From: Bodo Stroesser Date: Mon, 27 Apr 2020 15:08:23 +0000 (+0200) Subject: scsi: target: tcmu: Make pgr_support and alua_support attributes writable X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=356ba2a8bc8d;p=uclinux-h8%2Flinux.git scsi: target: tcmu: Make pgr_support and alua_support attributes writable Currently in tcmu reservation commands are handled by core's pr implementation (default) or completely rejected (emulate_pr set to 0). We additionally want to be able to do full reservation handling in userspace. Therefore we need a way to set TRANSPORT_FLAG_PASSTHROUGH_PGR. The inverted flag is displayed by attribute pgr_support. Since we moved the flag from transport/backend to se_device in the previous commit, we now can make it changeable per device by allowing to write the attribute. The new field transport_flags_changeable in transport/backend is used to reject writing if not allowed for a backend. Regarding ALUA we also want to be able to passthrough commands to userspace in tcmu. Therefore we need TRANSPORT_FLAG_PASSTHROUGH_ALUA to be changeable, because by setting it we can switch off all ALUA checks in core. So we also set TRANSPORT_FLAG_PASSTHROUGH_ALUA in tcmu's transport_flags_changeable. Of course, ALUA and reservation handling in userspace will work only, if session/nexus information is sent to userspace along with every command. This will be object of a patch series announced by Mike Christie. Link: https://lore.kernel.org/r/20200427150823.15350-5-bstroesser@ts.fujitsu.com Reviewed-by: Mike Christie Signed-off-by: Bodo Stroesser Signed-off-by: Martin K. Petersen --- diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c index 279989e32e64..f04352285155 100644 --- a/drivers/target/target_core_configfs.c +++ b/drivers/target/target_core_configfs.c @@ -1105,6 +1105,32 @@ static ssize_t alua_support_show(struct config_item *item, char *page) flags & TRANSPORT_FLAG_PASSTHROUGH_ALUA ? 0 : 1); } +static ssize_t alua_support_store(struct config_item *item, + const char *page, size_t count) +{ + struct se_dev_attrib *da = to_attrib(item); + struct se_device *dev = da->da_dev; + bool flag; + int ret; + + if (!(dev->transport->transport_flags_changeable & + TRANSPORT_FLAG_PASSTHROUGH_ALUA)) { + pr_err("dev[%p]: Unable to change SE Device alua_support:" + " alua_support has fixed value\n", dev); + return -EINVAL; + } + + ret = strtobool(page, &flag); + if (ret < 0) + return ret; + + if (flag) + dev->transport_flags &= ~TRANSPORT_FLAG_PASSTHROUGH_ALUA; + else + dev->transport_flags |= TRANSPORT_FLAG_PASSTHROUGH_ALUA; + return count; +} + static ssize_t pgr_support_show(struct config_item *item, char *page) { struct se_dev_attrib *da = to_attrib(item); @@ -1114,6 +1140,32 @@ static ssize_t pgr_support_show(struct config_item *item, char *page) flags & TRANSPORT_FLAG_PASSTHROUGH_PGR ? 0 : 1); } +static ssize_t pgr_support_store(struct config_item *item, + const char *page, size_t count) +{ + struct se_dev_attrib *da = to_attrib(item); + struct se_device *dev = da->da_dev; + bool flag; + int ret; + + if (!(dev->transport->transport_flags_changeable & + TRANSPORT_FLAG_PASSTHROUGH_PGR)) { + pr_err("dev[%p]: Unable to change SE Device pgr_support:" + " pgr_support has fixed value\n", dev); + return -EINVAL; + } + + ret = strtobool(page, &flag); + if (ret < 0) + return ret; + + if (flag) + dev->transport_flags &= ~TRANSPORT_FLAG_PASSTHROUGH_PGR; + else + dev->transport_flags |= TRANSPORT_FLAG_PASSTHROUGH_PGR; + return count; +} + CONFIGFS_ATTR(, emulate_model_alias); CONFIGFS_ATTR(, emulate_dpo); CONFIGFS_ATTR(, emulate_fua_write); @@ -1146,8 +1198,8 @@ CONFIGFS_ATTR(, unmap_granularity); CONFIGFS_ATTR(, unmap_granularity_alignment); CONFIGFS_ATTR(, unmap_zeroes_data); CONFIGFS_ATTR(, max_write_same_len); -CONFIGFS_ATTR_RO(, alua_support); -CONFIGFS_ATTR_RO(, pgr_support); +CONFIGFS_ATTR(, alua_support); +CONFIGFS_ATTR(, pgr_support); /* * dev_attrib attributes for devices using the target core SBC/SPC diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c index cb388b28f27e..72ffd359fc4d 100644 --- a/drivers/target/target_core_user.c +++ b/drivers/target/target_core_user.c @@ -2617,6 +2617,8 @@ static struct target_backend_ops tcmu_ops = { .name = "user", .owner = THIS_MODULE, .transport_flags_default = TRANSPORT_FLAG_PASSTHROUGH, + .transport_flags_changeable = TRANSPORT_FLAG_PASSTHROUGH_PGR | + TRANSPORT_FLAG_PASSTHROUGH_ALUA, .attach_hba = tcmu_attach_hba, .detach_hba = tcmu_detach_hba, .alloc_device = tcmu_alloc_device, diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h index 959163504f82..f51452e3b984 100644 --- a/include/target/target_core_backend.h +++ b/include/target/target_core_backend.h @@ -24,6 +24,7 @@ struct target_backend_ops { struct module *owner; u8 transport_flags_default; + u8 transport_flags_changeable; int (*attach_hba)(struct se_hba *, u32); void (*detach_hba)(struct se_hba *);