License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 17:07:57 +03:00
// SPDX-License-Identifier: GPL-2.0
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# include <linux/pagewalk.h>
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# include <linux/highmem.h>
# include <linux/sched.h>
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# include <linux/hugetlb.h>
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/*
* We want to know the real level where a entry is located ignoring any
* folding of levels which may be happening . For example if p4d is folded then
* a missing entry found at level 1 ( p4d ) is actually at level 0 ( pgd ) .
*/
static int real_depth ( int depth )
{
if ( depth = = 3 & & PTRS_PER_PMD = = 1 )
depth = 2 ;
if ( depth = = 2 & & PTRS_PER_PUD = = 1 )
depth = 1 ;
if ( depth = = 1 & & PTRS_PER_P4D = = 1 )
depth = 0 ;
return depth ;
}
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static int walk_pte_range_inner ( pte_t * pte , unsigned long addr ,
unsigned long end , struct mm_walk * walk )
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{
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const struct mm_walk_ops * ops = walk - > ops ;
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int err = 0 ;
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for ( ; ; ) {
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err = ops - > pte_entry ( pte , addr , addr + PAGE_SIZE , walk ) ;
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if ( err )
break ;
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if ( addr > = end - PAGE_SIZE )
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break ;
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addr + = PAGE_SIZE ;
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pte + + ;
}
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return err ;
}
static int walk_pte_range ( pmd_t * pmd , unsigned long addr , unsigned long end ,
struct mm_walk * walk )
{
pte_t * pte ;
int err = 0 ;
spinlock_t * ptl ;
if ( walk - > no_vma ) {
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/*
* pte_offset_map ( ) might apply user - specific validation .
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* Indeed , on x86_64 the pmd entries set up by init_espfix_ap ( )
* fit its pmd_bad ( ) check ( _PAGE_NX set and _PAGE_RW clear ) ,
* and CONFIG_EFI_PGT_DUMP efi_mm goes so far as to walk them .
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*/
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if ( walk - > mm = = & init_mm | | addr > = TASK_SIZE )
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pte = pte_offset_kernel ( pmd , addr ) ;
else
pte = pte_offset_map ( pmd , addr ) ;
if ( pte ) {
err = walk_pte_range_inner ( pte , addr , end , walk ) ;
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if ( walk - > mm ! = & init_mm & & addr < TASK_SIZE )
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pte_unmap ( pte ) ;
}
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} else {
pte = pte_offset_map_lock ( walk - > mm , pmd , addr , & ptl ) ;
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if ( pte ) {
err = walk_pte_range_inner ( pte , addr , end , walk ) ;
pte_unmap_unlock ( pte , ptl ) ;
}
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}
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if ( ! pte )
walk - > action = ACTION_AGAIN ;
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return err ;
}
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# ifdef CONFIG_ARCH_HAS_HUGEPD
static int walk_hugepd_range ( hugepd_t * phpd , unsigned long addr ,
unsigned long end , struct mm_walk * walk , int pdshift )
{
int err = 0 ;
const struct mm_walk_ops * ops = walk - > ops ;
int shift = hugepd_shift ( * phpd ) ;
int page_size = 1 < < shift ;
if ( ! ops - > pte_entry )
return 0 ;
if ( addr & ( page_size - 1 ) )
return 0 ;
for ( ; ; ) {
pte_t * pte ;
spin_lock ( & walk - > mm - > page_table_lock ) ;
pte = hugepte_offset ( * phpd , addr , pdshift ) ;
err = ops - > pte_entry ( pte , addr , addr + page_size , walk ) ;
spin_unlock ( & walk - > mm - > page_table_lock ) ;
if ( err )
break ;
if ( addr > = end - page_size )
break ;
addr + = page_size ;
}
return err ;
}
# else
static int walk_hugepd_range ( hugepd_t * phpd , unsigned long addr ,
unsigned long end , struct mm_walk * walk , int pdshift )
{
return 0 ;
}
# endif
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static int walk_pmd_range ( pud_t * pud , unsigned long addr , unsigned long end ,
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struct mm_walk * walk )
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{
pmd_t * pmd ;
unsigned long next ;
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const struct mm_walk_ops * ops = walk - > ops ;
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int err = 0 ;
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int depth = real_depth ( 3 ) ;
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pmd = pmd_offset ( pud , addr ) ;
do {
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again :
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next = pmd_addr_end ( addr , end ) ;
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if ( pmd_none ( * pmd ) ) {
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if ( ops - > pte_hole )
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err = ops - > pte_hole ( addr , next , depth , walk ) ;
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if ( err )
break ;
continue ;
}
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walk - > action = ACTION_SUBTREE ;
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/*
* This implies that each - > pmd_entry ( ) handler
* needs to know about pmd_trans_huge ( ) pmds
*/
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if ( ops - > pmd_entry )
err = ops - > pmd_entry ( pmd , addr , next , walk ) ;
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if ( err )
break ;
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if ( walk - > action = = ACTION_AGAIN )
goto again ;
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/*
* Check this here so we only break down trans_huge
* pages when we _need_ to
*/
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if ( ( ! walk - > vma & & ( pmd_leaf ( * pmd ) | | ! pmd_present ( * pmd ) ) ) | |
walk - > action = = ACTION_CONTINUE | |
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! ( ops - > pte_entry ) )
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continue ;
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if ( walk - > vma )
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split_huge_pmd ( walk - > vma , pmd , addr ) ;
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if ( is_hugepd ( __hugepd ( pmd_val ( * pmd ) ) ) )
err = walk_hugepd_range ( ( hugepd_t * ) pmd , addr , next , walk , PMD_SHIFT ) ;
else
err = walk_pte_range ( pmd , addr , next , walk ) ;
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if ( err )
break ;
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if ( walk - > action = = ACTION_AGAIN )
goto again ;
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} while ( pmd + + , addr = next , addr ! = end ) ;
return err ;
}
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static int walk_pud_range ( p4d_t * p4d , unsigned long addr , unsigned long end ,
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struct mm_walk * walk )
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{
pud_t * pud ;
unsigned long next ;
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const struct mm_walk_ops * ops = walk - > ops ;
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int err = 0 ;
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int depth = real_depth ( 2 ) ;
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pud = pud_offset ( p4d , addr ) ;
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do {
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again :
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next = pud_addr_end ( addr , end ) ;
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if ( pud_none ( * pud ) ) {
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if ( ops - > pte_hole )
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err = ops - > pte_hole ( addr , next , depth , walk ) ;
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if ( err )
break ;
continue ;
}
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walk - > action = ACTION_SUBTREE ;
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if ( ops - > pud_entry )
err = ops - > pud_entry ( pud , addr , next , walk ) ;
if ( err )
break ;
if ( walk - > action = = ACTION_AGAIN )
goto again ;
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if ( ( ! walk - > vma & & ( pud_leaf ( * pud ) | | ! pud_present ( * pud ) ) ) | |
walk - > action = = ACTION_CONTINUE | |
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! ( ops - > pmd_entry | | ops - > pte_entry ) )
continue ;
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if ( walk - > vma )
split_huge_pud ( walk - > vma , pud , addr ) ;
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if ( pud_none ( * pud ) )
goto again ;
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if ( is_hugepd ( __hugepd ( pud_val ( * pud ) ) ) )
err = walk_hugepd_range ( ( hugepd_t * ) pud , addr , next , walk , PUD_SHIFT ) ;
else
err = walk_pmd_range ( pud , addr , next , walk ) ;
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if ( err )
break ;
} while ( pud + + , addr = next , addr ! = end ) ;
return err ;
}
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static int walk_p4d_range ( pgd_t * pgd , unsigned long addr , unsigned long end ,
struct mm_walk * walk )
{
p4d_t * p4d ;
unsigned long next ;
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const struct mm_walk_ops * ops = walk - > ops ;
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int err = 0 ;
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int depth = real_depth ( 1 ) ;
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p4d = p4d_offset ( pgd , addr ) ;
do {
next = p4d_addr_end ( addr , end ) ;
if ( p4d_none_or_clear_bad ( p4d ) ) {
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if ( ops - > pte_hole )
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err = ops - > pte_hole ( addr , next , depth , walk ) ;
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if ( err )
break ;
continue ;
}
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if ( ops - > p4d_entry ) {
err = ops - > p4d_entry ( p4d , addr , next , walk ) ;
if ( err )
break ;
}
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if ( is_hugepd ( __hugepd ( p4d_val ( * p4d ) ) ) )
err = walk_hugepd_range ( ( hugepd_t * ) p4d , addr , next , walk , P4D_SHIFT ) ;
else if ( ops - > pud_entry | | ops - > pmd_entry | | ops - > pte_entry )
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err = walk_pud_range ( p4d , addr , next , walk ) ;
if ( err )
break ;
} while ( p4d + + , addr = next , addr ! = end ) ;
return err ;
}
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static int walk_pgd_range ( unsigned long addr , unsigned long end ,
struct mm_walk * walk )
{
pgd_t * pgd ;
unsigned long next ;
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const struct mm_walk_ops * ops = walk - > ops ;
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int err = 0 ;
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if ( walk - > pgd )
pgd = walk - > pgd + pgd_index ( addr ) ;
else
pgd = pgd_offset ( walk - > mm , addr ) ;
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do {
next = pgd_addr_end ( addr , end ) ;
if ( pgd_none_or_clear_bad ( pgd ) ) {
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if ( ops - > pte_hole )
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err = ops - > pte_hole ( addr , next , 0 , walk ) ;
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if ( err )
break ;
continue ;
}
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if ( ops - > pgd_entry ) {
err = ops - > pgd_entry ( pgd , addr , next , walk ) ;
if ( err )
break ;
}
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if ( is_hugepd ( __hugepd ( pgd_val ( * pgd ) ) ) )
err = walk_hugepd_range ( ( hugepd_t * ) pgd , addr , next , walk , PGDIR_SHIFT ) ;
else if ( ops - > p4d_entry | | ops - > pud_entry | | ops - > pmd_entry | | ops - > pte_entry )
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err = walk_p4d_range ( pgd , addr , next , walk ) ;
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if ( err )
break ;
} while ( pgd + + , addr = next , addr ! = end ) ;
return err ;
}
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# ifdef CONFIG_HUGETLB_PAGE
static unsigned long hugetlb_entry_end ( struct hstate * h , unsigned long addr ,
unsigned long end )
{
unsigned long boundary = ( addr & huge_page_mask ( h ) ) + huge_page_size ( h ) ;
return boundary < end ? boundary : end ;
}
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static int walk_hugetlb_range ( unsigned long addr , unsigned long end ,
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struct mm_walk * walk )
{
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struct vm_area_struct * vma = walk - > vma ;
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struct hstate * h = hstate_vma ( vma ) ;
unsigned long next ;
unsigned long hmask = huge_page_mask ( h ) ;
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unsigned long sz = huge_page_size ( h ) ;
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pte_t * pte ;
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const struct mm_walk_ops * ops = walk - > ops ;
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int err = 0 ;
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hugetlb_vma_lock_read ( vma ) ;
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do {
next = hugetlb_entry_end ( h , addr , end ) ;
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pte = hugetlb_walk ( vma , addr & hmask , sz ) ;
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if ( pte )
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err = ops - > hugetlb_entry ( pte , hmask , addr , next , walk ) ;
else if ( ops - > pte_hole )
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err = ops - > pte_hole ( addr , next , - 1 , walk ) ;
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if ( err )
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break ;
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} while ( addr = next , addr ! = end ) ;
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hugetlb_vma_unlock_read ( vma ) ;
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return err ;
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}
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# else /* CONFIG_HUGETLB_PAGE */
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static int walk_hugetlb_range ( unsigned long addr , unsigned long end ,
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struct mm_walk * walk )
{
return 0 ;
}
# endif /* CONFIG_HUGETLB_PAGE */
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/*
* Decide whether we really walk over the current vma on [ @ start , @ end )
* or skip it via the returned value . Return 0 if we do walk over the
* current vma , and return 1 if we skip the vma . Negative values means
* error , where we abort the current walk .
*/
static int walk_page_test ( unsigned long start , unsigned long end ,
struct mm_walk * walk )
{
struct vm_area_struct * vma = walk - > vma ;
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const struct mm_walk_ops * ops = walk - > ops ;
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if ( ops - > test_walk )
return ops - > test_walk ( start , end , walk ) ;
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/*
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* vma ( VM_PFNMAP ) doesn ' t have any valid struct pages behind VM_PFNMAP
* range , so we don ' t walk over it as we do for normal vmas . However ,
* Some callers are interested in handling hole range and they don ' t
* want to just ignore any single address range . Such users certainly
* define their - > pte_hole ( ) callbacks , so let ' s delegate them to handle
* vma ( VM_PFNMAP ) .
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*/
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if ( vma - > vm_flags & VM_PFNMAP ) {
int err = 1 ;
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if ( ops - > pte_hole )
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err = ops - > pte_hole ( start , end , - 1 , walk ) ;
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return err ? err : 1 ;
}
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return 0 ;
}
static int __walk_page_range ( unsigned long start , unsigned long end ,
struct mm_walk * walk )
{
int err = 0 ;
struct vm_area_struct * vma = walk - > vma ;
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const struct mm_walk_ops * ops = walk - > ops ;
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if ( ops - > pre_vma ) {
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err = ops - > pre_vma ( start , end , walk ) ;
if ( err )
return err ;
}
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if ( is_vm_hugetlb_page ( vma ) ) {
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if ( ops - > hugetlb_entry )
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err = walk_hugetlb_range ( start , end , walk ) ;
} else
err = walk_pgd_range ( start , end , walk ) ;
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if ( ops - > post_vma )
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ops - > post_vma ( walk ) ;
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return err ;
}
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static inline void process_mm_walk_lock ( struct mm_struct * mm ,
enum page_walk_lock walk_lock )
{
if ( walk_lock = = PGWALK_RDLOCK )
mmap_assert_locked ( mm ) ;
else
mmap_assert_write_locked ( mm ) ;
}
static inline void process_vma_walk_lock ( struct vm_area_struct * vma ,
enum page_walk_lock walk_lock )
{
# ifdef CONFIG_PER_VMA_LOCK
switch ( walk_lock ) {
case PGWALK_WRLOCK :
vma_start_write ( vma ) ;
break ;
case PGWALK_WRLOCK_VERIFY :
vma_assert_write_locked ( vma ) ;
break ;
case PGWALK_RDLOCK :
/* PGWALK_RDLOCK is handled by process_mm_walk_lock */
break ;
}
# endif
}
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/**
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* walk_page_range - walk page table with caller specific callbacks
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* @ mm : mm_struct representing the target process of page table walk
* @ start : start address of the virtual address range
* @ end : end address of the virtual address range
* @ ops : operation to call during the walk
* @ private : private data for callbacks ' usage
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*
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* Recursively walk the page table tree of the process represented by @ mm
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* within the virtual address range [ @ start , @ end ) . During walking , we can do
* some caller - specific works for each entry , by setting up pmd_entry ( ) ,
* pte_entry ( ) , and / or hugetlb_entry ( ) . If you don ' t set up for some of these
* callbacks , the associated entries / pages are just ignored .
* The return values of these callbacks are commonly defined like below :
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*
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* - 0 : succeeded to handle the current entry , and if you don ' t reach the
* end address yet , continue to walk .
* - > 0 : succeeded to handle the current entry , and return to the caller
* with caller specific value .
* - < 0 : failed to handle the current entry , and return to the caller
* with error code .
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*
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* Before starting to walk page table , some callers want to check whether
* they really want to walk over the current vma , typically by checking
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* its vm_flags . walk_page_test ( ) and @ ops - > test_walk ( ) are used for this
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* purpose .
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*
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* If operations need to be staged before and committed after a vma is walked ,
* there are two callbacks , pre_vma ( ) and post_vma ( ) . Note that post_vma ( ) ,
* since it is intended to handle commit - type operations , can ' t return any
* errors .
*
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* struct mm_walk keeps current values of some common data like vma and pmd ,
* which are useful for the access from callbacks . If you want to pass some
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* caller - specific data to callbacks , @ private should be helpful .
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*
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* Locking :
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* Callers of walk_page_range ( ) and walk_page_vma ( ) should hold @ mm - > mmap_lock ,
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* because these function traverse vma list and / or access to vma ' s data .
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*/
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int walk_page_range ( struct mm_struct * mm , unsigned long start ,
unsigned long end , const struct mm_walk_ops * ops ,
void * private )
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{
int err = 0 ;
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unsigned long next ;
struct vm_area_struct * vma ;
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struct mm_walk walk = {
. ops = ops ,
. mm = mm ,
. private = private ,
} ;
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if ( start > = end )
return - EINVAL ;
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if ( ! walk . mm )
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return - EINVAL ;
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process_mm_walk_lock ( walk . mm , ops - > walk_lock ) ;
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vma = find_vma ( walk . mm , start ) ;
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do {
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if ( ! vma ) { /* after the last vma */
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walk . vma = NULL ;
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next = end ;
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if ( ops - > pte_hole )
err = ops - > pte_hole ( start , next , - 1 , & walk ) ;
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} else if ( start < vma - > vm_start ) { /* outside vma */
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walk . vma = NULL ;
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next = min ( end , vma - > vm_start ) ;
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if ( ops - > pte_hole )
err = ops - > pte_hole ( start , next , - 1 , & walk ) ;
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} else { /* inside vma */
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process_vma_walk_lock ( vma , ops - > walk_lock ) ;
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walk . vma = vma ;
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next = min ( end , vma - > vm_end ) ;
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vma = find_vma ( mm , vma - > vm_end ) ;
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err = walk_page_test ( start , next , & walk ) ;
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if ( err > 0 ) {
/*
* positive return values are purely for
* controlling the pagewalk , so should never
* be passed to the callers .
*/
err = 0 ;
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continue ;
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}
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if ( err < 0 )
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break ;
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err = __walk_page_range ( start , next , & walk ) ;
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}
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if ( err )
break ;
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} while ( start = next , start < end ) ;
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return err ;
}
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/**
* walk_page_range_novma - walk a range of pagetables not backed by a vma
* @ mm : mm_struct representing the target process of page table walk
* @ start : start address of the virtual address range
* @ end : end address of the virtual address range
* @ ops : operation to call during the walk
* @ pgd : pgd to walk if different from mm - > pgd
* @ private : private data for callbacks ' usage
*
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* Similar to walk_page_range ( ) but can walk any page tables even if they are
* not backed by VMAs . Because ' unusual ' entries may be walked this function
* will also not lock the PTEs for the pte_entry ( ) callback . This is useful for
* walking the kernel pages tables or page tables for firmware .
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*
* Note : Be careful to walk the kernel pages tables , the caller may be need to
* take other effective approache ( mmap lock may be insufficient ) to prevent
* the intermediate kernel page tables belonging to the specified address range
* from being freed ( e . g . memory hot - remove ) .
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*/
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int walk_page_range_novma ( struct mm_struct * mm , unsigned long start ,
unsigned long end , const struct mm_walk_ops * ops ,
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pgd_t * pgd ,
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void * private )
{
struct mm_walk walk = {
. ops = ops ,
. mm = mm ,
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. pgd = pgd ,
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. private = private ,
. no_vma = true
} ;
if ( start > = end | | ! walk . mm )
return - EINVAL ;
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/*
* 1 ) For walking the user virtual address space :
*
* The mmap lock protects the page walker from changes to the page
* tables during the walk . However a read lock is insufficient to
* protect those areas which don ' t have a VMA as munmap ( ) detaches
* the VMAs before downgrading to a read lock and actually tearing
* down PTEs / page tables . In which case , the mmap write lock should
* be hold .
*
* 2 ) For walking the kernel virtual address space :
*
* The kernel intermediate page tables usually do not be freed , so
* the mmap map read lock is sufficient . But there are some exceptions .
* E . g . memory hot - remove . In which case , the mmap lock is insufficient
* to prevent the intermediate kernel pages tables belonging to the
* specified address range from being freed . The caller should take
* other actions to prevent this race .
*/
if ( mm = = & init_mm )
mmap_assert_locked ( walk . mm ) ;
else
mmap_assert_write_locked ( walk . mm ) ;
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return walk_pgd_range ( start , end , & walk ) ;
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}
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int walk_page_range_vma ( struct vm_area_struct * vma , unsigned long start ,
unsigned long end , const struct mm_walk_ops * ops ,
void * private )
{
struct mm_walk walk = {
. ops = ops ,
. mm = vma - > vm_mm ,
. vma = vma ,
. private = private ,
} ;
if ( start > = end | | ! walk . mm )
return - EINVAL ;
if ( start < vma - > vm_start | | end > vma - > vm_end )
return - EINVAL ;
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process_mm_walk_lock ( walk . mm , ops - > walk_lock ) ;
process_vma_walk_lock ( vma , ops - > walk_lock ) ;
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return __walk_page_range ( start , end , & walk ) ;
}
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int walk_page_vma ( struct vm_area_struct * vma , const struct mm_walk_ops * ops ,
void * private )
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{
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struct mm_walk walk = {
. ops = ops ,
. mm = vma - > vm_mm ,
. vma = vma ,
. private = private ,
} ;
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if ( ! walk . mm )
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return - EINVAL ;
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process_mm_walk_lock ( walk . mm , ops - > walk_lock ) ;
process_vma_walk_lock ( vma , ops - > walk_lock ) ;
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return __walk_page_range ( vma - > vm_start , vma - > vm_end , & walk ) ;
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}
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/**
* walk_page_mapping - walk all memory areas mapped into a struct address_space .
* @ mapping : Pointer to the struct address_space
* @ first_index : First page offset in the address_space
* @ nr : Number of incremental page offsets to cover
* @ ops : operation to call during the walk
* @ private : private data for callbacks ' usage
*
* This function walks all memory areas mapped into a struct address_space .
* The walk is limited to only the given page - size index range , but if
* the index boundaries cross a huge page - table entry , that entry will be
* included .
*
* Also see walk_page_range ( ) for additional information .
*
* Locking :
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* This function can ' t require that the struct mm_struct : : mmap_lock is held ,
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* since @ mapping may be mapped by multiple processes . Instead
* @ mapping - > i_mmap_rwsem must be held . This might have implications in the
* callbacks , and it ' s up tho the caller to ensure that the
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* struct mm_struct : : mmap_lock is not needed .
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*
* Also this means that a caller can ' t rely on the struct
* vm_area_struct : : vm_flags to be constant across a call ,
* except for immutable flags . Callers requiring this shouldn ' t use
* this function .
*
* Return : 0 on success , negative error code on failure , positive number on
* caller defined premature termination .
*/
int walk_page_mapping ( struct address_space * mapping , pgoff_t first_index ,
pgoff_t nr , const struct mm_walk_ops * ops ,
void * private )
{
struct mm_walk walk = {
. ops = ops ,
. private = private ,
} ;
struct vm_area_struct * vma ;
pgoff_t vba , vea , cba , cea ;
unsigned long start_addr , end_addr ;
int err = 0 ;
lockdep_assert_held ( & mapping - > i_mmap_rwsem ) ;
vma_interval_tree_foreach ( vma , & mapping - > i_mmap , first_index ,
first_index + nr - 1 ) {
/* Clip to the vma */
vba = vma - > vm_pgoff ;
vea = vba + vma_pages ( vma ) ;
cba = first_index ;
cba = max ( cba , vba ) ;
cea = first_index + nr ;
cea = min ( cea , vea ) ;
start_addr = ( ( cba - vba ) < < PAGE_SHIFT ) + vma - > vm_start ;
end_addr = ( ( cea - vba ) < < PAGE_SHIFT ) + vma - > vm_start ;
if ( start_addr > = end_addr )
continue ;
walk . vma = vma ;
walk . mm = vma - > vm_mm ;
err = walk_page_test ( vma - > vm_start , vma - > vm_end , & walk ) ;
if ( err > 0 ) {
err = 0 ;
break ;
} else if ( err < 0 )
break ;
err = __walk_page_range ( start_addr , end_addr , & walk ) ;
if ( err )
break ;
}
return err ;
}