drivers/infiniband/hw/mthca/mthca_mcg.c - maze/linux - Git at Google

 /*
  * Copyright (c) 2004 Topspin Communications.  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.
  *
  * $Id: mthca_mcg.c 1349 2004-12-16 21:09:43Z roland $
  */

 #include <linux/init.h>
 #include <linux/string.h>
 #include <linux/slab.h>

 #include "mthca_dev.h"
 #include "mthca_cmd.h"

 struct mthca_mgm {
 	__be32 next_gid_index;
 	u32    reserved[3];
 	u8     gid[16];
 	__be32 qp[MTHCA_QP_PER_MGM];
 };

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

 /*
  * 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_mgm(struct mthca_dev *dev,
 		    u8 *gid, struct mthca_mailbox *mgm_mailbox,
 		    u16 *hash, int *prev, int *index)
 {
 	struct mthca_mailbox *mailbox;
 	struct mthca_mgm *mgm = mgm_mailbox->buf;
 	u8 *mgid;
 	int err;
 	u8 status;

 	mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
 	if (IS_ERR(mailbox))
 		return -ENOMEM;
 	mgid = mailbox->buf;

 	memcpy(mgid, gid, 16);

 	err = mthca_MGID_HASH(dev, mailbox, hash, &status);
 	if (err)
 		goto out;
 	if (status) {
 		mthca_err(dev, "MGID_HASH returned status %02x\n", status);
 		err = -EINVAL;
 		goto out;
 	}

 	if (0)
 		mthca_dbg(dev, "Hash for %04x:%04x:%04x:%04x:"
 			  "%04x:%04x:%04x:%04x is %04x\n",
 			  be16_to_cpu(((__be16 *) gid)[0]),
 			  be16_to_cpu(((__be16 *) gid)[1]),
 			  be16_to_cpu(((__be16 *) gid)[2]),
 			  be16_to_cpu(((__be16 *) gid)[3]),
 			  be16_to_cpu(((__be16 *) gid)[4]),
 			  be16_to_cpu(((__be16 *) gid)[5]),
 			  be16_to_cpu(((__be16 *) gid)[6]),
 			  be16_to_cpu(((__be16 *) gid)[7]),
 			  *hash);

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

 	do {
 		err = mthca_READ_MGM(dev, *index, mgm_mailbox, &status);
 		if (err)
 			goto out;
 		if (status) {
 			mthca_err(dev, "READ_MGM returned status %02x\n", status);
 			err = -EINVAL;
 			goto out;
 		}

 		if (!memcmp(mgm->gid, zero_gid, 16)) {
 			if (*index != *hash) {
 				mthca_err(dev, "Found zero MGID in AMGM.\n");
 				err = -EINVAL;
 			}
 			goto out;
 		}

 		if (!memcmp(mgm->gid, gid, 16))
 			goto out;

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

 	*index = -1;

  out:
 	mthca_free_mailbox(dev, mailbox);
 	return err;
 }

 int mthca_multicast_attach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
 {
 	struct mthca_dev *dev = to_mdev(ibqp->device);
 	struct mthca_mailbox *mailbox;
 	struct mthca_mgm *mgm;
 	u16 hash;
 	int index, prev;
 	int link = 0;
 	int i;
 	int err;
 	u8 status;

 	mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
 	if (IS_ERR(mailbox))
 		return PTR_ERR(mailbox);
 	mgm = mailbox->buf;

 	mutex_lock(&dev->mcg_table.mutex);

 	err = find_mgm(dev, gid->raw, mailbox, &hash, &prev, &index);
 	if (err)
 		goto out;

 	if (index != -1) {
 		if (!memcmp(mgm->gid, zero_gid, 16))
 			memcpy(mgm->gid, gid->raw, 16);
 	} else {
 		link = 1;

 		index = mthca_alloc(&dev->mcg_table.alloc);
 		if (index == -1) {
 			mthca_err(dev, "No AMGM entries left\n");
 			err = -ENOMEM;
 			goto out;
 		}

 		err = mthca_READ_MGM(dev, index, mailbox, &status);
 		if (err)
 			goto out;
 		if (status) {
 			mthca_err(dev, "READ_MGM returned status %02x\n", status);
 			err = -EINVAL;
 			goto out;
 		}
 		memset(mgm, 0, sizeof *mgm);
 		memcpy(mgm->gid, gid->raw, 16);
 	}

 	for (i = 0; i < MTHCA_QP_PER_MGM; ++i)
 		if (mgm->qp[i] == cpu_to_be32(ibqp->qp_num | (1 << 31))) {
 			mthca_dbg(dev, "QP %06x already a member of MGM\n",
 				  ibqp->qp_num);
 			err = 0;
 			goto out;
 		} else if (!(mgm->qp[i] & cpu_to_be32(1 << 31))) {
 			mgm->qp[i] = cpu_to_be32(ibqp->qp_num | (1 << 31));
 			break;
 		}

 	if (i == MTHCA_QP_PER_MGM) {
 		mthca_err(dev, "MGM at index %x is full.\n", index);
 		err = -ENOMEM;
 		goto out;
 	}

 	err = mthca_WRITE_MGM(dev, index, mailbox, &status);
 	if (err)
 		goto out;
 	if (status) {
 		mthca_err(dev, "WRITE_MGM returned status %02x\n", status);
 		err = -EINVAL;
 		goto out;
 	}

 	if (!link)
 		goto out;

 	err = mthca_READ_MGM(dev, prev, mailbox, &status);
 	if (err)
 		goto out;
 	if (status) {
 		mthca_err(dev, "READ_MGM returned status %02x\n", status);
 		err = -EINVAL;
 		goto out;
 	}

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

 	err = mthca_WRITE_MGM(dev, prev, mailbox, &status);
 	if (err)
 		goto out;
 	if (status) {
 		mthca_err(dev, "WRITE_MGM returned status %02x\n", status);
 		err = -EINVAL;
 	}

  out:
 	if (err && link && index != -1) {
 		BUG_ON(index < dev->limits.num_mgms);
 		mthca_free(&dev->mcg_table.alloc, index);
 	}
 	mutex_unlock(&dev->mcg_table.mutex);

 	mthca_free_mailbox(dev, mailbox);
 	return err;
 }

 int mthca_multicast_detach(struct ib_qp *ibqp, union ib_gid *gid, u16 lid)
 {
 	struct mthca_dev *dev = to_mdev(ibqp->device);
 	struct mthca_mailbox *mailbox;
 	struct mthca_mgm *mgm;
 	u16 hash;
 	int prev, index;
 	int i, loc;
 	int err;
 	u8 status;

 	mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
 	if (IS_ERR(mailbox))
 		return PTR_ERR(mailbox);
 	mgm = mailbox->buf;

 	mutex_lock(&dev->mcg_table.mutex);

 	err = find_mgm(dev, gid->raw, mailbox, &hash, &prev, &index);
 	if (err)
 		goto out;

 	if (index == -1) {
 		mthca_err(dev, "MGID %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x "
 			  "not found\n",
 			  be16_to_cpu(((__be16 *) gid->raw)[0]),
 			  be16_to_cpu(((__be16 *) gid->raw)[1]),
 			  be16_to_cpu(((__be16 *) gid->raw)[2]),
 			  be16_to_cpu(((__be16 *) gid->raw)[3]),
 			  be16_to_cpu(((__be16 *) gid->raw)[4]),
 			  be16_to_cpu(((__be16 *) gid->raw)[5]),
 			  be16_to_cpu(((__be16 *) gid->raw)[6]),
 			  be16_to_cpu(((__be16 *) gid->raw)[7]));
 		err = -EINVAL;
 		goto out;
 	}

 	for (loc = -1, i = 0; i < MTHCA_QP_PER_MGM; ++i) {
 		if (mgm->qp[i] == cpu_to_be32(ibqp->qp_num | (1 << 31)))
 			loc = i;
 		if (!(mgm->qp[i] & cpu_to_be32(1 << 31)))
 			break;
 	}

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

 	mgm->qp[loc]   = mgm->qp[i - 1];
 	mgm->qp[i - 1] = 0;

 	err = mthca_WRITE_MGM(dev, index, mailbox, &status);
 	if (err)
 		goto out;
 	if (status) {
 		mthca_err(dev, "WRITE_MGM returned status %02x\n", status);
 		err = -EINVAL;
 		goto out;
 	}

 	if (i != 1)
 		goto out;

 	if (prev == -1) {
 		/* Remove entry from MGM */
 		int amgm_index_to_free = be32_to_cpu(mgm->next_gid_index) >> 6;
 		if (amgm_index_to_free) {
 			err = mthca_READ_MGM(dev, amgm_index_to_free,
 					     mailbox, &status);
 			if (err)
 				goto out;
 			if (status) {
 				mthca_err(dev, "READ_MGM returned status %02x\n",
 					  status);
 				err = -EINVAL;
 				goto out;
 			}
 		} else
 			memset(mgm->gid, 0, 16);

 		err = mthca_WRITE_MGM(dev, index, mailbox, &status);
 		if (err)
 			goto out;
 		if (status) {
 			mthca_err(dev, "WRITE_MGM returned status %02x\n", status);
 			err = -EINVAL;
 			goto out;
 		}
 		if (amgm_index_to_free) {
 			BUG_ON(amgm_index_to_free < dev->limits.num_mgms);
 			mthca_free(&dev->mcg_table.alloc, amgm_index_to_free);
 		}
 	} else {
 		/* Remove entry from AMGM */
 		int curr_next_index = be32_to_cpu(mgm->next_gid_index) >> 6;
 		err = mthca_READ_MGM(dev, prev, mailbox, &status);
 		if (err)
 			goto out;
 		if (status) {
 			mthca_err(dev, "READ_MGM returned status %02x\n", status);
 			err = -EINVAL;
 			goto out;
 		}

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

 		err = mthca_WRITE_MGM(dev, prev, mailbox, &status);
 		if (err)
 			goto out;
 		if (status) {
 			mthca_err(dev, "WRITE_MGM returned status %02x\n", status);
 			err = -EINVAL;
 			goto out;
 		}
 		BUG_ON(index < dev->limits.num_mgms);
 		mthca_free(&dev->mcg_table.alloc, index);
 	}

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

 	mthca_free_mailbox(dev, mailbox);
 	return err;
 }

 int __devinit mthca_init_mcg_table(struct mthca_dev *dev)
 {
 	int err;
 	int table_size = dev->limits.num_mgms + dev->limits.num_amgms;

 	err = mthca_alloc_init(&dev->mcg_table.alloc,
 			       table_size,
 			       table_size - 1,
 			       dev->limits.num_mgms);
 	if (err)
 		return err;

 	mutex_init(&dev->mcg_table.mutex);

 	return 0;
 }

 void mthca_cleanup_mcg_table(struct mthca_dev *dev)
 {
 	mthca_alloc_cleanup(&dev->mcg_table.alloc);
 }
	/*
	* Copyright (c) 2004 Topspin Communications. 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.
	*
	* $Id: mthca_mcg.c 1349 2004-12-16 21:09:43Z roland $
	*/

	#include <linux/init.h>
	#include <linux/string.h>
	#include <linux/slab.h>

	#include "mthca_dev.h"
	#include "mthca_cmd.h"

	struct mthca_mgm {
	__be32 next_gid_index;
	u32 reserved[3];
	u8 gid[16];
	__be32 qp[MTHCA_QP_PER_MGM];
	};

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

	/*
	* 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_mgm(struct mthca_dev *dev,
	u8 gid, struct mthca_mailbox mgm_mailbox,
	u16 hash, int prev, int *index)
	{
	struct mthca_mailbox *mailbox;
	struct mthca_mgm *mgm = mgm_mailbox->buf;
	u8 *mgid;
	int err;
	u8 status;

	mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
	if (IS_ERR(mailbox))
	return -ENOMEM;
	mgid = mailbox->buf;

	memcpy(mgid, gid, 16);

	err = mthca_MGID_HASH(dev, mailbox, hash, &status);
	if (err)
	goto out;
	if (status) {
	mthca_err(dev, "MGID_HASH returned status %02x\n", status);
	err = -EINVAL;
	goto out;
	}

	if (0)
	mthca_dbg(dev, "Hash for %04x:%04x:%04x:%04x:"
	"%04x:%04x:%04x:%04x is %04x\n",
	be16_to_cpu(((__be16 *) gid)[0]),
	be16_to_cpu(((__be16 *) gid)[1]),
	be16_to_cpu(((__be16 *) gid)[2]),
	be16_to_cpu(((__be16 *) gid)[3]),
	be16_to_cpu(((__be16 *) gid)[4]),
	be16_to_cpu(((__be16 *) gid)[5]),
	be16_to_cpu(((__be16 *) gid)[6]),
	be16_to_cpu(((__be16 *) gid)[7]),
	*hash);

	index = hash;
	*prev = -1;

	do {
	err = mthca_READ_MGM(dev, *index, mgm_mailbox, &status);
	if (err)
	goto out;
	if (status) {
	mthca_err(dev, "READ_MGM returned status %02x\n", status);
	err = -EINVAL;
	goto out;
	}

	if (!memcmp(mgm->gid, zero_gid, 16)) {
	if (index != hash) {
	mthca_err(dev, "Found zero MGID in AMGM.\n");
	err = -EINVAL;
	}
	goto out;
	}

	if (!memcmp(mgm->gid, gid, 16))
	goto out;

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

	*index = -1;

	out:
	mthca_free_mailbox(dev, mailbox);
	return err;
	}

	int mthca_multicast_attach(struct ib_qp ibqp, union ib_gid gid, u16 lid)
	{
	struct mthca_dev *dev = to_mdev(ibqp->device);
	struct mthca_mailbox *mailbox;
	struct mthca_mgm *mgm;
	u16 hash;
	int index, prev;
	int link = 0;
	int i;
	int err;
	u8 status;

	mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
	if (IS_ERR(mailbox))
	return PTR_ERR(mailbox);
	mgm = mailbox->buf;

	mutex_lock(&dev->mcg_table.mutex);

	err = find_mgm(dev, gid->raw, mailbox, &hash, &prev, &index);
	if (err)
	goto out;

	if (index != -1) {
	if (!memcmp(mgm->gid, zero_gid, 16))
	memcpy(mgm->gid, gid->raw, 16);
	} else {
	link = 1;

	index = mthca_alloc(&dev->mcg_table.alloc);
	if (index == -1) {
	mthca_err(dev, "No AMGM entries left\n");
	err = -ENOMEM;
	goto out;
	}

	err = mthca_READ_MGM(dev, index, mailbox, &status);
	if (err)
	goto out;
	if (status) {
	mthca_err(dev, "READ_MGM returned status %02x\n", status);
	err = -EINVAL;
	goto out;
	}
	memset(mgm, 0, sizeof *mgm);
	memcpy(mgm->gid, gid->raw, 16);
	}

	for (i = 0; i < MTHCA_QP_PER_MGM; ++i)
	if (mgm->qp[i] == cpu_to_be32(ibqp->qp_num \| (1 << 31))) {
	mthca_dbg(dev, "QP %06x already a member of MGM\n",
	ibqp->qp_num);
	err = 0;
	goto out;
	} else if (!(mgm->qp[i] & cpu_to_be32(1 << 31))) {
	mgm->qp[i] = cpu_to_be32(ibqp->qp_num \| (1 << 31));
	break;
	}

	if (i == MTHCA_QP_PER_MGM) {
	mthca_err(dev, "MGM at index %x is full.\n", index);
	err = -ENOMEM;
	goto out;
	}

	err = mthca_WRITE_MGM(dev, index, mailbox, &status);
	if (err)
	goto out;
	if (status) {
	mthca_err(dev, "WRITE_MGM returned status %02x\n", status);
	err = -EINVAL;
	goto out;
	}

	if (!link)
	goto out;

	err = mthca_READ_MGM(dev, prev, mailbox, &status);
	if (err)
	goto out;
	if (status) {
	mthca_err(dev, "READ_MGM returned status %02x\n", status);
	err = -EINVAL;
	goto out;
	}

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

	err = mthca_WRITE_MGM(dev, prev, mailbox, &status);
	if (err)
	goto out;
	if (status) {
	mthca_err(dev, "WRITE_MGM returned status %02x\n", status);
	err = -EINVAL;
	}

	out:
	if (err && link && index != -1) {
	BUG_ON(index < dev->limits.num_mgms);
	mthca_free(&dev->mcg_table.alloc, index);
	}
	mutex_unlock(&dev->mcg_table.mutex);

	mthca_free_mailbox(dev, mailbox);
	return err;
	}

	int mthca_multicast_detach(struct ib_qp ibqp, union ib_gid gid, u16 lid)
	{
	struct mthca_dev *dev = to_mdev(ibqp->device);
	struct mthca_mailbox *mailbox;
	struct mthca_mgm *mgm;
	u16 hash;
	int prev, index;
	int i, loc;
	int err;
	u8 status;

	mailbox = mthca_alloc_mailbox(dev, GFP_KERNEL);
	if (IS_ERR(mailbox))
	return PTR_ERR(mailbox);
	mgm = mailbox->buf;

	mutex_lock(&dev->mcg_table.mutex);

	err = find_mgm(dev, gid->raw, mailbox, &hash, &prev, &index);
	if (err)
	goto out;

	if (index == -1) {
	mthca_err(dev, "MGID %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x "
	"not found\n",
	be16_to_cpu(((__be16 *) gid->raw)[0]),
	be16_to_cpu(((__be16 *) gid->raw)[1]),
	be16_to_cpu(((__be16 *) gid->raw)[2]),
	be16_to_cpu(((__be16 *) gid->raw)[3]),
	be16_to_cpu(((__be16 *) gid->raw)[4]),
	be16_to_cpu(((__be16 *) gid->raw)[5]),
	be16_to_cpu(((__be16 *) gid->raw)[6]),
	be16_to_cpu(((__be16 *) gid->raw)[7]));
	err = -EINVAL;
	goto out;
	}

	for (loc = -1, i = 0; i < MTHCA_QP_PER_MGM; ++i) {
	if (mgm->qp[i] == cpu_to_be32(ibqp->qp_num \| (1 << 31)))
	loc = i;
	if (!(mgm->qp[i] & cpu_to_be32(1 << 31)))
	break;
	}

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

	mgm->qp[loc] = mgm->qp[i - 1];
	mgm->qp[i - 1] = 0;

	err = mthca_WRITE_MGM(dev, index, mailbox, &status);
	if (err)
	goto out;
	if (status) {
	mthca_err(dev, "WRITE_MGM returned status %02x\n", status);
	err = -EINVAL;
	goto out;
	}

	if (i != 1)
	goto out;

	if (prev == -1) {
	/* Remove entry from MGM */
	int amgm_index_to_free = be32_to_cpu(mgm->next_gid_index) >> 6;
	if (amgm_index_to_free) {
	err = mthca_READ_MGM(dev, amgm_index_to_free,
	mailbox, &status);
	if (err)
	goto out;
	if (status) {
	mthca_err(dev, "READ_MGM returned status %02x\n",
	status);
	err = -EINVAL;
	goto out;
	}
	} else
	memset(mgm->gid, 0, 16);

	err = mthca_WRITE_MGM(dev, index, mailbox, &status);
	if (err)
	goto out;
	if (status) {
	mthca_err(dev, "WRITE_MGM returned status %02x\n", status);
	err = -EINVAL;
	goto out;
	}
	if (amgm_index_to_free) {
	BUG_ON(amgm_index_to_free < dev->limits.num_mgms);
	mthca_free(&dev->mcg_table.alloc, amgm_index_to_free);
	}
	} else {
	/* Remove entry from AMGM */
	int curr_next_index = be32_to_cpu(mgm->next_gid_index) >> 6;
	err = mthca_READ_MGM(dev, prev, mailbox, &status);
	if (err)
	goto out;
	if (status) {
	mthca_err(dev, "READ_MGM returned status %02x\n", status);
	err = -EINVAL;
	goto out;
	}

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

	err = mthca_WRITE_MGM(dev, prev, mailbox, &status);
	if (err)
	goto out;
	if (status) {
	mthca_err(dev, "WRITE_MGM returned status %02x\n", status);
	err = -EINVAL;
	goto out;
	}
	BUG_ON(index < dev->limits.num_mgms);
	mthca_free(&dev->mcg_table.alloc, index);
	}

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

	mthca_free_mailbox(dev, mailbox);
	return err;
	}

	int __devinit mthca_init_mcg_table(struct mthca_dev *dev)
	{
	int err;
	int table_size = dev->limits.num_mgms + dev->limits.num_amgms;

	err = mthca_alloc_init(&dev->mcg_table.alloc,
	table_size,
	table_size - 1,
	dev->limits.num_mgms);
	if (err)
	return err;

	mutex_init(&dev->mcg_table.mutex);

	return 0;
	}

	void mthca_cleanup_mcg_table(struct mthca_dev *dev)
	{
	mthca_alloc_cleanup(&dev->mcg_table.alloc);
	}