Userspace tools like targetcli are not able to dynamically detect if a
tcmu device supports kernel features ALUA or PGRs. In some kernels it
can create ALUA groups, but writing/reading ALUA files can lead to
nice error codes but also crashes and hangs.
This patch, made over Nicks's for next branch, adds a device configfs
attribute to report the kernel features the device supports, so tools
can check that before attempting to activate some of these features
that were partially supported in older kernels.
It can also be used for future feautes like possibly inquiry suppport
if we do end up moving that to the kernel so we can properly report
port info.
Signed-off-by: Mike Christie <mchristi@xxxxxxxxxx>
---
drivers/target/target_core_user.c | 13 +++++++++++++
include/uapi/linux/target_core_user.h | 3 +++
2 files changed, 16 insertions(+)
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 2f1fa92..b891824 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -111,6 +111,7 @@ struct tcmu_dev {
char *name;
struct se_hba *hba;
+ uint64_t features;
#define TCMU_DEV_BIT_OPEN 0
#define TCMU_DEV_BIT_BROKEN 1
@@ -1104,6 +1105,7 @@ static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
udev->hba = hba;
udev->cmd_time_out = TCMU_TIME_OUT;
+ udev->features |= (TCMU_KERN_ALUA | TCMU_KERN_PGR);
init_waitqueue_head(&udev->wait_cmdr);
mutex_init(&udev->cmdr_lock);
@@ -1882,11 +1884,22 @@ static ssize_t tcmu_emulate_write_cache_store(struct config_item *item,
}
CONFIGFS_ATTR(tcmu_, emulate_write_cache);
+static ssize_t tcmu_features_show(struct config_item *item, char *page)
+{
+ struct se_dev_attrib *da = container_of(to_config_group(item),
+ struct se_dev_attrib, da_group);
+ struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
+
+ return snprintf(page, PAGE_SIZE, "0x%llx\n", udev->features);
+}
+CONFIGFS_ATTR_RO(tcmu_, features);
+
static struct configfs_attribute *tcmu_attrib_attrs[] = {
&tcmu_attr_cmd_time_out,
&tcmu_attr_dev_config,
&tcmu_attr_dev_size,
&tcmu_attr_emulate_write_cache,
+ &tcmu_attr_features,
NULL,
};
diff --git a/include/uapi/linux/target_core_user.h b/include/uapi/linux/target_core_user.h
index 24a1c4e..03de6e9 100644
--- a/include/uapi/linux/target_core_user.h
+++ b/include/uapi/linux/target_core_user.h
@@ -154,4 +154,7 @@ enum tcmu_genl_attr {
};
#define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
+#define TCMU_KERN_ALUA (1ULL << 0)
+#define TCMU_KERN_PGR (1ULL << 1)
+
#endif
--
1.8.3.1
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