Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

1 files changed, 889 insertions, 0 deletions

diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
new file mode 100644
index 000000000..f06faf577
--- /dev/null
+++ b/fs/lockd/clntproc.c
@@ -0,0 +1,889 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/lockd/clntproc.c
+ *
+ * RPC procedures for the client side NLM implementation
+ *
+ * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/filelock.h>
+#include <linux/nfs_fs.h>
+#include <linux/utsname.h>
+#include <linux/freezer.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/svc.h>
+
+#include "lockd.h"
+#include "trace.h"
+
+#define NLMDBG_FACILITY		NLMDBG_CLIENT
+#define NLMCLNT_GRACE_WAIT	(5*HZ)
+#define NLMCLNT_POLL_TIMEOUT	(30*HZ)
+#define NLMCLNT_MAX_RETRIES	3
+
+static int	nlmclnt_test(struct nlm_rqst *, struct file_lock *);
+static int	nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
+static int	nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
+static int	nlm_stat_to_errno(__be32 stat);
+static void	nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
+static int	nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
+
+static const struct rpc_call_ops nlmclnt_unlock_ops;
+static const struct rpc_call_ops nlmclnt_cancel_ops;
+
+/*
+ * Cookie counter for NLM requests
+ */
+static atomic_t	nlm_cookie = ATOMIC_INIT(0x1234);
+
+void nlmclnt_next_cookie(struct lockd_cookie *c)
+{
+	u32	cookie = atomic_inc_return(&nlm_cookie);
+
+	memcpy(c->data, &cookie, 4);
+	c->len=4;
+}
+
+static struct nlm_lockowner *
+nlmclnt_get_lockowner(struct nlm_lockowner *lockowner)
+{
+	refcount_inc(&lockowner->count);
+	return lockowner;
+}
+
+static void nlmclnt_put_lockowner(struct nlm_lockowner *lockowner)
+{
+	if (!refcount_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
+		return;
+	list_del(&lockowner->list);
+	spin_unlock(&lockowner->host->h_lock);
+	nlmclnt_release_host(lockowner->host);
+	kfree(lockowner);
+}
+
+static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
+{
+	struct nlm_lockowner *lockowner;
+	list_for_each_entry(lockowner, &host->h_lockowners, list) {
+		if (lockowner->pid == pid)
+			return -EBUSY;
+	}
+	return 0;
+}
+
+static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
+{
+	uint32_t res;
+	do {
+		res = host->h_pidcount++;
+	} while (nlm_pidbusy(host, res) < 0);
+	return res;
+}
+
+static struct nlm_lockowner *__nlmclnt_find_lockowner(struct nlm_host *host, fl_owner_t owner)
+{
+	struct nlm_lockowner *lockowner;
+	list_for_each_entry(lockowner, &host->h_lockowners, list) {
+		if (lockowner->owner != owner)
+			continue;
+		return nlmclnt_get_lockowner(lockowner);
+	}
+	return NULL;
+}
+
+static struct nlm_lockowner *nlmclnt_find_lockowner(struct nlm_host *host, fl_owner_t owner)
+{
+	struct nlm_lockowner *res, *new = NULL;
+
+	spin_lock(&host->h_lock);
+	res = __nlmclnt_find_lockowner(host, owner);
+	if (res == NULL) {
+		spin_unlock(&host->h_lock);
+		new = kmalloc_obj(*new);
+		spin_lock(&host->h_lock);
+		res = __nlmclnt_find_lockowner(host, owner);
+		if (res == NULL && new != NULL) {
+			res = new;
+			refcount_set(&new->count, 1);
+			new->owner = owner;
+			new->pid = __nlm_alloc_pid(host);
+			new->host = nlm_get_host(host);
+			list_add(&new->list, &host->h_lockowners);
+			new = NULL;
+		}
+	}
+	spin_unlock(&host->h_lock);
+	kfree(new);
+	return res;
+}
+
+/*
+ * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
+ */
+static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
+{
+	struct lockd_args *argp = &req->a_args;
+	struct lockd_lock *lock = &argp->lock;
+	char *nodename = req->a_host->h_rpcclnt->cl_nodename;
+
+	nlmclnt_next_cookie(&argp->cookie);
+	memcpy(&lock->fh, NFS_FH(file_inode(fl->c.flc_file)),
+	       sizeof(struct nfs_fh));
+	lock->caller  = nodename;
+	lock->oh.data = req->a_owner;
+	lock->oh.len  = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
+				(unsigned int)fl->fl_u.nfs_fl.owner->pid,
+				nodename);
+	lock->svid = fl->fl_u.nfs_fl.owner->pid;
+	lock->fl.fl_start = fl->fl_start;
+	lock->fl.fl_end = fl->fl_end;
+	lock->fl.c.flc_type = fl->c.flc_type;
+}
+
+static void nlmclnt_release_lockargs(struct nlm_rqst *req)
+{
+	WARN_ON_ONCE(req->a_args.lock.fl.fl_ops != NULL);
+}
+
+/**
+ * nlmclnt_proc - Perform a single client-side lock request
+ * @host: address of a valid nlm_host context representing the NLM server
+ * @cmd: fcntl-style file lock operation to perform
+ * @fl: address of arguments for the lock operation
+ * @data: address of data to be sent to callback operations
+ *
+ */
+int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl, void *data)
+{
+	struct nlm_rqst		*call;
+	int			status;
+	const struct nlmclnt_operations *nlmclnt_ops = host->h_nlmclnt_ops;
+
+	call = nlm_alloc_call(host);
+	if (call == NULL)
+		return -ENOMEM;
+
+	if (nlmclnt_ops && nlmclnt_ops->nlmclnt_alloc_call)
+		nlmclnt_ops->nlmclnt_alloc_call(data);
+
+	nlmclnt_locks_init_private(fl, host);
+	if (!fl->fl_u.nfs_fl.owner) {
+		/* lockowner allocation has failed */
+		nlmclnt_release_call(call);
+		return -ENOMEM;
+	}
+	/* Set up the argument struct */
+	nlmclnt_setlockargs(call, fl);
+	call->a_callback_data = data;
+
+	if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
+		if (fl->c.flc_type != F_UNLCK) {
+			call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
+			status = nlmclnt_lock(call, fl);
+		} else
+			status = nlmclnt_unlock(call, fl);
+	} else if (IS_GETLK(cmd))
+		status = nlmclnt_test(call, fl);
+	else
+		status = -EINVAL;
+	fl->fl_ops->fl_release_private(fl);
+	fl->fl_ops = NULL;
+
+	dprintk("lockd: clnt proc returns %d\n", status);
+	return status;
+}
+EXPORT_SYMBOL_GPL(nlmclnt_proc);
+
+/*
+ * Allocate an NLM RPC call struct
+ */
+struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
+{
+	struct nlm_rqst	*call;
+
+	for(;;) {
+		call = kzalloc_obj(*call);
+		if (call != NULL) {
+			refcount_set(&call->a_count, 1);
+			locks_init_lock(&call->a_args.lock.fl);
+			locks_init_lock(&call->a_res.lock.fl);
+			call->a_host = nlm_get_host(host);
+			return call;
+		}
+		if (signalled())
+			break;
+		printk("nlm_alloc_call: failed, waiting for memory\n");
+		schedule_timeout_interruptible(5*HZ);
+	}
+	return NULL;
+}
+
+void nlmclnt_release_call(struct nlm_rqst *call)
+{
+	const struct nlmclnt_operations *nlmclnt_ops = call->a_host->h_nlmclnt_ops;
+
+	if (!refcount_dec_and_test(&call->a_count))
+		return;
+	if (nlmclnt_ops && nlmclnt_ops->nlmclnt_release_call)
+		nlmclnt_ops->nlmclnt_release_call(call->a_callback_data);
+	nlmclnt_release_host(call->a_host);
+	nlmclnt_release_lockargs(call);
+	kfree(call);
+}
+
+static void nlmclnt_rpc_release(void *data)
+{
+	nlmclnt_release_call(data);
+}
+
+static int nlm_wait_on_grace(wait_queue_head_t *queue)
+{
+	DEFINE_WAIT(wait);
+	int status = -EINTR;
+
+	prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
+	if (!signalled ()) {
+		schedule_timeout(NLMCLNT_GRACE_WAIT);
+		try_to_freeze();
+		if (!signalled ())
+			status = 0;
+	}
+	finish_wait(queue, &wait);
+	return status;
+}
+
+/*
+ * Generic NLM call
+ */
+static int
+nlmclnt_call(const struct cred *cred, struct nlm_rqst *req, u32 proc)
+{
+	struct nlm_host	*host = req->a_host;
+	struct rpc_clnt	*clnt;
+	struct lockd_args *argp = &req->a_args;
+	struct lockd_res *resp = &req->a_res;
+	struct rpc_message msg = {
+		.rpc_argp	= argp,
+		.rpc_resp	= resp,
+		.rpc_cred	= cred,
+	};
+	int		status;
+
+	dprintk("lockd: call procedure %d on %s\n",
+			(int)proc, host->h_name);
+
+	do {
+		if (host->h_reclaiming && !argp->reclaim)
+			goto in_grace_period;
+
+		/* If we have no RPC client yet, create one. */
+		if ((clnt = nlm_bind_host(host)) == NULL)
+			return -ENOLCK;
+		msg.rpc_proc = &clnt->cl_procinfo[proc];
+
+		/* Perform the RPC call. If an error occurs, try again */
+		if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
+			dprintk("lockd: rpc_call returned error %d\n", -status);
+			switch (status) {
+			case -EPROTONOSUPPORT:
+				status = -EINVAL;
+				break;
+			case -ECONNREFUSED:
+			case -ETIMEDOUT:
+			case -ENOTCONN:
+				nlm_rebind_host(host);
+				status = -EAGAIN;
+				break;
+			case -ERESTARTSYS:
+				return signalled () ? -EINTR : status;
+			default:
+				break;
+			}
+			break;
+		} else
+		if (resp->status == nlm_lck_denied_grace_period) {
+			dprintk("lockd: server in grace period\n");
+			if (argp->reclaim) {
+				printk(KERN_WARNING
+				     "lockd: spurious grace period reject?!\n");
+				return -ENOLCK;
+			}
+		} else {
+			if (!argp->reclaim) {
+				/* We appear to be out of the grace period */
+				wake_up_all(&host->h_gracewait);
+			}
+			dprintk("lockd: server returns status %d\n",
+				ntohl(resp->status));
+			return 0;	/* Okay, call complete */
+		}
+
+in_grace_period:
+		/*
+		 * The server has rebooted and appears to be in the grace
+		 * period during which locks are only allowed to be
+		 * reclaimed.
+		 * We can only back off and try again later.
+		 */
+		status = nlm_wait_on_grace(&host->h_gracewait);
+	} while (status == 0);
+
+	return status;
+}
+
+/*
+ * Generic NLM call, async version.
+ */
+static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
+{
+	struct nlm_host	*host = req->a_host;
+	struct rpc_clnt	*clnt;
+	struct rpc_task_setup task_setup_data = {
+		.rpc_message = msg,
+		.callback_ops = tk_ops,
+		.callback_data = req,
+		.flags = RPC_TASK_ASYNC,
+	};
+
+	dprintk("lockd: call procedure %d on %s (async)\n",
+			(int)proc, host->h_name);
+
+	/* If we have no RPC client yet, create one. */
+	clnt = nlm_bind_host(host);
+	if (clnt == NULL)
+		goto out_err;
+	msg->rpc_proc = &clnt->cl_procinfo[proc];
+	task_setup_data.rpc_client = clnt;
+
+        /* bootstrap and kick off the async RPC call */
+	return rpc_run_task(&task_setup_data);
+out_err:
+	tk_ops->rpc_release(req);
+	return ERR_PTR(-ENOLCK);
+}
+
+static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
+{
+	struct rpc_task *task;
+
+	task = __nlm_async_call(req, proc, msg, tk_ops);
+	if (IS_ERR(task))
+		return PTR_ERR(task);
+	rpc_put_task(task);
+	return 0;
+}
+
+/*
+ * NLM asynchronous call.
+ */
+int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
+{
+	struct rpc_message msg = {
+		.rpc_argp	= &req->a_args,
+		.rpc_resp	= &req->a_res,
+	};
+	return nlm_do_async_call(req, proc, &msg, tk_ops);
+}
+
+int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
+{
+	struct rpc_message msg = {
+		.rpc_argp	= &req->a_res,
+	};
+	return nlm_do_async_call(req, proc, &msg, tk_ops);
+}
+
+/*
+ * NLM client asynchronous call.
+ *
+ * Note that although the calls are asynchronous, and are therefore
+ *      guaranteed to complete, we still always attempt to wait for
+ *      completion in order to be able to correctly track the lock
+ *      state.
+ */
+static int nlmclnt_async_call(const struct cred *cred, struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
+{
+	struct rpc_message msg = {
+		.rpc_argp	= &req->a_args,
+		.rpc_resp	= &req->a_res,
+		.rpc_cred	= cred,
+	};
+	struct rpc_task *task;
+	int err;
+
+	task = __nlm_async_call(req, proc, &msg, tk_ops);
+	if (IS_ERR(task))
+		return PTR_ERR(task);
+	err = rpc_wait_for_completion_task(task);
+	rpc_put_task(task);
+	return err;
+}
+
+/*
+ * TEST for the presence of a conflicting lock
+ */
+static int
+nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
+{
+	int	status;
+
+	status = nlmclnt_call(nfs_file_cred(fl->c.flc_file), req,
+			      NLMPROC_TEST);
+	if (status < 0)
+		goto out;
+
+	switch (req->a_res.status) {
+		case nlm_granted:
+			fl->c.flc_type = F_UNLCK;
+			break;
+		case nlm_lck_denied:
+			/*
+			 * Report the conflicting lock back to the application.
+			 */
+			fl->fl_start = req->a_res.lock.fl.fl_start;
+			fl->fl_end = req->a_res.lock.fl.fl_end;
+			fl->c.flc_type = req->a_res.lock.fl.c.flc_type;
+			fl->c.flc_pid = -req->a_res.lock.fl.c.flc_pid;
+			break;
+		default:
+			status = nlm_stat_to_errno(req->a_res.status);
+	}
+out:
+	trace_nlmclnt_test(&req->a_args.lock,
+			   (const struct sockaddr *)&req->a_host->h_addr,
+			   req->a_host->h_addrlen, req->a_res.status);
+	nlmclnt_release_call(req);
+	return status;
+}
+
+static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
+{
+	spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
+	new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
+	new->fl_u.nfs_fl.owner = nlmclnt_get_lockowner(fl->fl_u.nfs_fl.owner);
+	list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
+	spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
+}
+
+static void nlmclnt_locks_release_private(struct file_lock *fl)
+{
+	spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
+	list_del(&fl->fl_u.nfs_fl.list);
+	spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
+	nlmclnt_put_lockowner(fl->fl_u.nfs_fl.owner);
+}
+
+static const struct file_lock_operations nlmclnt_lock_ops = {
+	.fl_copy_lock = nlmclnt_locks_copy_lock,
+	.fl_release_private = nlmclnt_locks_release_private,
+};
+
+static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
+{
+	fl->fl_u.nfs_fl.state = 0;
+	fl->fl_u.nfs_fl.owner = nlmclnt_find_lockowner(host,
+						       fl->c.flc_owner);
+	INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
+	fl->fl_ops = &nlmclnt_lock_ops;
+}
+
+static int do_vfs_lock(struct file_lock *fl)
+{
+	return locks_lock_file_wait(fl->c.flc_file, fl);
+}
+
+/*
+ * LOCK: Try to create a lock
+ *
+ *			Programmer Harassment Alert
+ *
+ * When given a blocking lock request in a sync RPC call, the HPUX lockd
+ * will faithfully return LCK_BLOCKED but never cares to notify us when
+ * the lock could be granted. This way, our local process could hang
+ * around forever waiting for the callback.
+ *
+ *  Solution A:	Implement busy-waiting
+ *  Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
+ *
+ * For now I am implementing solution A, because I hate the idea of
+ * re-implementing lockd for a third time in two months. The async
+ * calls shouldn't be too hard to do, however.
+ *
+ * This is one of the lovely things about standards in the NFS area:
+ * they're so soft and squishy you can't really blame HP for doing this.
+ */
+static int
+nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
+{
+	const struct cred *cred = nfs_file_cred(fl->c.flc_file);
+	struct nlm_host	*host = req->a_host;
+	struct lockd_res *resp = &req->a_res;
+	struct nlm_wait block;
+	unsigned char flags = fl->c.flc_flags;
+	unsigned char type;
+	__be32 b_status;
+	int status = -ENOLCK;
+
+	if (nsm_monitor(host) < 0)
+		goto out;
+	req->a_args.state = nsm_local_state;
+
+	fl->c.flc_flags |= FL_ACCESS;
+	status = do_vfs_lock(fl);
+	fl->c.flc_flags = flags;
+	if (status < 0)
+		goto out;
+
+	nlmclnt_prepare_block(&block, host, fl);
+again:
+	/*
+	 * Initialise resp->status to a valid non-zero value,
+	 * since 0 == nlm_lck_granted
+	 */
+	resp->status = nlm_lck_blocked;
+
+	/*
+	 * A GRANTED callback can come at any time -- even before the reply
+	 * to the LOCK request arrives, so we queue the wait before
+	 * requesting the lock.
+	 */
+	nlmclnt_queue_block(&block);
+	for (;;) {
+		/* Reboot protection */
+		fl->fl_u.nfs_fl.state = host->h_state;
+		status = nlmclnt_call(cred, req, NLMPROC_LOCK);
+		if (status < 0)
+			break;
+		/* Did a reclaimer thread notify us of a server reboot? */
+		if (resp->status == nlm_lck_denied_grace_period)
+			continue;
+		if (resp->status != nlm_lck_blocked)
+			break;
+		/* Wait on an NLM blocking lock */
+		status = nlmclnt_wait(&block, req, NLMCLNT_POLL_TIMEOUT);
+		if (status < 0)
+			break;
+		if (block.b_status != nlm_lck_blocked)
+			break;
+	}
+	b_status = nlmclnt_dequeue_block(&block);
+	if (resp->status == nlm_lck_blocked)
+		resp->status = b_status;
+
+	/* if we were interrupted while blocking, then cancel the lock request
+	 * and exit
+	 */
+	if (resp->status == nlm_lck_blocked) {
+		if (!req->a_args.block)
+			goto out_unlock;
+		if (nlmclnt_cancel(host, req->a_args.block, fl) == 0)
+			goto out;
+	}
+
+	if (resp->status == nlm_granted) {
+		down_read(&host->h_rwsem);
+		/* Check whether or not the server has rebooted */
+		if (fl->fl_u.nfs_fl.state != host->h_state) {
+			up_read(&host->h_rwsem);
+			goto again;
+		}
+		/* Ensure the resulting lock will get added to granted list */
+		fl->c.flc_flags |= FL_SLEEP;
+		if (do_vfs_lock(fl) < 0)
+			printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__);
+		up_read(&host->h_rwsem);
+		fl->c.flc_flags = flags;
+		status = 0;
+	}
+	if (status < 0)
+		goto out_unlock;
+	/*
+	 * EAGAIN doesn't make sense for sleeping locks, and in some
+	 * cases NLM_LCK_DENIED is returned for a permanent error.  So
+	 * turn it into an ENOLCK.
+	 */
+	if (resp->status == nlm_lck_denied && (flags & FL_SLEEP))
+		status = -ENOLCK;
+	else
+		status = nlm_stat_to_errno(resp->status);
+out:
+	trace_nlmclnt_lock(&req->a_args.lock,
+			   (const struct sockaddr *)&req->a_host->h_addr,
+			   req->a_host->h_addrlen, req->a_res.status);
+	nlmclnt_release_call(req);
+	return status;
+out_unlock:
+	/* Fatal error: ensure that we remove the lock altogether */
+	trace_nlmclnt_lock(&req->a_args.lock,
+			   (const struct sockaddr *)&req->a_host->h_addr,
+			   req->a_host->h_addrlen, req->a_res.status);
+	dprintk("lockd: lock attempt ended in fatal error.\n"
+		"       Attempting to unlock.\n");
+	type = fl->c.flc_type;
+	fl->c.flc_type = F_UNLCK;
+	down_read(&host->h_rwsem);
+	do_vfs_lock(fl);
+	up_read(&host->h_rwsem);
+	fl->c.flc_type = type;
+	fl->c.flc_flags = flags;
+	nlmclnt_async_call(cred, req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
+	return status;
+}
+
+/*
+ * RECLAIM: Try to reclaim a lock
+ */
+int
+nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl,
+		struct nlm_rqst *req)
+{
+	int		status;
+
+	memset(req, 0, sizeof(*req));
+	locks_init_lock(&req->a_args.lock.fl);
+	locks_init_lock(&req->a_res.lock.fl);
+	req->a_host  = host;
+
+	/* Set up the argument struct */
+	nlmclnt_setlockargs(req, fl);
+	req->a_args.reclaim = 1;
+
+	status = nlmclnt_call(nfs_file_cred(fl->c.flc_file), req,
+			      NLMPROC_LOCK);
+	if (status >= 0 && req->a_res.status == nlm_granted)
+		return 0;
+
+	printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
+				"(errno %d, status %d)\n",
+				fl->c.flc_pid,
+				status, ntohl(req->a_res.status));
+
+	/*
+	 * FIXME: This is a serious failure. We can
+	 *
+	 *  a.	Ignore the problem
+	 *  b.	Send the owning process some signal (Linux doesn't have
+	 *	SIGLOST, though...)
+	 *  c.	Retry the operation
+	 *
+	 * Until someone comes up with a simple implementation
+	 * for b or c, I'll choose option a.
+	 */
+
+	return -ENOLCK;
+}
+
+/*
+ * UNLOCK: remove an existing lock
+ */
+static int
+nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
+{
+	struct nlm_host	*host = req->a_host;
+	struct lockd_res *resp = &req->a_res;
+	int status;
+	unsigned char flags = fl->c.flc_flags;
+
+	/*
+	 * Note: the server is supposed to either grant us the unlock
+	 * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
+	 * case, we want to unlock.
+	 */
+	fl->c.flc_flags |= FL_EXISTS;
+	down_read(&host->h_rwsem);
+	status = do_vfs_lock(fl);
+	up_read(&host->h_rwsem);
+	fl->c.flc_flags = flags;
+	if (status == -ENOENT) {
+		status = 0;
+		goto out;
+	}
+
+	refcount_inc(&req->a_count);
+	status = nlmclnt_async_call(nfs_file_cred(fl->c.flc_file), req,
+				    NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
+	if (status < 0)
+		goto out;
+
+	if (resp->status == nlm_granted)
+		goto out;
+
+	if (resp->status != nlm_lck_denied_nolocks)
+		printk("lockd: unexpected unlock status: %d\n",
+			ntohl(resp->status));
+	/* What to do now? I'm out of my depth... */
+	status = -ENOLCK;
+out:
+	trace_nlmclnt_unlock(&req->a_args.lock,
+			     (const struct sockaddr *)&req->a_host->h_addr,
+			     req->a_host->h_addrlen, req->a_res.status);
+	nlmclnt_release_call(req);
+	return status;
+}
+
+static void nlmclnt_unlock_prepare(struct rpc_task *task, void *data)
+{
+	struct nlm_rqst	*req = data;
+	const struct nlmclnt_operations *nlmclnt_ops = req->a_host->h_nlmclnt_ops;
+	bool defer_call = false;
+
+	if (nlmclnt_ops && nlmclnt_ops->nlmclnt_unlock_prepare)
+		defer_call = nlmclnt_ops->nlmclnt_unlock_prepare(task, req->a_callback_data);
+
+	if (!defer_call)
+		rpc_call_start(task);
+}
+
+static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
+{
+	struct nlm_rqst	*req = data;
+	u32 status = ntohl(req->a_res.status);
+
+	if (RPC_SIGNALLED(task))
+		goto die;
+
+	if (task->tk_status < 0) {
+		dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
+		switch (task->tk_status) {
+		case -EACCES:
+		case -EIO:
+			goto die;
+		default:
+			goto retry_rebind;
+		}
+	}
+	if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
+		rpc_delay(task, NLMCLNT_GRACE_WAIT);
+		goto retry_unlock;
+	}
+	if (status != NLM_LCK_GRANTED)
+		printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
+die:
+	return;
+ retry_rebind:
+	nlm_rebind_host(req->a_host);
+ retry_unlock:
+	rpc_restart_call(task);
+}
+
+static const struct rpc_call_ops nlmclnt_unlock_ops = {
+	.rpc_call_prepare = nlmclnt_unlock_prepare,
+	.rpc_call_done = nlmclnt_unlock_callback,
+	.rpc_release = nlmclnt_rpc_release,
+};
+
+/*
+ * Cancel a blocked lock request.
+ * We always use an async RPC call for this in order not to hang a
+ * process that has been Ctrl-C'ed.
+ */
+static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
+{
+	struct nlm_rqst	*req;
+	int status;
+
+	dprintk("lockd: blocking lock attempt was interrupted by a signal.\n"
+		"       Attempting to cancel lock.\n");
+
+	req = nlm_alloc_call(host);
+	if (!req)
+		return -ENOMEM;
+	req->a_flags = RPC_TASK_ASYNC;
+
+	nlmclnt_setlockargs(req, fl);
+	req->a_args.block = block;
+
+	refcount_inc(&req->a_count);
+	status = nlmclnt_async_call(nfs_file_cred(fl->c.flc_file), req,
+				    NLMPROC_CANCEL, &nlmclnt_cancel_ops);
+	if (status == 0 && req->a_res.status == nlm_lck_denied)
+		status = -ENOLCK;
+	nlmclnt_release_call(req);
+	return status;
+}
+
+static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
+{
+	struct nlm_rqst	*req = data;
+	u32 status = ntohl(req->a_res.status);
+
+	if (RPC_SIGNALLED(task))
+		goto die;
+
+	if (task->tk_status < 0) {
+		dprintk("lockd: CANCEL call error %d, retrying.\n",
+					task->tk_status);
+		goto retry_cancel;
+	}
+
+	switch (status) {
+	case NLM_LCK_GRANTED:
+	case NLM_LCK_DENIED_GRACE_PERIOD:
+	case NLM_LCK_DENIED:
+		/* Everything's good */
+		break;
+	case NLM_LCK_DENIED_NOLOCKS:
+		dprintk("lockd: CANCEL failed (server has no locks)\n");
+		goto retry_cancel;
+	default:
+		printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
+			status);
+	}
+
+die:
+	return;
+
+retry_cancel:
+	/* Don't ever retry more than 3 times */
+	if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
+		goto die;
+	nlm_rebind_host(req->a_host);
+	rpc_restart_call(task);
+	rpc_delay(task, 30 * HZ);
+}
+
+static const struct rpc_call_ops nlmclnt_cancel_ops = {
+	.rpc_call_done = nlmclnt_cancel_callback,
+	.rpc_release = nlmclnt_rpc_release,
+};
+
+/*
+ * Convert an NLM status code to a generic kernel errno
+ */
+static int
+nlm_stat_to_errno(__be32 status)
+{
+	switch(ntohl(status)) {
+	case NLM_LCK_GRANTED:
+		return 0;
+	case NLM_LCK_DENIED:
+		return -EAGAIN;
+	case NLM_LCK_DENIED_NOLOCKS:
+	case NLM_LCK_DENIED_GRACE_PERIOD:
+		return -ENOLCK;
+	case NLM_LCK_BLOCKED:
+		printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
+		return -ENOLCK;
+#ifdef CONFIG_LOCKD_V4
+	case NLM_DEADLCK:
+		return -EDEADLK;
+	case NLM_ROFS:
+		return -EROFS;
+	case NLM_STALE_FH:
+		return -ESTALE;
+	case NLM_FBIG:
+		return -EOVERFLOW;
+	case NLM_FAILED:
+		return -ENOLCK;
+#endif
+	}
+	printk(KERN_NOTICE "lockd: unexpected server status %d\n",
+		 ntohl(status));
+	return -ENOLCK;
+}