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1ed0f75d57
Reading/writing 2 bytes (u16) may need 2 folios to be written to, each
time it's just one byte so using memcpy for that is an overkill.
Add a branch for the split case so that memcpy is now used for u32 and
u64. Another side effect is that the u16 types now don't need additional
stack space, everything fits to registers.
Stack usage is reduced:
btrfs_get_16 -8 (32 -> 24)
btrfs_set_16 -16 (32 -> 16)
Code size reduction:
text data bss dec hex filename
1454691 115665 16088 1586444 18350c pre/btrfs.ko
1454459 115665 16088 1586212 183424 post/btrfs.ko
DELTA: -232
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
116 lines
4 KiB
C
116 lines
4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*/
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#include <linux/unaligned.h>
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#include "messages.h"
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#include "extent_io.h"
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#include "fs.h"
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#include "accessors.h"
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static void __cold report_setget_bounds(const struct extent_buffer *eb,
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const void *ptr, unsigned off, int size)
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{
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unsigned long member_offset = (unsigned long)ptr + off;
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btrfs_warn(eb->fs_info,
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"bad eb member %s: ptr 0x%lx start %llu member offset %lu size %d",
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(member_offset > eb->len ? "start" : "end"),
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(unsigned long)ptr, eb->start, member_offset, size);
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}
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/*
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* Macro templates that define helpers to read/write extent buffer data of a
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* given size, that are also used via ctree.h for access to item members by
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* specialized helpers.
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*
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* Generic helpers:
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* - btrfs_set_8 (for 8/16/32/64)
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* - btrfs_get_8 (for 8/16/32/64)
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*
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* The set/get functions handle data spanning two pages transparently, in case
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* metadata block size is larger than page. Every pointer to metadata items is
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* an offset into the extent buffer page array, cast to a specific type. This
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* gives us all the type checking.
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*
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* The extent buffer pages stored in the array folios may not form a contiguous
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* phyusical range, but the API functions assume the linear offset to the range
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* from 0 to metadata node size.
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*/
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#define DEFINE_BTRFS_SETGET_BITS(bits) \
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u##bits btrfs_get_##bits(const struct extent_buffer *eb, \
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const void *ptr, unsigned long off) \
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{ \
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const unsigned long member_offset = (unsigned long)ptr + off; \
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const unsigned long idx = get_eb_folio_index(eb, member_offset);\
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const unsigned long oil = get_eb_offset_in_folio(eb, \
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member_offset);\
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char *kaddr = folio_address(eb->folios[idx]); \
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const int part = eb->folio_size - oil; \
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u8 lebytes[sizeof(u##bits)]; \
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\
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if (unlikely(member_offset + sizeof(u##bits) > eb->len)) { \
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report_setget_bounds(eb, ptr, off, sizeof(u##bits)); \
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return 0; \
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} \
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if (INLINE_EXTENT_BUFFER_PAGES == 1 || sizeof(u##bits) == 1 || \
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likely(sizeof(u##bits) <= part)) \
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return get_unaligned_le##bits(kaddr + oil); \
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\
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if (sizeof(u##bits) == 2) { \
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lebytes[0] = *(kaddr + oil); \
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kaddr = folio_address(eb->folios[idx + 1]); \
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lebytes[1] = *kaddr; \
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} else { \
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memcpy(lebytes, kaddr + oil, part); \
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kaddr = folio_address(eb->folios[idx + 1]); \
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memcpy(lebytes + part, kaddr, sizeof(u##bits) - part); \
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} \
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return get_unaligned_le##bits(lebytes); \
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} \
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void btrfs_set_##bits(const struct extent_buffer *eb, void *ptr, \
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unsigned long off, u##bits val) \
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{ \
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const unsigned long member_offset = (unsigned long)ptr + off; \
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const unsigned long idx = get_eb_folio_index(eb, member_offset);\
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const unsigned long oil = get_eb_offset_in_folio(eb, \
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member_offset);\
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char *kaddr = folio_address(eb->folios[idx]); \
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const int part = eb->folio_size - oil; \
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u8 lebytes[sizeof(u##bits)]; \
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\
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if (unlikely(member_offset + sizeof(u##bits) > eb->len)) { \
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report_setget_bounds(eb, ptr, off, sizeof(u##bits)); \
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return; \
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} \
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if (INLINE_EXTENT_BUFFER_PAGES == 1 || sizeof(u##bits) == 1 || \
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likely(sizeof(u##bits) <= part)) { \
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put_unaligned_le##bits(val, kaddr + oil); \
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return; \
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} \
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put_unaligned_le##bits(val, lebytes); \
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if (sizeof(u##bits) == 2) { \
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*(kaddr + oil) = lebytes[0]; \
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kaddr = folio_address(eb->folios[idx + 1]); \
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*kaddr = lebytes[1]; \
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} else { \
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memcpy(kaddr + oil, lebytes, part); \
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kaddr = folio_address(eb->folios[idx + 1]); \
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memcpy(kaddr, lebytes + part, sizeof(u##bits) - part); \
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} \
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}
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DEFINE_BTRFS_SETGET_BITS(8)
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DEFINE_BTRFS_SETGET_BITS(16)
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DEFINE_BTRFS_SETGET_BITS(32)
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DEFINE_BTRFS_SETGET_BITS(64)
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void btrfs_node_key(const struct extent_buffer *eb,
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struct btrfs_disk_key *disk_key, int nr)
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{
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unsigned long ptr = btrfs_node_key_ptr_offset(eb, nr);
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read_eb_member(eb, (struct btrfs_key_ptr *)ptr,
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struct btrfs_key_ptr, key, disk_key);
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}
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