/utsname.h> > #include <linux/lockd/bind.h> > #include <linux/lockd/xdr.h> > @@ -58,7 +59,7 @@ struct nlm_host { > u32 h_state; /* pseudo-state counter */ > u32 h_nsmstate; /* true remote NSM state */ > u32 h_pidcount; /* Pseudopids */ > - atomic_t h_count; /* reference count */ > + refcount_t h_count; /* reference count */ > struct mutex h_mutex; /* mutex for pmap binding */ > unsigned long h_nextrebind; /* next portmap call */ > unsigned long h_expires; /* eligible for GC */ > -- > 2.7.4 -- 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
On Fri, Dec 22, 2017 at 09:29:15AM +0000, Reshetova, Elena wrote: > > On Wed, Nov 29, 2017 at 01:15:43PM +0200, Elena Reshetova wrote: > > atomic_t variables are currently used to implement reference > > counters with the following properties: > > - counter is initialized to 1 using atomic_set() > > - a resource is freed upon counter reaching zero > > - once counter reaches zero, its further > > increments aren't allowed > > - counter schema uses basic atomic operations > > (set, inc, inc_not_zero, dec_and_test, etc.) > > >Whoops, I forgot that this doesn't apply to h_count. > > >Well, it's confusing, because h_count is actually used in two different > >ways: depending on whether a nlm_host represents a client or server, it > >may have the above properties or not. > > > So, what happens when it is not having the above properties? Is the object > being reused or? The object isn't destroyed when the counter hits zero--zero is just taken as a hint to some garbage collection algorithm that it would be OK to destroy it. So decrementing to or incrementing from zero is OK. --b. -- 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
On Fri, Dec 22, 2017 at 09:25:53AM -0500, J. Bruce Fields wrote: > On Fri, Dec 22, 2017 at 09:29:15AM +0000, Reshetova, Elena wrote: > > > > On Wed, Nov 29, 2017 at 01:15:43PM +0200, Elena Reshetova wrote: > > > atomic_t variables are currently used to implement reference > > > counters with the following properties: > > > - counter is initialized to 1 using atomic_set() > > > - a resource is freed upon counter reaching zero > > > - once counter reaches zero, its further > > > increments aren't allowed > > > - counter schema uses basic atomic operations > > > (set, inc, inc_not_zero, dec_and_test, etc.) > > > > >Whoops, I forgot that this doesn't apply to h_count. > > > > >Well, it's confusing, because h_count is actually used in two different > > >ways: depending on whether a nlm_host represents a client or server, it > > >may have the above properties or not. > > > > > > So, what happens when it is not having the above properties? Is the object > > being reused or? > > The object isn't destroyed when the counter hits zero--zero is just > taken as a hint to some garbage collection algorithm that it would be OK > to destroy it. So decrementing to or incrementing from zero is OK. In more detail: the nlm_host objects that are used on the NFS server to represent NFS clients are put by nlmsvc_release_host, and then may eventually be freed by nlm_gc_hosts. The nlm_host objects that are used on the NFS client to represent NFS servers are put (and freed when h_count goes to zero) by nlmclnt_release_host. In both cases reference are taken by nlm_get_host. It would be possible to replace nlm_get_host by two different functions if that would help. Most callers are obviously only client-side or server-side. The only exception is next_host_state. It could be passed a pointer to the "get" function it should use. After that we might actually just want to define separate client and server structs like: struct nlm_clnt_host { struct nlm_host ch_host; refcount_t ch_count; ... } struct nlm_srv_host { struct nlm_host sh_host; refcount_t sh_count; ... } rather than have a single h_count which is used in two confusingly different ways. There are also some other nlm_host fields that really only make sense for client or server. --b. -- 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
> On Fri, Dec 22, 2017 at 09:25:53AM -0500, J. Bruce Fields wrote: > > On Fri, Dec 22, 2017 at 09:29:15AM +0000, Reshetova, Elena wrote: > > > > > > On Wed, Nov 29, 2017 at 01:15:43PM +0200, Elena Reshetova wrote: > > > > atomic_t variables are currently used to implement reference > > > > counters with the following properties: > > > > - counter is initialized to 1 using atomic_set() > > > > - a resource is freed upon counter reaching zero > > > > - once counter reaches zero, its further > > > > increments aren't allowed > > > > - counter schema uses basic atomic operations > > > > (set, inc, inc_not_zero, dec_and_test, etc.) > > > > > > >Whoops, I forgot that this doesn't apply to h_count. > > > > > > >Well, it's confusing, because h_count is actually used in two different > > > >ways: depending on whether a nlm_host represents a client or server, it > > > >may have the above properties or not. > > > > > > > > > So, what happens when it is not having the above properties? Is the object > > > being reused or? > > > > The object isn't destroyed when the counter hits zero--zero is just > > taken as a hint to some garbage collection algorithm that it would be OK > > to destroy it. So decrementing to or incrementing from zero is OK. > > In more detail: the nlm_host objects that are used on the NFS server to > represent NFS clients are put by nlmsvc_release_host, and then may > eventually be freed by nlm_gc_hosts. > > The nlm_host objects that are used on the NFS client to represent NFS > servers are put (and freed when h_count goes to zero) by > nlmclnt_release_host. > > In both cases reference are taken by nlm_get_host. It would be possible > to replace nlm_get_host by two different functions if that would help. > Most callers are obviously only client-side or server-side. The only > exception is next_host_state. It could be passed a pointer to the "get" > function it should use. > > After that we might actually just want to define separate client and > server structs like: > > struct nlm_clnt_host { > struct nlm_host ch_host; > refcount_t ch_count; > ... > } > > struct nlm_srv_host { > struct nlm_host sh_host; > refcount_t sh_count; > ... > } > > rather than have a single h_count which is used in two confusingly > different ways. There are also some other nlm_host fields that really > only make sense for client or server. This sounds reasonable for me, but obviously it is a bigger change and I might not have enough knowledge on NFS to make it correctly. In any case, even for the current server case, when freeing might not happen and object gets re-used later on, is it possible to simply re-initialize the object (and its reference counter) properly before reusing? I think this is the only thing that is needed from the correct refcounting POV in this case, so instead of using refcount_inc() on reused object, you would explicitly do refcount_set(counter, 1) when reuse happens. Best Regards, Elena > > --b. -- 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
On Wed, Dec 27, 2017 at 12:10:15PM +0000, Reshetova, Elena wrote: > > On Fri, Dec 22, 2017 at 09:25:53AM -0500, J. Bruce Fields wrote: > > > On Fri, Dec 22, 2017 at 09:29:15AM +0000, Reshetova, Elena wrote: > > > > > > > > On Wed, Nov 29, 2017 at 01:15:43PM +0200, Elena Reshetova wrote: > > > > > atomic_t variables are currently used to implement reference > > > > > counters with the following properties: > > > > > - counter is initialized to 1 using atomic_set() > > > > > - a resource is freed upon counter reaching zero > > > > > - once counter reaches zero, its further > > > > > increments aren't allowed > > > > > - counter schema uses basic atomic operations > > > > > (set, inc, inc_not_zero, dec_and_test, etc.) > > > > > > > > >Whoops, I forgot that this doesn't apply to h_count. > > > > > > > > >Well, it's confusing, because h_count is actually used in two different > > > > >ways: depending on whether a nlm_host represents a client or server, it > > > > >may have the above properties or not. > > > > > > > > > > > > So, what happens when it is not having the above properties? Is the object > > > > being reused or? > > > > > > The object isn't destroyed when the counter hits zero--zero is just > > > taken as a hint to some garbage collection algorithm that it would be OK > > > to destroy it. So decrementing to or incrementing from zero is OK. > > > > In more detail: the nlm_host objects that are used on the NFS server to > > represent NFS clients are put by nlmsvc_release_host, and then may > > eventually be freed by nlm_gc_hosts. > > > > The nlm_host objects that are used on the NFS client to represent NFS > > servers are put (and freed when h_count goes to zero) by > > nlmclnt_release_host. > > > > In both cases reference are taken by nlm_get_host. It would be possible > > to replace nlm_get_host by two different functions if that would help. > > Most callers are obviously only client-side or server-side. The only > > exception is next_host_state. It could be passed a pointer to the "get" > > function it should use. > > > > After that we might actually just want to define separate client and > > server structs like: > > > > struct nlm_clnt_host { > > struct nlm_host ch_host; > > refcount_t ch_count; > > ... > > } > > > > struct nlm_srv_host { > > struct nlm_host sh_host; > > refcount_t sh_count; > > ... > > } > > > > rather than have a single h_count which is used in two confusingly > > different ways. There are also some other nlm_host fields that really > > only make sense for client or server. > > This sounds reasonable for me, but obviously it is a bigger change and I might not > have enough knowledge on NFS to make it correctly. > > In any case, even for the current server case, when freeing might not happen and object gets > re-used later on, is it possible to simply re-initialize the object (and its reference counter) properly before reusing? The object still has useful information in it so we can't just reinitalize it completely. I guess we could make nlm_get_host do if (refcount_read(&host->h_count)) refcount_inc(&host->h_count); else refcount_set(&host->h_count, 1); Or we could just change the code so the refcount is always 1 higher in the NFS server case, so "1" instead of "0" is used to mean "nobody's using this, you can garbage collect this", and then it won't go to 0 until the garbage collector actually destroys it. This isn't an unusual pattern, what have other subsystems been doing? --b. > I think this is the only thing that is needed from the correct refcounting POV in this case, so > instead of using refcount_inc() on reused object, you would explicitly do refcount_set(counter, 1) when reuse happens. -- 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/fs/lockd/host.c b/fs/lockd/host.c index 826a891..11b6832 100644 --- a/fs/lockd/host.c +++ b/fs/lockd/host.c @@ -151,7 +151,7 @@ static struct nlm_host *nlm_alloc_host(struct nlm_lookup_host_info *ni, host->h_state = 0; host->h_nsmstate = 0; host->h_pidcount = 0; - atomic_set(&host->h_count, 1); + refcount_set(&host->h_count, 1); mutex_init(&host->h_mutex); host->h_nextrebind = now + NLM_HOST_REBIND; host->h_expires = now + NLM_HOST_EXPIRE; @@ -290,7 +290,7 @@ void nlmclnt_release_host(struct nlm_host *host) WARN_ON_ONCE(host->h_server); - if (atomic_dec_and_test(&host->h_count)) { + if (refcount_dec_and_test(&host->h_count)) { WARN_ON_ONCE(!list_empty(&host->h_lockowners)); WARN_ON_ONCE(!list_empty(&host->h_granted)); WARN_ON_ONCE(!list_empty(&host->h_reclaim)); @@ -410,7 +410,7 @@ void nlmsvc_release_host(struct nlm_host *host) dprintk("lockd: release server host %s\n", host->h_name); WARN_ON_ONCE(!host->h_server); - atomic_dec(&host->h_count); + refcount_dec(&host->h_count); } /* @@ -504,7 +504,7 @@ struct nlm_host * nlm_get_host(struct nlm_host *host) { if (host) { dprintk("lockd: get host %s\n", host->h_name); - atomic_inc(&host->h_count); + refcount_inc(&host->h_count); host->h_expires = jiffies + NLM_HOST_EXPIRE; } return host; @@ -593,7 +593,7 @@ static void nlm_complain_hosts(struct net *net) if (net && host->net != net) continue; dprintk(" %s (cnt %d use %d exp %ld net %x)\n", - host->h_name, atomic_read(&host->h_count), + host->h_name, refcount_read(&host->h_count), host->h_inuse, host->h_expires, host->net->ns.inum); } } @@ -662,11 +662,11 @@ nlm_gc_hosts(struct net *net) for_each_host_safe(host, next, chain, nlm_server_hosts) { if (net && host->net != net) continue; - if (atomic_read(&host->h_count) || host->h_inuse + if (refcount_read(&host->h_count) || host->h_inuse || time_before(jiffies, host->h_expires)) { dprintk("nlm_gc_hosts skipping %s " "(cnt %d use %d exp %ld net %x)\n", - host->h_name, atomic_read(&host->h_count), + host->h_name, refcount_read(&host->h_count), host->h_inuse, host->h_expires, host->net->ns.inum); continue; diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h index d7d313f..39dfeea 100644 --- a/include/linux/lockd/lockd.h +++ b/include/linux/lockd/lockd.h @@ -17,6 +17,7 @@ #include <net/ipv6.h> #include <linux/fs.h> #include <linux/kref.h> +#include <linux/refcount.h> #include <linux/utsname.h> #include <linux/lockd/bind.h> #include <linux/lockd/xdr.h> @@ -58,7 +59,7 @@ struct nlm_host { u32 h_state; /* pseudo-state counter */ u32 h_nsmstate; /* true remote NSM state */ u32 h_pidcount; /* Pseudopids */ - atomic_t h_count; /* reference count */ + refcount_t h_count; /* reference count */ struct mutex h_mutex; /* mutex for pmap binding */ unsigned long h_nextrebind; /* next portmap call */ unsigned long h_expires; /* eligible for GC */