From: Swen Schillig Date: Mon, 15 Aug 2011 12:40:32 +0000 (+0200) Subject: [SCSI] zfcp: support for hardware data router X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=86a9668a8d29ea711613e1cb37efa68e7c4db564;p=GitHub%2FLineageOS%2Fandroid_kernel_samsung_universal7580.git [SCSI] zfcp: support for hardware data router FICON Express8S supports hardware data router, which requires an adapted qdio request format. This part 2/2 exploits the functionality in zfcp. Signed-off-by: Swen Schillig Signed-off-by: Steffen Maier Signed-off-by: James Bottomley --- diff --git a/drivers/s390/scsi/zfcp_dbf.c b/drivers/s390/scsi/zfcp_dbf.c index 96d1462e0bf..967e7b70e97 100644 --- a/drivers/s390/scsi/zfcp_dbf.c +++ b/drivers/s390/scsi/zfcp_dbf.c @@ -163,6 +163,42 @@ void zfcp_dbf_hba_bit_err(char *tag, struct zfcp_fsf_req *req) spin_unlock_irqrestore(&dbf->hba_lock, flags); } +/** + * zfcp_dbf_hba_def_err - trace event for deferred error messages + * @adapter: pointer to struct zfcp_adapter + * @req_id: request id which caused the deferred error message + * @scount: number of sbals incl. the signaling sbal + * @pl: array of all involved sbals + */ +void zfcp_dbf_hba_def_err(struct zfcp_adapter *adapter, u64 req_id, u16 scount, + void **pl) +{ + struct zfcp_dbf *dbf = adapter->dbf; + struct zfcp_dbf_pay *payload = &dbf->pay_buf; + unsigned long flags; + u16 length; + + if (!pl) + return; + + spin_lock_irqsave(&dbf->pay_lock, flags); + memset(payload, 0, sizeof(*payload)); + + memcpy(payload->area, "def_err", 7); + payload->fsf_req_id = req_id; + payload->counter = 0; + length = min((u16)sizeof(struct qdio_buffer), + (u16)ZFCP_DBF_PAY_MAX_REC); + + while ((char *)pl[payload->counter] && payload->counter < scount) { + memcpy(payload->data, (char *)pl[payload->counter], length); + debug_event(dbf->pay, 1, payload, zfcp_dbf_plen(length)); + payload->counter++; + } + + spin_unlock_irqrestore(&dbf->pay_lock, flags); +} + static void zfcp_dbf_set_common(struct zfcp_dbf_rec *rec, struct zfcp_adapter *adapter, struct zfcp_port *port, diff --git a/drivers/s390/scsi/zfcp_def.h b/drivers/s390/scsi/zfcp_def.h index 527ba48eea5..ed5d921e82c 100644 --- a/drivers/s390/scsi/zfcp_def.h +++ b/drivers/s390/scsi/zfcp_def.h @@ -72,6 +72,7 @@ struct zfcp_reqlist; #define ZFCP_STATUS_COMMON_NOESC 0x00200000 /* adapter status */ +#define ZFCP_STATUS_ADAPTER_MB_ACT 0x00000001 #define ZFCP_STATUS_ADAPTER_QDIOUP 0x00000002 #define ZFCP_STATUS_ADAPTER_SIOSL_ISSUED 0x00000004 #define ZFCP_STATUS_ADAPTER_XCONFIG_OK 0x00000008 @@ -314,4 +315,10 @@ struct zfcp_fsf_req { void (*handler)(struct zfcp_fsf_req *); }; +static inline +int zfcp_adapter_multi_buffer_active(struct zfcp_adapter *adapter) +{ + return atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_MB_ACT; +} + #endif /* ZFCP_DEF_H */ diff --git a/drivers/s390/scsi/zfcp_ext.h b/drivers/s390/scsi/zfcp_ext.h index 03627cfd81c..2302e1cfb76 100644 --- a/drivers/s390/scsi/zfcp_ext.h +++ b/drivers/s390/scsi/zfcp_ext.h @@ -53,6 +53,7 @@ extern void zfcp_dbf_hba_fsf_uss(char *, struct zfcp_fsf_req *); extern void zfcp_dbf_hba_fsf_res(char *, struct zfcp_fsf_req *); extern void zfcp_dbf_hba_bit_err(char *, struct zfcp_fsf_req *); extern void zfcp_dbf_hba_berr(struct zfcp_dbf *, struct zfcp_fsf_req *); +extern void zfcp_dbf_hba_def_err(struct zfcp_adapter *, u64, u16, void **); extern void zfcp_dbf_san_req(char *, struct zfcp_fsf_req *, u32); extern void zfcp_dbf_san_res(char *, struct zfcp_fsf_req *); extern void zfcp_dbf_san_in_els(char *, struct zfcp_fsf_req *); diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c index fa86c6a2857..e9a787e2e6a 100644 --- a/drivers/s390/scsi/zfcp_fsf.c +++ b/drivers/s390/scsi/zfcp_fsf.c @@ -936,39 +936,47 @@ static int zfcp_fsf_setup_ct_els_sbals(struct zfcp_fsf_req *req, struct scatterlist *sg_resp) { struct zfcp_adapter *adapter = req->adapter; + struct zfcp_qdio *qdio = adapter->qdio; + struct fsf_qtcb *qtcb = req->qtcb; u32 feat = adapter->adapter_features; - int bytes; - if (!(feat & FSF_FEATURE_ELS_CT_CHAINED_SBALS)) { - if (!zfcp_qdio_sg_one_sbale(sg_req) || - !zfcp_qdio_sg_one_sbale(sg_resp)) - return -EOPNOTSUPP; + if (zfcp_adapter_multi_buffer_active(adapter)) { + if (zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, sg_req)) + return -EIO; + if (zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, sg_resp)) + return -EIO; - zfcp_fsf_setup_ct_els_unchained(adapter->qdio, &req->qdio_req, - sg_req, sg_resp); + zfcp_qdio_set_data_div(qdio, &req->qdio_req, + zfcp_qdio_sbale_count(sg_req)); + zfcp_qdio_set_sbale_last(qdio, &req->qdio_req); + zfcp_qdio_set_scount(qdio, &req->qdio_req); return 0; } /* use single, unchained SBAL if it can hold the request */ if (zfcp_qdio_sg_one_sbale(sg_req) && zfcp_qdio_sg_one_sbale(sg_resp)) { - zfcp_fsf_setup_ct_els_unchained(adapter->qdio, &req->qdio_req, + zfcp_fsf_setup_ct_els_unchained(qdio, &req->qdio_req, sg_req, sg_resp); return 0; } - bytes = zfcp_qdio_sbals_from_sg(adapter->qdio, &req->qdio_req, sg_req); - if (bytes <= 0) + if (!(feat & FSF_FEATURE_ELS_CT_CHAINED_SBALS)) + return -EOPNOTSUPP; + + if (zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, sg_req)) return -EIO; - zfcp_qdio_set_sbale_last(adapter->qdio, &req->qdio_req); - req->qtcb->bottom.support.req_buf_length = bytes; - zfcp_qdio_skip_to_last_sbale(&req->qdio_req); - bytes = zfcp_qdio_sbals_from_sg(adapter->qdio, &req->qdio_req, - sg_resp); - req->qtcb->bottom.support.resp_buf_length = bytes; - if (bytes <= 0) + qtcb->bottom.support.req_buf_length = zfcp_qdio_real_bytes(sg_req); + + zfcp_qdio_set_sbale_last(qdio, &req->qdio_req); + zfcp_qdio_skip_to_last_sbale(qdio, &req->qdio_req); + + if (zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, sg_resp)) return -EIO; - zfcp_qdio_set_sbale_last(adapter->qdio, &req->qdio_req); + + qtcb->bottom.support.resp_buf_length = zfcp_qdio_real_bytes(sg_resp); + + zfcp_qdio_set_sbale_last(qdio, &req->qdio_req); return 0; } @@ -1119,7 +1127,8 @@ int zfcp_fsf_send_els(struct zfcp_adapter *adapter, u32 d_id, req->status |= ZFCP_STATUS_FSFREQ_CLEANUP; - zfcp_qdio_sbal_limit(qdio, &req->qdio_req, 2); + if (!zfcp_adapter_multi_buffer_active(adapter)) + zfcp_qdio_sbal_limit(qdio, &req->qdio_req, 2); ret = zfcp_fsf_setup_ct_els(req, els->req, els->resp, timeout); @@ -2162,7 +2171,7 @@ int zfcp_fsf_fcp_cmnd(struct scsi_cmnd *scsi_cmnd) struct zfcp_fsf_req *req; struct fcp_cmnd *fcp_cmnd; u8 sbtype = SBAL_SFLAGS0_TYPE_READ; - int real_bytes, retval = -EIO, dix_bytes = 0; + int retval = -EIO; struct scsi_device *sdev = scsi_cmnd->device; struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(sdev); struct zfcp_adapter *adapter = zfcp_sdev->port->adapter; @@ -2216,18 +2225,22 @@ int zfcp_fsf_fcp_cmnd(struct scsi_cmnd *scsi_cmnd) if (scsi_prot_sg_count(scsi_cmnd)) { zfcp_qdio_set_data_div(qdio, &req->qdio_req, scsi_prot_sg_count(scsi_cmnd)); - dix_bytes = zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, + retval = zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, + scsi_prot_sglist(scsi_cmnd)); + if (retval) + goto failed_scsi_cmnd; + io->prot_data_length = zfcp_qdio_real_bytes( scsi_prot_sglist(scsi_cmnd)); - io->prot_data_length = dix_bytes; } - real_bytes = zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, - scsi_sglist(scsi_cmnd)); - - if (unlikely(real_bytes < 0) || unlikely(dix_bytes < 0)) + retval = zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, + scsi_sglist(scsi_cmnd)); + if (unlikely(retval)) goto failed_scsi_cmnd; zfcp_qdio_set_sbale_last(adapter->qdio, &req->qdio_req); + if (zfcp_adapter_multi_buffer_active(adapter)) + zfcp_qdio_set_scount(qdio, &req->qdio_req); retval = zfcp_fsf_req_send(req); if (unlikely(retval)) @@ -2329,7 +2342,7 @@ struct zfcp_fsf_req *zfcp_fsf_control_file(struct zfcp_adapter *adapter, struct zfcp_qdio *qdio = adapter->qdio; struct zfcp_fsf_req *req = NULL; struct fsf_qtcb_bottom_support *bottom; - int retval = -EIO, bytes; + int retval = -EIO; u8 direction; if (!(adapter->adapter_features & FSF_FEATURE_CFDC)) @@ -2362,13 +2375,17 @@ struct zfcp_fsf_req *zfcp_fsf_control_file(struct zfcp_adapter *adapter, bottom->operation_subtype = FSF_CFDC_OPERATION_SUBTYPE; bottom->option = fsf_cfdc->option; - bytes = zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, fsf_cfdc->sg); + retval = zfcp_qdio_sbals_from_sg(qdio, &req->qdio_req, fsf_cfdc->sg); - if (bytes != ZFCP_CFDC_MAX_SIZE) { + if (retval || + (zfcp_qdio_real_bytes(fsf_cfdc->sg) != ZFCP_CFDC_MAX_SIZE)) { zfcp_fsf_req_free(req); + retval = -EIO; goto out; } - zfcp_qdio_set_sbale_last(adapter->qdio, &req->qdio_req); + zfcp_qdio_set_sbale_last(qdio, &req->qdio_req); + if (zfcp_adapter_multi_buffer_active(adapter)) + zfcp_qdio_set_scount(qdio, &req->qdio_req); zfcp_fsf_start_timer(req, ZFCP_FSF_REQUEST_TIMEOUT); retval = zfcp_fsf_req_send(req); diff --git a/drivers/s390/scsi/zfcp_qdio.c b/drivers/s390/scsi/zfcp_qdio.c index d9c40ea73ee..df9e69f5474 100644 --- a/drivers/s390/scsi/zfcp_qdio.c +++ b/drivers/s390/scsi/zfcp_qdio.c @@ -15,6 +15,10 @@ #define QBUFF_PER_PAGE (PAGE_SIZE / sizeof(struct qdio_buffer)) +static bool enable_multibuffer; +module_param_named(datarouter, enable_multibuffer, bool, 0400); +MODULE_PARM_DESC(datarouter, "Enable hardware data router support"); + static int zfcp_qdio_buffers_enqueue(struct qdio_buffer **sbal) { int pos; @@ -37,8 +41,11 @@ static void zfcp_qdio_handler_error(struct zfcp_qdio *qdio, char *id, dev_warn(&adapter->ccw_device->dev, "A QDIO problem occurred\n"); - if (qdio_err & QDIO_ERROR_SLSB_STATE) + if (qdio_err & QDIO_ERROR_SLSB_STATE) { zfcp_qdio_siosl(adapter); + zfcp_erp_adapter_shutdown(adapter, 0, id); + return; + } zfcp_erp_adapter_reopen(adapter, ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED | ZFCP_STATUS_COMMON_ERP_FAILED, id); @@ -93,9 +100,27 @@ static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err, unsigned long parm) { struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm; - int sbal_idx, sbal_no; + struct zfcp_adapter *adapter = qdio->adapter; + struct qdio_buffer_element *sbale; + int sbal_no, sbal_idx; + void *pl[ZFCP_QDIO_MAX_SBALS_PER_REQ + 1]; + u64 req_id; + u8 scount; if (unlikely(qdio_err)) { + memset(pl, 0, ZFCP_QDIO_MAX_SBALS_PER_REQ * sizeof(void *)); + if (zfcp_adapter_multi_buffer_active(adapter)) { + sbale = qdio->res_q[idx]->element; + req_id = (u64) sbale->addr; + scount = sbale->scount + 1; /* incl. signaling SBAL */ + + for (sbal_no = 0; sbal_no < scount; sbal_no++) { + sbal_idx = (idx + sbal_no) % + QDIO_MAX_BUFFERS_PER_Q; + pl[sbal_no] = qdio->res_q[sbal_idx]; + } + zfcp_dbf_hba_def_err(adapter, req_id, scount, pl); + } zfcp_qdio_handler_error(qdio, "qdires1", qdio_err); return; } @@ -155,7 +180,7 @@ zfcp_qdio_sbal_chain(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req) static struct qdio_buffer_element * zfcp_qdio_sbale_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req) { - if (q_req->sbale_curr == ZFCP_QDIO_LAST_SBALE_PER_SBAL) + if (q_req->sbale_curr == qdio->max_sbale_per_sbal - 1) return zfcp_qdio_sbal_chain(qdio, q_req); q_req->sbale_curr++; return zfcp_qdio_sbale_curr(qdio, q_req); @@ -167,13 +192,12 @@ zfcp_qdio_sbale_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req) * @q_req: pointer to struct zfcp_qdio_req * @sg: scatter-gather list * @max_sbals: upper bound for number of SBALs to be used - * Returns: number of bytes, or error (negativ) + * Returns: zero or -EINVAL on error */ int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req, struct scatterlist *sg) { struct qdio_buffer_element *sbale; - int bytes = 0; /* set storage-block type for this request */ sbale = zfcp_qdio_sbale_req(qdio, q_req); @@ -187,14 +211,10 @@ int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req, q_req->sbal_number); return -EINVAL; } - sbale->addr = sg_virt(sg); sbale->length = sg->length; - - bytes += sg->length; } - - return bytes; + return 0; } static int zfcp_qdio_sbal_check(struct zfcp_qdio *qdio) @@ -283,6 +303,8 @@ static void zfcp_qdio_setup_init_data(struct qdio_initialize *id, memcpy(id->adapter_name, dev_name(&id->cdev->dev), 8); ASCEBC(id->adapter_name, 8); id->qib_rflags = QIB_RFLAGS_ENABLE_DATA_DIV; + if (enable_multibuffer) + id->qdr_ac |= QDR_AC_MULTI_BUFFER_ENABLE; id->no_input_qs = 1; id->no_output_qs = 1; id->input_handler = zfcp_qdio_int_resp; @@ -378,6 +400,17 @@ int zfcp_qdio_open(struct zfcp_qdio *qdio) atomic_set_mask(ZFCP_STATUS_ADAPTER_DATA_DIV_ENABLED, &qdio->adapter->status); + if (ssqd.qdioac2 & CHSC_AC2_MULTI_BUFFER_ENABLED) { + atomic_set_mask(ZFCP_STATUS_ADAPTER_MB_ACT, &adapter->status); + qdio->max_sbale_per_sbal = QDIO_MAX_ELEMENTS_PER_BUFFER; + } else { + atomic_clear_mask(ZFCP_STATUS_ADAPTER_MB_ACT, &adapter->status); + qdio->max_sbale_per_sbal = QDIO_MAX_ELEMENTS_PER_BUFFER - 1; + } + + qdio->max_sbale_per_req = + ZFCP_QDIO_MAX_SBALS_PER_REQ * qdio->max_sbale_per_sbal + - 2; if (qdio_activate(cdev)) goto failed_qdio; @@ -397,6 +430,11 @@ int zfcp_qdio_open(struct zfcp_qdio *qdio) atomic_set(&qdio->req_q_free, QDIO_MAX_BUFFERS_PER_Q); atomic_set_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &qdio->adapter->status); + if (adapter->scsi_host) { + adapter->scsi_host->sg_tablesize = qdio->max_sbale_per_req; + adapter->scsi_host->max_sectors = qdio->max_sbale_per_req * 8; + } + return 0; failed_qdio: diff --git a/drivers/s390/scsi/zfcp_qdio.h b/drivers/s390/scsi/zfcp_qdio.h index 54e22ace012..8ac7f5342d2 100644 --- a/drivers/s390/scsi/zfcp_qdio.h +++ b/drivers/s390/scsi/zfcp_qdio.h @@ -13,20 +13,9 @@ #define ZFCP_QDIO_SBALE_LEN PAGE_SIZE -/* DMQ bug workaround: don't use last SBALE */ -#define ZFCP_QDIO_MAX_SBALES_PER_SBAL (QDIO_MAX_ELEMENTS_PER_BUFFER - 1) - -/* index of last SBALE (with respect to DMQ bug workaround) */ -#define ZFCP_QDIO_LAST_SBALE_PER_SBAL (ZFCP_QDIO_MAX_SBALES_PER_SBAL - 1) - /* Max SBALS for chaining */ #define ZFCP_QDIO_MAX_SBALS_PER_REQ 36 -/* max. number of (data buffer) SBALEs in largest SBAL chain - * request ID + QTCB in SBALE 0 + 1 of first SBAL in chain */ -#define ZFCP_QDIO_MAX_SBALES_PER_REQ \ - (ZFCP_QDIO_MAX_SBALS_PER_REQ * ZFCP_QDIO_MAX_SBALES_PER_SBAL - 2) - /** * struct zfcp_qdio - basic qdio data structure * @res_q: response queue @@ -53,6 +42,8 @@ struct zfcp_qdio { atomic_t req_q_full; wait_queue_head_t req_q_wq; struct zfcp_adapter *adapter; + u16 max_sbale_per_sbal; + u16 max_sbale_per_req; }; /** @@ -155,7 +146,7 @@ void zfcp_qdio_fill_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req, { struct qdio_buffer_element *sbale; - BUG_ON(q_req->sbale_curr == ZFCP_QDIO_LAST_SBALE_PER_SBAL); + BUG_ON(q_req->sbale_curr == qdio->max_sbale_per_sbal - 1); q_req->sbale_curr++; sbale = zfcp_qdio_sbale_curr(qdio, q_req); sbale->addr = data; @@ -195,9 +186,10 @@ int zfcp_qdio_sg_one_sbale(struct scatterlist *sg) * @q_req: The current zfcp_qdio_req */ static inline -void zfcp_qdio_skip_to_last_sbale(struct zfcp_qdio_req *q_req) +void zfcp_qdio_skip_to_last_sbale(struct zfcp_qdio *qdio, + struct zfcp_qdio_req *q_req) { - q_req->sbale_curr = ZFCP_QDIO_LAST_SBALE_PER_SBAL; + q_req->sbale_curr = qdio->max_sbale_per_sbal - 1; } /** @@ -228,8 +220,52 @@ void zfcp_qdio_set_data_div(struct zfcp_qdio *qdio, { struct qdio_buffer_element *sbale; - sbale = &qdio->req_q[q_req->sbal_first]->element[0]; + sbale = qdio->req_q[q_req->sbal_first]->element; sbale->length = count; } +/** + * zfcp_qdio_sbale_count - count sbale used + * @sg: pointer to struct scatterlist + */ +static inline +unsigned int zfcp_qdio_sbale_count(struct scatterlist *sg) +{ + unsigned int count = 0; + + for (; sg; sg = sg_next(sg)) + count++; + + return count; +} + +/** + * zfcp_qdio_real_bytes - count bytes used + * @sg: pointer to struct scatterlist + */ +static inline +unsigned int zfcp_qdio_real_bytes(struct scatterlist *sg) +{ + unsigned int real_bytes = 0; + + for (; sg; sg = sg_next(sg)) + real_bytes += sg->length; + + return real_bytes; +} + +/** + * zfcp_qdio_set_scount - set SBAL count value + * @qdio: pointer to struct zfcp_qdio + * @q_req: The current zfcp_qdio_req + */ +static inline +void zfcp_qdio_set_scount(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req) +{ + struct qdio_buffer_element *sbale; + + sbale = qdio->req_q[q_req->sbal_first]->element; + sbale->scount = q_req->sbal_number - 1; +} + #endif /* ZFCP_QDIO_H */ diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c index 96c31a70445..09126a9d62f 100644 --- a/drivers/s390/scsi/zfcp_scsi.c +++ b/drivers/s390/scsi/zfcp_scsi.c @@ -306,8 +306,8 @@ static struct scsi_host_template zfcp_scsi_host_template = { .proc_name = "zfcp", .can_queue = 4096, .this_id = -1, - .sg_tablesize = ZFCP_QDIO_MAX_SBALES_PER_REQ, - .max_sectors = (ZFCP_QDIO_MAX_SBALES_PER_REQ * 8), + .sg_tablesize = 1, /* adjusted later */ + .max_sectors = 8, /* adjusted later */ .dma_boundary = ZFCP_QDIO_SBALE_LEN - 1, .cmd_per_lun = 1, .use_clustering = 1, @@ -665,9 +665,9 @@ void zfcp_scsi_set_prot(struct zfcp_adapter *adapter) adapter->adapter_features & FSF_FEATURE_DIX_PROT_TCPIP) { mask |= SHOST_DIX_TYPE1_PROTECTION; scsi_host_set_guard(shost, SHOST_DIX_GUARD_IP); - shost->sg_prot_tablesize = ZFCP_QDIO_MAX_SBALES_PER_REQ / 2; - shost->sg_tablesize = ZFCP_QDIO_MAX_SBALES_PER_REQ / 2; - shost->max_sectors = ZFCP_QDIO_MAX_SBALES_PER_REQ * 8 / 2; + shost->sg_prot_tablesize = adapter->qdio->max_sbale_per_req / 2; + shost->sg_tablesize = adapter->qdio->max_sbale_per_req / 2; + shost->max_sectors = shost->sg_tablesize * 8; } scsi_host_set_prot(shost, mask);