netdevsim: bpf: support fake map offload
Add to netdevsim ability to pretend it's offloading BPF maps. We only allow allocation of tiny 2 entry maps, to keep things simple. Mutex lock may seem heavy for the operations we perform, but we want to make sure callbacks can sleep. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Jakub Kicinski
Daniel Borkmann
parent
064a07cba2
commit
395cacb5f1
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@ -17,6 +17,7 @@
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#include <linux/bpf_verifier.h>
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#include <linux/debugfs.h>
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#include <linux/kernel.h>
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#include <linux/mutex.h>
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#include <linux/rtnetlink.h>
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#include <net/pkt_cls.h>
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@ -31,6 +32,19 @@ struct nsim_bpf_bound_prog {
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struct list_head l;
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};
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#define NSIM_BPF_MAX_KEYS 2
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struct nsim_bpf_bound_map {
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struct netdevsim *ns;
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struct bpf_offloaded_map *map;
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struct mutex mutex;
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struct nsim_map_entry {
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void *key;
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void *value;
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} entry[NSIM_BPF_MAX_KEYS];
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struct list_head l;
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};
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static int nsim_debugfs_bpf_string_read(struct seq_file *file, void *data)
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{
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const char **str = file->private;
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@ -284,6 +298,224 @@ nsim_setup_prog_hw_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
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return 0;
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}
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static bool
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nsim_map_key_match(struct bpf_map *map, struct nsim_map_entry *e, void *key)
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{
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return e->key && !memcmp(key, e->key, map->key_size);
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}
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static int nsim_map_key_find(struct bpf_offloaded_map *offmap, void *key)
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{
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struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
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unsigned int i;
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for (i = 0; i < ARRAY_SIZE(nmap->entry); i++)
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if (nsim_map_key_match(&offmap->map, &nmap->entry[i], key))
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return i;
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return -ENOENT;
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}
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static int
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nsim_map_alloc_elem(struct bpf_offloaded_map *offmap, unsigned int idx)
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{
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struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
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nmap->entry[idx].key = kmalloc(offmap->map.key_size, GFP_USER);
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if (!nmap->entry[idx].key)
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return -ENOMEM;
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nmap->entry[idx].value = kmalloc(offmap->map.value_size, GFP_USER);
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if (!nmap->entry[idx].value) {
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kfree(nmap->entry[idx].key);
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nmap->entry[idx].key = NULL;
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return -ENOMEM;
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}
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return 0;
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}
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static int
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nsim_map_get_next_key(struct bpf_offloaded_map *offmap,
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void *key, void *next_key)
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{
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struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
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int idx = -ENOENT;
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mutex_lock(&nmap->mutex);
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if (key)
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idx = nsim_map_key_find(offmap, key);
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if (idx == -ENOENT)
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idx = 0;
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else
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idx++;
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for (; idx < ARRAY_SIZE(nmap->entry); idx++) {
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if (nmap->entry[idx].key) {
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memcpy(next_key, nmap->entry[idx].key,
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offmap->map.key_size);
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break;
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}
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}
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mutex_unlock(&nmap->mutex);
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if (idx == ARRAY_SIZE(nmap->entry))
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return -ENOENT;
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return 0;
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}
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static int
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nsim_map_lookup_elem(struct bpf_offloaded_map *offmap, void *key, void *value)
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{
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struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
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int idx;
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mutex_lock(&nmap->mutex);
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idx = nsim_map_key_find(offmap, key);
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if (idx >= 0)
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memcpy(value, nmap->entry[idx].value, offmap->map.value_size);
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mutex_unlock(&nmap->mutex);
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return idx < 0 ? idx : 0;
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}
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static int
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nsim_map_update_elem(struct bpf_offloaded_map *offmap,
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void *key, void *value, u64 flags)
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{
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struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
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int idx, err = 0;
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mutex_lock(&nmap->mutex);
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idx = nsim_map_key_find(offmap, key);
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if (idx < 0 && flags == BPF_EXIST) {
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err = idx;
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goto exit_unlock;
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}
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if (idx >= 0 && flags == BPF_NOEXIST) {
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err = -EEXIST;
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goto exit_unlock;
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}
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if (idx < 0) {
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for (idx = 0; idx < ARRAY_SIZE(nmap->entry); idx++)
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if (!nmap->entry[idx].key)
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break;
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if (idx == ARRAY_SIZE(nmap->entry)) {
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err = -E2BIG;
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goto exit_unlock;
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}
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err = nsim_map_alloc_elem(offmap, idx);
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if (err)
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goto exit_unlock;
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}
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memcpy(nmap->entry[idx].key, key, offmap->map.key_size);
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memcpy(nmap->entry[idx].value, value, offmap->map.value_size);
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exit_unlock:
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mutex_unlock(&nmap->mutex);
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return err;
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}
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static int nsim_map_delete_elem(struct bpf_offloaded_map *offmap, void *key)
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{
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struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
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int idx;
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if (offmap->map.map_type == BPF_MAP_TYPE_ARRAY)
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return -EINVAL;
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mutex_lock(&nmap->mutex);
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idx = nsim_map_key_find(offmap, key);
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if (idx >= 0) {
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kfree(nmap->entry[idx].key);
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kfree(nmap->entry[idx].value);
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memset(&nmap->entry[idx], 0, sizeof(nmap->entry[idx]));
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}
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mutex_unlock(&nmap->mutex);
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return idx < 0 ? idx : 0;
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}
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static const struct bpf_map_dev_ops nsim_bpf_map_ops = {
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.map_get_next_key = nsim_map_get_next_key,
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.map_lookup_elem = nsim_map_lookup_elem,
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.map_update_elem = nsim_map_update_elem,
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.map_delete_elem = nsim_map_delete_elem,
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};
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static int
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nsim_bpf_map_alloc(struct netdevsim *ns, struct bpf_offloaded_map *offmap)
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{
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struct nsim_bpf_bound_map *nmap;
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unsigned int i;
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int err;
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if (WARN_ON(offmap->map.map_type != BPF_MAP_TYPE_ARRAY &&
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offmap->map.map_type != BPF_MAP_TYPE_HASH))
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return -EINVAL;
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if (offmap->map.max_entries > NSIM_BPF_MAX_KEYS)
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return -ENOMEM;
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if (offmap->map.map_flags)
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return -EINVAL;
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nmap = kzalloc(sizeof(*nmap), GFP_USER);
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if (!nmap)
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return -ENOMEM;
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offmap->dev_priv = nmap;
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nmap->ns = ns;
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nmap->map = offmap;
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mutex_init(&nmap->mutex);
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if (offmap->map.map_type == BPF_MAP_TYPE_ARRAY) {
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for (i = 0; i < ARRAY_SIZE(nmap->entry); i++) {
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u32 *key;
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err = nsim_map_alloc_elem(offmap, i);
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if (err)
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goto err_free;
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key = nmap->entry[i].key;
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*key = i;
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}
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}
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offmap->dev_ops = &nsim_bpf_map_ops;
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list_add_tail(&nmap->l, &ns->bpf_bound_maps);
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return 0;
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err_free:
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while (--i) {
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kfree(nmap->entry[i].key);
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kfree(nmap->entry[i].value);
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}
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kfree(nmap);
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return err;
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}
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static void nsim_bpf_map_free(struct bpf_offloaded_map *offmap)
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{
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struct nsim_bpf_bound_map *nmap = offmap->dev_priv;
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unsigned int i;
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for (i = 0; i < ARRAY_SIZE(nmap->entry); i++) {
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kfree(nmap->entry[i].key);
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kfree(nmap->entry[i].value);
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}
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list_del_init(&nmap->l);
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mutex_destroy(&nmap->mutex);
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kfree(nmap);
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}
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int nsim_bpf(struct net_device *dev, struct netdev_bpf *bpf)
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{
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struct netdevsim *ns = netdev_priv(dev);
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@ -328,6 +560,14 @@ int nsim_bpf(struct net_device *dev, struct netdev_bpf *bpf)
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return err;
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return nsim_xdp_set_prog(ns, bpf);
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case BPF_OFFLOAD_MAP_ALLOC:
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if (!ns->bpf_map_accept)
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return -EOPNOTSUPP;
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return nsim_bpf_map_alloc(ns, bpf->offmap);
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case BPF_OFFLOAD_MAP_FREE:
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nsim_bpf_map_free(bpf->offmap);
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return 0;
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default:
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return -EINVAL;
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}
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@ -336,6 +576,7 @@ int nsim_bpf(struct net_device *dev, struct netdev_bpf *bpf)
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int nsim_bpf_init(struct netdevsim *ns)
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{
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INIT_LIST_HEAD(&ns->bpf_bound_progs);
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INIT_LIST_HEAD(&ns->bpf_bound_maps);
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debugfs_create_u32("bpf_offloaded_id", 0400, ns->ddir,
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&ns->bpf_offloaded_id);
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@ -362,12 +603,17 @@ int nsim_bpf_init(struct netdevsim *ns)
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debugfs_create_bool("bpf_xdpoffload_accept", 0600, ns->ddir,
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&ns->bpf_xdpoffload_accept);
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ns->bpf_map_accept = true;
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debugfs_create_bool("bpf_map_accept", 0600, ns->ddir,
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&ns->bpf_map_accept);
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return 0;
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}
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void nsim_bpf_uninit(struct netdevsim *ns)
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{
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WARN_ON(!list_empty(&ns->bpf_bound_progs));
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WARN_ON(!list_empty(&ns->bpf_bound_maps));
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WARN_ON(ns->xdp_prog);
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WARN_ON(ns->bpf_offloaded);
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}
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@ -61,6 +61,9 @@ struct netdevsim {
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bool bpf_tc_non_bound_accept;
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bool bpf_xdpdrv_accept;
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bool bpf_xdpoffload_accept;
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bool bpf_map_accept;
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struct list_head bpf_bound_maps;
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};
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extern struct dentry *nsim_ddir;
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