lib: move freader into buildid.h

Move struct freader and prototypes of the functions operating on it into
the buildid.h.

This allows reusing freader outside buildid, e.g. for file dynptr
support added later.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20251026203853.135105-4-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

3 files changed, 31 insertions, 24 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 545a4776795e..7564692f2f3c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4648,6 +4648,7 @@ F:	Documentation/userspace-api/ebpf/
 F:	arch/*/net/*
 F:	include/linux/bpf*
 F:	include/linux/btf*
+F:	include/linux/buildid.h
 F:	include/linux/filter.h
 F:	include/trace/events/xdp.h
 F:	include/uapi/linux/bpf*
diff --git a/include/linux/buildid.h b/include/linux/buildid.h
index 014a88c41073..831c1b4b626c 100644
--- a/include/linux/buildid.h
+++ b/include/linux/buildid.h
@@ -18,4 +18,29 @@ void init_vmlinux_build_id(void);
 static inline void init_vmlinux_build_id(void) { }
 #endif
 
+struct freader {
+	void *buf;
+	u32 buf_sz;
+	int err;
+	union {
+		struct {
+			struct file *file;
+			struct folio *folio;
+			void *addr;
+			loff_t folio_off;
+			bool may_fault;
+		};
+		struct {
+			const char *data;
+			u64 data_sz;
+		};
+	};
+};
+
+void freader_init_from_file(struct freader *r, void *buf, u32 buf_sz,
+			    struct file *file, bool may_fault);
+void freader_init_from_mem(struct freader *r, const char *data, u64 data_sz);
+const void *freader_fetch(struct freader *r, loff_t file_off, size_t sz);
+void freader_cleanup(struct freader *r);
+
 #endif
diff --git a/lib/buildid.c b/lib/buildid.c
index c4b0f376fb34..df06e492810d 100644
--- a/lib/buildid.c
+++ b/lib/buildid.c
@@ -11,27 +11,8 @@
 
 #define MAX_PHDR_CNT 256
 
-struct freader {
-	void *buf;
-	u32 buf_sz;
-	int err;
-	union {
-		struct {
-			struct file *file;
-			struct folio *folio;
-			void *addr;
-			loff_t folio_off;
-			bool may_fault;
-		};
-		struct {
-			const char *data;
-			u64 data_sz;
-		};
-	};
-};
-
-static void freader_init_from_file(struct freader *r, void *buf, u32 buf_sz,
-				   struct file *file, bool may_fault)
+void freader_init_from_file(struct freader *r, void *buf, u32 buf_sz,
+			    struct file *file, bool may_fault)
 {
 	memset(r, 0, sizeof(*r));
 	r->buf = buf;
@@ -40,7 +21,7 @@ static void freader_init_from_file(struct freader *r, void *buf, u32 buf_sz,
 	r->may_fault = may_fault;
 }
 
-static void freader_init_from_mem(struct freader *r, const char *data, u64 data_sz)
+void freader_init_from_mem(struct freader *r, const char *data, u64 data_sz)
 {
 	memset(r, 0, sizeof(*r));
 	r->data = data;
@@ -92,7 +73,7 @@ static int freader_get_folio(struct freader *r, loff_t file_off)
 	return 0;
 }
 
-static const void *freader_fetch(struct freader *r, loff_t file_off, size_t sz)
+const void *freader_fetch(struct freader *r, loff_t file_off, size_t sz)
 {
 	size_t folio_sz;
 
@@ -147,7 +128,7 @@ static const void *freader_fetch(struct freader *r, loff_t file_off, size_t sz)
 	return r->addr + (file_off - r->folio_off);
 }
 
-static void freader_cleanup(struct freader *r)
+void freader_cleanup(struct freader *r)
 {
 	if (!r->buf)
 		return; /* non-file-backed mode */