cregit-Linux how code gets into the kernel

Release 4.11 fs/btrfs/struct-funcs.c

Directory: fs/btrfs
/*
 * Copyright (C) 2007 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/highmem.h>
#include <asm/unaligned.h>

#include "ctree.h"


static inline u8 get_unaligned_le8(const void *p) { return *(u8 *)p; }

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Li Zefan20100.00%1100.00%
Total20100.00%1100.00%


static inline void put_unaligned_le8(u8 val, void *p) { *(u8 *)p = val; }

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Li Zefan23100.00%1100.00%
Total23100.00%1100.00%

/* * this is some deeply nasty code. * * The end result is that anyone who #includes ctree.h gets a * declaration for the btrfs_set_foo functions and btrfs_foo functions, * which are wrappers of btrfs_set_token_#bits functions and * btrfs_get_token_#bits functions, which are defined in this file. * * These setget functions do all the extent_buffer related mapping * required to efficiently read and write specific fields in the extent * buffers. Every pointer to metadata items in btrfs is really just * an unsigned long offset into the extent buffer which has been * cast to a specific type. This gives us all the gcc type checking. * * The extent buffer api is used to do the page spanning work required to * have a metadata blocksize different from the page size. */ #define DEFINE_BTRFS_SETGET_BITS(bits) \ u##bits btrfs_get_token_##bits(struct extent_buffer *eb, void *ptr, \ unsigned long off, \ struct btrfs_map_token *token) \ { \ unsigned long part_offset = (unsigned long)ptr; \ unsigned long offset = part_offset + off; \ void *p; \ int err; \ char *kaddr; \ unsigned long map_start; \ unsigned long map_len; \ int size = sizeof(u##bits); \ u##bits res; \ \ if (token && token->kaddr && token->offset <= offset && \ token->eb == eb && \ (token->offset + PAGE_SIZE >= offset + size)) { \ kaddr = token->kaddr; \ p = kaddr + part_offset - token->offset; \ res = get_unaligned_le##bits(p + off); \ return res; \ } \ err = map_private_extent_buffer(eb, offset, size, \ &kaddr, &map_start, &map_len); \ if (err) { \ __le##bits leres; \ \ read_extent_buffer(eb, &leres, offset, size); \ return le##bits##_to_cpu(leres); \ } \ p = kaddr + part_offset - map_start; \ res = get_unaligned_le##bits(p + off); \ if (token) { \ token->kaddr = kaddr; \ token->offset = map_start; \ token->eb = eb; \ } \ return res; \ } \ void btrfs_set_token_##bits(struct extent_buffer *eb, \ void *ptr, unsigned long off, u##bits val, \ struct btrfs_map_token *token) \ { \ unsigned long part_offset = (unsigned long)ptr; \ unsigned long offset = part_offset + off; \ void *p; \ int err; \ char *kaddr; \ unsigned long map_start; \ unsigned long map_len; \ int size = sizeof(u##bits); \ \ if (token && token->kaddr && token->offset <= offset && \ token->eb == eb && \ (token->offset + PAGE_SIZE >= offset + size)) { \ kaddr = token->kaddr; \ p = kaddr + part_offset - token->offset; \ put_unaligned_le##bits(val, p + off); \ return; \ } \ err = map_private_extent_buffer(eb, offset, size, \ &kaddr, &map_start, &map_len); \ if (err) { \ __le##bits val2; \ \ val2 = cpu_to_le##bits(val); \ write_extent_buffer(eb, &val2, offset, size); \ return; \ } \ p = kaddr + part_offset - map_start; \ put_unaligned_le##bits(val, p + off); \ if (token) { \ token->kaddr = kaddr; \ token->offset = map_start; \ token->eb = eb; \ } \ } DEFINE_BTRFS_SETGET_BITS(8) DEFINE_BTRFS_SETGET_BITS(16) DEFINE_BTRFS_SETGET_BITS(32) DEFINE_BTRFS_SETGET_BITS(64)
void btrfs_node_key(struct extent_buffer *eb, struct btrfs_disk_key *disk_key, int nr) { unsigned long ptr = btrfs_node_key_ptr_offset(nr); read_eb_member(eb, (struct btrfs_key_ptr *)ptr, struct btrfs_key_ptr, key, disk_key); }

Contributors

PersonTokensPropCommitsCommitProp
Chris Mason46100.00%1100.00%
Total46100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Li Zefan6653.23%120.00%
Chris Mason5645.16%240.00%
Nicholas D Steeves10.81%120.00%
Kirill A. Shutemov10.81%120.00%
Total124100.00%5100.00%
Directory: fs/btrfs
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