Whatever happened to this patch?

-- Steve


On Tue, 10 Oct 2023 22:54:19 +0900
"Masami Hiramatsu (Google)" <[email protected]> wrote:

> From: Masami Hiramatsu (Google) <[email protected]>
> 
> Move the BTF APIs used in tracing to the BTF library code for sharing it
> with others.
> Previously, to avoid complex dependency in a series I made it on the
> tracing tree, but now it is a good time to move it to BPF tree because
> these functions are pure BTF functions.
> 
> Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
> ---
>  include/linux/btf.h        |   24 +++++++++
>  kernel/bpf/btf.c           |  115 +++++++++++++++++++++++++++++++++++++++++
>  kernel/trace/Makefile      |    1 
>  kernel/trace/trace_btf.c   |  122 
> --------------------------------------------
>  kernel/trace/trace_btf.h   |   11 ----
>  kernel/trace/trace_probe.c |    2 -
>  6 files changed, 140 insertions(+), 135 deletions(-)
>  delete mode 100644 kernel/trace/trace_btf.c
>  delete mode 100644 kernel/trace/trace_btf.h
> 
> diff --git a/include/linux/btf.h b/include/linux/btf.h
> index 928113a80a95..8372d93ea402 100644
> --- a/include/linux/btf.h
> +++ b/include/linux/btf.h
> @@ -507,6 +507,14 @@ btf_get_prog_ctx_type(struct bpf_verifier_log *log, 
> const struct btf *btf,
>  int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type 
> prog_type);
>  bool btf_types_are_same(const struct btf *btf1, u32 id1,
>                       const struct btf *btf2, u32 id2);
> +const struct btf_type *btf_find_func_proto(const char *func_name,
> +                                        struct btf **btf_p);
> +const struct btf_param *btf_get_func_param(const struct btf_type *func_proto,
> +                                        s32 *nr);
> +const struct btf_member *btf_find_struct_member(struct btf *btf,
> +                                             const struct btf_type *type,
> +                                             const char *member_name,
> +                                             u32 *anon_offset);
>  #else
>  static inline const struct btf_type *btf_type_by_id(const struct btf *btf,
>                                                   u32 type_id)
> @@ -559,6 +567,22 @@ static inline bool btf_types_are_same(const struct btf 
> *btf1, u32 id1,
>  {
>       return false;
>  }
> +static inline const struct btf_type *btf_find_func_proto(const char 
> *func_name,
> +                                                      struct btf **btf_p)
> +{
> +     return NULL;
> +}
> +static inline const struct btf_param *
> +btf_get_func_param(const struct btf_type *func_proto, s32 *nr)
> +{
> +     return NULL;
> +}
> +static inline const struct btf_member *
> +btf_find_struct_member(struct btf *btf, const struct btf_type *type,
> +                    const char *member_name, u32 *anon_offset)
> +{
> +     return NULL;
> +}
>  #endif
>  
>  static inline bool btf_type_is_struct_ptr(struct btf *btf, const struct 
> btf_type *t)
> diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> index 8090d7fb11ef..e5cbf3b31b78 100644
> --- a/kernel/bpf/btf.c
> +++ b/kernel/bpf/btf.c
> @@ -912,6 +912,121 @@ static const struct btf_type 
> *btf_type_skip_qualifiers(const struct btf *btf,
>       return t;
>  }
>  
> +/*
> + * Find a function proto type by name, and return the btf_type with its btf
> + * in *@btf_p. Return NULL if not found.
> + * Note that caller has to call btf_put(*@btf_p) after using the btf_type.
> + */
> +const struct btf_type *btf_find_func_proto(const char *func_name, struct btf 
> **btf_p)
> +{
> +     const struct btf_type *t;
> +     s32 id;
> +
> +     id = bpf_find_btf_id(func_name, BTF_KIND_FUNC, btf_p);
> +     if (id < 0)
> +             return NULL;
> +
> +     /* Get BTF_KIND_FUNC type */
> +     t = btf_type_by_id(*btf_p, id);
> +     if (!t || !btf_type_is_func(t))
> +             goto err;
> +
> +     /* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */
> +     t = btf_type_by_id(*btf_p, t->type);
> +     if (!t || !btf_type_is_func_proto(t))
> +             goto err;
> +
> +     return t;
> +err:
> +     btf_put(*btf_p);
> +     return NULL;
> +}
> +
> +/*
> + * Get function parameter with the number of parameters.
> + * This can return NULL if the function has no parameters.
> + * It can return -EINVAL if the @func_proto is not a function proto type.
> + */
> +const struct btf_param *btf_get_func_param(const struct btf_type 
> *func_proto, s32 *nr)
> +{
> +     if (!btf_type_is_func_proto(func_proto))
> +             return ERR_PTR(-EINVAL);
> +
> +     *nr = btf_type_vlen(func_proto);
> +     if (*nr > 0)
> +             return (const struct btf_param *)(func_proto + 1);
> +     else
> +             return NULL;
> +}
> +
> +#define BTF_ANON_STACK_MAX   16
> +
> +struct btf_anon_stack {
> +     u32 tid;
> +     u32 offset;
> +};
> +
> +/*
> + * Find a member of data structure/union by name and return it.
> + * Return NULL if not found, or -EINVAL if parameter is invalid.
> + * If the member is an member of anonymous union/structure, the offset
> + * of that anonymous union/structure is stored into @anon_offset. Caller
> + * can calculate the correct offset from the root data structure by
> + * adding anon_offset to the member's offset.
> + */
> +const struct btf_member *btf_find_struct_member(struct btf *btf,
> +                                             const struct btf_type *type,
> +                                             const char *member_name,
> +                                             u32 *anon_offset)
> +{
> +     struct btf_anon_stack *anon_stack;
> +     const struct btf_member *member;
> +     u32 tid, cur_offset = 0;
> +     const char *name;
> +     int i, top = 0;
> +
> +     anon_stack = kcalloc(BTF_ANON_STACK_MAX, sizeof(*anon_stack), 
> GFP_KERNEL);
> +     if (!anon_stack)
> +             return ERR_PTR(-ENOMEM);
> +
> +retry:
> +     if (!btf_type_is_struct(type)) {
> +             member = ERR_PTR(-EINVAL);
> +             goto out;
> +     }
> +
> +     for_each_member(i, type, member) {
> +             if (!member->name_off) {
> +                     /* Anonymous union/struct: push it for later use */
> +                     type = btf_type_skip_modifiers(btf, member->type, &tid);
> +                     if (type && top < BTF_ANON_STACK_MAX) {
> +                             anon_stack[top].tid = tid;
> +                             anon_stack[top++].offset =
> +                                     cur_offset + member->offset;
> +                     }
> +             } else {
> +                     name = btf_name_by_offset(btf, member->name_off);
> +                     if (name && !strcmp(member_name, name)) {
> +                             if (anon_offset)
> +                                     *anon_offset = cur_offset;
> +                             goto out;
> +                     }
> +             }
> +     }
> +     if (top > 0) {
> +             /* Pop from the anonymous stack and retry */
> +             tid = anon_stack[--top].tid;
> +             cur_offset = anon_stack[top].offset;
> +             type = btf_type_by_id(btf, tid);
> +             goto retry;
> +     }
> +     member = NULL;
> +
> +out:
> +     kfree(anon_stack);
> +     return member;
> +}
> +
>  #define BTF_SHOW_MAX_ITER    10
>  
>  #define BTF_KIND_BIT(kind)   (1ULL << kind)
> diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
> index 057cd975d014..64b61f67a403 100644
> --- a/kernel/trace/Makefile
> +++ b/kernel/trace/Makefile
> @@ -99,7 +99,6 @@ obj-$(CONFIG_KGDB_KDB) += trace_kdb.o
>  endif
>  obj-$(CONFIG_DYNAMIC_EVENTS) += trace_dynevent.o
>  obj-$(CONFIG_PROBE_EVENTS) += trace_probe.o
> -obj-$(CONFIG_PROBE_EVENTS_BTF_ARGS) += trace_btf.o
>  obj-$(CONFIG_UPROBE_EVENTS) += trace_uprobe.o
>  obj-$(CONFIG_BOOTTIME_TRACING) += trace_boot.o
>  obj-$(CONFIG_FTRACE_RECORD_RECURSION) += trace_recursion_record.o
> diff --git a/kernel/trace/trace_btf.c b/kernel/trace/trace_btf.c
> deleted file mode 100644
> index ca224d53bfdc..000000000000
> --- a/kernel/trace/trace_btf.c
> +++ /dev/null
> @@ -1,122 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -#include <linux/btf.h>
> -#include <linux/kernel.h>
> -#include <linux/slab.h>
> -
> -#include "trace_btf.h"
> -
> -/*
> - * Find a function proto type by name, and return the btf_type with its btf
> - * in *@btf_p. Return NULL if not found.
> - * Note that caller has to call btf_put(*@btf_p) after using the btf_type.
> - */
> -const struct btf_type *btf_find_func_proto(const char *func_name, struct btf 
> **btf_p)
> -{
> -     const struct btf_type *t;
> -     s32 id;
> -
> -     id = bpf_find_btf_id(func_name, BTF_KIND_FUNC, btf_p);
> -     if (id < 0)
> -             return NULL;
> -
> -     /* Get BTF_KIND_FUNC type */
> -     t = btf_type_by_id(*btf_p, id);
> -     if (!t || !btf_type_is_func(t))
> -             goto err;
> -
> -     /* The type of BTF_KIND_FUNC is BTF_KIND_FUNC_PROTO */
> -     t = btf_type_by_id(*btf_p, t->type);
> -     if (!t || !btf_type_is_func_proto(t))
> -             goto err;
> -
> -     return t;
> -err:
> -     btf_put(*btf_p);
> -     return NULL;
> -}
> -
> -/*
> - * Get function parameter with the number of parameters.
> - * This can return NULL if the function has no parameters.
> - * It can return -EINVAL if the @func_proto is not a function proto type.
> - */
> -const struct btf_param *btf_get_func_param(const struct btf_type 
> *func_proto, s32 *nr)
> -{
> -     if (!btf_type_is_func_proto(func_proto))
> -             return ERR_PTR(-EINVAL);
> -
> -     *nr = btf_type_vlen(func_proto);
> -     if (*nr > 0)
> -             return (const struct btf_param *)(func_proto + 1);
> -     else
> -             return NULL;
> -}
> -
> -#define BTF_ANON_STACK_MAX   16
> -
> -struct btf_anon_stack {
> -     u32 tid;
> -     u32 offset;
> -};
> -
> -/*
> - * Find a member of data structure/union by name and return it.
> - * Return NULL if not found, or -EINVAL if parameter is invalid.
> - * If the member is an member of anonymous union/structure, the offset
> - * of that anonymous union/structure is stored into @anon_offset. Caller
> - * can calculate the correct offset from the root data structure by
> - * adding anon_offset to the member's offset.
> - */
> -const struct btf_member *btf_find_struct_member(struct btf *btf,
> -                                             const struct btf_type *type,
> -                                             const char *member_name,
> -                                             u32 *anon_offset)
> -{
> -     struct btf_anon_stack *anon_stack;
> -     const struct btf_member *member;
> -     u32 tid, cur_offset = 0;
> -     const char *name;
> -     int i, top = 0;
> -
> -     anon_stack = kcalloc(BTF_ANON_STACK_MAX, sizeof(*anon_stack), 
> GFP_KERNEL);
> -     if (!anon_stack)
> -             return ERR_PTR(-ENOMEM);
> -
> -retry:
> -     if (!btf_type_is_struct(type)) {
> -             member = ERR_PTR(-EINVAL);
> -             goto out;
> -     }
> -
> -     for_each_member(i, type, member) {
> -             if (!member->name_off) {
> -                     /* Anonymous union/struct: push it for later use */
> -                     type = btf_type_skip_modifiers(btf, member->type, &tid);
> -                     if (type && top < BTF_ANON_STACK_MAX) {
> -                             anon_stack[top].tid = tid;
> -                             anon_stack[top++].offset =
> -                                     cur_offset + member->offset;
> -                     }
> -             } else {
> -                     name = btf_name_by_offset(btf, member->name_off);
> -                     if (name && !strcmp(member_name, name)) {
> -                             if (anon_offset)
> -                                     *anon_offset = cur_offset;
> -                             goto out;
> -                     }
> -             }
> -     }
> -     if (top > 0) {
> -             /* Pop from the anonymous stack and retry */
> -             tid = anon_stack[--top].tid;
> -             cur_offset = anon_stack[top].offset;
> -             type = btf_type_by_id(btf, tid);
> -             goto retry;
> -     }
> -     member = NULL;
> -
> -out:
> -     kfree(anon_stack);
> -     return member;
> -}
> -
> diff --git a/kernel/trace/trace_btf.h b/kernel/trace/trace_btf.h
> deleted file mode 100644
> index 4bc44bc261e6..000000000000
> --- a/kernel/trace/trace_btf.h
> +++ /dev/null
> @@ -1,11 +0,0 @@
> -/* SPDX-License-Identifier: GPL-2.0 */
> -#include <linux/btf.h>
> -
> -const struct btf_type *btf_find_func_proto(const char *func_name,
> -                                        struct btf **btf_p);
> -const struct btf_param *btf_get_func_param(const struct btf_type *func_proto,
> -                                        s32 *nr);
> -const struct btf_member *btf_find_struct_member(struct btf *btf,
> -                                             const struct btf_type *type,
> -                                             const char *member_name,
> -                                             u32 *anon_offset);
> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> index 4dc74d73fc1d..b33c424b8ee0 100644
> --- a/kernel/trace/trace_probe.c
> +++ b/kernel/trace/trace_probe.c
> @@ -12,7 +12,7 @@
>  #define pr_fmt(fmt)  "trace_probe: " fmt
>  
>  #include <linux/bpf.h>
> -#include "trace_btf.h"
> +#include <linux/btf.h>
>  
>  #include "trace_probe.h"
>  


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