Files
linux-torvalds-mirror/kernel/trace/trace_btf.c
Linus Torvalds bf4afc53b7 Convert 'alloc_obj' family to use the new default GFP_KERNEL argument
This was done entirely with mindless brute force, using

    git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
        xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'

to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.

Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.

For the same reason the 'flex' versions will be done as a separate
conversion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 17:09:51 -08:00

123 lines
3.0 KiB
C

// 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 = kzalloc_objs(*anon_stack, BTF_ANON_STACK_MAX);
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 */
if (btf_type_skip_modifiers(btf, member->type, &tid) &&
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;
}