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-rw-r--r--include/linux/bpf.h11
-rw-r--r--include/uapi/linux/bpf.h38
2 files changed, 47 insertions, 2 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index e0dbe0c0a17e..33e543b86e1a 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -451,7 +451,7 @@ enum bpf_type_flag {
/* DYNPTR points to memory local to the bpf program. */
DYNPTR_TYPE_LOCAL = BIT(8 + BPF_BASE_TYPE_BITS),
- /* DYNPTR points to a ringbuf record. */
+ /* DYNPTR points to a kernel-produced ringbuf record. */
DYNPTR_TYPE_RINGBUF = BIT(9 + BPF_BASE_TYPE_BITS),
/* Size is known at compile time. */
@@ -656,6 +656,7 @@ enum bpf_reg_type {
PTR_TO_MEM, /* reg points to valid memory region */
PTR_TO_BUF, /* reg points to a read/write buffer */
PTR_TO_FUNC, /* reg points to a bpf program function */
+ PTR_TO_DYNPTR, /* reg points to a dynptr */
__BPF_REG_TYPE_MAX,
/* Extended reg_types. */
@@ -1394,6 +1395,11 @@ struct bpf_array {
#define BPF_MAP_CAN_READ BIT(0)
#define BPF_MAP_CAN_WRITE BIT(1)
+/* Maximum number of user-producer ring buffer samples that can be drained in
+ * a call to bpf_user_ringbuf_drain().
+ */
+#define BPF_MAX_USER_RINGBUF_SAMPLES (128 * 1024)
+
static inline u32 bpf_map_flags_to_cap(struct bpf_map *map)
{
u32 access_flags = map->map_flags & (BPF_F_RDONLY_PROG | BPF_F_WRONLY_PROG);
@@ -2495,6 +2501,7 @@ extern const struct bpf_func_proto bpf_loop_proto;
extern const struct bpf_func_proto bpf_copy_from_user_task_proto;
extern const struct bpf_func_proto bpf_set_retval_proto;
extern const struct bpf_func_proto bpf_get_retval_proto;
+extern const struct bpf_func_proto bpf_user_ringbuf_drain_proto;
const struct bpf_func_proto *tracing_prog_func_proto(
enum bpf_func_id func_id, const struct bpf_prog *prog);
@@ -2639,7 +2646,7 @@ enum bpf_dynptr_type {
BPF_DYNPTR_TYPE_INVALID,
/* Points to memory that is local to the bpf program */
BPF_DYNPTR_TYPE_LOCAL,
- /* Underlying data is a ringbuf record */
+ /* Underlying data is a kernel-produced ringbuf record */
BPF_DYNPTR_TYPE_RINGBUF,
};
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index e18c85324db6..ead35f39f185 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -5388,6 +5388,43 @@ union bpf_attr {
* Return
* Current *ktime*.
*
+ * long bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void *ctx, u64 flags)
+ * Description
+ * Drain samples from the specified user ring buffer, and invoke
+ * the provided callback for each such sample:
+ *
+ * long (\*callback_fn)(struct bpf_dynptr \*dynptr, void \*ctx);
+ *
+ * If **callback_fn** returns 0, the helper will continue to try
+ * and drain the next sample, up to a maximum of
+ * BPF_MAX_USER_RINGBUF_SAMPLES samples. If the return value is 1,
+ * the helper will skip the rest of the samples and return. Other
+ * return values are not used now, and will be rejected by the
+ * verifier.
+ * Return
+ * The number of drained samples if no error was encountered while
+ * draining samples, or 0 if no samples were present in the ring
+ * buffer. If a user-space producer was epoll-waiting on this map,
+ * and at least one sample was drained, they will receive an event
+ * notification notifying them of available space in the ring
+ * buffer. If the BPF_RB_NO_WAKEUP flag is passed to this
+ * function, no wakeup notification will be sent. If the
+ * BPF_RB_FORCE_WAKEUP flag is passed, a wakeup notification will
+ * be sent even if no sample was drained.
+ *
+ * On failure, the returned value is one of the following:
+ *
+ * **-EBUSY** if the ring buffer is contended, and another calling
+ * context was concurrently draining the ring buffer.
+ *
+ * **-EINVAL** if user-space is not properly tracking the ring
+ * buffer due to the producer position not being aligned to 8
+ * bytes, a sample not being aligned to 8 bytes, or the producer
+ * position not matching the advertised length of a sample.
+ *
+ * **-E2BIG** if user-space has tried to publish a sample which is
+ * larger than the size of the ring buffer, or which cannot fit
+ * within a struct bpf_dynptr.
*/
#define __BPF_FUNC_MAPPER(FN) \
FN(unspec), \
@@ -5599,6 +5636,7 @@ union bpf_attr {
FN(tcp_raw_check_syncookie_ipv4), \
FN(tcp_raw_check_syncookie_ipv6), \
FN(ktime_get_tai_ns), \
+ FN(user_ringbuf_drain), \
/* */
/* integer value in 'imm' field of BPF_CALL instruction selects which helper