nbd: Convert nbd_index_idr to XArray

Signed-off-by: Matthew Wilcox <willy@infradead.org>

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index e21d2ded732b735c13f7ebbd02533ed081afe0ca..7e50c1dfade8d350763c4de654de6a9d97bc80ef 100644 (file)
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -46,8 +46,8 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/nbd.h>
 
-static DEFINE_IDR(nbd_index_idr);
-static DEFINE_MUTEX(nbd_index_mutex);
+static DEFINE_XARRAY_ALLOC(nbd_devs);
+static DEFINE_MUTEX(nbd_global_mutex);
 static int nbd_total_devices = 0;
 
 struct nbd_sock {
@@ -227,10 +227,9 @@ static void nbd_dev_remove(struct nbd_device *nbd)
 
 static void nbd_put(struct nbd_device *nbd)
 {
-       if (refcount_dec_and_mutex_lock(&nbd->refs,
-                                       &nbd_index_mutex)) {
-               idr_remove(&nbd_index_idr, nbd->index);
-               mutex_unlock(&nbd_index_mutex);
+       if (refcount_dec_and_mutex_lock(&nbd->refs, &nbd_global_mutex)) {
+               xa_erase(&nbd_devs, nbd->index);
+               mutex_unlock(&nbd_global_mutex);
                nbd_dev_remove(nbd);
        }
 }
@@ -1354,7 +1353,7 @@ static int nbd_open(struct block_device *bdev, fmode_t mode)
        struct nbd_device *nbd;
        int ret = 0;
 
-       mutex_lock(&nbd_index_mutex);
+       mutex_lock(&nbd_global_mutex);
        nbd = bdev->bd_disk->private_data;
        if (!nbd) {
                ret = -ENXIO;
@@ -1386,7 +1385,7 @@ static int nbd_open(struct block_device *bdev, fmode_t mode)
                bdev->bd_invalidated = 1;
        }
 out:
-       mutex_unlock(&nbd_index_mutex);
+       mutex_unlock(&nbd_global_mutex);
        return ret;
 }
 
@@ -1574,15 +1573,13 @@ static int nbd_dev_add(int index)
                goto out_free_nbd;
 
        if (index >= 0) {
-               err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
-                               GFP_KERNEL);
-               if (err == -ENOSPC)
-                       err = -EEXIST;
+               err = xa_insert(&nbd_devs, index, nbd, GFP_KERNEL);
        } else {
-               err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
-               if (err >= 0)
-                       index = err;
+               err = xa_alloc(&nbd_devs, &index, nbd, xa_limit_32b,
+                               GFP_KERNEL);
        }
+       if (err == -EBUSY)
+               err = -EEXIST;
        if (err < 0)
                goto out_free_disk;
 
@@ -1599,7 +1596,7 @@ static int nbd_dev_add(int index)
 
        err = blk_mq_alloc_tag_set(&nbd->tag_set);
        if (err)
-               goto out_free_idr;
+               goto out_free_dev;
 
        q = blk_mq_init_queue(&nbd->tag_set);
        if (IS_ERR(q)) {
@@ -1636,8 +1633,8 @@ static int nbd_dev_add(int index)
 
 out_free_tags:
        blk_mq_free_tag_set(&nbd->tag_set);
-out_free_idr:
-       idr_remove(&nbd_index_idr, index);
+out_free_dev:
+       xa_erase(&nbd_devs, index);
 out_free_disk:
        put_disk(disk);
 out_free_nbd:
@@ -1646,18 +1643,6 @@ out:
        return err;
 }
 
-static int find_free_cb(int id, void *ptr, void *data)
-{
-       struct nbd_device *nbd = ptr;
-       struct nbd_device **found = data;
-
-       if (!refcount_read(&nbd->config_refs)) {
-               *found = nbd;
-               return 1;
-       }
-       return 0;
-}
-
 /* Netlink interface. */
 static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
        [NBD_ATTR_INDEX]                =       { .type = NLA_U32 },
@@ -1730,46 +1715,51 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
                return -EINVAL;
        }
 again:
-       mutex_lock(&nbd_index_mutex);
+       mutex_lock(&nbd_global_mutex);
        if (index == -1) {
-               ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd);
-               if (ret == 0) {
+               unsigned long i;
+               xa_for_each(&nbd_devs, i, nbd) {
+                       if (!refcount_read(&nbd->config_refs))
+                               break;
+               }
+
+               if (!nbd) {
                        int new_index;
                        new_index = nbd_dev_add(-1);
                        if (new_index < 0) {
-                               mutex_unlock(&nbd_index_mutex);
+                               mutex_unlock(&nbd_global_mutex);
                                printk(KERN_ERR "nbd: failed to add new device\n");
                                return new_index;
                        }
-                       nbd = idr_find(&nbd_index_idr, new_index);
+                       nbd = xa_load(&nbd_devs, new_index);
                }
        } else {
-               nbd = idr_find(&nbd_index_idr, index);
+               nbd = xa_load(&nbd_devs, index);
                if (!nbd) {
                        ret = nbd_dev_add(index);
                        if (ret < 0) {
-                               mutex_unlock(&nbd_index_mutex);
+                               mutex_unlock(&nbd_global_mutex);
                                printk(KERN_ERR "nbd: failed to add new device\n");
                                return ret;
                        }
-                       nbd = idr_find(&nbd_index_idr, index);
+                       nbd = xa_load(&nbd_devs, index);
                }
        }
        if (!nbd) {
+               mutex_unlock(&nbd_global_mutex);
                printk(KERN_ERR "nbd: couldn't find device at index %d\n",
                       index);
-               mutex_unlock(&nbd_index_mutex);
                return -EINVAL;
        }
        if (!refcount_inc_not_zero(&nbd->refs)) {
-               mutex_unlock(&nbd_index_mutex);
+               mutex_unlock(&nbd_global_mutex);
                if (index == -1)
                        goto again;
                printk(KERN_ERR "nbd: device at index %d is going down\n",
                       index);
                return -EINVAL;
        }
-       mutex_unlock(&nbd_index_mutex);
+       mutex_unlock(&nbd_global_mutex);
 
        mutex_lock(&nbd->config_lock);
        if (refcount_read(&nbd->config_refs)) {
@@ -1893,21 +1883,21 @@ static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
                return -EINVAL;
        }
        index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
-       mutex_lock(&nbd_index_mutex);
-       nbd = idr_find(&nbd_index_idr, index);
+       mutex_lock(&nbd_global_mutex);
+       nbd = xa_load(&nbd_devs, index);
        if (!nbd) {
-               mutex_unlock(&nbd_index_mutex);
+               mutex_unlock(&nbd_global_mutex);
                printk(KERN_ERR "nbd: couldn't find device at index %d\n",
                       index);
                return -EINVAL;
        }
        if (!refcount_inc_not_zero(&nbd->refs)) {
-               mutex_unlock(&nbd_index_mutex);
+               mutex_unlock(&nbd_global_mutex);
                printk(KERN_ERR "nbd: device at index %d is going down\n",
                       index);
                return -EINVAL;
        }
-       mutex_unlock(&nbd_index_mutex);
+       mutex_unlock(&nbd_global_mutex);
        if (!refcount_inc_not_zero(&nbd->config_refs)) {
                nbd_put(nbd);
                return 0;
@@ -1934,21 +1924,21 @@ static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
                return -EINVAL;
        }
        index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
-       mutex_lock(&nbd_index_mutex);
-       nbd = idr_find(&nbd_index_idr, index);
+       mutex_lock(&nbd_global_mutex);
+       nbd = xa_load(&nbd_devs, index);
        if (!nbd) {
-               mutex_unlock(&nbd_index_mutex);
+               mutex_unlock(&nbd_global_mutex);
                printk(KERN_ERR "nbd: couldn't find a device at index %d\n",
                       index);
                return -EINVAL;
        }
        if (!refcount_inc_not_zero(&nbd->refs)) {
-               mutex_unlock(&nbd_index_mutex);
+               mutex_unlock(&nbd_global_mutex);
                printk(KERN_ERR "nbd: device at index %d is going down\n",
                       index);
                return -EINVAL;
        }
-       mutex_unlock(&nbd_index_mutex);
+       mutex_unlock(&nbd_global_mutex);
 
        if (!refcount_inc_not_zero(&nbd->config_refs)) {
                dev_err(nbd_to_dev(nbd),
@@ -2094,7 +2084,7 @@ static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
        /* This is a little racey, but for status it's ok.  The
         * reason we don't take a ref here is because we can't
         * take a ref in the index == -1 case as we would need
-        * to put under the nbd_index_mutex, which could
+        * to put under the nbd_global_mutex, which could
         * deadlock if we are configured to remove ourselves
         * once we're disconnected.
         */
@@ -2114,16 +2104,11 @@ static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
        return 0;
 }
 
-static int status_cb(int id, void *ptr, void *data)
-{
-       struct nbd_device *nbd = ptr;
-       return populate_nbd_status(nbd, (struct sk_buff *)data);
-}
-
 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
 {
        struct nlattr *dev_list;
        struct sk_buff *reply;
+       struct nbd_device *nbd;
        void *reply_head;
        size_t msg_size;
        int index = -1;
@@ -2132,7 +2117,7 @@ static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
        if (info->attrs[NBD_ATTR_INDEX])
                index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
 
-       mutex_lock(&nbd_index_mutex);
+       mutex_lock(&nbd_global_mutex);
 
        msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
                                  nla_attr_size(sizeof(u8)));
@@ -2150,14 +2135,17 @@ static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
 
        dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST);
        if (index == -1) {
-               ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
-               if (ret) {
-                       nlmsg_free(reply);
-                       goto out;
+               unsigned long i;
+
+               xa_for_each(&nbd_devs, i, nbd) {
+                       ret = populate_nbd_status(nbd, reply);
+                       if (ret) {
+                               nlmsg_free(reply);
+                               goto out;
+                       }
                }
        } else {
-               struct nbd_device *nbd;
-               nbd = idr_find(&nbd_index_idr, index);
+               nbd = xa_load(&nbd_devs, index);
                if (nbd) {
                        ret = populate_nbd_status(nbd, reply);
                        if (ret) {
@@ -2170,7 +2158,7 @@ static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
        genlmsg_end(reply, reply_head);
        ret = genlmsg_reply(reply, info);
 out:
-       mutex_unlock(&nbd_index_mutex);
+       mutex_unlock(&nbd_global_mutex);
        return ret;
 }
 
@@ -2279,42 +2267,27 @@ static int __init nbd_init(void)
        }
        nbd_dbg_init();
 
-       mutex_lock(&nbd_index_mutex);
+       mutex_lock(&nbd_global_mutex);
        for (i = 0; i < nbds_max; i++)
                nbd_dev_add(i);
-       mutex_unlock(&nbd_index_mutex);
-       return 0;
-}
-
-static int nbd_exit_cb(int id, void *ptr, void *data)
-{
-       struct list_head *list = (struct list_head *)data;
-       struct nbd_device *nbd = ptr;
-
-       list_add_tail(&nbd->list, list);
+       mutex_unlock(&nbd_global_mutex);
        return 0;
 }
 
 static void __exit nbd_cleanup(void)
 {
        struct nbd_device *nbd;
-       LIST_HEAD(del_list);
+       unsigned long index;
 
        nbd_dbg_close();
 
-       mutex_lock(&nbd_index_mutex);
-       idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
-       mutex_unlock(&nbd_index_mutex);
-
-       while (!list_empty(&del_list)) {
-               nbd = list_first_entry(&del_list, struct nbd_device, list);
-               list_del_init(&nbd->list);
+       xa_for_each(&nbd_devs, index, nbd) {
                if (refcount_read(&nbd->refs) != 1)
                        printk(KERN_ERR "nbd: possibly leaking a device\n");
                nbd_put(nbd);
        }
 
-       idr_destroy(&nbd_index_idr);
+       xa_destroy(&nbd_devs);
        genl_unregister_family(&nbd_genl_family);
        destroy_workqueue(recv_workqueue);
        unregister_blkdev(NBD_MAJOR, "nbd");