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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 /drivers/scsi
parent13a3cf08fa1e4b3a252f24202d47a556242aea03 (diff)
downloadop-kernel-dev-8f9b565482c537821588444e09ff732c7d65ed6e.zip
op-kernel-dev-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 'drivers/scsi')
-rw-r--r--drivers/scsi/qla2xxx/tcm_qla2xxx.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/scsi/qla2xxx/tcm_qla2xxx.c b/drivers/scsi/qla2xxx/tcm_qla2xxx.c
index c621623..edeb3ae 100644
--- a/drivers/scsi/qla2xxx/tcm_qla2xxx.c
+++ b/drivers/scsi/qla2xxx/tcm_qla2xxx.c
@@ -1808,6 +1808,11 @@ 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,
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