From c07d424d6118d528ef71b22b7424bfc359c307a5 Mon Sep 17 00:00:00 2001 From: David Dillow Date: Sun, 16 Jan 2011 13:57:10 -0500 Subject: [PATCH] IB/srp: add support for indirect tables that don't fit in SRP_CMD This allows us to guarantee the ability to submit up to 8 MB requests based on the current value of SCSI_MAX_SG_CHAIN_SEGMENTS. While FMR will usually condense the requests into 8 SG entries, it is imperative that the target support external tables in case the FMR mapping fails or is not supported. We add a safety valve to allow targets without the needed support to reap the benefits of the large tables, but fail in a manner that lets the user know that the data didn't make it to the device. The user must add "allow_ext_sg=1" to the target parameters to indicate that the target has the needed support. If indirect_sg_entries is not specified in the modules options, then the sg_tablesize for the target will default to cmd_sg_entries unless overridden by the target options. Signed-off-by: David Dillow --- drivers/infiniband/ulp/srp/ib_srp.c | 117 +++++++++++++++++++++++++--- drivers/infiniband/ulp/srp/ib_srp.h | 5 ++ 2 files changed, 110 insertions(+), 12 deletions(-) diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c index 9ce129ab3beb..4ec7dddbbf49 100644 --- a/drivers/infiniband/ulp/srp/ib_srp.c +++ b/drivers/infiniband/ulp/srp/ib_srp.c @@ -61,6 +61,8 @@ MODULE_LICENSE("Dual BSD/GPL"); static unsigned int srp_sg_tablesize; static unsigned int cmd_sg_entries; +static unsigned int indirect_sg_entries; +static bool allow_ext_sg; static int topspin_workarounds = 1; module_param(srp_sg_tablesize, uint, 0444); @@ -70,6 +72,14 @@ module_param(cmd_sg_entries, uint, 0444); MODULE_PARM_DESC(cmd_sg_entries, "Default number of gather/scatter entries in the SRP command (default is 12, max 255)"); +module_param(indirect_sg_entries, uint, 0444); +MODULE_PARM_DESC(indirect_sg_entries, + "Default max number of gather/scatter entries (default is 12, max is " __stringify(SCSI_MAX_SG_CHAIN_SEGMENTS) ")"); + +module_param(allow_ext_sg, bool, 0444); +MODULE_PARM_DESC(allow_ext_sg, + "Default behavior when there are more than cmd_sg_entries S/G entries after mapping; fails the request when false (default false)"); + module_param(topspin_workarounds, int, 0444); MODULE_PARM_DESC(topspin_workarounds, "Enable workarounds for Topspin/Cisco SRP target bugs if != 0"); @@ -446,12 +456,19 @@ static bool srp_change_state(struct srp_target_port *target, static void srp_free_req_data(struct srp_target_port *target) { + struct ib_device *ibdev = target->srp_host->srp_dev->dev; struct srp_request *req; int i; for (i = 0, req = target->req_ring; i < SRP_CMD_SQ_SIZE; ++i, ++req) { kfree(req->fmr_list); kfree(req->map_page); + if (req->indirect_dma_addr) { + ib_dma_unmap_single(ibdev, req->indirect_dma_addr, + target->indirect_size, + DMA_TO_DEVICE); + } + kfree(req->indirect_desc); } } @@ -790,7 +807,6 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target, struct ib_device *ibdev; struct srp_map_state state; struct srp_indirect_buf *indirect_hdr; - dma_addr_t indirect_addr; u32 table_len; u8 fmt; @@ -841,8 +857,11 @@ static int srp_map_data(struct scsi_cmnd *scmnd, struct srp_target_port *target, */ indirect_hdr = (void *) cmd->add_data; + ib_dma_sync_single_for_cpu(ibdev, req->indirect_dma_addr, + target->indirect_size, DMA_TO_DEVICE); + memset(&state, 0, sizeof(state)); - state.desc = indirect_hdr->desc_list; + state.desc = req->indirect_desc; state.pages = req->map_page; state.next_fmr = req->fmr_list; @@ -872,7 +891,11 @@ backtrack: if (use_fmr == SRP_MAP_ALLOW_FMR && srp_map_finish_fmr(&state, target)) goto backtrack; - /* We've mapped the request, fill in the command buffer. + /* We've mapped the request, now pull as much of the indirect + * descriptor table as we can into the command buffer. If this + * target is not using an external indirect table, we are + * guaranteed to fit into the command, as the SCSI layer won't + * give us more S/G entries than we allow. */ req->nfmr = state.nfmr; if (state.ndesc == 1) { @@ -881,27 +904,39 @@ backtrack: */ struct srp_direct_buf *buf = (void *) cmd->add_data; - *buf = indirect_hdr->desc_list[0]; + *buf = req->indirect_desc[0]; goto map_complete; } + if (unlikely(target->cmd_sg_cnt < state.ndesc && + !target->allow_ext_sg)) { + shost_printk(KERN_ERR, target->scsi_host, + "Could not fit S/G list into SRP_CMD\n"); + return -EIO; + } + + count = min(state.ndesc, target->cmd_sg_cnt); table_len = state.ndesc * sizeof (struct srp_direct_buf); fmt = SRP_DATA_DESC_INDIRECT; len = sizeof(struct srp_cmd) + sizeof (struct srp_indirect_buf); - len += table_len; + len += count * sizeof (struct srp_direct_buf); - indirect_addr = req->cmd->dma + sizeof *cmd + sizeof *indirect_hdr; + memcpy(indirect_hdr->desc_list, req->indirect_desc, + count * sizeof (struct srp_direct_buf)); - indirect_hdr->table_desc.va = cpu_to_be64(indirect_addr); + indirect_hdr->table_desc.va = cpu_to_be64(req->indirect_dma_addr); indirect_hdr->table_desc.key = cpu_to_be32(target->rkey); indirect_hdr->table_desc.len = cpu_to_be32(table_len); indirect_hdr->len = cpu_to_be32(state.total_len); if (scmnd->sc_data_direction == DMA_TO_DEVICE) - cmd->data_out_desc_cnt = state.ndesc; + cmd->data_out_desc_cnt = count; else - cmd->data_in_desc_cnt = state.ndesc; + cmd->data_in_desc_cnt = count; + + ib_dma_sync_single_for_device(ibdev, req->indirect_dma_addr, table_len, + DMA_TO_DEVICE); map_complete: if (scmnd->sc_data_direction == DMA_TO_DEVICE) @@ -1759,6 +1794,14 @@ static ssize_t show_cmd_sg_entries(struct device *dev, return sprintf(buf, "%u\n", target->cmd_sg_cnt); } +static ssize_t show_allow_ext_sg(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct srp_target_port *target = host_to_target(class_to_shost(dev)); + + return sprintf(buf, "%s\n", target->allow_ext_sg ? "true" : "false"); +} + static DEVICE_ATTR(id_ext, S_IRUGO, show_id_ext, NULL); static DEVICE_ATTR(ioc_guid, S_IRUGO, show_ioc_guid, NULL); static DEVICE_ATTR(service_id, S_IRUGO, show_service_id, NULL); @@ -1770,6 +1813,7 @@ static DEVICE_ATTR(zero_req_lim, S_IRUGO, show_zero_req_lim, NULL); static DEVICE_ATTR(local_ib_port, S_IRUGO, show_local_ib_port, NULL); static DEVICE_ATTR(local_ib_device, S_IRUGO, show_local_ib_device, NULL); static DEVICE_ATTR(cmd_sg_entries, S_IRUGO, show_cmd_sg_entries, NULL); +static DEVICE_ATTR(allow_ext_sg, S_IRUGO, show_allow_ext_sg, NULL); static struct device_attribute *srp_host_attrs[] = { &dev_attr_id_ext, @@ -1783,6 +1827,7 @@ static struct device_attribute *srp_host_attrs[] = { &dev_attr_local_ib_port, &dev_attr_local_ib_device, &dev_attr_cmd_sg_entries, + &dev_attr_allow_ext_sg, NULL }; @@ -1868,6 +1913,8 @@ enum { SRP_OPT_IO_CLASS = 1 << 7, SRP_OPT_INITIATOR_EXT = 1 << 8, SRP_OPT_CMD_SG_ENTRIES = 1 << 9, + SRP_OPT_ALLOW_EXT_SG = 1 << 10, + SRP_OPT_SG_TABLESIZE = 1 << 11, SRP_OPT_ALL = (SRP_OPT_ID_EXT | SRP_OPT_IOC_GUID | SRP_OPT_DGID | @@ -1886,6 +1933,8 @@ static const match_table_t srp_opt_tokens = { { SRP_OPT_IO_CLASS, "io_class=%x" }, { SRP_OPT_INITIATOR_EXT, "initiator_ext=%s" }, { SRP_OPT_CMD_SG_ENTRIES, "cmd_sg_entries=%u" }, + { SRP_OPT_ALLOW_EXT_SG, "allow_ext_sg=%u" }, + { SRP_OPT_SG_TABLESIZE, "sg_tablesize=%u" }, { SRP_OPT_ERR, NULL } }; @@ -2021,6 +2070,23 @@ static int srp_parse_options(const char *buf, struct srp_target_port *target) target->cmd_sg_cnt = token; break; + case SRP_OPT_ALLOW_EXT_SG: + if (match_int(args, &token)) { + printk(KERN_WARNING PFX "bad allow_ext_sg parameter '%s'\n", p); + goto out; + } + target->allow_ext_sg = !!token; + break; + + case SRP_OPT_SG_TABLESIZE: + if (match_int(args, &token) || token < 1 || + token > SCSI_MAX_SG_CHAIN_SEGMENTS) { + printk(KERN_WARNING PFX "bad max sg_tablesize parameter '%s'\n", p); + goto out; + } + target->sg_tablesize = token; + break; + default: printk(KERN_WARNING PFX "unknown parameter or missing value " "'%s' in target creation request\n", p); @@ -2051,6 +2117,8 @@ static ssize_t srp_create_target(struct device *dev, container_of(dev, struct srp_host, dev); struct Scsi_Host *target_host; struct srp_target_port *target; + struct ib_device *ibdev = host->srp_dev->dev; + dma_addr_t dma_addr; int i, ret; target_host = scsi_host_alloc(&srp_template, @@ -2070,12 +2138,22 @@ static ssize_t srp_create_target(struct device *dev, target->lkey = host->srp_dev->mr->lkey; target->rkey = host->srp_dev->mr->rkey; target->cmd_sg_cnt = cmd_sg_entries; + target->sg_tablesize = indirect_sg_entries ? : cmd_sg_entries; + target->allow_ext_sg = allow_ext_sg; ret = srp_parse_options(buf, target); if (ret) goto err; - target_host->sg_tablesize = target->cmd_sg_cnt; + if (!host->srp_dev->fmr_pool && !target->allow_ext_sg && + target->cmd_sg_cnt < target->sg_tablesize) { + printk(KERN_WARNING PFX "No FMR pool and no external indirect descriptors, limiting sg_tablesize to cmd_sg_cnt\n"); + target->sg_tablesize = target->cmd_sg_cnt; + } + + target_host->sg_tablesize = target->sg_tablesize; + target->indirect_size = target->sg_tablesize * + sizeof (struct srp_direct_buf); target->max_iu_len = sizeof (struct srp_cmd) + sizeof (struct srp_indirect_buf) + target->cmd_sg_cnt * sizeof (struct srp_direct_buf); @@ -2090,14 +2168,22 @@ static ssize_t srp_create_target(struct device *dev, GFP_KERNEL); req->map_page = kmalloc(SRP_FMR_SIZE * sizeof (void *), GFP_KERNEL); - if (!req->fmr_list || !req->map_page) + req->indirect_desc = kmalloc(target->indirect_size, GFP_KERNEL); + if (!req->fmr_list || !req->map_page || !req->indirect_desc) goto err_free_mem; + dma_addr = ib_dma_map_single(ibdev, req->indirect_desc, + target->indirect_size, + DMA_TO_DEVICE); + if (ib_dma_mapping_error(ibdev, dma_addr)) + goto err_free_mem; + + req->indirect_dma_addr = dma_addr; req->index = i; list_add_tail(&req->list, &target->free_reqs); } - ib_query_gid(host->srp_dev->dev, host->port, 0, &target->path.sgid); + ib_query_gid(ibdev, host->port, 0, &target->path.sgid); shost_printk(KERN_DEBUG, target->scsi_host, PFX "new target: id_ext %016llx ioc_guid %016llx pkey %04x " @@ -2377,6 +2463,13 @@ static int __init srp_init_module(void) cmd_sg_entries = 255; } + if (!indirect_sg_entries) + indirect_sg_entries = cmd_sg_entries; + else if (indirect_sg_entries < cmd_sg_entries) { + printk(KERN_WARNING PFX "Bumping up indirect_sg_entries to match cmd_sg_entries (%u)\n", cmd_sg_entries); + indirect_sg_entries = cmd_sg_entries; + } + ib_srp_transport_template = srp_attach_transport(&ib_srp_transport_functions); if (!ib_srp_transport_template) diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h index b43b5e7acbde..cf696218eeeb 100644 --- a/drivers/infiniband/ulp/srp/ib_srp.h +++ b/drivers/infiniband/ulp/srp/ib_srp.h @@ -117,6 +117,8 @@ struct srp_request { struct srp_iu *cmd; struct ib_pool_fmr **fmr_list; u64 *map_page; + struct srp_direct_buf *indirect_desc; + dma_addr_t indirect_dma_addr; short nfmr; short index; }; @@ -137,6 +139,8 @@ struct srp_target_port { enum srp_target_state state; unsigned int max_iu_len; unsigned int cmd_sg_cnt; + unsigned int indirect_size; + bool allow_ext_sg; /* Everything above this point is used in the hot path of * command processing. Try to keep them packed into cachelines. @@ -151,6 +155,7 @@ struct srp_target_port { struct Scsi_Host *scsi_host; char target_name[32]; unsigned int scsi_id; + unsigned int sg_tablesize; struct ib_sa_path_rec path; __be16 orig_dgid[8]; -- 2.20.1