[PATCH 5/7] lightnvm: control life of nvm_dev in driver

From: Matias BjÃrling
Date: Fri Sep 16 2016 - 08:26:35 EST

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LightNVM compatible device drivers does not have a method to expose
LightNVM specific sysfs entries.

To enable LightNVM sysfs entries to be exposed, lightnvm device
drivers require a struct device to attach it to. To allow both the
actual device driver and lightnvm sysfs entries to coexist, the device
driver tracks the lifetime of the nvm_dev structure.

This patch refactors NVMe and null_blk to handle the lifetime of struct
nvm_dev, which eliminates the need for struct gendisk when a lightnvm
compatible device is provided.

Signed-off-by: Matias BjÃrling <m@xxxxxxxxxxx>
---
drivers/block/null_blk.c | 22 ++++++++++++++++++++--
drivers/lightnvm/core.c | 35 ++++++++---------------------------
drivers/nvme/host/core.c | 36 +++++++++++++++---------------------
drivers/nvme/host/lightnvm.c | 31 ++++++++++++++++++++++++-------
drivers/nvme/host/nvme.h | 12 +++++++-----
include/linux/lightnvm.h | 15 +++++++++------
6 files changed, 83 insertions(+), 68 deletions(-)

diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index 895867a..91e1de8 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -34,6 +34,7 @@ struct nullb {
unsigned int index;
struct request_queue *q;
struct gendisk *disk;
+ struct nvm_dev *ndev;
struct blk_mq_tag_set tag_set;
struct hrtimer timer;
unsigned int queue_depth;
@@ -550,12 +551,29 @@ static struct nvm_dev_ops null_lnvm_dev_ops = {

static int null_nvm_register(struct nullb *nullb)
{
- return nvm_register(nullb->q, nullb->disk_name, &null_lnvm_dev_ops);
+ struct nvm_dev *dev;
+ int rv;
+
+ dev = nvm_alloc_dev(0);
+ if (!dev)
+ return -ENOMEM;
+
+ dev->q = nullb->q;
+ memcpy(dev->name, nullb->disk_name, DISK_NAME_LEN);
+ dev->ops = &null_lnvm_dev_ops;
+
+ rv = nvm_register(dev);
+ if (rv) {
+ kfree(dev);
+ return rv;
+ }
+ nullb->ndev = dev;
+ return 0;
}

static void null_nvm_unregister(struct nullb *nullb)
{
- nvm_unregister(nullb->disk_name);
+ nvm_unregister(nullb->ndev);
}
#else
static int null_nvm_register(struct nullb *nullb)
diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index 25c5df9..a99b59d 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -660,23 +660,16 @@ static void nvm_exit(struct nvm_dev *dev)
pr_info("nvm: successfully unloaded\n");
}

-int nvm_register(struct request_queue *q, char *disk_name,
- struct nvm_dev_ops *ops)
+struct nvm_dev *nvm_alloc_dev(int node)
+{
+ return kzalloc_node(sizeof(struct nvm_dev), GFP_KERNEL, node);
+}
+EXPORT_SYMBOL(nvm_alloc_dev);
+
+int nvm_register(struct nvm_dev *dev)
{
- struct nvm_dev *dev;
int ret;

- if (!ops->identity)
- return -EINVAL;
-
- dev = kzalloc(sizeof(struct nvm_dev), GFP_KERNEL);
- if (!dev)
- return -ENOMEM;
-
- dev->q = q;
- dev->ops = ops;
- strncpy(dev->name, disk_name, DISK_NAME_LEN);
-
ret = nvm_init(dev);
if (ret)
goto err_init;
@@ -714,29 +707,17 @@ int nvm_register(struct request_queue *q, char *disk_name,
return 0;
err_init:
kfree(dev->lun_map);
- kfree(dev);
return ret;
}
EXPORT_SYMBOL(nvm_register);

-void nvm_unregister(char *disk_name)
+void nvm_unregister(struct nvm_dev *dev)
{
- struct nvm_dev *dev;
-
down_write(&nvm_lock);
- dev = nvm_find_nvm_dev(disk_name);
- if (!dev) {
- pr_err("nvm: could not find device %s to unregister\n",
- disk_name);
- up_write(&nvm_lock);
- return;
- }
-
list_del(&dev->devices);
up_write(&nvm_lock);

nvm_exit(dev);
- kfree(dev);
}
EXPORT_SYMBOL(nvm_unregister);

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 2c3da33..3c707d8 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -156,12 +156,14 @@ static void nvme_free_ns(struct kref *kref)
{
struct nvme_ns *ns = container_of(kref, struct nvme_ns, kref);

- if (ns->type == NVME_NS_LIGHTNVM)
- nvme_nvm_unregister(ns->queue, ns->disk->disk_name);
+ if (ns->ndev)
+ nvme_nvm_unregister(ns);

- spin_lock(&dev_list_lock);
- ns->disk->private_data = NULL;
- spin_unlock(&dev_list_lock);
+ if (ns->disk) {
+ spin_lock(&dev_list_lock);
+ ns->disk->private_data = NULL;
+ spin_unlock(&dev_list_lock);
+ }

put_disk(ns->disk);
ida_simple_remove(&ns->ctrl->ns_ida, ns->instance);
@@ -891,8 +893,7 @@ static void nvme_config_discard(struct nvme_ns *ns)
static int nvme_revalidate_ns(struct nvme_ns *ns, struct nvme_id_ns **id)
{
if (nvme_identify_ns(ns->ctrl, ns->ns_id, id)) {
- dev_warn(disk_to_dev(ns->disk), "%s: Identify failure\n",
- __func__);
+ dev_warn(ns->ctrl->dev, "%s: Identify failure\n", __func__);
return -ENODEV;
}

@@ -1683,18 +1684,11 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
goto out_free_queue;

if (nvme_nvm_ns_supported(ns, id)) {
- if (nvme_nvm_register(ns->queue, disk_name)) {
- dev_warn(ctrl->dev,
- "%s: LightNVM init failure\n", __func__);
+ if (nvme_nvm_register(ns, disk_name, node)) {
+ dev_warn(ctrl->dev, "%s: LightNVM init failure\n",
+ __func__);
goto out_free_id;
}
-
- disk = alloc_disk_node(0, node);
- if (!disk)
- goto out_free_id;
- memcpy(disk->disk_name, disk_name, DISK_NAME_LEN);
- ns->disk = disk;
- ns->type = NVME_NS_LIGHTNVM;
} else {
disk = alloc_disk_node(0, node);
if (!disk)
@@ -1718,7 +1712,7 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)

kfree(id);

- if (ns->type == NVME_NS_LIGHTNVM)
+ if (ns->ndev)
return;

device_add_disk(ctrl->device, ns->disk);
@@ -1742,7 +1736,7 @@ static void nvme_ns_remove(struct nvme_ns *ns)
if (test_and_set_bit(NVME_NS_REMOVING, &ns->flags))
return;

- if (ns->disk->flags & GENHD_FL_UP) {
+ if (ns->disk && ns->disk->flags & GENHD_FL_UP) {
if (blk_get_integrity(ns->disk))
blk_integrity_unregister(ns->disk);
sysfs_remove_group(&disk_to_dev(ns->disk)->kobj,
@@ -1765,7 +1759,7 @@ static void nvme_validate_ns(struct nvme_ctrl *ctrl, unsigned nsid)

ns = nvme_find_get_ns(ctrl, nsid);
if (ns) {
- if (revalidate_disk(ns->disk))
+ if (ns->disk && revalidate_disk(ns->disk))
nvme_ns_remove(ns);
nvme_put_ns(ns);
} else
@@ -2070,7 +2064,7 @@ void nvme_kill_queues(struct nvme_ctrl *ctrl)
* Revalidating a dead namespace sets capacity to 0. This will
* end buffered writers dirtying pages that can't be synced.
*/
- if (!test_and_set_bit(NVME_NS_DEAD, &ns->flags))
+ if (ns->disk && !test_and_set_bit(NVME_NS_DEAD, &ns->flags))
revalidate_disk(ns->disk);

blk_set_queue_dying(ns->queue);
diff --git a/drivers/nvme/host/lightnvm.c b/drivers/nvme/host/lightnvm.c
index 7268a7a..798fcd9 100644
--- a/drivers/nvme/host/lightnvm.c
+++ b/drivers/nvme/host/lightnvm.c
@@ -474,9 +474,8 @@ static inline void nvme_nvm_rqtocmd(struct request *rq, struct nvm_rq *rqd,
c->ph_rw.length = cpu_to_le16(rqd->nr_ppas - 1);

if (rqd->opcode == NVM_OP_HBWRITE || rqd->opcode == NVM_OP_HBREAD)
- /* momentarily hardcode the shift configuration. lba_shift from
- * nvm_dev will be available in a follow-up patch */
- c->hb_rw.slba = cpu_to_le64(rqd->bio->bi_iter.bi_sector >> 3);
+ c->hb_rw.slba = cpu_to_le64(nvme_block_nr(ns,
+ rqd->bio->bi_iter.bi_sector));
}

static void nvme_nvm_end_io(struct request *rq, int error)
@@ -593,14 +592,32 @@ static struct nvm_dev_ops nvme_nvm_dev_ops = {
.max_phys_sect = 64,
};

-int nvme_nvm_register(struct request_queue *q, char *disk_name)
+int nvme_nvm_register(struct nvme_ns *ns, char *disk_name, int node)
{
- return nvm_register(q, disk_name, &nvme_nvm_dev_ops);
+ struct request_queue *q = ns->queue;
+ struct nvm_dev *dev;
+ int ret;
+
+ dev = nvm_alloc_dev(node);
+ if (!dev)
+ return -ENOMEM;
+
+ dev->q = q;
+ memcpy(dev->name, disk_name, DISK_NAME_LEN);
+ dev->ops = &nvme_nvm_dev_ops;
+ ns->ndev = dev;
+
+ ret = nvm_register(dev);
+
+ ns->lba_shift = ilog2(dev->sec_size) - 9;
+
+ return ret;
}

-void nvme_nvm_unregister(struct request_queue *q, char *disk_name)
+void nvme_nvm_unregister(struct nvme_ns *ns)
{
- nvm_unregister(disk_name);
+ nvm_unregister(ns->ndev);
+ kfree(ns->ndev);
}

/* move to shared place when used in multiple places. */
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index ab18b78..e0535c1 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -18,6 +18,7 @@
#include <linux/pci.h>
#include <linux/kref.h>
#include <linux/blk-mq.h>
+#include <linux/lightnvm.h>

enum {
/*
@@ -154,6 +155,7 @@ struct nvme_ns {
struct nvme_ctrl *ctrl;
struct request_queue *queue;
struct gendisk *disk;
+ struct nvm_dev *ndev;
struct kref kref;
int instance;

@@ -165,7 +167,6 @@ struct nvme_ns {
u16 ms;
bool ext;
u8 pi_type;
- int type;
unsigned long flags;

#define NVME_NS_REMOVING 0
@@ -307,15 +308,16 @@ int nvme_sg_get_version_num(int __user *ip);

#ifdef CONFIG_NVM
int nvme_nvm_ns_supported(struct nvme_ns *ns, struct nvme_id_ns *id);
-int nvme_nvm_register(struct request_queue *q, char *disk_name);
-void nvme_nvm_unregister(struct request_queue *q, char *disk_name);
+int nvme_nvm_register(struct nvme_ns *ns, char *disk_name, int node);
+void nvme_nvm_unregister(struct nvme_ns *ns);
#else
-static inline int nvme_nvm_register(struct request_queue *q, char *disk_name)
+static inline int nvme_nvm_register(struct nvme_ns *ns, char *disk_name,
+ int node)
{
return 0;
}

-static inline void nvme_nvm_unregister(struct request_queue *q, char *disk_name) {};
+static inline void nvme_nvm_unregister(struct nvme_ns *ns) {};

static inline int nvme_nvm_ns_supported(struct nvme_ns *ns, struct nvme_id_ns *id)
{
diff --git a/include/linux/lightnvm.h b/include/linux/lightnvm.h
index ba78b83..5afc263 100644
--- a/include/linux/lightnvm.h
+++ b/include/linux/lightnvm.h
@@ -524,9 +524,9 @@ extern struct nvm_block *nvm_get_blk(struct nvm_dev *, struct nvm_lun *,
unsigned long);
extern void nvm_put_blk(struct nvm_dev *, struct nvm_block *);

-extern int nvm_register(struct request_queue *, char *,
- struct nvm_dev_ops *);
-extern void nvm_unregister(char *);
+extern struct nvm_dev *nvm_alloc_dev(int);
+extern int nvm_register(struct nvm_dev *);
+extern void nvm_unregister(struct nvm_dev *);

void nvm_mark_blk(struct nvm_dev *dev, struct ppa_addr ppa, int type);

@@ -575,11 +575,14 @@ extern int nvm_dev_factory(struct nvm_dev *, int flags);
#else /* CONFIG_NVM */
struct nvm_dev_ops;

-static inline int nvm_register(struct request_queue *q, char *disk_name,
- struct nvm_dev_ops *ops)
+static inline struct nvm_dev *nvm_alloc_dev(int node)
+{
+ return ERR_PTR(-EINVAL);
+}
+static inline int nvm_register(struct nvm_dev *dev)
{
return -EINVAL;
}
-static inline void nvm_unregister(char *disk_name) {}
+static inline void nvm_unregister(struct nvm_dev *dev) {}
#endif /* CONFIG_NVM */
#endif /* LIGHTNVM.H */
--
2.1.4

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