[19/24] lustre: lnet: add "lnetctl peer list"
diff mbox series

Message ID 153895437828.16383.14376327105039832285.stgit@noble
State New
Headers show
Series
  • Port Dynamic Discovery to drivers/staging
Related show

Commit Message

NeilBrown Oct. 7, 2018, 11:19 p.m. UTC
From: Olaf Weber <olaf@sgi.com>

Add IOC_LIBCFS_GET_PEER_LIST to obtain a list of the primary
NIDs of all peers known to the system. The list is written
into a userspace buffer by the kernel. The typical usage is
to make a first call to determine the required buffer size,
then a second call to obtain the list.

Extend the "lnetctl peer" set of commands with a "list"
subcommand that uses this interface.

Modify the IOC_LIBCFS_GET_PEER_NI ioctl (which is new in the
Multi-Rail code) to use a NID to indicate the peer to look
up, and then pass out the data for all NIDs of that peer.

Re-implement "lnetctl peer show" to obtain the list of NIDs
using IOC_LIBCFS_GET_PEER_LIST followed by one or more
IOC_LIBCFS_GET_PEER_NI calls to get information for each
peer.

Make sure to copy the structure from kernel space to
user space even if the ioctl handler returns an error.
This is needed because if the buffer passed in by the
user space is not big enough to copy the data, we want
to pass the requested size to user space in the structure
passed in. The return code in this case is -E2BIG.

WC-bug-id: https://jira.whamcloud.com/browse/LU-9480
Signed-off-by: Olaf Weber <olaf@sgi.com>
Reviewed-on: https://review.whamcloud.com/25790
Reviewed-by: Amir Shehata <amir.shehata@intel.com>
Tested-by: Amir Shehata <amir.shehata@intel.com>
Signed-off-by: NeilBrown <neilb@suse.com>
---
 .../staging/lustre/include/linux/lnet/lib-lnet.h   |    9 -
 .../staging/lustre/include/linux/lnet/lib-types.h  |    3 
 .../lustre/include/uapi/linux/lnet/libcfs_ioctl.h  |    3 
 drivers/staging/lustre/lnet/lnet/api-ni.c          |   30 ++-
 drivers/staging/lustre/lnet/lnet/peer.c            |  222 +++++++++++++-------
 5 files changed, 169 insertions(+), 98 deletions(-)

Comments

James Simmons Oct. 14, 2018, 11:38 p.m. UTC | #1
> From: Olaf Weber <olaf@sgi.com>
> 
> Add IOC_LIBCFS_GET_PEER_LIST to obtain a list of the primary
> NIDs of all peers known to the system. The list is written
> into a userspace buffer by the kernel. The typical usage is
> to make a first call to determine the required buffer size,
> then a second call to obtain the list.
> 
> Extend the "lnetctl peer" set of commands with a "list"
> subcommand that uses this interface.
> 
> Modify the IOC_LIBCFS_GET_PEER_NI ioctl (which is new in the
> Multi-Rail code) to use a NID to indicate the peer to look
> up, and then pass out the data for all NIDs of that peer.
> 
> Re-implement "lnetctl peer show" to obtain the list of NIDs
> using IOC_LIBCFS_GET_PEER_LIST followed by one or more
> IOC_LIBCFS_GET_PEER_NI calls to get information for each
> peer.
> 
> Make sure to copy the structure from kernel space to
> user space even if the ioctl handler returns an error.
> This is needed because if the buffer passed in by the
> user space is not big enough to copy the data, we want
> to pass the requested size to user space in the structure
> passed in. The return code in this case is -E2BIG.

Reviewed-by: James Simmons <jsimmons@infradead.org>
 
> WC-bug-id: https://jira.whamcloud.com/browse/LU-9480
> Signed-off-by: Olaf Weber <olaf@sgi.com>
> Reviewed-on: https://review.whamcloud.com/25790
> Reviewed-by: Amir Shehata <amir.shehata@intel.com>
> Tested-by: Amir Shehata <amir.shehata@intel.com>
> Signed-off-by: NeilBrown <neilb@suse.com>
> ---
>  .../staging/lustre/include/linux/lnet/lib-lnet.h   |    9 -
>  .../staging/lustre/include/linux/lnet/lib-types.h  |    3 
>  .../lustre/include/uapi/linux/lnet/libcfs_ioctl.h  |    3 
>  drivers/staging/lustre/lnet/lnet/api-ni.c          |   30 ++-
>  drivers/staging/lustre/lnet/lnet/peer.c            |  222 +++++++++++++-------
>  5 files changed, 169 insertions(+), 98 deletions(-)
> 
> diff --git a/drivers/staging/lustre/include/linux/lnet/lib-lnet.h b/drivers/staging/lustre/include/linux/lnet/lib-lnet.h
> index f82a699371f2..58e3a9c4e39f 100644
> --- a/drivers/staging/lustre/include/linux/lnet/lib-lnet.h
> +++ b/drivers/staging/lustre/include/linux/lnet/lib-lnet.h
> @@ -462,6 +462,8 @@ int lnet_get_rtr_pool_cfg(int idx, struct lnet_ioctl_pool_cfg *pool_cfg);
>  struct lnet_ni *lnet_get_next_ni_locked(struct lnet_net *mynet,
>  					struct lnet_ni *prev);
>  struct lnet_ni *lnet_get_ni_idx_locked(int idx);
> +int lnet_get_peer_list(__u32 *countp, __u32 *sizep,
> +		       struct lnet_process_id __user *ids);
>  
>  void lnet_router_debugfs_init(void);
>  void lnet_router_debugfs_fini(void);
> @@ -730,10 +732,9 @@ bool lnet_peer_is_pref_nid_locked(struct lnet_peer_ni *lpni, lnet_nid_t nid);
>  int lnet_peer_ni_set_non_mr_pref_nid(struct lnet_peer_ni *lpni, lnet_nid_t nid);
>  int lnet_add_peer_ni(lnet_nid_t key_nid, lnet_nid_t nid, bool mr);
>  int lnet_del_peer_ni(lnet_nid_t key_nid, lnet_nid_t nid);
> -int lnet_get_peer_info(__u32 idx, lnet_nid_t *primary_nid, lnet_nid_t *nid,
> -		       bool *mr,
> -		       struct lnet_peer_ni_credit_info __user *peer_ni_info,
> -		       struct lnet_ioctl_element_stats __user *peer_ni_stats);
> +int lnet_get_peer_info(lnet_nid_t *primary_nid, lnet_nid_t *nid,
> +		       __u32 *nnis, bool *mr, __u32 *sizep,
> +		       void __user *bulk);
>  int lnet_get_peer_ni_info(__u32 peer_index, __u64 *nid,
>  			  char alivness[LNET_MAX_STR_LEN],
>  			  __u32 *cpt_iter, __u32 *refcount,
> diff --git a/drivers/staging/lustre/include/linux/lnet/lib-types.h b/drivers/staging/lustre/include/linux/lnet/lib-types.h
> index 07baa86e61ab..8543a67420d7 100644
> --- a/drivers/staging/lustre/include/linux/lnet/lib-types.h
> +++ b/drivers/staging/lustre/include/linux/lnet/lib-types.h
> @@ -651,7 +651,6 @@ struct lnet_peer_net {
>   *    pt_hash[...]
>   *    pt_peer_list
>   *    pt_peers
> - *    pt_peer_nnids
>   * protected by pt_zombie_lock:
>   *    pt_zombie_list
>   *    pt_zombies
> @@ -667,8 +666,6 @@ struct lnet_peer_table {
>  	struct list_head	pt_peer_list;
>  	/* # peers */
>  	int			pt_peers;
> -	/* # NIDS on listed peers */
> -	int			pt_peer_nnids;
>  	/* # zombies to go to deathrow (and not there yet) */
>  	int			 pt_zombies;
>  	/* zombie peers_ni */
> diff --git a/drivers/staging/lustre/include/uapi/linux/lnet/libcfs_ioctl.h b/drivers/staging/lustre/include/uapi/linux/lnet/libcfs_ioctl.h
> index 2a9beed23985..2607620e8ef8 100644
> --- a/drivers/staging/lustre/include/uapi/linux/lnet/libcfs_ioctl.h
> +++ b/drivers/staging/lustre/include/uapi/linux/lnet/libcfs_ioctl.h
> @@ -144,6 +144,7 @@ struct libcfs_debug_ioctl_data {
>  #define IOC_LIBCFS_GET_LOCAL_NI		_IOWR(IOC_LIBCFS_TYPE, 97, IOCTL_CONFIG_SIZE)
>  #define IOC_LIBCFS_SET_NUMA_RANGE	_IOWR(IOC_LIBCFS_TYPE, 98, IOCTL_CONFIG_SIZE)
>  #define IOC_LIBCFS_GET_NUMA_RANGE	_IOWR(IOC_LIBCFS_TYPE, 99, IOCTL_CONFIG_SIZE)
> -#define IOC_LIBCFS_MAX_NR		99
> +#define IOC_LIBCFS_GET_PEER_LIST	_IOWR(IOC_LIBCFS_TYPE, 100, IOCTL_CONFIG_SIZE)
> +#define IOC_LIBCFS_MAX_NR		100
>  
>  #endif /* __LIBCFS_IOCTL_H__ */
> diff --git a/drivers/staging/lustre/lnet/lnet/api-ni.c b/drivers/staging/lustre/lnet/lnet/api-ni.c
> index 955d1711eda4..f624abe7db80 100644
> --- a/drivers/staging/lustre/lnet/lnet/api-ni.c
> +++ b/drivers/staging/lustre/lnet/lnet/api-ni.c
> @@ -3117,21 +3117,31 @@ LNetCtl(unsigned int cmd, void *arg)
>  
>  	case IOC_LIBCFS_GET_PEER_NI: {
>  		struct lnet_ioctl_peer_cfg *cfg = arg;
> -		struct lnet_peer_ni_credit_info __user *lpni_cri;
> -		struct lnet_ioctl_element_stats __user *lpni_stats;
> -		size_t usr_size = sizeof(*lpni_cri) + sizeof(*lpni_stats);
>  
> -		if ((cfg->prcfg_hdr.ioc_len != sizeof(*cfg)) ||
> -		    (cfg->prcfg_size != usr_size))
> +		if (cfg->prcfg_hdr.ioc_len < sizeof(*cfg))
>  			return -EINVAL;
>  
> -		lpni_cri = cfg->prcfg_bulk;
> -		lpni_stats = cfg->prcfg_bulk + sizeof(*lpni_cri);
> +		mutex_lock(&the_lnet.ln_api_mutex);
> +		rc = lnet_get_peer_info(&cfg->prcfg_prim_nid,
> +					&cfg->prcfg_cfg_nid,
> +					&cfg->prcfg_count,
> +					&cfg->prcfg_mr,
> +					&cfg->prcfg_size,
> +					(void __user *)cfg->prcfg_bulk);
> +		mutex_unlock(&the_lnet.ln_api_mutex);
> +		return rc;
> +	}
> +
> +	case IOC_LIBCFS_GET_PEER_LIST: {
> +		struct lnet_ioctl_peer_cfg *cfg = arg;
> +
> +		if (cfg->prcfg_hdr.ioc_len < sizeof(*cfg))
> +			return -EINVAL;
>  
>  		mutex_lock(&the_lnet.ln_api_mutex);
> -		rc = lnet_get_peer_info(cfg->prcfg_count, &cfg->prcfg_prim_nid,
> -					&cfg->prcfg_cfg_nid, &cfg->prcfg_mr,
> -					lpni_cri, lpni_stats);
> +		rc = lnet_get_peer_list(&cfg->prcfg_count, &cfg->prcfg_size,
> +					(struct lnet_process_id __user *)
> +					cfg->prcfg_bulk);
>  		mutex_unlock(&the_lnet.ln_api_mutex);
>  		return rc;
>  	}
> diff --git a/drivers/staging/lustre/lnet/lnet/peer.c b/drivers/staging/lustre/lnet/lnet/peer.c
> index 1ef4a44e752e..8dff3b767577 100644
> --- a/drivers/staging/lustre/lnet/lnet/peer.c
> +++ b/drivers/staging/lustre/lnet/lnet/peer.c
> @@ -263,9 +263,7 @@ lnet_peer_detach_peer_ni_locked(struct lnet_peer_ni *lpni)
>  
>  	/* Update peer NID count. */
>  	lp = lpn->lpn_peer;
> -	ptable = the_lnet.ln_peer_tables[lp->lp_cpt];
>  	lp->lp_nnis--;
> -	ptable->pt_peer_nnids--;
>  
>  	/*
>  	 * If there are no more peer nets, make the peer unfindable
> @@ -277,6 +275,7 @@ lnet_peer_detach_peer_ni_locked(struct lnet_peer_ni *lpni)
>  	 */
>  	if (list_empty(&lp->lp_peer_nets)) {
>  		list_del_init(&lp->lp_peer_list);
> +		ptable = the_lnet.ln_peer_tables[lp->lp_cpt];
>  		ptable->pt_peers--;
>  	} else if (the_lnet.ln_dc_state != LNET_DC_STATE_RUNNING) {
>  		/* Discovery isn't running, nothing to do here. */
> @@ -637,44 +636,6 @@ lnet_find_peer(lnet_nid_t nid)
>  	return lp;
>  }
>  
> -struct lnet_peer_ni *
> -lnet_get_peer_ni_idx_locked(int idx, struct lnet_peer_net **lpn,
> -			    struct lnet_peer **lp)
> -{
> -	struct lnet_peer_table	*ptable;
> -	struct lnet_peer_ni	*lpni;
> -	int			lncpt;
> -	int			cpt;
> -
> -	lncpt = cfs_percpt_number(the_lnet.ln_peer_tables);
> -
> -	for (cpt = 0; cpt < lncpt; cpt++) {
> -		ptable = the_lnet.ln_peer_tables[cpt];
> -		if (ptable->pt_peer_nnids > idx)
> -			break;
> -		idx -= ptable->pt_peer_nnids;
> -	}
> -	if (cpt >= lncpt)
> -		return NULL;
> -
> -	list_for_each_entry((*lp), &ptable->pt_peer_list, lp_peer_list) {
> -		if ((*lp)->lp_nnis <= idx) {
> -			idx -= (*lp)->lp_nnis;
> -			continue;
> -		}
> -		list_for_each_entry((*lpn), &((*lp)->lp_peer_nets),
> -				    lpn_peer_nets) {
> -			list_for_each_entry(lpni, &((*lpn)->lpn_peer_nis),
> -					    lpni_peer_nis) {
> -				if (idx-- == 0)
> -					return lpni;
> -			}
> -		}
> -	}
> -
> -	return NULL;
> -}
> -
>  struct lnet_peer_ni *
>  lnet_get_next_peer_ni_locked(struct lnet_peer *peer,
>  			     struct lnet_peer_net *peer_net,
> @@ -734,6 +695,69 @@ lnet_get_next_peer_ni_locked(struct lnet_peer *peer,
>  	return lpni;
>  }
>  
> +/* Call with the ln_api_mutex held */
> +int
> +lnet_get_peer_list(__u32 *countp, __u32 *sizep,
> +		   struct lnet_process_id __user *ids)
> +{
> +	struct lnet_process_id id;
> +	struct lnet_peer_table *ptable;
> +	struct lnet_peer *lp;
> +	__u32 count = 0;
> +	__u32 size = 0;
> +	int lncpt;
> +	int cpt;
> +	__u32 i;
> +	int rc;
> +
> +	rc = -ESHUTDOWN;
> +	if (the_lnet.ln_state == LNET_STATE_SHUTDOWN)
> +		goto done;
> +
> +	lncpt = cfs_percpt_number(the_lnet.ln_peer_tables);
> +
> +	/*
> +	 * Count the number of peers, and return E2BIG if the buffer
> +	 * is too small. We'll also return the desired size.
> +	 */
> +	rc = -E2BIG;
> +	for (cpt = 0; cpt < lncpt; cpt++) {
> +		ptable = the_lnet.ln_peer_tables[cpt];
> +		count += ptable->pt_peers;
> +	}
> +	size = count * sizeof(*ids);
> +	if (size > *sizep)
> +		goto done;
> +
> +	/*
> +	 * Walk the peer lists and copy out the primary nids.
> +	 * This is safe because the peer lists are only modified
> +	 * while the ln_api_mutex is held. So we don't need to
> +	 * hold the lnet_net_lock as well, and can therefore
> +	 * directly call copy_to_user().
> +	 */
> +	rc = -EFAULT;
> +	memset(&id, 0, sizeof(id));
> +	id.pid = LNET_PID_LUSTRE;
> +	i = 0;
> +	for (cpt = 0; cpt < lncpt; cpt++) {
> +		ptable = the_lnet.ln_peer_tables[cpt];
> +		list_for_each_entry(lp, &ptable->pt_peer_list, lp_peer_list) {
> +			if (i >= count)
> +				goto done;
> +			id.nid = lp->lp_primary_nid;
> +			if (copy_to_user(&ids[i], &id, sizeof(id)))
> +				goto done;
> +			i++;
> +		}
> +	}
> +	rc = 0;
> +done:
> +	*countp = count;
> +	*sizep = size;
> +	return rc;
> +}
> +
>  /*
>   * Start pushes to peers that need to be updated for a configuration
>   * change on this node.
> @@ -1128,7 +1152,6 @@ lnet_peer_attach_peer_ni(struct lnet_peer *lp,
>  	spin_unlock(&lp->lp_lock);
>  
>  	lp->lp_nnis++;
> -	the_lnet.ln_peer_tables[lp->lp_cpt]->pt_peer_nnids++;
>  	lnet_net_unlock(LNET_LOCK_EX);
>  
>  	CDEBUG(D_NET, "peer %s NID %s flags %#x\n",
> @@ -3273,55 +3296,94 @@ lnet_get_peer_ni_info(__u32 peer_index, __u64 *nid,
>  }
>  
>  /* ln_api_mutex is held, which keeps the peer list stable */
> -int lnet_get_peer_info(__u32 idx, lnet_nid_t *primary_nid, lnet_nid_t *nid,
> -		       bool *mr,
> -		       struct lnet_peer_ni_credit_info __user *peer_ni_info,
> -		       struct lnet_ioctl_element_stats __user *peer_ni_stats)
> +int lnet_get_peer_info(lnet_nid_t *primary_nid, lnet_nid_t *nidp,
> +		       __u32 *nnis, bool *mr, __u32 *sizep,
> +		       void __user *bulk)
>  {
> -	struct lnet_ioctl_element_stats ni_stats;
> -	struct lnet_peer_ni_credit_info ni_info;
> -	struct lnet_peer_ni *lpni = NULL;
> -	struct lnet_peer_net *lpn = NULL;
> -	struct lnet_peer *lp = NULL;
> +	struct lnet_ioctl_element_stats *lpni_stats;
> +	struct lnet_peer_ni_credit_info *lpni_info;
> +	struct lnet_peer_ni *lpni;
> +	struct lnet_peer *lp;
> +	lnet_nid_t nid;
> +	__u32 size;
>  	int rc;
>  
> -	lpni = lnet_get_peer_ni_idx_locked(idx, &lpn, &lp);
> +	lp = lnet_find_peer(*primary_nid);
>  
> -	if (!lpni)
> -		return -ENOENT;
> +	if (!lp) {
> +		rc = -ENOENT;
> +		goto out;
> +	}
> +
> +	size = sizeof(nid) + sizeof(*lpni_info) + sizeof(*lpni_stats);
> +	size *= lp->lp_nnis;
> +	if (size > *sizep) {
> +		*sizep = size;
> +		rc = -E2BIG;
> +		goto out_lp_decref;
> +	}
>  
>  	*primary_nid = lp->lp_primary_nid;
>  	*mr = lnet_peer_is_multi_rail(lp);
> -	*nid = lpni->lpni_nid;
> -	snprintf(ni_info.cr_aliveness, LNET_MAX_STR_LEN, "NA");
> -	if (lnet_isrouter(lpni) ||
> -	    lnet_peer_aliveness_enabled(lpni))
> -		snprintf(ni_info.cr_aliveness, LNET_MAX_STR_LEN,
> -			 lpni->lpni_alive ? "up" : "down");
> -
> -	ni_info.cr_refcount = atomic_read(&lpni->lpni_refcount);
> -	ni_info.cr_ni_peer_tx_credits = lpni->lpni_net ?
> -		lpni->lpni_net->net_tunables.lct_peer_tx_credits : 0;
> -	ni_info.cr_peer_tx_credits = lpni->lpni_txcredits;
> -	ni_info.cr_peer_rtr_credits = lpni->lpni_rtrcredits;
> -	ni_info.cr_peer_min_rtr_credits = lpni->lpni_minrtrcredits;
> -	ni_info.cr_peer_min_tx_credits = lpni->lpni_mintxcredits;
> -	ni_info.cr_peer_tx_qnob = lpni->lpni_txqnob;
> -
> -	ni_stats.iel_send_count = atomic_read(&lpni->lpni_stats.send_count);
> -	ni_stats.iel_recv_count = atomic_read(&lpni->lpni_stats.recv_count);
> -	ni_stats.iel_drop_count = atomic_read(&lpni->lpni_stats.drop_count);
> -
> -	/* If copy_to_user fails */
> -	rc = -EFAULT;
> -	if (copy_to_user(peer_ni_info, &ni_info, sizeof(ni_info)))
> -		goto copy_failed;
> +	*nidp = lp->lp_primary_nid;
> +	*nnis = lp->lp_nnis;
> +	*sizep = size;
>  
> -	if (copy_to_user(peer_ni_stats, &ni_stats, sizeof(ni_stats)))
> -		goto copy_failed;
> +	/* Allocate helper buffers. */
> +	rc = -ENOMEM;
> +	lpni_info = kzalloc(sizeof(*lpni_info), GFP_KERNEL);
> +	if (!lpni_info)
> +		goto out_lp_decref;
> +	lpni_stats = kzalloc(sizeof(*lpni_stats), GFP_KERNEL);
> +	if (!lpni_stats)
> +		goto out_free_info;
>  
> +	lpni = NULL;
> +	rc = -EFAULT;
> +	while ((lpni = lnet_get_next_peer_ni_locked(lp, NULL, lpni)) != NULL) {
> +		nid = lpni->lpni_nid;
> +		if (copy_to_user(bulk, &nid, sizeof(nid)))
> +			goto out_free_stats;
> +		bulk += sizeof(nid);
> +
> +		memset(lpni_info, 0, sizeof(*lpni_info));
> +		snprintf(lpni_info->cr_aliveness, LNET_MAX_STR_LEN, "NA");
> +		if (lnet_isrouter(lpni) ||
> +		    lnet_peer_aliveness_enabled(lpni))
> +			snprintf(lpni_info->cr_aliveness, LNET_MAX_STR_LEN,
> +				 lpni->lpni_alive ? "up" : "down");
> +
> +		lpni_info->cr_refcount = atomic_read(&lpni->lpni_refcount);
> +		lpni_info->cr_ni_peer_tx_credits = lpni->lpni_net ?
> +			lpni->lpni_net->net_tunables.lct_peer_tx_credits : 0;
> +		lpni_info->cr_peer_tx_credits = lpni->lpni_txcredits;
> +		lpni_info->cr_peer_rtr_credits = lpni->lpni_rtrcredits;
> +		lpni_info->cr_peer_min_rtr_credits = lpni->lpni_minrtrcredits;
> +		lpni_info->cr_peer_min_tx_credits = lpni->lpni_mintxcredits;
> +		lpni_info->cr_peer_tx_qnob = lpni->lpni_txqnob;
> +		if (copy_to_user(bulk, lpni_info, sizeof(*lpni_info)))
> +			goto out_free_stats;
> +		bulk += sizeof(*lpni_info);
> +
> +		memset(lpni_stats, 0, sizeof(*lpni_stats));
> +		lpni_stats->iel_send_count =
> +			atomic_read(&lpni->lpni_stats.send_count);
> +		lpni_stats->iel_recv_count =
> +			atomic_read(&lpni->lpni_stats.recv_count);
> +		lpni_stats->iel_drop_count =
> +			atomic_read(&lpni->lpni_stats.drop_count);
> +		if (copy_to_user(bulk, lpni_stats, sizeof(*lpni_stats)))
> +			goto out_free_stats;
> +		bulk += sizeof(*lpni_stats);
> +	}
>  	rc = 0;
>  
> -copy_failed:
> +out_free_stats:
> +	kfree(lpni_stats);
> +out_free_info:
> +	kfree(lpni_info);
> +out_lp_decref:
> +	lnet_peer_decref_locked(lp);
> +out:
>  	return rc;
>  }
> 
> 
>

Patch
diff mbox series

diff --git a/drivers/staging/lustre/include/linux/lnet/lib-lnet.h b/drivers/staging/lustre/include/linux/lnet/lib-lnet.h
index f82a699371f2..58e3a9c4e39f 100644
--- a/drivers/staging/lustre/include/linux/lnet/lib-lnet.h
+++ b/drivers/staging/lustre/include/linux/lnet/lib-lnet.h
@@ -462,6 +462,8 @@  int lnet_get_rtr_pool_cfg(int idx, struct lnet_ioctl_pool_cfg *pool_cfg);
 struct lnet_ni *lnet_get_next_ni_locked(struct lnet_net *mynet,
 					struct lnet_ni *prev);
 struct lnet_ni *lnet_get_ni_idx_locked(int idx);
+int lnet_get_peer_list(__u32 *countp, __u32 *sizep,
+		       struct lnet_process_id __user *ids);
 
 void lnet_router_debugfs_init(void);
 void lnet_router_debugfs_fini(void);
@@ -730,10 +732,9 @@  bool lnet_peer_is_pref_nid_locked(struct lnet_peer_ni *lpni, lnet_nid_t nid);
 int lnet_peer_ni_set_non_mr_pref_nid(struct lnet_peer_ni *lpni, lnet_nid_t nid);
 int lnet_add_peer_ni(lnet_nid_t key_nid, lnet_nid_t nid, bool mr);
 int lnet_del_peer_ni(lnet_nid_t key_nid, lnet_nid_t nid);
-int lnet_get_peer_info(__u32 idx, lnet_nid_t *primary_nid, lnet_nid_t *nid,
-		       bool *mr,
-		       struct lnet_peer_ni_credit_info __user *peer_ni_info,
-		       struct lnet_ioctl_element_stats __user *peer_ni_stats);
+int lnet_get_peer_info(lnet_nid_t *primary_nid, lnet_nid_t *nid,
+		       __u32 *nnis, bool *mr, __u32 *sizep,
+		       void __user *bulk);
 int lnet_get_peer_ni_info(__u32 peer_index, __u64 *nid,
 			  char alivness[LNET_MAX_STR_LEN],
 			  __u32 *cpt_iter, __u32 *refcount,
diff --git a/drivers/staging/lustre/include/linux/lnet/lib-types.h b/drivers/staging/lustre/include/linux/lnet/lib-types.h
index 07baa86e61ab..8543a67420d7 100644
--- a/drivers/staging/lustre/include/linux/lnet/lib-types.h
+++ b/drivers/staging/lustre/include/linux/lnet/lib-types.h
@@ -651,7 +651,6 @@  struct lnet_peer_net {
  *    pt_hash[...]
  *    pt_peer_list
  *    pt_peers
- *    pt_peer_nnids
  * protected by pt_zombie_lock:
  *    pt_zombie_list
  *    pt_zombies
@@ -667,8 +666,6 @@  struct lnet_peer_table {
 	struct list_head	pt_peer_list;
 	/* # peers */
 	int			pt_peers;
-	/* # NIDS on listed peers */
-	int			pt_peer_nnids;
 	/* # zombies to go to deathrow (and not there yet) */
 	int			 pt_zombies;
 	/* zombie peers_ni */
diff --git a/drivers/staging/lustre/include/uapi/linux/lnet/libcfs_ioctl.h b/drivers/staging/lustre/include/uapi/linux/lnet/libcfs_ioctl.h
index 2a9beed23985..2607620e8ef8 100644
--- a/drivers/staging/lustre/include/uapi/linux/lnet/libcfs_ioctl.h
+++ b/drivers/staging/lustre/include/uapi/linux/lnet/libcfs_ioctl.h
@@ -144,6 +144,7 @@  struct libcfs_debug_ioctl_data {
 #define IOC_LIBCFS_GET_LOCAL_NI		_IOWR(IOC_LIBCFS_TYPE, 97, IOCTL_CONFIG_SIZE)
 #define IOC_LIBCFS_SET_NUMA_RANGE	_IOWR(IOC_LIBCFS_TYPE, 98, IOCTL_CONFIG_SIZE)
 #define IOC_LIBCFS_GET_NUMA_RANGE	_IOWR(IOC_LIBCFS_TYPE, 99, IOCTL_CONFIG_SIZE)
-#define IOC_LIBCFS_MAX_NR		99
+#define IOC_LIBCFS_GET_PEER_LIST	_IOWR(IOC_LIBCFS_TYPE, 100, IOCTL_CONFIG_SIZE)
+#define IOC_LIBCFS_MAX_NR		100
 
 #endif /* __LIBCFS_IOCTL_H__ */
diff --git a/drivers/staging/lustre/lnet/lnet/api-ni.c b/drivers/staging/lustre/lnet/lnet/api-ni.c
index 955d1711eda4..f624abe7db80 100644
--- a/drivers/staging/lustre/lnet/lnet/api-ni.c
+++ b/drivers/staging/lustre/lnet/lnet/api-ni.c
@@ -3117,21 +3117,31 @@  LNetCtl(unsigned int cmd, void *arg)
 
 	case IOC_LIBCFS_GET_PEER_NI: {
 		struct lnet_ioctl_peer_cfg *cfg = arg;
-		struct lnet_peer_ni_credit_info __user *lpni_cri;
-		struct lnet_ioctl_element_stats __user *lpni_stats;
-		size_t usr_size = sizeof(*lpni_cri) + sizeof(*lpni_stats);
 
-		if ((cfg->prcfg_hdr.ioc_len != sizeof(*cfg)) ||
-		    (cfg->prcfg_size != usr_size))
+		if (cfg->prcfg_hdr.ioc_len < sizeof(*cfg))
 			return -EINVAL;
 
-		lpni_cri = cfg->prcfg_bulk;
-		lpni_stats = cfg->prcfg_bulk + sizeof(*lpni_cri);
+		mutex_lock(&the_lnet.ln_api_mutex);
+		rc = lnet_get_peer_info(&cfg->prcfg_prim_nid,
+					&cfg->prcfg_cfg_nid,
+					&cfg->prcfg_count,
+					&cfg->prcfg_mr,
+					&cfg->prcfg_size,
+					(void __user *)cfg->prcfg_bulk);
+		mutex_unlock(&the_lnet.ln_api_mutex);
+		return rc;
+	}
+
+	case IOC_LIBCFS_GET_PEER_LIST: {
+		struct lnet_ioctl_peer_cfg *cfg = arg;
+
+		if (cfg->prcfg_hdr.ioc_len < sizeof(*cfg))
+			return -EINVAL;
 
 		mutex_lock(&the_lnet.ln_api_mutex);
-		rc = lnet_get_peer_info(cfg->prcfg_count, &cfg->prcfg_prim_nid,
-					&cfg->prcfg_cfg_nid, &cfg->prcfg_mr,
-					lpni_cri, lpni_stats);
+		rc = lnet_get_peer_list(&cfg->prcfg_count, &cfg->prcfg_size,
+					(struct lnet_process_id __user *)
+					cfg->prcfg_bulk);
 		mutex_unlock(&the_lnet.ln_api_mutex);
 		return rc;
 	}
diff --git a/drivers/staging/lustre/lnet/lnet/peer.c b/drivers/staging/lustre/lnet/lnet/peer.c
index 1ef4a44e752e..8dff3b767577 100644
--- a/drivers/staging/lustre/lnet/lnet/peer.c
+++ b/drivers/staging/lustre/lnet/lnet/peer.c
@@ -263,9 +263,7 @@  lnet_peer_detach_peer_ni_locked(struct lnet_peer_ni *lpni)
 
 	/* Update peer NID count. */
 	lp = lpn->lpn_peer;
-	ptable = the_lnet.ln_peer_tables[lp->lp_cpt];
 	lp->lp_nnis--;
-	ptable->pt_peer_nnids--;
 
 	/*
 	 * If there are no more peer nets, make the peer unfindable
@@ -277,6 +275,7 @@  lnet_peer_detach_peer_ni_locked(struct lnet_peer_ni *lpni)
 	 */
 	if (list_empty(&lp->lp_peer_nets)) {
 		list_del_init(&lp->lp_peer_list);
+		ptable = the_lnet.ln_peer_tables[lp->lp_cpt];
 		ptable->pt_peers--;
 	} else if (the_lnet.ln_dc_state != LNET_DC_STATE_RUNNING) {
 		/* Discovery isn't running, nothing to do here. */
@@ -637,44 +636,6 @@  lnet_find_peer(lnet_nid_t nid)
 	return lp;
 }
 
-struct lnet_peer_ni *
-lnet_get_peer_ni_idx_locked(int idx, struct lnet_peer_net **lpn,
-			    struct lnet_peer **lp)
-{
-	struct lnet_peer_table	*ptable;
-	struct lnet_peer_ni	*lpni;
-	int			lncpt;
-	int			cpt;
-
-	lncpt = cfs_percpt_number(the_lnet.ln_peer_tables);
-
-	for (cpt = 0; cpt < lncpt; cpt++) {
-		ptable = the_lnet.ln_peer_tables[cpt];
-		if (ptable->pt_peer_nnids > idx)
-			break;
-		idx -= ptable->pt_peer_nnids;
-	}
-	if (cpt >= lncpt)
-		return NULL;
-
-	list_for_each_entry((*lp), &ptable->pt_peer_list, lp_peer_list) {
-		if ((*lp)->lp_nnis <= idx) {
-			idx -= (*lp)->lp_nnis;
-			continue;
-		}
-		list_for_each_entry((*lpn), &((*lp)->lp_peer_nets),
-				    lpn_peer_nets) {
-			list_for_each_entry(lpni, &((*lpn)->lpn_peer_nis),
-					    lpni_peer_nis) {
-				if (idx-- == 0)
-					return lpni;
-			}
-		}
-	}
-
-	return NULL;
-}
-
 struct lnet_peer_ni *
 lnet_get_next_peer_ni_locked(struct lnet_peer *peer,
 			     struct lnet_peer_net *peer_net,
@@ -734,6 +695,69 @@  lnet_get_next_peer_ni_locked(struct lnet_peer *peer,
 	return lpni;
 }
 
+/* Call with the ln_api_mutex held */
+int
+lnet_get_peer_list(__u32 *countp, __u32 *sizep,
+		   struct lnet_process_id __user *ids)
+{
+	struct lnet_process_id id;
+	struct lnet_peer_table *ptable;
+	struct lnet_peer *lp;
+	__u32 count = 0;
+	__u32 size = 0;
+	int lncpt;
+	int cpt;
+	__u32 i;
+	int rc;
+
+	rc = -ESHUTDOWN;
+	if (the_lnet.ln_state == LNET_STATE_SHUTDOWN)
+		goto done;
+
+	lncpt = cfs_percpt_number(the_lnet.ln_peer_tables);
+
+	/*
+	 * Count the number of peers, and return E2BIG if the buffer
+	 * is too small. We'll also return the desired size.
+	 */
+	rc = -E2BIG;
+	for (cpt = 0; cpt < lncpt; cpt++) {
+		ptable = the_lnet.ln_peer_tables[cpt];
+		count += ptable->pt_peers;
+	}
+	size = count * sizeof(*ids);
+	if (size > *sizep)
+		goto done;
+
+	/*
+	 * Walk the peer lists and copy out the primary nids.
+	 * This is safe because the peer lists are only modified
+	 * while the ln_api_mutex is held. So we don't need to
+	 * hold the lnet_net_lock as well, and can therefore
+	 * directly call copy_to_user().
+	 */
+	rc = -EFAULT;
+	memset(&id, 0, sizeof(id));
+	id.pid = LNET_PID_LUSTRE;
+	i = 0;
+	for (cpt = 0; cpt < lncpt; cpt++) {
+		ptable = the_lnet.ln_peer_tables[cpt];
+		list_for_each_entry(lp, &ptable->pt_peer_list, lp_peer_list) {
+			if (i >= count)
+				goto done;
+			id.nid = lp->lp_primary_nid;
+			if (copy_to_user(&ids[i], &id, sizeof(id)))
+				goto done;
+			i++;
+		}
+	}
+	rc = 0;
+done:
+	*countp = count;
+	*sizep = size;
+	return rc;
+}
+
 /*
  * Start pushes to peers that need to be updated for a configuration
  * change on this node.
@@ -1128,7 +1152,6 @@  lnet_peer_attach_peer_ni(struct lnet_peer *lp,
 	spin_unlock(&lp->lp_lock);
 
 	lp->lp_nnis++;
-	the_lnet.ln_peer_tables[lp->lp_cpt]->pt_peer_nnids++;
 	lnet_net_unlock(LNET_LOCK_EX);
 
 	CDEBUG(D_NET, "peer %s NID %s flags %#x\n",
@@ -3273,55 +3296,94 @@  lnet_get_peer_ni_info(__u32 peer_index, __u64 *nid,
 }
 
 /* ln_api_mutex is held, which keeps the peer list stable */
-int lnet_get_peer_info(__u32 idx, lnet_nid_t *primary_nid, lnet_nid_t *nid,
-		       bool *mr,
-		       struct lnet_peer_ni_credit_info __user *peer_ni_info,
-		       struct lnet_ioctl_element_stats __user *peer_ni_stats)
+int lnet_get_peer_info(lnet_nid_t *primary_nid, lnet_nid_t *nidp,
+		       __u32 *nnis, bool *mr, __u32 *sizep,
+		       void __user *bulk)
 {
-	struct lnet_ioctl_element_stats ni_stats;
-	struct lnet_peer_ni_credit_info ni_info;
-	struct lnet_peer_ni *lpni = NULL;
-	struct lnet_peer_net *lpn = NULL;
-	struct lnet_peer *lp = NULL;
+	struct lnet_ioctl_element_stats *lpni_stats;
+	struct lnet_peer_ni_credit_info *lpni_info;
+	struct lnet_peer_ni *lpni;
+	struct lnet_peer *lp;
+	lnet_nid_t nid;
+	__u32 size;
 	int rc;
 
-	lpni = lnet_get_peer_ni_idx_locked(idx, &lpn, &lp);
+	lp = lnet_find_peer(*primary_nid);
 
-	if (!lpni)
-		return -ENOENT;
+	if (!lp) {
+		rc = -ENOENT;
+		goto out;
+	}
+
+	size = sizeof(nid) + sizeof(*lpni_info) + sizeof(*lpni_stats);
+	size *= lp->lp_nnis;
+	if (size > *sizep) {
+		*sizep = size;
+		rc = -E2BIG;
+		goto out_lp_decref;
+	}
 
 	*primary_nid = lp->lp_primary_nid;
 	*mr = lnet_peer_is_multi_rail(lp);
-	*nid = lpni->lpni_nid;
-	snprintf(ni_info.cr_aliveness, LNET_MAX_STR_LEN, "NA");
-	if (lnet_isrouter(lpni) ||
-	    lnet_peer_aliveness_enabled(lpni))
-		snprintf(ni_info.cr_aliveness, LNET_MAX_STR_LEN,
-			 lpni->lpni_alive ? "up" : "down");
-
-	ni_info.cr_refcount = atomic_read(&lpni->lpni_refcount);
-	ni_info.cr_ni_peer_tx_credits = lpni->lpni_net ?
-		lpni->lpni_net->net_tunables.lct_peer_tx_credits : 0;
-	ni_info.cr_peer_tx_credits = lpni->lpni_txcredits;
-	ni_info.cr_peer_rtr_credits = lpni->lpni_rtrcredits;
-	ni_info.cr_peer_min_rtr_credits = lpni->lpni_minrtrcredits;
-	ni_info.cr_peer_min_tx_credits = lpni->lpni_mintxcredits;
-	ni_info.cr_peer_tx_qnob = lpni->lpni_txqnob;
-
-	ni_stats.iel_send_count = atomic_read(&lpni->lpni_stats.send_count);
-	ni_stats.iel_recv_count = atomic_read(&lpni->lpni_stats.recv_count);
-	ni_stats.iel_drop_count = atomic_read(&lpni->lpni_stats.drop_count);
-
-	/* If copy_to_user fails */
-	rc = -EFAULT;
-	if (copy_to_user(peer_ni_info, &ni_info, sizeof(ni_info)))
-		goto copy_failed;
+	*nidp = lp->lp_primary_nid;
+	*nnis = lp->lp_nnis;
+	*sizep = size;
 
-	if (copy_to_user(peer_ni_stats, &ni_stats, sizeof(ni_stats)))
-		goto copy_failed;
+	/* Allocate helper buffers. */
+	rc = -ENOMEM;
+	lpni_info = kzalloc(sizeof(*lpni_info), GFP_KERNEL);
+	if (!lpni_info)
+		goto out_lp_decref;
+	lpni_stats = kzalloc(sizeof(*lpni_stats), GFP_KERNEL);
+	if (!lpni_stats)
+		goto out_free_info;
 
+	lpni = NULL;
+	rc = -EFAULT;
+	while ((lpni = lnet_get_next_peer_ni_locked(lp, NULL, lpni)) != NULL) {
+		nid = lpni->lpni_nid;
+		if (copy_to_user(bulk, &nid, sizeof(nid)))
+			goto out_free_stats;
+		bulk += sizeof(nid);
+
+		memset(lpni_info, 0, sizeof(*lpni_info));
+		snprintf(lpni_info->cr_aliveness, LNET_MAX_STR_LEN, "NA");
+		if (lnet_isrouter(lpni) ||
+		    lnet_peer_aliveness_enabled(lpni))
+			snprintf(lpni_info->cr_aliveness, LNET_MAX_STR_LEN,
+				 lpni->lpni_alive ? "up" : "down");
+
+		lpni_info->cr_refcount = atomic_read(&lpni->lpni_refcount);
+		lpni_info->cr_ni_peer_tx_credits = lpni->lpni_net ?
+			lpni->lpni_net->net_tunables.lct_peer_tx_credits : 0;
+		lpni_info->cr_peer_tx_credits = lpni->lpni_txcredits;
+		lpni_info->cr_peer_rtr_credits = lpni->lpni_rtrcredits;
+		lpni_info->cr_peer_min_rtr_credits = lpni->lpni_minrtrcredits;
+		lpni_info->cr_peer_min_tx_credits = lpni->lpni_mintxcredits;
+		lpni_info->cr_peer_tx_qnob = lpni->lpni_txqnob;
+		if (copy_to_user(bulk, lpni_info, sizeof(*lpni_info)))
+			goto out_free_stats;
+		bulk += sizeof(*lpni_info);
+
+		memset(lpni_stats, 0, sizeof(*lpni_stats));
+		lpni_stats->iel_send_count =
+			atomic_read(&lpni->lpni_stats.send_count);
+		lpni_stats->iel_recv_count =
+			atomic_read(&lpni->lpni_stats.recv_count);
+		lpni_stats->iel_drop_count =
+			atomic_read(&lpni->lpni_stats.drop_count);
+		if (copy_to_user(bulk, lpni_stats, sizeof(*lpni_stats)))
+			goto out_free_stats;
+		bulk += sizeof(*lpni_stats);
+	}
 	rc = 0;
 
-copy_failed:
+out_free_stats:
+	kfree(lpni_stats);
+out_free_info:
+	kfree(lpni_info);
+out_lp_decref:
+	lnet_peer_decref_locked(lp);
+out:
 	return rc;
 }