Merge branch 'bpf-persistent'

Daniel Borkmann says:

====================
BPF updates

This set adds support for persistent maps/progs. Please see
individual patches for further details. A man-page update
to bpf(2) will be sent later on, also a iproute2 patch for
support in tc.

v1 -> v2:
  - Reworked most of patch 4 and 5
  - Rebased to latest net-next
====================

Signed-off-by: David S. Miller <[email protected]>

Author: davem330

include/linux/bpf.h

@@ -167,11 +167,18 @@ struct bpf_prog *bpf_prog_get(u32 ufd);
 void bpf_prog_put(struct bpf_prog *prog);
 void bpf_prog_put_rcu(struct bpf_prog *prog);
 
-struct bpf_map *bpf_map_get(struct fd f);
+struct bpf_map *bpf_map_get(u32 ufd);
+struct bpf_map *__bpf_map_get(struct fd f);
 void bpf_map_put(struct bpf_map *map);
 
 extern int sysctl_unprivileged_bpf_disabled;
 
+int bpf_map_new_fd(struct bpf_map *map);
+int bpf_prog_new_fd(struct bpf_prog *prog);
+
+int bpf_obj_pin_user(u32 ufd, const char __user *pathname);
+int bpf_obj_get_user(const char __user *pathname);
+
 /* verify correctness of eBPF program */
 int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
 #else

include/uapi/linux/bpf.h

@@ -63,50 +63,16 @@ struct bpf_insn {
 	__s32	imm;		/* signed immediate constant */
 };
 
-/* BPF syscall commands */
+/* BPF syscall commands, see bpf(2) man-page for details. */
 enum bpf_cmd {
-	/* create a map with given type and attributes
-	 * fd = bpf(BPF_MAP_CREATE, union bpf_attr *, u32 size)
-	 * returns fd or negative error
-	 * map is deleted when fd is closed
-	 */
 	BPF_MAP_CREATE,
-
-	/* lookup key in a given map
-	 * err = bpf(BPF_MAP_LOOKUP_ELEM, union bpf_attr *attr, u32 size)
-	 * Using attr->map_fd, attr->key, attr->value
-	 * returns zero and stores found elem into value
-	 * or negative error
-	 */
 	BPF_MAP_LOOKUP_ELEM,
-
-	/* create or update key/value pair in a given map
-	 * err = bpf(BPF_MAP_UPDATE_ELEM, union bpf_attr *attr, u32 size)
-	 * Using attr->map_fd, attr->key, attr->value, attr->flags
-	 * returns zero or negative error
-	 */
 	BPF_MAP_UPDATE_ELEM,
-
-	/* find and delete elem by key in a given map
-	 * err = bpf(BPF_MAP_DELETE_ELEM, union bpf_attr *attr, u32 size)
-	 * Using attr->map_fd, attr->key
-	 * returns zero or negative error
-	 */
 	BPF_MAP_DELETE_ELEM,
-
-	/* lookup key in a given map and return next key
-	 * err = bpf(BPF_MAP_GET_NEXT_KEY, union bpf_attr *attr, u32 size)
-	 * Using attr->map_fd, attr->key, attr->next_key
-	 * returns zero and stores next key or negative error
-	 */
 	BPF_MAP_GET_NEXT_KEY,
-
-	/* verify and load eBPF program
-	 * prog_fd = bpf(BPF_PROG_LOAD, union bpf_attr *attr, u32 size)
-	 * Using attr->prog_type, attr->insns, attr->license
-	 * returns fd or negative error
-	 */
 	BPF_PROG_LOAD,
+	BPF_OBJ_PIN,
+	BPF_OBJ_GET,
 };
 
 enum bpf_map_type {
@@ -160,6 +126,11 @@ union bpf_attr {
 		__aligned_u64	log_buf;	/* user supplied buffer */
 		__u32		kern_version;	/* checked when prog_type=kprobe */
 	};
+
+	struct { /* anonymous struct used by BPF_OBJ_* commands */
+		__aligned_u64	pathname;
+		__u32		bpf_fd;
+	};
 } __attribute__((aligned(8)));
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper

include/uapi/linux/magic.h

@@ -75,5 +75,6 @@
 #define ANON_INODE_FS_MAGIC	0x09041934
 #define BTRFS_TEST_MAGIC	0x73727279
 #define NSFS_MAGIC		0x6e736673
+#define BPF_FS_MAGIC		0xcafe4a11
 
 #endif /* __LINUX_MAGIC_H__ */

kernel/bpf/Makefile

@@ -1,2 +1,4 @@
 obj-y := core.o
-obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o hashtab.o arraymap.o helpers.o
+
+obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o
+obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o

kernel/bpf/core.c

@@ -92,6 +92,7 @@ struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
 
 	fp->pages = size / PAGE_SIZE;
 	fp->aux = aux;
+	fp->aux->prog = fp;
 
 	return fp;
 }
@@ -116,6 +117,7 @@ struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
 
 		memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
 		fp->pages = size / PAGE_SIZE;
+		fp->aux->prog = fp;
 
 		/* We keep fp->aux from fp_old around in the new
 		 * reallocated structure.
@@ -726,7 +728,6 @@ void bpf_prog_free(struct bpf_prog *fp)
 	struct bpf_prog_aux *aux = fp->aux;
 
 	INIT_WORK(&aux->work, bpf_prog_free_deferred);
-	aux->prog = fp;
 	schedule_work(&aux->work);
 }
 EXPORT_SYMBOL_GPL(bpf_prog_free);