Remove nested functions from disk and file read hooks.

* include/grub/disk.h (grub_disk_read_hook_t): New type.
	(struct grub_disk): Add read_hook_data member.
	* include/grub/file.h (struct grub_file): Likewise.
	* include/grub/fshelp.h (grub_fshelp_read_file): Add read_hook_data
	argument.

	Update all callers.

include/grub/disk.h

@@ -19,6 +19,8 @@
 #ifndef GRUB_DISK_HEADER
 #define GRUB_DISK_HEADER	1
 
+#include <config.h>
+
 #include <grub/symbol.h>
 #include <grub/err.h>
 #include <grub/types.h>
@@ -99,6 +101,10 @@ extern grub_disk_dev_t EXPORT_VAR (grub_disk_dev_list);
 
 struct grub_partition;
 
+typedef void (*grub_disk_read_hook_t) (grub_disk_addr_t sector,
+				       unsigned offset, unsigned length,
+				       void *data);
+
 /* Disk.  */
 struct grub_disk
 {
@@ -122,8 +128,10 @@ struct grub_disk
 
   /* Called when a sector was read. OFFSET is between 0 and
      the sector size minus 1, and LENGTH is between 0 and the sector size.  */
-  void NESTED_FUNC_ATTR (*read_hook) (grub_disk_addr_t sector,
-		     unsigned offset, unsigned length);
+  grub_disk_read_hook_t read_hook;
+
+  /* Caller-specific data passed to the read hook.  */
+  void *read_hook_data;
 
   /* Device-specific data.  */
   void *data;

include/grub/file.h

@@ -23,6 +23,7 @@
 #include <grub/err.h>
 #include <grub/device.h>
 #include <grub/fs.h>
+#include <grub/disk.h>
 
 /* File description.  */
 struct grub_file
@@ -46,8 +47,10 @@ struct grub_file
   void *data;
 
   /* This is called when a sector is read. Used only for a disk device.  */
-  void NESTED_FUNC_ATTR (*read_hook) (grub_disk_addr_t sector,
-		     unsigned offset, unsigned length);
+  grub_disk_read_hook_t read_hook;
+
+  /* Caller-specific data passed to the read hook.  */
+  void *read_hook_data;
 };
 typedef struct grub_file *grub_file_t;
 

include/grub/fshelp.h

@@ -23,6 +23,7 @@
 #include <grub/types.h>
 #include <grub/symbol.h>
 #include <grub/err.h>
+#include <grub/disk.h>
 
 typedef struct grub_fshelp_node *grub_fshelp_node_t;
 
@@ -68,9 +69,8 @@ EXPORT_FUNC(grub_fshelp_find_file) (const char *path,
    blocks have a size of LOG2BLOCKSIZE (in log2).  */
 grub_ssize_t
 EXPORT_FUNC(grub_fshelp_read_file) (grub_disk_t disk, grub_fshelp_node_t node,
-				    void NESTED_FUNC_ATTR (*read_hook) (grub_disk_addr_t sector,
-                                                                        unsigned offset,
-                                                                        unsigned length),
+				    grub_disk_read_hook_t read_hook,
+				    void *read_hook_data,
 				    grub_off_t pos, grub_size_t len, char *buf,
 				    grub_disk_addr_t (*get_block) (grub_fshelp_node_t node,
                                                                    grub_disk_addr_t block),