| Message ID | 1439455550-2626-1-git-send-email-nab@daterainc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi nab, On Thu, 13 Aug 2015, 1:45am -0700, Nicholas A. Bellinger wrote: > From: Nicholas Bellinger <nab@linux-iscsi.org> > > Hi Arun, Roland & Co, > > Based upon the feedback from last week, here is a proper > patch for target-core to honor a fabric provided SGL limit > using residual count plus underflow response bit. > > Everything appears to be working as expected with tcm-loop > LUNs with basic I/O and sg_raw to test CDB underflow, but > still needs to be verified on real qla2xxx hardware over > the next days for v4.2.0 code. > > Please review + test. Changes look good. I could not test the changes, though. I have requested internally to test this patch. Himanshu (copied) will get back with the test results (Thanks Himanshu). Regards, -Arun > > --nab > > This patch adds an optional fabric driver provided SGL limit > that target-core will honor as it's own internal I/O maximum > transfer length limit, as exposed by EVPD=0xb0 block limits > parameters. > > This is required for handling cases when host I/O transfer > length exceeds the requested EVPD block limits maximum > transfer length. The initial user of this logic is qla2xxx, > so that we can avoid having to reject I/Os from some legacy > FC hosts where EVPD=0xb0 parameters are not honored. > > When se_cmd payload length exceeds the provided limit in > target_check_max_data_sg_nents() code, se_cmd->data_length + > se_cmd->prot_length are reset with se_cmd->residual_count > plus underflow bit for outgoing TFO response callbacks. > It also checks for existing CDB level underflow + overflow > and recalculates final residual_count as necessary. > > Note this patch currently assumes 1:1 mapping of PAGE_SIZE > per struct scatterlist entry. > > Reported-by: Craig Watson <craig.watson@vanguard-rugged.com> > Cc: Craig Watson <craig.watson@vanguard-rugged.com> > Cc: Roland Dreier <roland@purestorage.com> > Cc: Arun Easi <arun.easi@qlogic.com> > Cc: Giridhar Malavali <giridhar.malavali@qlogic.com> > Cc: Andrew Vasquez <andrew.vasquez@qlogic.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Hannes Reinecke <hare@suse.de> > Cc: Martin K. Petersen <martin.petersen@oracle.com> > Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> > --- > drivers/scsi/qla2xxx/tcm_qla2xxx.c | 5 ++++ > drivers/target/target_core_spc.c | 13 +++++++-- > drivers/target/target_core_transport.c | 51 +++++++++++++++++++++++++++++++++- > include/target/target_core_fabric.h | 13 +++++++++ > 4 files changed, 78 insertions(+), 4 deletions(-) > > diff --git a/drivers/scsi/qla2xxx/tcm_qla2xxx.c b/drivers/scsi/qla2xxx/tcm_qla2xxx.c > index 9224a06..6649809 100644 > --- a/drivers/scsi/qla2xxx/tcm_qla2xxx.c > +++ b/drivers/scsi/qla2xxx/tcm_qla2xxx.c > @@ -1804,6 +1804,11 @@ static const struct target_core_fabric_ops tcm_qla2xxx_ops = { > .module = THIS_MODULE, > .name = "qla2xxx", > .node_acl_size = sizeof(struct tcm_qla2xxx_nacl), > + /* > + * XXX: Limit assumes single page per scatter-gather-list entry. > + * Current maximum is ~4.9 MB per se_cmd->t_data_sg with PAGE_SIZE=4096 > + */ > + .max_data_sg_nents = 1200, > .get_fabric_name = tcm_qla2xxx_get_fabric_name, > .tpg_get_wwn = tcm_qla2xxx_get_fabric_wwn, > .tpg_get_tag = tcm_qla2xxx_get_tag, > diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c > index 556ea1b..da6130a 100644 > --- a/drivers/target/target_core_spc.c > +++ b/drivers/target/target_core_spc.c > @@ -484,8 +484,8 @@ static sense_reason_t > spc_emulate_evpd_b0(struct se_cmd *cmd, unsigned char *buf) > { > struct se_device *dev = cmd->se_dev; > - int have_tp = 0; > - int opt, min; > + u32 mtl = 0; > + int have_tp = 0, opt, min; > > /* > * Following spc3r22 section 6.5.3 Block Limits VPD page, when > @@ -516,8 +516,15 @@ spc_emulate_evpd_b0(struct se_cmd *cmd, unsigned char *buf) > > /* > * Set MAXIMUM TRANSFER LENGTH > + * > + * XXX: Currently assumes single PAGE_SIZE per scatterlist for fabrics > + * enforcing maximum HW scatter-gather-list entry limit > */ > - put_unaligned_be32(dev->dev_attrib.hw_max_sectors, &buf[8]); > + if (cmd->se_tfo->max_data_sg_nents) { > + mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE) / > + dev->dev_attrib.block_size; > + } > + put_unaligned_be32(min_not_zero(mtl, dev->dev_attrib.hw_max_sectors), &buf[8]); > > /* > * Set OPTIMAL TRANSFER LENGTH > diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c > index ce8574b..652471a1 100644 > --- a/drivers/target/target_core_transport.c > +++ b/drivers/target/target_core_transport.c > @@ -1074,6 +1074,55 @@ transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83) > } > EXPORT_SYMBOL(transport_set_vpd_ident); > > +static sense_reason_t > +target_check_max_data_sg_nents(struct se_cmd *cmd, struct se_device *dev, > + unsigned int size) > +{ > + u32 mtl; > + > + if (!cmd->se_tfo->max_data_sg_nents) > + return TCM_NO_SENSE; > + /* > + * Check if fabric enforced maximum SGL entries per I/O descriptor > + * exceeds se_cmd->data_length. If true, set SCF_UNDERFLOW_BIT + > + * residual_count and reduce original cmd->data_length to maximum > + * length based on single PAGE_SIZE entry scatter-lists. > + */ > + mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE); > + if (cmd->data_length > mtl) { > + /* > + * If an existing CDB overflow is present, calculate new residual > + * based on CDB size minus fabric maximum transfer length. > + * > + * If an existing CDB underflow is present, calculate new residual > + * based on original cmd->data_length minus fabric maximum transfer > + * length. > + * > + * Otherwise, set the underflow residual based on cmd->data_length > + * minus fabric maximum transfer length. > + */ > + if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) { > + cmd->residual_count = (size - mtl); > + } else if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) { > + u32 orig_dl = size + cmd->residual_count; > + cmd->residual_count = (orig_dl - mtl); > + } else { > + cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT; > + cmd->residual_count = (cmd->data_length - mtl); > + } > + cmd->data_length = mtl; > + /* > + * Reset sbc_check_prot() calculated protection payload > + * length based upon the new smaller MTL. > + */ > + if (cmd->prot_length) { > + u32 sectors = (mtl / dev->dev_attrib.block_size); > + cmd->prot_length = dev->prot_length * sectors; > + } > + } > + return TCM_NO_SENSE; > +} > + > sense_reason_t > target_cmd_size_check(struct se_cmd *cmd, unsigned int size) > { > @@ -1119,7 +1168,7 @@ target_cmd_size_check(struct se_cmd *cmd, unsigned int size) > } > } > > - return 0; > + return target_check_max_data_sg_nents(cmd, dev, size); > > } > > diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h > index 18afef9..995f2e1 100644 > --- a/include/target/target_core_fabric.h > +++ b/include/target/target_core_fabric.h > @@ -5,6 +5,19 @@ struct target_core_fabric_ops { > struct module *module; > const char *name; > size_t node_acl_size; > + /* > + * Limits number of scatterlist entries per SCF_SCSI_DATA_CDB payload. > + * Setting this value tells target-core to enforce this limit, and > + * report as INQUIRY EVPD=b0 MAXIMUM TRANSFER LENGTH. > + * > + * target-core will currently reset se_cmd->data_length to this > + * maximum size, and set OVERFLOW residual count if length exceeds > + * this limit. > + * > + * XXX: Not all initiator hosts honor this block-limit EVPD > + * XXX: Currently assumes single PAGE_SIZE per scatterlist entry > + */ > + u32 max_data_sg_nents; > char *(*get_fabric_name)(void); > char *(*tpg_get_wwn)(struct se_portal_group *); > u16 (*tpg_get_tag)(struct se_portal_group *); > -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/scsi/qla2xxx/tcm_qla2xxx.c b/drivers/scsi/qla2xxx/tcm_qla2xxx.c index 9224a06..6649809 100644 --- a/drivers/scsi/qla2xxx/tcm_qla2xxx.c +++ b/drivers/scsi/qla2xxx/tcm_qla2xxx.c @@ -1804,6 +1804,11 @@ static const struct target_core_fabric_ops tcm_qla2xxx_ops = { .module = THIS_MODULE, .name = "qla2xxx", .node_acl_size = sizeof(struct tcm_qla2xxx_nacl), + /* + * XXX: Limit assumes single page per scatter-gather-list entry. + * Current maximum is ~4.9 MB per se_cmd->t_data_sg with PAGE_SIZE=4096 + */ + .max_data_sg_nents = 1200, .get_fabric_name = tcm_qla2xxx_get_fabric_name, .tpg_get_wwn = tcm_qla2xxx_get_fabric_wwn, .tpg_get_tag = tcm_qla2xxx_get_tag, diff --git a/drivers/target/target_core_spc.c b/drivers/target/target_core_spc.c index 556ea1b..da6130a 100644 --- a/drivers/target/target_core_spc.c +++ b/drivers/target/target_core_spc.c @@ -484,8 +484,8 @@ static sense_reason_t spc_emulate_evpd_b0(struct se_cmd *cmd, unsigned char *buf) { struct se_device *dev = cmd->se_dev; - int have_tp = 0; - int opt, min; + u32 mtl = 0; + int have_tp = 0, opt, min; /* * Following spc3r22 section 6.5.3 Block Limits VPD page, when @@ -516,8 +516,15 @@ spc_emulate_evpd_b0(struct se_cmd *cmd, unsigned char *buf) /* * Set MAXIMUM TRANSFER LENGTH + * + * XXX: Currently assumes single PAGE_SIZE per scatterlist for fabrics + * enforcing maximum HW scatter-gather-list entry limit */ - put_unaligned_be32(dev->dev_attrib.hw_max_sectors, &buf[8]); + if (cmd->se_tfo->max_data_sg_nents) { + mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE) / + dev->dev_attrib.block_size; + } + put_unaligned_be32(min_not_zero(mtl, dev->dev_attrib.hw_max_sectors), &buf[8]); /* * Set OPTIMAL TRANSFER LENGTH diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index ce8574b..652471a1 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -1074,6 +1074,55 @@ transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83) } EXPORT_SYMBOL(transport_set_vpd_ident); +static sense_reason_t +target_check_max_data_sg_nents(struct se_cmd *cmd, struct se_device *dev, + unsigned int size) +{ + u32 mtl; + + if (!cmd->se_tfo->max_data_sg_nents) + return TCM_NO_SENSE; + /* + * Check if fabric enforced maximum SGL entries per I/O descriptor + * exceeds se_cmd->data_length. If true, set SCF_UNDERFLOW_BIT + + * residual_count and reduce original cmd->data_length to maximum + * length based on single PAGE_SIZE entry scatter-lists. + */ + mtl = (cmd->se_tfo->max_data_sg_nents * PAGE_SIZE); + if (cmd->data_length > mtl) { + /* + * If an existing CDB overflow is present, calculate new residual + * based on CDB size minus fabric maximum transfer length. + * + * If an existing CDB underflow is present, calculate new residual + * based on original cmd->data_length minus fabric maximum transfer + * length. + * + * Otherwise, set the underflow residual based on cmd->data_length + * minus fabric maximum transfer length. + */ + if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) { + cmd->residual_count = (size - mtl); + } else if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) { + u32 orig_dl = size + cmd->residual_count; + cmd->residual_count = (orig_dl - mtl); + } else { + cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT; + cmd->residual_count = (cmd->data_length - mtl); + } + cmd->data_length = mtl; + /* + * Reset sbc_check_prot() calculated protection payload + * length based upon the new smaller MTL. + */ + if (cmd->prot_length) { + u32 sectors = (mtl / dev->dev_attrib.block_size); + cmd->prot_length = dev->prot_length * sectors; + } + } + return TCM_NO_SENSE; +} + sense_reason_t target_cmd_size_check(struct se_cmd *cmd, unsigned int size) { @@ -1119,7 +1168,7 @@ target_cmd_size_check(struct se_cmd *cmd, unsigned int size) } } - return 0; + return target_check_max_data_sg_nents(cmd, dev, size); } diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h index 18afef9..995f2e1 100644 --- a/include/target/target_core_fabric.h +++ b/include/target/target_core_fabric.h @@ -5,6 +5,19 @@ struct target_core_fabric_ops { struct module *module; const char *name; size_t node_acl_size; + /* + * Limits number of scatterlist entries per SCF_SCSI_DATA_CDB payload. + * Setting this value tells target-core to enforce this limit, and + * report as INQUIRY EVPD=b0 MAXIMUM TRANSFER LENGTH. + * + * target-core will currently reset se_cmd->data_length to this + * maximum size, and set OVERFLOW residual count if length exceeds + * this limit. + * + * XXX: Not all initiator hosts honor this block-limit EVPD + * XXX: Currently assumes single PAGE_SIZE per scatterlist entry + */ + u32 max_data_sg_nents; char *(*get_fabric_name)(void); char *(*tpg_get_wwn)(struct se_portal_group *); u16 (*tpg_get_tag)(struct se_portal_group *);