mlx4_core: Add "native" argument to mlx4_cmd and its callers (where needed)

[mirror_ubuntu-artful-kernel.git] / drivers / net / ethernet / mellanox / mlx4 / mcg.c

/*
 * Copyright (c) 2006, 2007 Cisco Systems, Inc.  All rights reserved.
 * Copyright (c) 2007, 2008 Mellanox Technologies. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/string.h>
#include <linux/etherdevice.h>

#include <linux/mlx4/cmd.h>
#include <linux/export.h>

#include "mlx4.h"

#define MGM_QPN_MASK       0x00FFFFFF
#define MGM_BLCK_LB_BIT    30

static const u8 zero_gid[16];	/* automatically initialized to 0 */

static int mlx4_READ_ENTRY(struct mlx4_dev *dev, int index,
			   struct mlx4_cmd_mailbox *mailbox)
{
	return mlx4_cmd_box(dev, 0, mailbox->dma, index, 0, MLX4_CMD_READ_MCG,
			    MLX4_CMD_TIME_CLASS_A, MLX4_CMD_NATIVE);
}

static int mlx4_WRITE_ENTRY(struct mlx4_dev *dev, int index,
			    struct mlx4_cmd_mailbox *mailbox)
{
	return mlx4_cmd(dev, mailbox->dma, index, 0, MLX4_CMD_WRITE_MCG,
			MLX4_CMD_TIME_CLASS_A, MLX4_CMD_NATIVE);
}

static int mlx4_WRITE_PROMISC(struct mlx4_dev *dev, u8 vep_num, u8 port, u8 steer,
			      struct mlx4_cmd_mailbox *mailbox)
{
	u32 in_mod;

	in_mod = (u32) vep_num << 24 | (u32) port << 16 | steer << 1;
	return mlx4_cmd(dev, mailbox->dma, in_mod, 0x1,
			MLX4_CMD_WRITE_MCG, MLX4_CMD_TIME_CLASS_A,
			MLX4_CMD_NATIVE);
}

static int mlx4_GID_HASH(struct mlx4_dev *dev, struct mlx4_cmd_mailbox *mailbox,
			 u16 *hash, u8 op_mod)
{
	u64 imm;
	int err;

	err = mlx4_cmd_imm(dev, mailbox->dma, &imm, 0, op_mod,
			   MLX4_CMD_MGID_HASH, MLX4_CMD_TIME_CLASS_A,
			   MLX4_CMD_NATIVE);

	if (!err)
		*hash = imm;

	return err;
}

static struct mlx4_promisc_qp *get_promisc_qp(struct mlx4_dev *dev, u8 pf_num,
					      enum mlx4_steer_type steer,
					      u32 qpn)
{
	struct mlx4_steer *s_steer = &mlx4_priv(dev)->steer[pf_num];
	struct mlx4_promisc_qp *pqp;

	list_for_each_entry(pqp, &s_steer->promisc_qps[steer], list) {
		if (pqp->qpn == qpn)
			return pqp;
	}
	/* not found */
	return NULL;
}

/*
 * Add new entry to steering data structure.
 * All promisc QPs should be added as well
 */
static int new_steering_entry(struct mlx4_dev *dev, u8 vep_num, u8 port,
			      enum mlx4_steer_type steer,
			      unsigned int index, u32 qpn)
{
	struct mlx4_steer *s_steer;
	struct mlx4_cmd_mailbox *mailbox;
	struct mlx4_mgm *mgm;
	u32 members_count;
	struct mlx4_steer_index *new_entry;
	struct mlx4_promisc_qp *pqp;
	struct mlx4_promisc_qp *dqp = NULL;
	u32 prot;
	int err;
	u8 pf_num;

	pf_num = (dev->caps.num_ports == 1) ? vep_num : (vep_num << 1) | (port - 1);
	s_steer = &mlx4_priv(dev)->steer[pf_num];
	new_entry = kzalloc(sizeof *new_entry, GFP_KERNEL);
	if (!new_entry)
		return -ENOMEM;

	INIT_LIST_HEAD(&new_entry->duplicates);
	new_entry->index = index;
	list_add_tail(&new_entry->list, &s_steer->steer_entries[steer]);

	/* If the given qpn is also a promisc qp,
	 * it should be inserted to duplicates list
	 */
	pqp = get_promisc_qp(dev, pf_num, steer, qpn);
	if (pqp) {
		dqp = kmalloc(sizeof *dqp, GFP_KERNEL);
		if (!dqp) {
			err = -ENOMEM;
			goto out_alloc;
		}
		dqp->qpn = qpn;
		list_add_tail(&dqp->list, &new_entry->duplicates);
	}

	/* if no promisc qps for this vep, we are done */
	if (list_empty(&s_steer->promisc_qps[steer]))
		return 0;

	/* now need to add all the promisc qps to the new
	 * steering entry, as they should also receive the packets
	 * destined to this address */
	mailbox = mlx4_alloc_cmd_mailbox(dev);
	if (IS_ERR(mailbox)) {
		err = -ENOMEM;
		goto out_alloc;
	}
	mgm = mailbox->buf;

	err = mlx4_READ_ENTRY(dev, index, mailbox);
	if (err)
		goto out_mailbox;

	members_count = be32_to_cpu(mgm->members_count) & 0xffffff;
	prot = be32_to_cpu(mgm->members_count) >> 30;
	list_for_each_entry(pqp, &s_steer->promisc_qps[steer], list) {
		/* don't add already existing qpn */
		if (pqp->qpn == qpn)
			continue;
		if (members_count == MLX4_QP_PER_MGM) {
			/* out of space */
			err = -ENOMEM;
			goto out_mailbox;
		}

		/* add the qpn */
		mgm->qp[members_count++] = cpu_to_be32(pqp->qpn & MGM_QPN_MASK);
	}
	/* update the qps count and update the entry with all the promisc qps*/
	mgm->members_count = cpu_to_be32(members_count | (prot << 30));
	err = mlx4_WRITE_ENTRY(dev, index, mailbox);

out_mailbox:
	mlx4_free_cmd_mailbox(dev, mailbox);
	if (!err)
		return 0;
out_alloc:
	if (dqp) {
		list_del(&dqp->list);
		kfree(dqp);
	}
	list_del(&new_entry->list);
	kfree(new_entry);
	return err;
}

/* update the data structures with existing steering entry */
static int existing_steering_entry(struct mlx4_dev *dev, u8 vep_num, u8 port,
				   enum mlx4_steer_type steer,
				   unsigned int index, u32 qpn)
{
	struct mlx4_steer *s_steer;
	struct mlx4_steer_index *tmp_entry, *entry = NULL;
	struct mlx4_promisc_qp *pqp;
	struct mlx4_promisc_qp *dqp;
	u8 pf_num;

	pf_num = (dev->caps.num_ports == 1) ? vep_num : (vep_num << 1) | (port - 1);
	s_steer = &mlx4_priv(dev)->steer[pf_num];

	pqp = get_promisc_qp(dev, pf_num, steer, qpn);
	if (!pqp)
		return 0; /* nothing to do */

	list_for_each_entry(tmp_entry, &s_steer->steer_entries[steer], list) {
		if (tmp_entry->index == index) {
			entry = tmp_entry;
			break;
		}
	}
	if (unlikely(!entry)) {
		mlx4_warn(dev, "Steering entry at index %x is not registered\n", index);
		return -EINVAL;
	}

	/* the given qpn is listed as a promisc qpn
	 * we need to add it as a duplicate to this entry
	 * for future references */
	list_for_each_entry(dqp, &entry->duplicates, list) {
		if (qpn == dqp->qpn)
			return 0; /* qp is already duplicated */
	}

	/* add the qp as a duplicate on this index */
	dqp = kmalloc(sizeof *dqp, GFP_KERNEL);
	if (!dqp)
		return -ENOMEM;
	dqp->qpn = qpn;
	list_add_tail(&dqp->list, &entry->duplicates);

	return 0;
}

/* Check whether a qpn is a duplicate on steering entry
 * If so, it should not be removed from mgm */
static bool check_duplicate_entry(struct mlx4_dev *dev, u8 vep_num, u8 port,
				  enum mlx4_steer_type steer,
				  unsigned int index, u32 qpn)
{
	struct mlx4_steer *s_steer;
	struct mlx4_steer_index *tmp_entry, *entry = NULL;
	struct mlx4_promisc_qp *dqp, *tmp_dqp;
	u8 pf_num;

	pf_num = (dev->caps.num_ports == 1) ? vep_num : (vep_num << 1) | (port - 1);
	s_steer = &mlx4_priv(dev)->steer[pf_num];

	/* if qp is not promisc, it cannot be duplicated */
	if (!get_promisc_qp(dev, pf_num, steer, qpn))
		return false;

	/* The qp is promisc qp so it is a duplicate on this index
	 * Find the index entry, and remove the duplicate */
	list_for_each_entry(tmp_entry, &s_steer->steer_entries[steer], list) {
		if (tmp_entry->index == index) {
			entry = tmp_entry;
			break;
		}
	}
	if (unlikely(!entry)) {
		mlx4_warn(dev, "Steering entry for index %x is not registered\n", index);
		return false;
	}
	list_for_each_entry_safe(dqp, tmp_dqp, &entry->duplicates, list) {
		if (dqp->qpn == qpn) {
			list_del(&dqp->list);
			kfree(dqp);
		}
	}
	return true;
}

/* I a steering entry contains only promisc QPs, it can be removed. */
static bool can_remove_steering_entry(struct mlx4_dev *dev, u8 vep_num, u8 port,
				      enum mlx4_steer_type steer,
				      unsigned int index, u32 tqpn)
{
	struct mlx4_steer *s_steer;
	struct mlx4_cmd_mailbox *mailbox;
	struct mlx4_mgm *mgm;
	struct mlx4_steer_index *entry = NULL, *tmp_entry;
	u32 qpn;
	u32 members_count;
	bool ret = false;
	int i;
	u8 pf_num;

	pf_num = (dev->caps.num_ports == 1) ? vep_num : (vep_num << 1) | (port - 1);
	s_steer = &mlx4_priv(dev)->steer[pf_num];

	mailbox = mlx4_alloc_cmd_mailbox(dev);
	if (IS_ERR(mailbox))
		return false;
	mgm = mailbox->buf;

	if (mlx4_READ_ENTRY(dev, index, mailbox))
		goto out;
	members_count = be32_to_cpu(mgm->members_count) & 0xffffff;
	for (i = 0;  i < members_count; i++) {
		qpn = be32_to_cpu(mgm->qp[i]) & MGM_QPN_MASK;
		if (!get_promisc_qp(dev, pf_num, steer, qpn) && qpn != tqpn) {
			/* the qp is not promisc, the entry can't be removed */
			goto out;
		}
	}
	 /* All the qps currently registered for this entry are promiscuous,
	  * Checking for duplicates */
	ret = true;
	list_for_each_entry_safe(entry, tmp_entry, &s_steer->steer_entries[steer], list) {
		if (entry->index == index) {
			if (list_empty(&entry->duplicates)) {
				list_del(&entry->list);
				kfree(entry);
			} else {
				/* This entry contains duplicates so it shouldn't be removed */
				ret = false;
				goto out;
			}
		}
	}

out:
	mlx4_free_cmd_mailbox(dev, mailbox);
	return ret;
}

static int add_promisc_qp(struct mlx4_dev *dev, u8 vep_num, u8 port,
			  enum mlx4_steer_type steer, u32 qpn)
{
	struct mlx4_steer *s_steer;
	struct mlx4_cmd_mailbox *mailbox;
	struct mlx4_mgm *mgm;
	struct mlx4_steer_index *entry;
	struct mlx4_promisc_qp *pqp;
	struct mlx4_promisc_qp *dqp;
	u32 members_count;
	u32 prot;
	int i;
	bool found;
	int last_index;
	int err;
	u8 pf_num;
	struct mlx4_priv *priv = mlx4_priv(dev);
	pf_num = (dev->caps.num_ports == 1) ? vep_num : (vep_num << 1) | (port - 1);
	s_steer = &mlx4_priv(dev)->steer[pf_num];

	mutex_lock(&priv->mcg_table.mutex);

	if (get_promisc_qp(dev, pf_num, steer, qpn)) {
		err = 0;  /* Noting to do, already exists */
		goto out_mutex;
	}

	pqp = kmalloc(sizeof *pqp, GFP_KERNEL);
	if (!pqp) {
		err = -ENOMEM;
		goto out_mutex;
	}
	pqp->qpn = qpn;

	mailbox = mlx4_alloc_cmd_mailbox(dev);
	if (IS_ERR(mailbox)) {
		err = -ENOMEM;
		goto out_alloc;
	}
	mgm = mailbox->buf;

	/* the promisc qp needs to be added for each one of the steering
	 * entries, if it already exists, needs to be added as a duplicate
	 * for this entry */
	list_for_each_entry(entry, &s_steer->steer_entries[steer], list) {
		err = mlx4_READ_ENTRY(dev, entry->index, mailbox);
		if (err)
			goto out_mailbox;

		members_count = be32_to_cpu(mgm->members_count) & 0xffffff;
		prot = be32_to_cpu(mgm->members_count) >> 30;
		found = false;
		for (i = 0; i < members_count; i++) {
			if ((be32_to_cpu(mgm->qp[i]) & MGM_QPN_MASK) == qpn) {
				/* Entry already exists, add to duplicates */
				dqp = kmalloc(sizeof *dqp, GFP_KERNEL);
				if (!dqp)
					goto out_mailbox;
				dqp->qpn = qpn;
				list_add_tail(&dqp->list, &entry->duplicates);
				found = true;
			}
		}
		if (!found) {
			/* Need to add the qpn to mgm */
			if (members_count == MLX4_QP_PER_MGM) {
				/* entry is full */
				err = -ENOMEM;
				goto out_mailbox;
			}
			mgm->qp[members_count++] = cpu_to_be32(qpn & MGM_QPN_MASK);
			mgm->members_count = cpu_to_be32(members_count | (prot << 30));
			err = mlx4_WRITE_ENTRY(dev, entry->index, mailbox);
			if (err)
				goto out_mailbox;
		}
		last_index = entry->index;
	}

	/* add the new qpn to list of promisc qps */
	list_add_tail(&pqp->list, &s_steer->promisc_qps[steer]);
	/* now need to add all the promisc qps to default entry */
	memset(mgm, 0, sizeof *mgm);
	members_count = 0;
	list_for_each_entry(dqp, &s_steer->promisc_qps[steer], list)
		mgm->qp[members_count++] = cpu_to_be32(dqp->qpn & MGM_QPN_MASK);
	mgm->members_count = cpu_to_be32(members_count | MLX4_PROT_ETH << 30);

	err = mlx4_WRITE_PROMISC(dev, vep_num, port, steer, mailbox);
	if (err)
		goto out_list;

	mlx4_free_cmd_mailbox(dev, mailbox);
	mutex_unlock(&priv->mcg_table.mutex);
	return 0;

out_list:
	list_del(&pqp->list);
out_mailbox:
	mlx4_free_cmd_mailbox(dev, mailbox);
out_alloc:
	kfree(pqp);
out_mutex:
	mutex_unlock(&priv->mcg_table.mutex);
	return err;
}

static int remove_promisc_qp(struct mlx4_dev *dev, u8 vep_num, u8 port,
			     enum mlx4_steer_type steer, u32 qpn)
{
	struct mlx4_priv *priv = mlx4_priv(dev);
	struct mlx4_steer *s_steer;
	struct mlx4_cmd_mailbox *mailbox;
	struct mlx4_mgm *mgm;
	struct mlx4_steer_index *entry;
	struct mlx4_promisc_qp *pqp;
	struct mlx4_promisc_qp *dqp;
	u32 members_count;
	bool found;
	bool back_to_list = false;
	int loc, i;
	int err;
	u8 pf_num;

	pf_num = (dev->caps.num_ports == 1) ? vep_num : (vep_num << 1) | (port - 1);
	s_steer = &mlx4_priv(dev)->steer[pf_num];
	mutex_lock(&priv->mcg_table.mutex);

	pqp = get_promisc_qp(dev, pf_num, steer, qpn);
	if (unlikely(!pqp)) {
		mlx4_warn(dev, "QP %x is not promiscuous QP\n", qpn);
		/* nothing to do */
		err = 0;
		goto out_mutex;
	}

	/*remove from list of promisc qps */
	list_del(&pqp->list);

	/* set the default entry not to include the removed one */
	mailbox = mlx4_alloc_cmd_mailbox(dev);
	if (IS_ERR(mailbox)) {
		err = -ENOMEM;
		back_to_list = true;
		goto out_list;
	}
	mgm = mailbox->buf;
	members_count = 0;
	list_for_each_entry(dqp, &s_steer->promisc_qps[steer], list)
		mgm->qp[members_count++] = cpu_to_be32(dqp->qpn & MGM_QPN_MASK);
	mgm->members_count = cpu_to_be32(members_count | MLX4_PROT_ETH << 30);

	err = mlx4_WRITE_PROMISC(dev, vep_num, port, steer, mailbox);
	if (err)
		goto out_mailbox;

	/* remove the qp from all the steering entries*/
	list_for_each_entry(entry, &s_steer->steer_entries[steer], list) {
		found = false;
		list_for_each_entry(dqp, &entry->duplicates, list) {
			if (dqp->qpn == qpn) {
				found = true;
				break;
			}
		}
		if (found) {
			/* a duplicate, no need to change the mgm,
			 * only update the duplicates list */
			list_del(&dqp->list);
			kfree(dqp);
		} else {
			err = mlx4_READ_ENTRY(dev, entry->index, mailbox);
				if (err)
					goto out_mailbox;
			members_count = be32_to_cpu(mgm->members_count) & 0xffffff;
			for (loc = -1, i = 0; i < members_count; ++i)
				if ((be32_to_cpu(mgm->qp[i]) & MGM_QPN_MASK) == qpn)
					loc = i;

			mgm->members_count = cpu_to_be32(--members_count |
							 (MLX4_PROT_ETH << 30));
			mgm->qp[loc] = mgm->qp[i - 1];
			mgm->qp[i - 1] = 0;

			err = mlx4_WRITE_ENTRY(dev, entry->index, mailbox);
				if (err)
					goto out_mailbox;
		}

	}

out_mailbox:
	mlx4_free_cmd_mailbox(dev, mailbox);
out_list:
	if (back_to_list)
		list_add_tail(&pqp->list, &s_steer->promisc_qps[steer]);
	else
		kfree(pqp);
out_mutex:
	mutex_unlock(&priv->mcg_table.mutex);
	return err;
}

/*
 * Caller must hold MCG table semaphore.  gid and mgm parameters must
 * be properly aligned for command interface.
 *
 *  Returns 0 unless a firmware command error occurs.
 *
 * If GID is found in MGM or MGM is empty, *index = *hash, *prev = -1
 * and *mgm holds MGM entry.
 *
 * if GID is found in AMGM, *index = index in AMGM, *prev = index of
 * previous entry in hash chain and *mgm holds AMGM entry.
 *
 * If no AMGM exists for given gid, *index = -1, *prev = index of last
 * entry in hash chain and *mgm holds end of hash chain.
 */
static int find_entry(struct mlx4_dev *dev, u8 port,
		      u8 *gid, enum mlx4_protocol prot,
		      enum mlx4_steer_type steer,
		      struct mlx4_cmd_mailbox *mgm_mailbox,
		      u16 *hash, int *prev, int *index)
{
	struct mlx4_cmd_mailbox *mailbox;
	struct mlx4_mgm *mgm = mgm_mailbox->buf;
	u8 *mgid;
	int err;
	u8 op_mod = (prot == MLX4_PROT_ETH) ?
		!!(dev->caps.flags & MLX4_DEV_CAP_FLAG_VEP_MC_STEER) : 0;

	mailbox = mlx4_alloc_cmd_mailbox(dev);
	if (IS_ERR(mailbox))
		return -ENOMEM;
	mgid = mailbox->buf;

	memcpy(mgid, gid, 16);

	err = mlx4_GID_HASH(dev, mailbox, hash, op_mod);
	mlx4_free_cmd_mailbox(dev, mailbox);
	if (err)
		return err;

	if (0)
		mlx4_dbg(dev, "Hash for %pI6 is %04x\n", gid, *hash);

	*index = *hash;
	*prev  = -1;

	do {
		err = mlx4_READ_ENTRY(dev, *index, mgm_mailbox);
		if (err)
			return err;

		if (!(be32_to_cpu(mgm->members_count) & 0xffffff)) {
			if (*index != *hash) {
				mlx4_err(dev, "Found zero MGID in AMGM.\n");
				err = -EINVAL;
			}
			return err;
		}

		if (!memcmp(mgm->gid, gid, 16) &&
		    be32_to_cpu(mgm->members_count) >> 30 == prot)
			return err;

		*prev = *index;
		*index = be32_to_cpu(mgm->next_gid_index) >> 6;
	} while (*index);

	*index = -1;
	return err;
}

int mlx4_qp_attach_common(struct mlx4_dev *dev, struct mlx4_qp *qp, u8 gid[16],
			  int block_mcast_loopback, enum mlx4_protocol prot,
			  enum mlx4_steer_type steer)
{
	struct mlx4_priv *priv = mlx4_priv(dev);
	struct mlx4_cmd_mailbox *mailbox;
	struct mlx4_mgm *mgm;
	u32 members_count;
	u16 hash;
	int index, prev;
	int link = 0;
	int i;
	int err;
	u8 port = gid[5];
	u8 new_entry = 0;

	mailbox = mlx4_alloc_cmd_mailbox(dev);
	if (IS_ERR(mailbox))
		return PTR_ERR(mailbox);
	mgm = mailbox->buf;

	mutex_lock(&priv->mcg_table.mutex);
	err = find_entry(dev, port, gid, prot, steer,
			 mailbox, &hash, &prev, &index);
	if (err)
		goto out;

	if (index != -1) {
		if (!(be32_to_cpu(mgm->members_count) & 0xffffff)) {
			new_entry = 1;
			memcpy(mgm->gid, gid, 16);
		}
	} else {
		link = 1;

		index = mlx4_bitmap_alloc(&priv->mcg_table.bitmap);
		if (index == -1) {
			mlx4_err(dev, "No AMGM entries left\n");
			err = -ENOMEM;
			goto out;
		}
		index += dev->caps.num_mgms;

		memset(mgm, 0, sizeof *mgm);
		memcpy(mgm->gid, gid, 16);
	}

	members_count = be32_to_cpu(mgm->members_count) & 0xffffff;
	if (members_count == MLX4_QP_PER_MGM) {
		mlx4_err(dev, "MGM at index %x is full.\n", index);
		err = -ENOMEM;
		goto out;
	}

	for (i = 0; i < members_count; ++i)
		if ((be32_to_cpu(mgm->qp[i]) & MGM_QPN_MASK) == qp->qpn) {
			mlx4_dbg(dev, "QP %06x already a member of MGM\n", qp->qpn);
			err = 0;
			goto out;
		}

	if (block_mcast_loopback)
		mgm->qp[members_count++] = cpu_to_be32((qp->qpn & MGM_QPN_MASK) |
						       (1U << MGM_BLCK_LB_BIT));
	else
		mgm->qp[members_count++] = cpu_to_be32(qp->qpn & MGM_QPN_MASK);

	mgm->members_count = cpu_to_be32(members_count | (u32) prot << 30);

	err = mlx4_WRITE_ENTRY(dev, index, mailbox);
	if (err)
		goto out;

	if (!link)
		goto out;

	err = mlx4_READ_ENTRY(dev, prev, mailbox);
	if (err)
		goto out;

	mgm->next_gid_index = cpu_to_be32(index << 6);

	err = mlx4_WRITE_ENTRY(dev, prev, mailbox);
	if (err)
		goto out;

out:
	if (prot == MLX4_PROT_ETH) {
		/* manage the steering entry for promisc mode */
		if (new_entry)
			new_steering_entry(dev, 0, port, steer, index, qp->qpn);
		else
			existing_steering_entry(dev, 0, port, steer,
						index, qp->qpn);
	}
	if (err && link && index != -1) {
		if (index < dev->caps.num_mgms)
			mlx4_warn(dev, "Got AMGM index %d < %d",
				  index, dev->caps.num_mgms);
		else
			mlx4_bitmap_free(&priv->mcg_table.bitmap,
					 index - dev->caps.num_mgms);
	}
	mutex_unlock(&priv->mcg_table.mutex);

	mlx4_free_cmd_mailbox(dev, mailbox);
	return err;
}

int mlx4_qp_detach_common(struct mlx4_dev *dev, struct mlx4_qp *qp, u8 gid[16],
			  enum mlx4_protocol prot, enum mlx4_steer_type steer)
{
	struct mlx4_priv *priv = mlx4_priv(dev);
	struct mlx4_cmd_mailbox *mailbox;
	struct mlx4_mgm *mgm;
	u32 members_count;
	u16 hash;
	int prev, index;
	int i, loc;
	int err;
	u8 port = gid[5];
	bool removed_entry = false;

	mailbox = mlx4_alloc_cmd_mailbox(dev);
	if (IS_ERR(mailbox))
		return PTR_ERR(mailbox);
	mgm = mailbox->buf;

	mutex_lock(&priv->mcg_table.mutex);

	err = find_entry(dev, port, gid, prot, steer,
			 mailbox, &hash, &prev, &index);
	if (err)
		goto out;

	if (index == -1) {
		mlx4_err(dev, "MGID %pI6 not found\n", gid);
		err = -EINVAL;
		goto out;
	}

	/* if this pq is also a promisc qp, it shouldn't be removed */
	if (prot == MLX4_PROT_ETH &&
	    check_duplicate_entry(dev, 0, port, steer, index, qp->qpn))
		goto out;

	members_count = be32_to_cpu(mgm->members_count) & 0xffffff;
	for (loc = -1, i = 0; i < members_count; ++i)
		if ((be32_to_cpu(mgm->qp[i]) & MGM_QPN_MASK) == qp->qpn)
			loc = i;

	if (loc == -1) {
		mlx4_err(dev, "QP %06x not found in MGM\n", qp->qpn);
		err = -EINVAL;
		goto out;
	}


	mgm->members_count = cpu_to_be32(--members_count | (u32) prot << 30);
	mgm->qp[loc]       = mgm->qp[i - 1];
	mgm->qp[i - 1]     = 0;

	if (prot == MLX4_PROT_ETH)
		removed_entry = can_remove_steering_entry(dev, 0, port, steer, index, qp->qpn);
	if (i != 1 && (prot != MLX4_PROT_ETH || !removed_entry)) {
		err = mlx4_WRITE_ENTRY(dev, index, mailbox);
		goto out;
	}

	/* We are going to delete the entry, members count should be 0 */
	mgm->members_count = cpu_to_be32((u32) prot << 30);

	if (prev == -1) {
		/* Remove entry from MGM */
		int amgm_index = be32_to_cpu(mgm->next_gid_index) >> 6;
		if (amgm_index) {
			err = mlx4_READ_ENTRY(dev, amgm_index, mailbox);
			if (err)
				goto out;
		} else
			memset(mgm->gid, 0, 16);

		err = mlx4_WRITE_ENTRY(dev, index, mailbox);
		if (err)
			goto out;

		if (amgm_index) {
			if (amgm_index < dev->caps.num_mgms)
				mlx4_warn(dev, "MGM entry %d had AMGM index %d < %d",
					  index, amgm_index, dev->caps.num_mgms);
			else
				mlx4_bitmap_free(&priv->mcg_table.bitmap,
						 amgm_index - dev->caps.num_mgms);
		}
	} else {
		/* Remove entry from AMGM */
		int cur_next_index = be32_to_cpu(mgm->next_gid_index) >> 6;
		err = mlx4_READ_ENTRY(dev, prev, mailbox);
		if (err)
			goto out;

		mgm->next_gid_index = cpu_to_be32(cur_next_index << 6);

		err = mlx4_WRITE_ENTRY(dev, prev, mailbox);
		if (err)
			goto out;

		if (index < dev->caps.num_mgms)
			mlx4_warn(dev, "entry %d had next AMGM index %d < %d",
				  prev, index, dev->caps.num_mgms);
		else
			mlx4_bitmap_free(&priv->mcg_table.bitmap,
					 index - dev->caps.num_mgms);
	}

out:
	mutex_unlock(&priv->mcg_table.mutex);

	mlx4_free_cmd_mailbox(dev, mailbox);
	return err;
}


int mlx4_multicast_attach(struct mlx4_dev *dev, struct mlx4_qp *qp, u8 gid[16],
			  int block_mcast_loopback, enum mlx4_protocol prot)
{
	enum mlx4_steer_type steer;

	steer = (is_valid_ether_addr(&gid[10])) ? MLX4_UC_STEER : MLX4_MC_STEER;

	if (prot == MLX4_PROT_ETH &&
			!(dev->caps.flags & MLX4_DEV_CAP_FLAG_VEP_MC_STEER))
		return 0;

	if (prot == MLX4_PROT_ETH)
		gid[7] |= (steer << 1);

	return mlx4_qp_attach_common(dev, qp, gid,
				     block_mcast_loopback, prot,
				     steer);
}
EXPORT_SYMBOL_GPL(mlx4_multicast_attach);

int mlx4_multicast_detach(struct mlx4_dev *dev, struct mlx4_qp *qp, u8 gid[16],
			  enum mlx4_protocol prot)
{
	enum mlx4_steer_type steer;

	steer = (is_valid_ether_addr(&gid[10])) ? MLX4_UC_STEER : MLX4_MC_STEER;

	if (prot == MLX4_PROT_ETH &&
			!(dev->caps.flags & MLX4_DEV_CAP_FLAG_VEP_MC_STEER))
		return 0;

	if (prot == MLX4_PROT_ETH) {
		gid[7] |= (steer << 1);
	}

	return mlx4_qp_detach_common(dev, qp, gid, prot, steer);
}
EXPORT_SYMBOL_GPL(mlx4_multicast_detach);


int mlx4_multicast_promisc_add(struct mlx4_dev *dev, u32 qpn, u8 port)
{
	if (!(dev->caps.flags & MLX4_DEV_CAP_FLAG_VEP_MC_STEER))
		return 0;


	return add_promisc_qp(dev, 0, port, MLX4_MC_STEER, qpn);
}
EXPORT_SYMBOL_GPL(mlx4_multicast_promisc_add);

int mlx4_multicast_promisc_remove(struct mlx4_dev *dev, u32 qpn, u8 port)
{
	if (!(dev->caps.flags & MLX4_DEV_CAP_FLAG_VEP_MC_STEER))
		return 0;


	return remove_promisc_qp(dev, 0, port, MLX4_MC_STEER, qpn);
}
EXPORT_SYMBOL_GPL(mlx4_multicast_promisc_remove);

int mlx4_unicast_promisc_add(struct mlx4_dev *dev, u32 qpn, u8 port)
{
	if (!(dev->caps.flags & MLX4_DEV_CAP_FLAG_VEP_MC_STEER))
		return 0;


	return add_promisc_qp(dev, 0, port, MLX4_UC_STEER, qpn);
}
EXPORT_SYMBOL_GPL(mlx4_unicast_promisc_add);

int mlx4_unicast_promisc_remove(struct mlx4_dev *dev, u32 qpn, u8 port)
{
	if (!(dev->caps.flags & MLX4_DEV_CAP_FLAG_VEP_MC_STEER))
		return 0;

	return remove_promisc_qp(dev, 0, port, MLX4_UC_STEER, qpn);
}
EXPORT_SYMBOL_GPL(mlx4_unicast_promisc_remove);

int mlx4_init_mcg_table(struct mlx4_dev *dev)
{
	struct mlx4_priv *priv = mlx4_priv(dev);
	int err;

	err = mlx4_bitmap_init(&priv->mcg_table.bitmap, dev->caps.num_amgms,
			       dev->caps.num_amgms - 1, 0, 0);
	if (err)
		return err;

	mutex_init(&priv->mcg_table.mutex);

	return 0;
}

void mlx4_cleanup_mcg_table(struct mlx4_dev *dev)
{
	mlx4_bitmap_cleanup(&mlx4_priv(dev)->mcg_table.bitmap);
}