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authorNicholas Bellinger <nab@linux-iscsi.org>2015-07-30 18:28:13 -0700
committerNicholas Bellinger <nab@linux-iscsi.org>2015-09-11 00:31:39 -0700
commit8f9b565482c537821588444e09ff732c7d65ed6e (patch)
treeb411dd3479eb5f3f86e2eb390c1c973e4b31ee12 /include/target
parent13a3cf08fa1e4b3a252f24202d47a556242aea03 (diff)
downloadlinux-stericsson-8f9b565482c537821588444e09ff732c7d65ed6e.tar.gz
target/qla2xxx: Honor max_data_sg_nents I/O transfer limit
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> Tested-by: Himanshu Madhani <himanshu.madhani@qlogic.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>
Diffstat (limited to 'include/target')
-rw-r--r--include/target/target_core_fabric.h13
1 files changed, 13 insertions, 0 deletions
diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
index 69355feabd1d..7fb2557a760e 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 UNDERFLOW 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 *);