bpf: add helper for copying attrs to struct bpf_map

All map types reimplement the field-by-field copy of union bpf_attr
members into struct bpf_map.  Add a helper to perform this operation.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

7 files changed, 16 insertions, 40 deletions

diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index ce5b669003b2..192151ec9d12 100644
--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -94,13 +94,7 @@ static struct bpf_map *cpu_map_alloc(union bpf_attr *attr)
         if (!cmap)
                 return ERR_PTR(-ENOMEM);
 
-        /* mandatory map attributes */
-        cmap->map.map_type = attr->map_type;
-        cmap->map.key_size = attr->key_size;
-        cmap->map.value_size = attr->value_size;
-        cmap->map.max_entries = attr->max_entries;
-        cmap->map.map_flags = attr->map_flags;
-        cmap->map.numa_node = bpf_map_attr_numa_node(attr);
+        bpf_map_init_from_attr(&cmap->map, attr);
 
         /* Pre-limit array size based on NR_CPUS, not final CPU check */
         if (cmap->map.max_entries > NR_CPUS) {
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index ebdef54bf7df..565f9ece9115 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -93,13 +93,7 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr)
         if (!dtab)
                 return ERR_PTR(-ENOMEM);
 
-        /* mandatory map attributes */
-        dtab->map.map_type = attr->map_type;
-        dtab->map.key_size = attr->key_size;
-        dtab->map.value_size = attr->value_size;
-        dtab->map.max_entries = attr->max_entries;
-        dtab->map.map_flags = attr->map_flags;
-        dtab->map.numa_node = bpf_map_attr_numa_node(attr);
+        bpf_map_init_from_attr(&dtab->map, attr);
 
         /* make sure page count doesn't overflow */
         cost = (u64) dtab->map.max_entries * sizeof(struct bpf_dtab_netdev *);
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 7fd6519444d3..b76828f23b49 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -304,7 +304,6 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
          */
         bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
         bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
-        int numa_node = bpf_map_attr_numa_node(attr);
         struct bpf_htab *htab;
         int err, i;
         u64 cost;
@@ -313,13 +312,7 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
         if (!htab)
                 return ERR_PTR(-ENOMEM);
 
-        /* mandatory map attributes */
-        htab->map.map_type = attr->map_type;
-        htab->map.key_size = attr->key_size;
-        htab->map.value_size = attr->value_size;
-        htab->map.max_entries = attr->max_entries;
-        htab->map.map_flags = attr->map_flags;
-        htab->map.numa_node = numa_node;
+        bpf_map_init_from_attr(&htab->map, attr);
 
         if (percpu_lru) {
                 /* ensure each CPU's lru list has >=1 elements.
diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c
index 885e45479680..584e02227671 100644
--- a/kernel/bpf/lpm_trie.c
+++ b/kernel/bpf/lpm_trie.c
@@ -522,12 +522,7 @@ static struct bpf_map *trie_alloc(union bpf_attr *attr)
                 return ERR_PTR(-ENOMEM);
 
         /* copy mandatory map attributes */
-        trie->map.map_type = attr->map_type;
-        trie->map.key_size = attr->key_size;
-        trie->map.value_size = attr->value_size;
-        trie->map.max_entries = attr->max_entries;
-        trie->map.map_flags = attr->map_flags;
-        trie->map.numa_node = bpf_map_attr_numa_node(attr);
+        bpf_map_init_from_attr(&trie->map, attr);
         trie->data_size = attr->key_size -
                           offsetof(struct bpf_lpm_trie_key, data);
         trie->max_prefixlen = trie->data_size * 8;
diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index 079968680bc3..0314d1783d77 100644
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -513,13 +513,7 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
         if (!stab)
                 return ERR_PTR(-ENOMEM);
 
-        /* mandatory map attributes */
-        stab->map.map_type = attr->map_type;
-        stab->map.key_size = attr->key_size;
-        stab->map.value_size = attr->value_size;
-        stab->map.max_entries = attr->max_entries;
-        stab->map.map_flags = attr->map_flags;
-        stab->map.numa_node = bpf_map_attr_numa_node(attr);
+        bpf_map_init_from_attr(&stab->map, attr);
 
         /* make sure page count doesn't overflow */
         cost = (u64) stab->map.max_entries * sizeof(struct sock *);
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index 6c63c2222ea8..b0ecf43f5894 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -88,14 +88,10 @@ static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
         if (cost >= U32_MAX - PAGE_SIZE)
                 goto free_smap;
 
-        smap->map.map_type = attr->map_type;
-        smap->map.key_size = attr->key_size;
+        bpf_map_init_from_attr(&smap->map, attr);
         smap->map.value_size = value_size;
-        smap->map.max_entries = attr->max_entries;
-        smap->map.map_flags = attr->map_flags;
         smap->n_buckets = n_buckets;
         smap->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
-        smap->map.numa_node = bpf_map_attr_numa_node(attr);
 
         err = bpf_map_precharge_memlock(smap->map.pages);
         if (err)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index c0ac03a04880..a3f726bb42ea 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -143,6 +143,16 @@ void bpf_map_area_free(void *area)
         kvfree(area);
 }
 
+void bpf_map_init_from_attr(struct bpf_map *map, union bpf_attr *attr)
+{
+        map->map_type = attr->map_type;
+        map->key_size = attr->key_size;
+        map->value_size = attr->value_size;
+        map->max_entries = attr->max_entries;
+        map->map_flags = attr->map_flags;
+        map->numa_node = bpf_map_attr_numa_node(attr);
+}
+
 int bpf_map_precharge_memlock(u32 pages)
 {
         struct user_struct *user = get_current_user();