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Commit f5358a17 authored by Roland Dreier's avatar Roland Dreier
Browse files

IB/srp: Use FMRs to map gather/scatter lists 



Create an SRP FMR pool on HCAs that support FMRs, and use FMRs to map
gather/scatter lists that have more than one entry into a single
memory region that appears virtually contiguous to the SRP target
(which is the RDMA initiator).

This patch bails out on FMR mapping for SCSI commands where the
gather/scatter list cannot be mapped into a single FMR because there
are sub-page-sized entries in middle of the list.  An unaligned
start or end of the list is OK.

Based on a patch by Vu Pham <vuhuong@mellanox.com>.

Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent a26026c1

drivers/infiniband/ulp/srp/ib_srp.c

+208 −82
Original line number Diff line number Diff line
@@ -105,7 +105,8 @@ static struct srp_iu *srp_alloc_iu(struct srp_host *host, size_t size, 
	if (!iu->buf)

		goto out_free_iu;



	iu->dma = dma_map_single(host->dev->dma_device, iu->buf, size, direction);

	iu->dma = dma_map_single(host->dev->dev->dma_device,

				 iu->buf, size, direction);

	if (dma_mapping_error(iu->dma))

		goto out_free_buf;
@@ -127,7 +128,8 @@ static void srp_free_iu(struct srp_host *host, struct srp_iu *iu) 
	if (!iu)

		return;



	dma_unmap_single(host->dev->dma_device, iu->dma, iu->size, iu->direction);

	dma_unmap_single(host->dev->dev->dma_device,

			 iu->dma, iu->size, iu->direction);

	kfree(iu->buf);

	kfree(iu);

}
@@ -147,7 +149,7 @@ static int srp_init_qp(struct srp_target_port *target, 
	if (!attr)

		return -ENOMEM;



	ret = ib_find_cached_pkey(target->srp_host->dev,

	ret = ib_find_cached_pkey(target->srp_host->dev->dev,

				  target->srp_host->port,

				  be16_to_cpu(target->path.pkey),

				  &attr->pkey_index);
@@ -179,7 +181,7 @@ static int srp_create_target_ib(struct srp_target_port *target) 
	if (!init_attr)

		return -ENOMEM;



	target->cq = ib_create_cq(target->srp_host->dev, srp_completion,

	target->cq = ib_create_cq(target->srp_host->dev->dev, srp_completion,

				  NULL, target, SRP_CQ_SIZE);

	if (IS_ERR(target->cq)) {

		ret = PTR_ERR(target->cq);
@@ -198,7 +200,7 @@ static int srp_create_target_ib(struct srp_target_port *target) 
	init_attr->send_cq             = target->cq;

	init_attr->recv_cq             = target->cq;



	target->qp = ib_create_qp(target->srp_host->pd, init_attr);

	target->qp = ib_create_qp(target->srp_host->dev->pd, init_attr);

	if (IS_ERR(target->qp)) {

		ret = PTR_ERR(target->qp);

		ib_destroy_cq(target->cq);
@@ -250,7 +252,7 @@ static int srp_lookup_path(struct srp_target_port *target) 


	init_completion(&target->done);



	target->path_query_id = ib_sa_path_rec_get(target->srp_host->dev,

	target->path_query_id = ib_sa_path_rec_get(target->srp_host->dev->dev,

						   target->srp_host->port,

						   &target->path,

						   IB_SA_PATH_REC_DGID		|
@@ -421,6 +423,11 @@ static void srp_unmap_data(struct scsi_cmnd *scmnd, 
	     scmnd->sc_data_direction != DMA_FROM_DEVICE))

		return;



	if (req->fmr) {

		ib_fmr_pool_unmap(req->fmr);

		req->fmr = NULL;

	}



	/*

	 * This handling of non-SG commands can be killed when the

	 * SCSI midlayer no longer generates non-SG commands.
@@ -433,7 +440,7 @@ static void srp_unmap_data(struct scsi_cmnd *scmnd, 
		scat  = &req->fake_sg;

	}



	dma_unmap_sg(target->srp_host->dev->dma_device, scat, nents,

	dma_unmap_sg(target->srp_host->dev->dev->dma_device, scat, nents,

		     scmnd->sc_data_direction);

}
@@ -459,7 +466,7 @@ static int srp_reconnect_target(struct srp_target_port *target) 
	 * Now get a new local CM ID so that we avoid confusing the

	 * target in case things are really fouled up.

	 */

	new_cm_id = ib_create_cm_id(target->srp_host->dev,

	new_cm_id = ib_create_cm_id(target->srp_host->dev->dev,

				    srp_cm_handler, target);

	if (IS_ERR(new_cm_id)) {

		ret = PTR_ERR(new_cm_id);
@@ -528,14 +535,79 @@ static int srp_reconnect_target(struct srp_target_port *target) 
	return ret;

}



static int srp_map_fmr(struct srp_device *dev, struct scatterlist *scat,

		       int sg_cnt, struct srp_request *req,

		       struct srp_direct_buf *buf)

{

	u64 io_addr = 0;

	u64 *dma_pages;

	u32 len;

	int page_cnt;

	int i, j;

	int ret;



	if (!dev->fmr_pool)

		return -ENODEV;



	len = page_cnt = 0;

	for (i = 0; i < sg_cnt; ++i) {

		if (sg_dma_address(&scat[i]) & ~dev->fmr_page_mask) {

			if (i > 0)

				return -EINVAL;

			else

				++page_cnt;

		}

		if ((sg_dma_address(&scat[i]) + sg_dma_len(&scat[i])) &

		    ~dev->fmr_page_mask) {

			if (i < sg_cnt - 1)

				return -EINVAL;

			else

				++page_cnt;

		}



		len += sg_dma_len(&scat[i]);

	}



	page_cnt += len >> dev->fmr_page_shift;

	if (page_cnt > SRP_FMR_SIZE)

		return -ENOMEM;



	dma_pages = kmalloc(sizeof (u64) * page_cnt, GFP_ATOMIC);

	if (!dma_pages)

		return -ENOMEM;



	page_cnt = 0;

	for (i = 0; i < sg_cnt; ++i)

		for (j = 0; j < sg_dma_len(&scat[i]); j += dev->fmr_page_size)

			dma_pages[page_cnt++] =

				(sg_dma_address(&scat[i]) & dev->fmr_page_mask) + j;



	req->fmr = ib_fmr_pool_map_phys(dev->fmr_pool,

					dma_pages, page_cnt, &io_addr);

	if (IS_ERR(req->fmr)) {

		ret = PTR_ERR(req->fmr);

		goto out;

	}



	buf->va  = cpu_to_be64(sg_dma_address(&scat[0]) & ~dev->fmr_page_mask);

	buf->key = cpu_to_be32(req->fmr->fmr->rkey);

	buf->len = cpu_to_be32(len);



	ret = 0;



out:

	kfree(dma_pages);



	return ret;

}



static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target,

			struct srp_request *req)

{

	struct scatterlist *scat;

	struct srp_cmd *cmd = req->cmd->buf;

	int len, nents, count;

	int i;

	u8 fmt;

	u8 fmt = SRP_DATA_DESC_DIRECT;



	if (!scmnd->request_buffer || scmnd->sc_data_direction == DMA_NONE)

		return sizeof (struct srp_cmd);
@@ -560,53 +632,63 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target, 
		sg_init_one(scat, scmnd->request_buffer, scmnd->request_bufflen);

	}



	count = dma_map_sg(target->srp_host->dev->dma_device, scat, nents,

			   scmnd->sc_data_direction);

	count = dma_map_sg(target->srp_host->dev->dev->dma_device,

			   scat, nents, scmnd->sc_data_direction);



	fmt = SRP_DATA_DESC_DIRECT;

	len = sizeof (struct srp_cmd) +	sizeof (struct srp_direct_buf);



	if (count == 1) {

		/*

		 * The midlayer only generated a single gather/scatter

		 * entry, or DMA mapping coalesced everything to a

		 * single entry.  So a direct descriptor along with

		 * the DMA MR suffices.

		 */

		struct srp_direct_buf *buf = (void *) cmd->add_data;



		fmt = SRP_DATA_DESC_DIRECT;



		buf->va  = cpu_to_be64(sg_dma_address(scat));

		buf->key = cpu_to_be32(target->srp_host->mr->rkey);

		buf->key = cpu_to_be32(target->srp_host->dev->mr->rkey);

		buf->len = cpu_to_be32(sg_dma_len(scat));



		len = sizeof (struct srp_cmd) +

			sizeof (struct srp_direct_buf);

	} else {

	} else if (srp_map_fmr(target->srp_host->dev, scat, count, req,

			       (void *) cmd->add_data)) {

		/*

		 * FMR mapping failed, and the scatterlist has more

		 * than one entry.  Generate an indirect memory

		 * descriptor.

		 */

		struct srp_indirect_buf *buf = (void *) cmd->add_data;

		u32 datalen = 0;

		int i;



		fmt = SRP_DATA_DESC_INDIRECT;

		len = sizeof (struct srp_cmd) +

			sizeof (struct srp_indirect_buf) +

			count * sizeof (struct srp_direct_buf);



		for (i = 0; i < count; ++i) {

			buf->desc_list[i].va  =

				cpu_to_be64(sg_dma_address(&scat[i]));

			buf->desc_list[i].key =

				cpu_to_be32(target->srp_host->dev->mr->rkey);

			buf->desc_list[i].len =

				cpu_to_be32(sg_dma_len(&scat[i]));

			datalen += sg_dma_len(&scat[i]);

		}



		if (scmnd->sc_data_direction == DMA_TO_DEVICE)

			cmd->data_out_desc_cnt = count;

		else

			cmd->data_in_desc_cnt = count;



		buf->table_desc.va  = cpu_to_be64(req->cmd->dma +

						  sizeof *cmd +

						  sizeof *buf);

		buf->table_desc.va  =

			cpu_to_be64(req->cmd->dma + sizeof *cmd + sizeof *buf);

		buf->table_desc.key =

			cpu_to_be32(target->srp_host->mr->rkey);

			cpu_to_be32(target->srp_host->dev->mr->rkey);

		buf->table_desc.len =

			cpu_to_be32(count * sizeof (struct srp_direct_buf));



		for (i = 0; i < count; ++i) {

			buf->desc_list[i].va  = cpu_to_be64(sg_dma_address(&scat[i]));

			buf->desc_list[i].key =

				cpu_to_be32(target->srp_host->mr->rkey);

			buf->desc_list[i].len = cpu_to_be32(sg_dma_len(&scat[i]));



			datalen += sg_dma_len(&scat[i]);

		}



		buf->len = cpu_to_be32(datalen);



		len = sizeof (struct srp_cmd) +

			sizeof (struct srp_indirect_buf) +

			count * sizeof (struct srp_direct_buf);

	}



	if (scmnd->sc_data_direction == DMA_TO_DEVICE)
@@ -689,7 +771,7 @@ static void srp_handle_recv(struct srp_target_port *target, struct ib_wc *wc) 


	iu = target->rx_ring[wc->wr_id & ~SRP_OP_RECV];



	dma_sync_single_for_cpu(target->srp_host->dev->dma_device, iu->dma,

	dma_sync_single_for_cpu(target->srp_host->dev->dev->dma_device, iu->dma,

				target->max_ti_iu_len, DMA_FROM_DEVICE);



	opcode = *(u8 *) iu->buf;
@@ -726,7 +808,7 @@ static void srp_handle_recv(struct srp_target_port *target, struct ib_wc *wc) 
		break;

	}



	dma_sync_single_for_device(target->srp_host->dev->dma_device, iu->dma,

	dma_sync_single_for_device(target->srp_host->dev->dev->dma_device, iu->dma,

				   target->max_ti_iu_len, DMA_FROM_DEVICE);

}
@@ -770,7 +852,7 @@ static int __srp_post_recv(struct srp_target_port *target) 


	list.addr   = iu->dma;

	list.length = iu->size;

	list.lkey   = target->srp_host->mr->lkey;

	list.lkey   = target->srp_host->dev->mr->lkey;



	wr.next     = NULL;

	wr.sg_list  = &list;
@@ -828,7 +910,7 @@ static int __srp_post_send(struct srp_target_port *target, 


	list.addr   = iu->dma;

	list.length = len;

	list.lkey   = target->srp_host->mr->lkey;

	list.lkey   = target->srp_host->dev->mr->lkey;



	wr.next       = NULL;

	wr.wr_id      = target->tx_head & SRP_SQ_SIZE;
@@ -870,7 +952,7 @@ static int srp_queuecommand(struct scsi_cmnd *scmnd, 
	if (!iu)

		goto err;



	dma_sync_single_for_cpu(target->srp_host->dev->dma_device, iu->dma,

	dma_sync_single_for_cpu(target->srp_host->dev->dev->dma_device, iu->dma,

				SRP_MAX_IU_LEN, DMA_TO_DEVICE);



	req = list_entry(target->free_reqs.next, struct srp_request, list);
@@ -903,7 +985,7 @@ static int srp_queuecommand(struct scsi_cmnd *scmnd, 
		goto err_unmap;

	}



	dma_sync_single_for_device(target->srp_host->dev->dma_device, iu->dma,

	dma_sync_single_for_device(target->srp_host->dev->dev->dma_device, iu->dma,

				   SRP_MAX_IU_LEN, DMA_TO_DEVICE);



	if (__srp_post_send(target, iu, len)) {
@@ -1365,7 +1447,7 @@ static int srp_add_target(struct srp_host *host, struct srp_target_port *target) 
	sprintf(target->target_name, "SRP.T10:%016llX",

		 (unsigned long long) be64_to_cpu(target->id_ext));



	if (scsi_add_host(target->scsi_host, host->dev->dma_device))

	if (scsi_add_host(target->scsi_host, host->dev->dev->dma_device))

		return -ENODEV;



	mutex_lock(&host->target_mutex);
@@ -1558,7 +1640,7 @@ static ssize_t srp_create_target(struct class_device *class_dev, 
	if (ret)

		goto err;



	ib_get_cached_gid(host->dev, host->port, 0, &target->path.sgid);

	ib_get_cached_gid(host->dev->dev, host->port, 0, &target->path.sgid);



	printk(KERN_DEBUG PFX "new target: id_ext %016llx ioc_guid %016llx pkey %04x "

	       "service_id %016llx dgid %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n",
@@ -1579,7 +1661,7 @@ static ssize_t srp_create_target(struct class_device *class_dev, 
	if (ret)

		goto err;



	target->cm_id = ib_create_cm_id(host->dev, srp_cm_handler, target);

	target->cm_id = ib_create_cm_id(host->dev->dev, srp_cm_handler, target);

	if (IS_ERR(target->cm_id)) {

		ret = PTR_ERR(target->cm_id);

		goto err_free;
@@ -1619,7 +1701,7 @@ static ssize_t show_ibdev(struct class_device *class_dev, char *buf) 
	struct srp_host *host =

		container_of(class_dev, struct srp_host, class_dev);



	return sprintf(buf, "%s\n", host->dev->name);

	return sprintf(buf, "%s\n", host->dev->dev->name);

}



static CLASS_DEVICE_ATTR(ibdev, S_IRUGO, show_ibdev, NULL);
@@ -1634,7 +1716,7 @@ static ssize_t show_port(struct class_device *class_dev, char *buf) 


static CLASS_DEVICE_ATTR(port, S_IRUGO, show_port, NULL);



static struct srp_host *srp_add_port(struct ib_device *device, u8 port)

static struct srp_host *srp_add_port(struct srp_device *device, u8 port)

{

	struct srp_host *host;
@@ -1649,26 +1731,15 @@ static struct srp_host *srp_add_port(struct ib_device *device, u8 port) 
	host->port = port;



	host->initiator_port_id[7] = port;

	memcpy(host->initiator_port_id + 8, &device->node_guid, 8);



	host->pd   = ib_alloc_pd(device);

	if (IS_ERR(host->pd))

		goto err_free;



	host->mr   = ib_get_dma_mr(host->pd,

				   IB_ACCESS_LOCAL_WRITE |

				   IB_ACCESS_REMOTE_READ |

				   IB_ACCESS_REMOTE_WRITE);

	if (IS_ERR(host->mr))

		goto err_pd;

	memcpy(host->initiator_port_id + 8, &device->dev->node_guid, 8);



	host->class_dev.class = &srp_class;

	host->class_dev.dev   = device->dma_device;

	host->class_dev.dev   = device->dev->dma_device;

	snprintf(host->class_dev.class_id, BUS_ID_SIZE, "srp-%s-%d",

		 device->name, port);

		 device->dev->name, port);



	if (class_device_register(&host->class_dev))

		goto err_mr;

		goto free_host;

	if (class_device_create_file(&host->class_dev, &class_device_attr_add_target))

		goto err_class;

	if (class_device_create_file(&host->class_dev, &class_device_attr_ibdev))
@@ -1681,13 +1752,7 @@ static struct srp_host *srp_add_port(struct ib_device *device, u8 port) 
err_class:

	class_device_unregister(&host->class_dev);



err_mr:

	ib_dereg_mr(host->mr);



err_pd:

	ib_dealloc_pd(host->pd);



err_free:

free_host:

	kfree(host);



	return NULL;
@@ -1695,15 +1760,62 @@ static struct srp_host *srp_add_port(struct ib_device *device, u8 port) 


static void srp_add_one(struct ib_device *device)

{

	struct list_head *dev_list;

	struct srp_device *srp_dev;

	struct ib_device_attr *dev_attr;

	struct ib_fmr_pool_param fmr_param;

	struct srp_host *host;

	int s, e, p;



	dev_list = kmalloc(sizeof *dev_list, GFP_KERNEL);

	if (!dev_list)

	dev_attr = kmalloc(sizeof *dev_attr, GFP_KERNEL);

	if (!dev_attr)

		return;



	INIT_LIST_HEAD(dev_list);

	if (ib_query_device(device, dev_attr)) {

		printk(KERN_WARNING PFX "Query device failed for %s\n",

		       device->name);

		goto free_attr;

	}



	srp_dev = kmalloc(sizeof *srp_dev, GFP_KERNEL);

	if (!srp_dev)

		goto free_attr;



	/*

	 * Use the smallest page size supported by the HCA, down to a

	 * minimum of 512 bytes (which is the smallest sector that a

	 * SCSI command will ever carry).

	 */

	srp_dev->fmr_page_shift = max(9, ffs(dev_attr->page_size_cap) - 1);

	srp_dev->fmr_page_size  = 1 << srp_dev->fmr_page_shift;

	srp_dev->fmr_page_mask  = ~((unsigned long) srp_dev->fmr_page_size - 1);



	INIT_LIST_HEAD(&srp_dev->dev_list);



	srp_dev->dev = device;

	srp_dev->pd  = ib_alloc_pd(device);

	if (IS_ERR(srp_dev->pd))

		goto free_dev;



	srp_dev->mr = ib_get_dma_mr(srp_dev->pd,

				    IB_ACCESS_LOCAL_WRITE |

				    IB_ACCESS_REMOTE_READ |

				    IB_ACCESS_REMOTE_WRITE);

	if (IS_ERR(srp_dev->mr))

		goto err_pd;



	memset(&fmr_param, 0, sizeof fmr_param);

	fmr_param.pool_size	    = SRP_FMR_POOL_SIZE;

	fmr_param.dirty_watermark   = SRP_FMR_DIRTY_SIZE;

	fmr_param.cache		    = 1;

	fmr_param.max_pages_per_fmr = SRP_FMR_SIZE;

	fmr_param.page_shift	    = srp_dev->fmr_page_shift;

	fmr_param.access	    = (IB_ACCESS_LOCAL_WRITE |

				       IB_ACCESS_REMOTE_WRITE |

				       IB_ACCESS_REMOTE_READ);



	srp_dev->fmr_pool = ib_create_fmr_pool(srp_dev->pd, &fmr_param);

	if (IS_ERR(srp_dev->fmr_pool))

		srp_dev->fmr_pool = NULL;



	if (device->node_type == IB_NODE_SWITCH) {

		s = 0;
@@ -1714,25 +1826,36 @@ static void srp_add_one(struct ib_device *device) 
	}



	for (p = s; p <= e; ++p) {

		host = srp_add_port(device, p);

		host = srp_add_port(srp_dev, p);

		if (host)

			list_add_tail(&host->list, dev_list);

			list_add_tail(&host->list, &srp_dev->dev_list);

	}



	ib_set_client_data(device, &srp_client, dev_list);

	ib_set_client_data(device, &srp_client, srp_dev);



	goto free_attr;



err_pd:

	ib_dealloc_pd(srp_dev->pd);



free_dev:

	kfree(srp_dev);



free_attr:

	kfree(dev_attr);

}



static void srp_remove_one(struct ib_device *device)

{

	struct list_head *dev_list;

	struct srp_device *srp_dev;

	struct srp_host *host, *tmp_host;

	LIST_HEAD(target_list);

	struct srp_target_port *target, *tmp_target;

	unsigned long flags;



	dev_list = ib_get_client_data(device, &srp_client);

	srp_dev = ib_get_client_data(device, &srp_client);



	list_for_each_entry_safe(host, tmp_host, dev_list, list) {

	list_for_each_entry_safe(host, tmp_host, &srp_dev->dev_list, list) {

		class_device_unregister(&host->class_dev);

		/*

		 * Wait for the sysfs entry to go away, so that no new
@@ -1770,12 +1893,15 @@ static void srp_remove_one(struct ib_device *device) 
			scsi_host_put(target->scsi_host);

		}



		ib_dereg_mr(host->mr);

		ib_dealloc_pd(host->pd);

		kfree(host);

	}



	kfree(dev_list);

	if (srp_dev->fmr_pool)

		ib_destroy_fmr_pool(srp_dev->fmr_pool);

	ib_dereg_mr(srp_dev->mr);

	ib_dealloc_pd(srp_dev->pd);



	kfree(srp_dev);

}



static int __init srp_init_module(void)

drivers/infiniband/ulp/srp/ib_srp.h

+20 −5
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ 
#include <rdma/ib_verbs.h>

#include <rdma/ib_sa.h>

#include <rdma/ib_cm.h>

#include <rdma/ib_fmr_pool.h>



enum {

	SRP_PATH_REC_TIMEOUT_MS	= 1000,
@@ -62,7 +63,11 @@ enum { 
	SRP_SQ_SIZE		= SRP_RQ_SIZE - 1,

	SRP_CQ_SIZE		= SRP_SQ_SIZE + SRP_RQ_SIZE,



	SRP_TAG_TSK_MGMT	= 1 << (SRP_RQ_SHIFT + 1)

	SRP_TAG_TSK_MGMT	= 1 << (SRP_RQ_SHIFT + 1),



	SRP_FMR_SIZE		= 256,

	SRP_FMR_POOL_SIZE	= 1024,

	SRP_FMR_DIRTY_SIZE	= SRP_FMR_POOL_SIZE / 4

};



#define SRP_OP_RECV		(1 << 31)
@@ -77,12 +82,21 @@ enum srp_target_state { 
	SRP_TARGET_REMOVED

};



struct srp_host {

	u8			initiator_port_id[16];

struct srp_device {

	struct list_head	dev_list;

	struct ib_device       *dev;

	u8                      port;

	struct ib_pd	       *pd;

	struct ib_mr	       *mr;

	struct ib_fmr_pool     *fmr_pool;

	int			fmr_page_shift;

	int			fmr_page_size;

	unsigned long		fmr_page_mask;

};



struct srp_host {

	u8			initiator_port_id[16];

	struct srp_device      *dev;

	u8			port;

	struct class_device	class_dev;

	struct list_head	target_list;

	struct mutex		target_mutex;
@@ -95,6 +109,7 @@ struct srp_request { 
	struct scsi_cmnd       *scmnd;

	struct srp_iu	       *cmd;

	struct srp_iu	       *tsk_mgmt;

	struct ib_pool_fmr     *fmr;

	/*

	 * Fake scatterlist used when scmnd->use_sg==0.  Can be killed

	 * when the SCSI midlayer no longer generates non-SG commands.