scsi: zfcp: make DIX experimental, disabled, and independent of DIF

Introduce separate zfcp module parameters to individually select support
for: DIF which should work (zfcp.dif, which used to be DIF+DIX, disabled)
or DIX+DIF which can cause trouble (zfcp.dix, new, disabled).

If DIX is enabled, we warn on zfcp driver initialization.  As before, this
also reduces the maximum I/O request size to half, to support the worst
case of merged single sector requests with one protection data scatter
gather element per sector. This can impact the maximum throughput.

In DIF-only mode (zfcp.dif=1 zfcp.dix=0), we can use the full maximum I/O
request size as there is no protection data for zfcp.

Signed-off-by: Steffen Maier <maier@linux.ibm.com>
Signed-off-by: Fedor Loshakov <loshakov@linux.ibm.com>
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Fedor Loshakov
2018-11-29 13:09:56 +01:00
committed by Martin K. Petersen
parent 1ff2d8c43b
commit 636db60b8e
3 changed files with 11 additions and 3 deletions

View File

@@ -27,7 +27,11 @@ MODULE_PARM_DESC(queue_depth, "Default queue depth for new SCSI devices");
static bool enable_dif;
module_param_named(dif, enable_dif, bool, 0400);
MODULE_PARM_DESC(dif, "Enable DIF/DIX data integrity support");
MODULE_PARM_DESC(dif, "Enable DIF data integrity support (default off)");
bool zfcp_experimental_dix;
module_param_named(dix, zfcp_experimental_dix, bool, 0400);
MODULE_PARM_DESC(dix, "Enable experimental DIX (data integrity extension) support which implies DIF support (default off)");
static bool allow_lun_scan = true;
module_param(allow_lun_scan, bool, 0600);
@@ -790,11 +794,11 @@ void zfcp_scsi_set_prot(struct zfcp_adapter *adapter)
data_div = atomic_read(&adapter->status) &
ZFCP_STATUS_ADAPTER_DATA_DIV_ENABLED;
if (enable_dif &&
if ((enable_dif || zfcp_experimental_dix) &&
adapter->adapter_features & FSF_FEATURE_DIF_PROT_TYPE1)
mask |= SHOST_DIF_TYPE1_PROTECTION;
if (enable_dif && data_div &&
if (zfcp_experimental_dix && data_div &&
adapter->adapter_features & FSF_FEATURE_DIX_PROT_TCPIP) {
mask |= SHOST_DIX_TYPE1_PROTECTION;
scsi_host_set_guard(shost, SHOST_DIX_GUARD_IP);