Add helpers for driver sysfs code for the following functionality: - get/set iopolicy with mpath_iopolicy_store() and mpath_iopolicy_show() - show device path per NUMA node - "multipath" attribute group, equivalent to nvme_ns_mpath_attr_group - device groups attribute array, similar to nvme_ns_attr_groups but not containing NVMe members.
Signed-off-by: John Garry <[email protected]> --- include/linux/multipath.h | 5 +++ lib/multipath.c | 94 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 99 insertions(+) diff --git a/include/linux/multipath.h b/include/linux/multipath.h index 44e26c16b3dc4..4dff0911c2002 100644 --- a/include/linux/multipath.h +++ b/include/linux/multipath.h @@ -7,6 +7,8 @@ #include <linux/srcu.h> extern const struct block_device_operations mpath_ops; +extern const struct attribute_group mpath_attr_group; +extern const struct attribute_group *mpath_device_groups[]; enum mpath_iopolicy_e { MPATH_IOPOLICY_NUMA, @@ -120,6 +122,9 @@ int mpath_alloc_head_disk(struct mpath_head *mpath_head, struct queue_limits *lim, int numa_node); void mpath_device_set_live(struct mpath_device *mpath_device); bool mpath_can_remove_head(struct mpath_head *mpath_head); +ssize_t mpath_numa_nodes_show(struct mpath_device *mpath_device, char *buf); +ssize_t mpath_iopolicy_show(enum mpath_iopolicy_e *iopolicy, char *buf); +bool mpath_iopolicy_store(enum mpath_iopolicy_e *iopolicy, const char *buf); ssize_t mpath_delayed_removal_secs_show(struct mpath_head *mpath_head, char *buf); ssize_t mpath_delayed_removal_secs_store(struct mpath_head *mpath_head, diff --git a/lib/multipath.c b/lib/multipath.c index 1fa4bd6677051..3ff4f42a096c2 100644 --- a/lib/multipath.c +++ b/lib/multipath.c @@ -616,6 +616,100 @@ void mpath_device_set_live(struct mpath_device *mpath_device) } EXPORT_SYMBOL_GPL(mpath_device_set_live); +static struct attribute dummy_attr = { + .name = "dummy", +}; + +static struct attribute *mpath_attrs[] = { + &dummy_attr, + NULL +}; + +static bool multipath_sysfs_group_visible(struct kobject *kobj) +{ + struct device *dev = container_of(kobj, struct device, kobj); + struct gendisk *disk = dev_to_disk(dev); + + return is_mpath_disk(disk); +} +DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE(multipath_sysfs) + +const struct attribute_group mpath_attr_group = { + .name = "multipath", + .attrs = mpath_attrs, + .is_visible = SYSFS_GROUP_VISIBLE(multipath_sysfs), +}; +EXPORT_SYMBOL_GPL(mpath_attr_group); + +const struct attribute_group *mpath_device_groups[] = { + &mpath_attr_group, + NULL +}; +EXPORT_SYMBOL_GPL(mpath_device_groups); + +ssize_t mpath_iopolicy_show(enum mpath_iopolicy_e *iopolicy, char *buf) +{ + return sysfs_emit(buf, "%s\n", + mpath_iopolicy_names[READ_ONCE(*iopolicy)]); +} +EXPORT_SYMBOL_GPL(mpath_iopolicy_show); + +static void mpath_iopolicy_update(enum mpath_iopolicy_e *iopolicy, + int new) +{ + int old = READ_ONCE(*iopolicy); + + if (old == new) + return; + + WRITE_ONCE(*iopolicy, new); + + pr_info("iopolicy changed from %s to %s\n", + mpath_iopolicy_names[old], + mpath_iopolicy_names[new]); +} + +bool mpath_iopolicy_store(enum mpath_iopolicy_e *iopolicy, const char *buf) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(mpath_iopolicy_names); i++) { + if (sysfs_streq(buf, mpath_iopolicy_names[i])) { + mpath_iopolicy_update(iopolicy, i); + return true; + } + } + + return false; +} +EXPORT_SYMBOL_GPL(mpath_iopolicy_store); + +ssize_t mpath_numa_nodes_show(struct mpath_device *mpath_device, char *buf) +{ + struct mpath_head *mpath_head = mpath_device->mpath_head; + int node, srcu_idx; + nodemask_t numa_nodes; + struct mpath_device *current_mpath_dev; + + if (mpath_read_iopolicy(mpath_head) != MPATH_IOPOLICY_NUMA) + return 0; + + nodes_clear(numa_nodes); + + srcu_idx = srcu_read_lock(&mpath_head->srcu); + for_each_node(node) { + current_mpath_dev = + srcu_dereference(mpath_head->current_path[node], + &mpath_head->srcu); + if (current_mpath_dev == mpath_device) + node_set(node, numa_nodes); + } + srcu_read_unlock(&mpath_head->srcu, srcu_idx); + + return sysfs_emit(buf, "%*pbl\n", nodemask_pr_args(&numa_nodes)); +} +EXPORT_SYMBOL_GPL(mpath_numa_nodes_show); + ssize_t mpath_delayed_removal_secs_show(struct mpath_head *mpath_head, char *buf) { -- 2.43.7
