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 14:07:57 +00:00
|
|
|
// SPDX-License-Identifier: GPL-2.0
|
2005-04-16 22:20:36 +00:00
|
|
|
/*
|
|
|
|
* linux/mm/mempool.c
|
|
|
|
*
|
|
|
|
* memory buffer pool support. Such pools are mostly used
|
|
|
|
* for guaranteed, deadlock-free memory allocations during
|
|
|
|
* extreme VM load.
|
|
|
|
*
|
|
|
|
* started by Ingo Molnar, Copyright (C) 2001
|
2015-04-15 23:14:17 +00:00
|
|
|
* debugging by David Rientjes, Copyright (C) 2015
|
2005-04-16 22:20:36 +00:00
|
|
|
*/
|
|
|
|
|
|
|
|
#include <linux/mm.h>
|
|
|
|
#include <linux/slab.h>
|
2015-04-15 23:14:17 +00:00
|
|
|
#include <linux/highmem.h>
|
2015-04-15 23:15:05 +00:00
|
|
|
#include <linux/kasan.h>
|
2014-06-06 21:38:19 +00:00
|
|
|
#include <linux/kmemleak.h>
|
2011-10-16 06:01:52 +00:00
|
|
|
#include <linux/export.h>
|
2005-04-16 22:20:36 +00:00
|
|
|
#include <linux/mempool.h>
|
|
|
|
#include <linux/blkdev.h>
|
|
|
|
#include <linux/writeback.h>
|
2015-04-15 23:14:14 +00:00
|
|
|
#include "slab.h"
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2015-04-15 23:14:17 +00:00
|
|
|
#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB_DEBUG_ON)
|
|
|
|
static void poison_error(mempool_t *pool, void *element, size_t size,
|
|
|
|
size_t byte)
|
|
|
|
{
|
|
|
|
const int nr = pool->curr_nr;
|
|
|
|
const int start = max_t(int, byte - (BITS_PER_LONG / 8), 0);
|
|
|
|
const int end = min_t(int, byte + (BITS_PER_LONG / 8), size);
|
|
|
|
int i;
|
|
|
|
|
|
|
|
pr_err("BUG: mempool element poison mismatch\n");
|
|
|
|
pr_err("Mempool %p size %zu\n", pool, size);
|
|
|
|
pr_err(" nr=%d @ %p: %s0x", nr, element, start > 0 ? "... " : "");
|
|
|
|
for (i = start; i < end; i++)
|
|
|
|
pr_cont("%x ", *(u8 *)(element + i));
|
|
|
|
pr_cont("%s\n", end < size ? "..." : "");
|
|
|
|
dump_stack();
|
|
|
|
}
|
|
|
|
|
|
|
|
static void __check_element(mempool_t *pool, void *element, size_t size)
|
|
|
|
{
|
|
|
|
u8 *obj = element;
|
|
|
|
size_t i;
|
|
|
|
|
|
|
|
for (i = 0; i < size; i++) {
|
|
|
|
u8 exp = (i < size - 1) ? POISON_FREE : POISON_END;
|
|
|
|
|
|
|
|
if (obj[i] != exp) {
|
|
|
|
poison_error(pool, element, size, i);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
memset(obj, POISON_INUSE, size);
|
|
|
|
}
|
|
|
|
|
|
|
|
static void check_element(mempool_t *pool, void *element)
|
|
|
|
{
|
|
|
|
/* Mempools backed by slab allocator */
|
2020-10-13 23:57:14 +00:00
|
|
|
if (pool->free == mempool_free_slab || pool->free == mempool_kfree) {
|
2015-04-15 23:14:17 +00:00
|
|
|
__check_element(pool, element, ksize(element));
|
2020-10-13 23:57:14 +00:00
|
|
|
} else if (pool->free == mempool_free_pages) {
|
|
|
|
/* Mempools backed by page allocator */
|
2015-04-15 23:14:17 +00:00
|
|
|
int order = (int)(long)pool->pool_data;
|
|
|
|
void *addr = kmap_atomic((struct page *)element);
|
|
|
|
|
|
|
|
__check_element(pool, addr, 1UL << (PAGE_SHIFT + order));
|
|
|
|
kunmap_atomic(addr);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
static void __poison_element(void *element, size_t size)
|
|
|
|
{
|
|
|
|
u8 *obj = element;
|
|
|
|
|
|
|
|
memset(obj, POISON_FREE, size - 1);
|
|
|
|
obj[size - 1] = POISON_END;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void poison_element(mempool_t *pool, void *element)
|
|
|
|
{
|
|
|
|
/* Mempools backed by slab allocator */
|
2020-10-13 23:57:14 +00:00
|
|
|
if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc) {
|
2015-04-15 23:14:17 +00:00
|
|
|
__poison_element(element, ksize(element));
|
2020-10-13 23:57:14 +00:00
|
|
|
} else if (pool->alloc == mempool_alloc_pages) {
|
|
|
|
/* Mempools backed by page allocator */
|
2015-04-15 23:14:17 +00:00
|
|
|
int order = (int)(long)pool->pool_data;
|
|
|
|
void *addr = kmap_atomic((struct page *)element);
|
|
|
|
|
|
|
|
__poison_element(addr, 1UL << (PAGE_SHIFT + order));
|
|
|
|
kunmap_atomic(addr);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
#else /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */
|
|
|
|
static inline void check_element(mempool_t *pool, void *element)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
static inline void poison_element(mempool_t *pool, void *element)
|
|
|
|
{
|
|
|
|
}
|
|
|
|
#endif /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */
|
|
|
|
|
2018-02-06 23:36:30 +00:00
|
|
|
static __always_inline void kasan_poison_element(mempool_t *pool, void *element)
|
2015-04-15 23:15:05 +00:00
|
|
|
{
|
2016-06-24 21:49:34 +00:00
|
|
|
if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
|
2018-02-06 23:36:30 +00:00
|
|
|
kasan_poison_kfree(element, _RET_IP_);
|
2020-10-13 23:57:14 +00:00
|
|
|
else if (pool->alloc == mempool_alloc_pages)
|
2015-04-15 23:15:05 +00:00
|
|
|
kasan_free_pages(element, (unsigned long)pool->pool_data);
|
|
|
|
}
|
|
|
|
|
2018-08-17 22:45:22 +00:00
|
|
|
static void kasan_unpoison_element(mempool_t *pool, void *element)
|
2015-04-15 23:15:05 +00:00
|
|
|
{
|
2016-06-24 21:49:34 +00:00
|
|
|
if (pool->alloc == mempool_alloc_slab || pool->alloc == mempool_kmalloc)
|
2020-12-22 20:02:59 +00:00
|
|
|
kasan_unpoison_range(element, __ksize(element));
|
2020-10-13 23:57:14 +00:00
|
|
|
else if (pool->alloc == mempool_alloc_pages)
|
2015-04-15 23:15:05 +00:00
|
|
|
kasan_alloc_pages(element, (unsigned long)pool->pool_data);
|
|
|
|
}
|
|
|
|
|
2018-02-06 23:36:30 +00:00
|
|
|
static __always_inline void add_element(mempool_t *pool, void *element)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
BUG_ON(pool->curr_nr >= pool->min_nr);
|
2015-04-15 23:14:17 +00:00
|
|
|
poison_element(pool, element);
|
2015-04-15 23:15:05 +00:00
|
|
|
kasan_poison_element(pool, element);
|
2005-04-16 22:20:36 +00:00
|
|
|
pool->elements[pool->curr_nr++] = element;
|
|
|
|
}
|
|
|
|
|
2018-08-17 22:45:22 +00:00
|
|
|
static void *remove_element(mempool_t *pool)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2015-04-15 23:14:17 +00:00
|
|
|
void *element = pool->elements[--pool->curr_nr];
|
|
|
|
|
|
|
|
BUG_ON(pool->curr_nr < 0);
|
2018-08-17 22:45:22 +00:00
|
|
|
kasan_unpoison_element(pool, element);
|
2016-03-11 21:08:07 +00:00
|
|
|
check_element(pool, element);
|
2015-04-15 23:14:17 +00:00
|
|
|
return element;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2015-05-04 23:52:20 +00:00
|
|
|
/**
|
|
|
|
* mempool_exit - exit a mempool initialized with mempool_init()
|
|
|
|
* @pool: pointer to the memory pool which was initialized with
|
|
|
|
* mempool_init().
|
|
|
|
*
|
|
|
|
* Free all reserved elements in @pool and @pool itself. This function
|
|
|
|
* only sleeps if the free_fn() function sleeps.
|
|
|
|
*
|
|
|
|
* May be called on a zeroed but uninitialized mempool (i.e. allocated with
|
|
|
|
* kzalloc()).
|
|
|
|
*/
|
|
|
|
void mempool_exit(mempool_t *pool)
|
|
|
|
{
|
|
|
|
while (pool->curr_nr) {
|
2018-08-17 22:45:22 +00:00
|
|
|
void *element = remove_element(pool);
|
2015-05-04 23:52:20 +00:00
|
|
|
pool->free(element, pool->pool_data);
|
|
|
|
}
|
|
|
|
kfree(pool->elements);
|
|
|
|
pool->elements = NULL;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(mempool_exit);
|
|
|
|
|
2012-01-10 23:08:26 +00:00
|
|
|
/**
|
|
|
|
* mempool_destroy - deallocate a memory pool
|
|
|
|
* @pool: pointer to the memory pool which was allocated via
|
|
|
|
* mempool_create().
|
|
|
|
*
|
|
|
|
* Free all reserved elements in @pool and @pool itself. This function
|
|
|
|
* only sleeps if the free_fn() function sleeps.
|
|
|
|
*/
|
|
|
|
void mempool_destroy(mempool_t *pool)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2015-09-08 22:00:53 +00:00
|
|
|
if (unlikely(!pool))
|
|
|
|
return;
|
|
|
|
|
2015-05-04 23:52:20 +00:00
|
|
|
mempool_exit(pool);
|
2005-04-16 22:20:36 +00:00
|
|
|
kfree(pool);
|
|
|
|
}
|
2012-01-10 23:08:26 +00:00
|
|
|
EXPORT_SYMBOL(mempool_destroy);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2015-05-04 23:52:20 +00:00
|
|
|
int mempool_init_node(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn,
|
|
|
|
mempool_free_t *free_fn, void *pool_data,
|
|
|
|
gfp_t gfp_mask, int node_id)
|
|
|
|
{
|
|
|
|
spin_lock_init(&pool->lock);
|
|
|
|
pool->min_nr = min_nr;
|
|
|
|
pool->pool_data = pool_data;
|
|
|
|
pool->alloc = alloc_fn;
|
|
|
|
pool->free = free_fn;
|
|
|
|
init_waitqueue_head(&pool->wait);
|
|
|
|
|
|
|
|
pool->elements = kmalloc_array_node(min_nr, sizeof(void *),
|
|
|
|
gfp_mask, node_id);
|
|
|
|
if (!pool->elements)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* First pre-allocate the guaranteed number of buffers.
|
|
|
|
*/
|
|
|
|
while (pool->curr_nr < pool->min_nr) {
|
|
|
|
void *element;
|
|
|
|
|
|
|
|
element = pool->alloc(gfp_mask, pool->pool_data);
|
|
|
|
if (unlikely(!element)) {
|
|
|
|
mempool_exit(pool);
|
|
|
|
return -ENOMEM;
|
|
|
|
}
|
|
|
|
add_element(pool, element);
|
|
|
|
}
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(mempool_init_node);
|
|
|
|
|
|
|
|
/**
|
|
|
|
* mempool_init - initialize a memory pool
|
2018-08-22 04:53:03 +00:00
|
|
|
* @pool: pointer to the memory pool that should be initialized
|
2015-05-04 23:52:20 +00:00
|
|
|
* @min_nr: the minimum number of elements guaranteed to be
|
|
|
|
* allocated for this pool.
|
|
|
|
* @alloc_fn: user-defined element-allocation function.
|
|
|
|
* @free_fn: user-defined element-freeing function.
|
|
|
|
* @pool_data: optional private data available to the user-defined functions.
|
|
|
|
*
|
|
|
|
* Like mempool_create(), but initializes the pool in (i.e. embedded in another
|
|
|
|
* structure).
|
2019-03-05 23:48:42 +00:00
|
|
|
*
|
|
|
|
* Return: %0 on success, negative error code otherwise.
|
2015-05-04 23:52:20 +00:00
|
|
|
*/
|
|
|
|
int mempool_init(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn,
|
|
|
|
mempool_free_t *free_fn, void *pool_data)
|
|
|
|
{
|
|
|
|
return mempool_init_node(pool, min_nr, alloc_fn, free_fn,
|
|
|
|
pool_data, GFP_KERNEL, NUMA_NO_NODE);
|
|
|
|
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(mempool_init);
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/**
|
|
|
|
* mempool_create - create a memory pool
|
|
|
|
* @min_nr: the minimum number of elements guaranteed to be
|
|
|
|
* allocated for this pool.
|
|
|
|
* @alloc_fn: user-defined element-allocation function.
|
|
|
|
* @free_fn: user-defined element-freeing function.
|
|
|
|
* @pool_data: optional private data available to the user-defined functions.
|
|
|
|
*
|
|
|
|
* this function creates and allocates a guaranteed size, preallocated
|
2007-02-10 09:45:59 +00:00
|
|
|
* memory pool. The pool can be used from the mempool_alloc() and mempool_free()
|
2005-04-16 22:20:36 +00:00
|
|
|
* functions. This function might sleep. Both the alloc_fn() and the free_fn()
|
2007-02-10 09:45:59 +00:00
|
|
|
* functions might sleep - as long as the mempool_alloc() function is not called
|
2005-04-16 22:20:36 +00:00
|
|
|
* from IRQ contexts.
|
2019-03-05 23:48:42 +00:00
|
|
|
*
|
|
|
|
* Return: pointer to the created memory pool object or %NULL on error.
|
2005-04-16 22:20:36 +00:00
|
|
|
*/
|
2005-06-23 07:08:19 +00:00
|
|
|
mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
|
2005-04-16 22:20:36 +00:00
|
|
|
mempool_free_t *free_fn, void *pool_data)
|
|
|
|
{
|
2012-06-05 03:40:53 +00:00
|
|
|
return mempool_create_node(min_nr,alloc_fn,free_fn, pool_data,
|
|
|
|
GFP_KERNEL, NUMA_NO_NODE);
|
2005-06-23 07:08:19 +00:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(mempool_create);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2005-06-23 07:08:19 +00:00
|
|
|
mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn,
|
2012-06-05 03:40:53 +00:00
|
|
|
mempool_free_t *free_fn, void *pool_data,
|
|
|
|
gfp_t gfp_mask, int node_id)
|
2005-06-23 07:08:19 +00:00
|
|
|
{
|
|
|
|
mempool_t *pool;
|
2015-05-04 23:52:20 +00:00
|
|
|
|
2013-09-11 21:23:07 +00:00
|
|
|
pool = kzalloc_node(sizeof(*pool), gfp_mask, node_id);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!pool)
|
|
|
|
return NULL;
|
2015-05-04 23:52:20 +00:00
|
|
|
|
|
|
|
if (mempool_init_node(pool, min_nr, alloc_fn, free_fn, pool_data,
|
|
|
|
gfp_mask, node_id)) {
|
2005-04-16 22:20:36 +00:00
|
|
|
kfree(pool);
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
return pool;
|
|
|
|
}
|
2005-06-23 07:08:19 +00:00
|
|
|
EXPORT_SYMBOL(mempool_create_node);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
/**
|
|
|
|
* mempool_resize - resize an existing memory pool
|
|
|
|
* @pool: pointer to the memory pool which was allocated via
|
|
|
|
* mempool_create().
|
|
|
|
* @new_min_nr: the new minimum number of elements guaranteed to be
|
|
|
|
* allocated for this pool.
|
|
|
|
*
|
|
|
|
* This function shrinks/grows the pool. In the case of growing,
|
|
|
|
* it cannot be guaranteed that the pool will be grown to the new
|
|
|
|
* size immediately, but new mempool_free() calls will refill it.
|
2015-04-14 22:48:21 +00:00
|
|
|
* This function may sleep.
|
2005-04-16 22:20:36 +00:00
|
|
|
*
|
|
|
|
* Note, the caller must guarantee that no mempool_destroy is called
|
|
|
|
* while this function is running. mempool_alloc() & mempool_free()
|
|
|
|
* might be called (eg. from IRQ contexts) while this function executes.
|
2019-03-05 23:48:42 +00:00
|
|
|
*
|
|
|
|
* Return: %0 on success, negative error code otherwise.
|
2005-04-16 22:20:36 +00:00
|
|
|
*/
|
2015-04-14 22:48:21 +00:00
|
|
|
int mempool_resize(mempool_t *pool, int new_min_nr)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
void *element;
|
|
|
|
void **new_elements;
|
|
|
|
unsigned long flags;
|
|
|
|
|
|
|
|
BUG_ON(new_min_nr <= 0);
|
2015-04-14 22:48:21 +00:00
|
|
|
might_sleep();
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
spin_lock_irqsave(&pool->lock, flags);
|
|
|
|
if (new_min_nr <= pool->min_nr) {
|
|
|
|
while (new_min_nr < pool->curr_nr) {
|
2018-08-17 22:45:22 +00:00
|
|
|
element = remove_element(pool);
|
2005-04-16 22:20:36 +00:00
|
|
|
spin_unlock_irqrestore(&pool->lock, flags);
|
|
|
|
pool->free(element, pool->pool_data);
|
|
|
|
spin_lock_irqsave(&pool->lock, flags);
|
|
|
|
}
|
|
|
|
pool->min_nr = new_min_nr;
|
|
|
|
goto out_unlock;
|
|
|
|
}
|
|
|
|
spin_unlock_irqrestore(&pool->lock, flags);
|
|
|
|
|
|
|
|
/* Grow the pool */
|
2015-04-14 22:48:21 +00:00
|
|
|
new_elements = kmalloc_array(new_min_nr, sizeof(*new_elements),
|
|
|
|
GFP_KERNEL);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!new_elements)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
spin_lock_irqsave(&pool->lock, flags);
|
|
|
|
if (unlikely(new_min_nr <= pool->min_nr)) {
|
|
|
|
/* Raced, other resize will do our work */
|
|
|
|
spin_unlock_irqrestore(&pool->lock, flags);
|
|
|
|
kfree(new_elements);
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
memcpy(new_elements, pool->elements,
|
|
|
|
pool->curr_nr * sizeof(*new_elements));
|
|
|
|
kfree(pool->elements);
|
|
|
|
pool->elements = new_elements;
|
|
|
|
pool->min_nr = new_min_nr;
|
|
|
|
|
|
|
|
while (pool->curr_nr < pool->min_nr) {
|
|
|
|
spin_unlock_irqrestore(&pool->lock, flags);
|
2015-04-14 22:48:21 +00:00
|
|
|
element = pool->alloc(GFP_KERNEL, pool->pool_data);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (!element)
|
|
|
|
goto out;
|
|
|
|
spin_lock_irqsave(&pool->lock, flags);
|
|
|
|
if (pool->curr_nr < pool->min_nr) {
|
|
|
|
add_element(pool, element);
|
|
|
|
} else {
|
|
|
|
spin_unlock_irqrestore(&pool->lock, flags);
|
|
|
|
pool->free(element, pool->pool_data); /* Raced */
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
out_unlock:
|
|
|
|
spin_unlock_irqrestore(&pool->lock, flags);
|
|
|
|
out:
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(mempool_resize);
|
|
|
|
|
|
|
|
/**
|
|
|
|
* mempool_alloc - allocate an element from a specific memory pool
|
|
|
|
* @pool: pointer to the memory pool which was allocated via
|
|
|
|
* mempool_create().
|
|
|
|
* @gfp_mask: the usual allocation bitmask.
|
|
|
|
*
|
2007-02-10 09:45:59 +00:00
|
|
|
* this function only sleeps if the alloc_fn() function sleeps or
|
2005-04-16 22:20:36 +00:00
|
|
|
* returns NULL. Note that due to preallocation, this function
|
|
|
|
* *never* fails when called from process contexts. (it might
|
|
|
|
* fail if called from an IRQ context.)
|
2016-07-28 22:48:44 +00:00
|
|
|
* Note: using __GFP_ZERO is not supported.
|
2019-03-05 23:48:42 +00:00
|
|
|
*
|
|
|
|
* Return: pointer to the allocated element or %NULL on error.
|
2005-04-16 22:20:36 +00:00
|
|
|
*/
|
2016-03-17 21:19:19 +00:00
|
|
|
void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
|
|
|
void *element;
|
|
|
|
unsigned long flags;
|
2017-06-20 10:06:13 +00:00
|
|
|
wait_queue_entry_t wait;
|
2005-10-21 07:18:50 +00:00
|
|
|
gfp_t gfp_temp;
|
2005-05-01 15:58:37 +00:00
|
|
|
|
2014-06-04 23:07:00 +00:00
|
|
|
VM_WARN_ON_ONCE(gfp_mask & __GFP_ZERO);
|
2015-11-07 00:28:21 +00:00
|
|
|
might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
|
2005-05-01 15:58:36 +00:00
|
|
|
|
2016-07-28 22:48:44 +00:00
|
|
|
gfp_mask |= __GFP_NOMEMALLOC; /* don't allocate emergency reserves */
|
2005-05-01 15:58:36 +00:00
|
|
|
gfp_mask |= __GFP_NORETRY; /* don't loop in __alloc_pages */
|
|
|
|
gfp_mask |= __GFP_NOWARN; /* failures are OK */
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2015-11-07 00:28:21 +00:00
|
|
|
gfp_temp = gfp_mask & ~(__GFP_DIRECT_RECLAIM|__GFP_IO);
|
2005-05-01 15:58:37 +00:00
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
repeat_alloc:
|
2005-05-01 15:58:37 +00:00
|
|
|
|
|
|
|
element = pool->alloc(gfp_temp, pool->pool_data);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (likely(element != NULL))
|
|
|
|
return element;
|
|
|
|
|
|
|
|
spin_lock_irqsave(&pool->lock, flags);
|
|
|
|
if (likely(pool->curr_nr)) {
|
2018-08-17 22:45:22 +00:00
|
|
|
element = remove_element(pool);
|
2005-04-16 22:20:36 +00:00
|
|
|
spin_unlock_irqrestore(&pool->lock, flags);
|
mempool: fix and document synchronization and memory barrier usage
mempool_alloc/free() use undocumented smp_mb()'s. The code is slightly
broken and misleading.
The lockless part is in mempool_free(). It wants to determine whether the
item being freed needs to be returned to the pool or backing allocator
without grabbing pool->lock. Two things need to be guaranteed for correct
operation.
1. pool->curr_nr + #allocated should never dip below pool->min_nr.
2. Waiters shouldn't be left dangling.
For #1, The only necessary condition is that curr_nr visible at free is
from after the allocation of the element being freed (details in the
comment). For most cases, this is true without any barrier but there can
be fringe cases where the allocated pointer is passed to the freeing task
without going through memory barriers. To cover this case, wmb is
necessary before returning from allocation and rmb is necessary before
reading curr_nr. IOW,
ALLOCATING TASK FREEING TASK
update pool state after alloc;
wmb();
pass pointer to freeing task;
read pointer;
rmb();
read pool state to free;
The current code doesn't have wmb after pool update during allocation and
may theoretically, on machines where unlock doesn't behave as full wmb,
lead to pool depletion and deadlock. smp_wmb() needs to be added after
successful allocation from reserved elements and smp_mb() in
mempool_free() can be replaced with smp_rmb().
For #2, the waiter needs to add itself to waitqueue and then check the
wait condition and the waker needs to update the wait condition and then
wake up. Because waitqueue operations always go through full spinlock
synchronization, there is no need for extra memory barriers.
Furthermore, mempool_alloc() is already holding pool->lock when it decides
that it needs to wait. There is no reason to do unlock - add waitqueue -
test condition again. It can simply add itself to waitqueue while holding
pool->lock and then unlock and sleep.
This patch adds smp_wmb() after successful allocation from reserved pool,
replaces smp_mb() in mempool_free() with smp_rmb() and extend pool->lock
over waitqueue addition. More importantly, it explains what memory
barriers do and how the lockless testing is correct.
-v2: Oleg pointed out that unlock doesn't imply wmb. Added explicit
smp_wmb() after successful allocation from reserved pool and
updated comments accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 23:08:23 +00:00
|
|
|
/* paired with rmb in mempool_free(), read comment there */
|
|
|
|
smp_wmb();
|
2014-06-06 21:38:19 +00:00
|
|
|
/*
|
|
|
|
* Update the allocation stack trace as this is more useful
|
|
|
|
* for debugging.
|
|
|
|
*/
|
|
|
|
kmemleak_update_trace(element);
|
2005-04-16 22:20:36 +00:00
|
|
|
return element;
|
|
|
|
}
|
|
|
|
|
2012-01-10 23:08:28 +00:00
|
|
|
/*
|
2015-11-07 00:28:21 +00:00
|
|
|
* We use gfp mask w/o direct reclaim or IO for the first round. If
|
2012-01-10 23:08:28 +00:00
|
|
|
* alloc failed with that and @pool was empty, retry immediately.
|
|
|
|
*/
|
2016-07-28 22:48:44 +00:00
|
|
|
if (gfp_temp != gfp_mask) {
|
2012-01-10 23:08:28 +00:00
|
|
|
spin_unlock_irqrestore(&pool->lock, flags);
|
|
|
|
gfp_temp = gfp_mask;
|
|
|
|
goto repeat_alloc;
|
|
|
|
}
|
|
|
|
|
2015-11-07 00:28:21 +00:00
|
|
|
/* We must not sleep if !__GFP_DIRECT_RECLAIM */
|
|
|
|
if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) {
|
mempool: fix and document synchronization and memory barrier usage
mempool_alloc/free() use undocumented smp_mb()'s. The code is slightly
broken and misleading.
The lockless part is in mempool_free(). It wants to determine whether the
item being freed needs to be returned to the pool or backing allocator
without grabbing pool->lock. Two things need to be guaranteed for correct
operation.
1. pool->curr_nr + #allocated should never dip below pool->min_nr.
2. Waiters shouldn't be left dangling.
For #1, The only necessary condition is that curr_nr visible at free is
from after the allocation of the element being freed (details in the
comment). For most cases, this is true without any barrier but there can
be fringe cases where the allocated pointer is passed to the freeing task
without going through memory barriers. To cover this case, wmb is
necessary before returning from allocation and rmb is necessary before
reading curr_nr. IOW,
ALLOCATING TASK FREEING TASK
update pool state after alloc;
wmb();
pass pointer to freeing task;
read pointer;
rmb();
read pool state to free;
The current code doesn't have wmb after pool update during allocation and
may theoretically, on machines where unlock doesn't behave as full wmb,
lead to pool depletion and deadlock. smp_wmb() needs to be added after
successful allocation from reserved elements and smp_mb() in
mempool_free() can be replaced with smp_rmb().
For #2, the waiter needs to add itself to waitqueue and then check the
wait condition and the waker needs to update the wait condition and then
wake up. Because waitqueue operations always go through full spinlock
synchronization, there is no need for extra memory barriers.
Furthermore, mempool_alloc() is already holding pool->lock when it decides
that it needs to wait. There is no reason to do unlock - add waitqueue -
test condition again. It can simply add itself to waitqueue while holding
pool->lock and then unlock and sleep.
This patch adds smp_wmb() after successful allocation from reserved pool,
replaces smp_mb() in mempool_free() with smp_rmb() and extend pool->lock
over waitqueue addition. More importantly, it explains what memory
barriers do and how the lockless testing is correct.
-v2: Oleg pointed out that unlock doesn't imply wmb. Added explicit
smp_wmb() after successful allocation from reserved pool and
updated comments accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 23:08:23 +00:00
|
|
|
spin_unlock_irqrestore(&pool->lock, flags);
|
2005-04-16 22:20:36 +00:00
|
|
|
return NULL;
|
mempool: fix and document synchronization and memory barrier usage
mempool_alloc/free() use undocumented smp_mb()'s. The code is slightly
broken and misleading.
The lockless part is in mempool_free(). It wants to determine whether the
item being freed needs to be returned to the pool or backing allocator
without grabbing pool->lock. Two things need to be guaranteed for correct
operation.
1. pool->curr_nr + #allocated should never dip below pool->min_nr.
2. Waiters shouldn't be left dangling.
For #1, The only necessary condition is that curr_nr visible at free is
from after the allocation of the element being freed (details in the
comment). For most cases, this is true without any barrier but there can
be fringe cases where the allocated pointer is passed to the freeing task
without going through memory barriers. To cover this case, wmb is
necessary before returning from allocation and rmb is necessary before
reading curr_nr. IOW,
ALLOCATING TASK FREEING TASK
update pool state after alloc;
wmb();
pass pointer to freeing task;
read pointer;
rmb();
read pool state to free;
The current code doesn't have wmb after pool update during allocation and
may theoretically, on machines where unlock doesn't behave as full wmb,
lead to pool depletion and deadlock. smp_wmb() needs to be added after
successful allocation from reserved elements and smp_mb() in
mempool_free() can be replaced with smp_rmb().
For #2, the waiter needs to add itself to waitqueue and then check the
wait condition and the waker needs to update the wait condition and then
wake up. Because waitqueue operations always go through full spinlock
synchronization, there is no need for extra memory barriers.
Furthermore, mempool_alloc() is already holding pool->lock when it decides
that it needs to wait. There is no reason to do unlock - add waitqueue -
test condition again. It can simply add itself to waitqueue while holding
pool->lock and then unlock and sleep.
This patch adds smp_wmb() after successful allocation from reserved pool,
replaces smp_mb() in mempool_free() with smp_rmb() and extend pool->lock
over waitqueue addition. More importantly, it explains what memory
barriers do and how the lockless testing is correct.
-v2: Oleg pointed out that unlock doesn't imply wmb. Added explicit
smp_wmb() after successful allocation from reserved pool and
updated comments accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 23:08:23 +00:00
|
|
|
}
|
2005-04-16 22:20:36 +00:00
|
|
|
|
mempool: fix and document synchronization and memory barrier usage
mempool_alloc/free() use undocumented smp_mb()'s. The code is slightly
broken and misleading.
The lockless part is in mempool_free(). It wants to determine whether the
item being freed needs to be returned to the pool or backing allocator
without grabbing pool->lock. Two things need to be guaranteed for correct
operation.
1. pool->curr_nr + #allocated should never dip below pool->min_nr.
2. Waiters shouldn't be left dangling.
For #1, The only necessary condition is that curr_nr visible at free is
from after the allocation of the element being freed (details in the
comment). For most cases, this is true without any barrier but there can
be fringe cases where the allocated pointer is passed to the freeing task
without going through memory barriers. To cover this case, wmb is
necessary before returning from allocation and rmb is necessary before
reading curr_nr. IOW,
ALLOCATING TASK FREEING TASK
update pool state after alloc;
wmb();
pass pointer to freeing task;
read pointer;
rmb();
read pool state to free;
The current code doesn't have wmb after pool update during allocation and
may theoretically, on machines where unlock doesn't behave as full wmb,
lead to pool depletion and deadlock. smp_wmb() needs to be added after
successful allocation from reserved elements and smp_mb() in
mempool_free() can be replaced with smp_rmb().
For #2, the waiter needs to add itself to waitqueue and then check the
wait condition and the waker needs to update the wait condition and then
wake up. Because waitqueue operations always go through full spinlock
synchronization, there is no need for extra memory barriers.
Furthermore, mempool_alloc() is already holding pool->lock when it decides
that it needs to wait. There is no reason to do unlock - add waitqueue -
test condition again. It can simply add itself to waitqueue while holding
pool->lock and then unlock and sleep.
This patch adds smp_wmb() after successful allocation from reserved pool,
replaces smp_mb() in mempool_free() with smp_rmb() and extend pool->lock
over waitqueue addition. More importantly, it explains what memory
barriers do and how the lockless testing is correct.
-v2: Oleg pointed out that unlock doesn't imply wmb. Added explicit
smp_wmb() after successful allocation from reserved pool and
updated comments accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 23:08:23 +00:00
|
|
|
/* Let's wait for someone else to return an element to @pool */
|
2005-06-23 07:10:01 +00:00
|
|
|
init_wait(&wait);
|
2005-04-16 22:20:36 +00:00
|
|
|
prepare_to_wait(&pool->wait, &wait, TASK_UNINTERRUPTIBLE);
|
|
|
|
|
mempool: fix and document synchronization and memory barrier usage
mempool_alloc/free() use undocumented smp_mb()'s. The code is slightly
broken and misleading.
The lockless part is in mempool_free(). It wants to determine whether the
item being freed needs to be returned to the pool or backing allocator
without grabbing pool->lock. Two things need to be guaranteed for correct
operation.
1. pool->curr_nr + #allocated should never dip below pool->min_nr.
2. Waiters shouldn't be left dangling.
For #1, The only necessary condition is that curr_nr visible at free is
from after the allocation of the element being freed (details in the
comment). For most cases, this is true without any barrier but there can
be fringe cases where the allocated pointer is passed to the freeing task
without going through memory barriers. To cover this case, wmb is
necessary before returning from allocation and rmb is necessary before
reading curr_nr. IOW,
ALLOCATING TASK FREEING TASK
update pool state after alloc;
wmb();
pass pointer to freeing task;
read pointer;
rmb();
read pool state to free;
The current code doesn't have wmb after pool update during allocation and
may theoretically, on machines where unlock doesn't behave as full wmb,
lead to pool depletion and deadlock. smp_wmb() needs to be added after
successful allocation from reserved elements and smp_mb() in
mempool_free() can be replaced with smp_rmb().
For #2, the waiter needs to add itself to waitqueue and then check the
wait condition and the waker needs to update the wait condition and then
wake up. Because waitqueue operations always go through full spinlock
synchronization, there is no need for extra memory barriers.
Furthermore, mempool_alloc() is already holding pool->lock when it decides
that it needs to wait. There is no reason to do unlock - add waitqueue -
test condition again. It can simply add itself to waitqueue while holding
pool->lock and then unlock and sleep.
This patch adds smp_wmb() after successful allocation from reserved pool,
replaces smp_mb() in mempool_free() with smp_rmb() and extend pool->lock
over waitqueue addition. More importantly, it explains what memory
barriers do and how the lockless testing is correct.
-v2: Oleg pointed out that unlock doesn't imply wmb. Added explicit
smp_wmb() after successful allocation from reserved pool and
updated comments accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 23:08:23 +00:00
|
|
|
spin_unlock_irqrestore(&pool->lock, flags);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* FIXME: this should be io_schedule(). The timeout is there as a
|
|
|
|
* workaround for some DM problems in 2.6.18.
|
|
|
|
*/
|
|
|
|
io_schedule_timeout(5*HZ);
|
|
|
|
|
|
|
|
finish_wait(&pool->wait, &wait);
|
2005-04-16 22:20:36 +00:00
|
|
|
goto repeat_alloc;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(mempool_alloc);
|
|
|
|
|
|
|
|
/**
|
|
|
|
* mempool_free - return an element to the pool.
|
|
|
|
* @element: pool element pointer.
|
|
|
|
* @pool: pointer to the memory pool which was allocated via
|
|
|
|
* mempool_create().
|
|
|
|
*
|
|
|
|
* this function only sleeps if the free_fn() function sleeps.
|
|
|
|
*/
|
|
|
|
void mempool_free(void *element, mempool_t *pool)
|
|
|
|
{
|
|
|
|
unsigned long flags;
|
|
|
|
|
2007-07-16 06:42:00 +00:00
|
|
|
if (unlikely(element == NULL))
|
|
|
|
return;
|
|
|
|
|
mempool: fix and document synchronization and memory barrier usage
mempool_alloc/free() use undocumented smp_mb()'s. The code is slightly
broken and misleading.
The lockless part is in mempool_free(). It wants to determine whether the
item being freed needs to be returned to the pool or backing allocator
without grabbing pool->lock. Two things need to be guaranteed for correct
operation.
1. pool->curr_nr + #allocated should never dip below pool->min_nr.
2. Waiters shouldn't be left dangling.
For #1, The only necessary condition is that curr_nr visible at free is
from after the allocation of the element being freed (details in the
comment). For most cases, this is true without any barrier but there can
be fringe cases where the allocated pointer is passed to the freeing task
without going through memory barriers. To cover this case, wmb is
necessary before returning from allocation and rmb is necessary before
reading curr_nr. IOW,
ALLOCATING TASK FREEING TASK
update pool state after alloc;
wmb();
pass pointer to freeing task;
read pointer;
rmb();
read pool state to free;
The current code doesn't have wmb after pool update during allocation and
may theoretically, on machines where unlock doesn't behave as full wmb,
lead to pool depletion and deadlock. smp_wmb() needs to be added after
successful allocation from reserved elements and smp_mb() in
mempool_free() can be replaced with smp_rmb().
For #2, the waiter needs to add itself to waitqueue and then check the
wait condition and the waker needs to update the wait condition and then
wake up. Because waitqueue operations always go through full spinlock
synchronization, there is no need for extra memory barriers.
Furthermore, mempool_alloc() is already holding pool->lock when it decides
that it needs to wait. There is no reason to do unlock - add waitqueue -
test condition again. It can simply add itself to waitqueue while holding
pool->lock and then unlock and sleep.
This patch adds smp_wmb() after successful allocation from reserved pool,
replaces smp_mb() in mempool_free() with smp_rmb() and extend pool->lock
over waitqueue addition. More importantly, it explains what memory
barriers do and how the lockless testing is correct.
-v2: Oleg pointed out that unlock doesn't imply wmb. Added explicit
smp_wmb() after successful allocation from reserved pool and
updated comments accordingly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-10 23:08:23 +00:00
|
|
|
/*
|
|
|
|
* Paired with the wmb in mempool_alloc(). The preceding read is
|
|
|
|
* for @element and the following @pool->curr_nr. This ensures
|
|
|
|
* that the visible value of @pool->curr_nr is from after the
|
|
|
|
* allocation of @element. This is necessary for fringe cases
|
|
|
|
* where @element was passed to this task without going through
|
|
|
|
* barriers.
|
|
|
|
*
|
|
|
|
* For example, assume @p is %NULL at the beginning and one task
|
|
|
|
* performs "p = mempool_alloc(...);" while another task is doing
|
|
|
|
* "while (!p) cpu_relax(); mempool_free(p, ...);". This function
|
|
|
|
* may end up using curr_nr value which is from before allocation
|
|
|
|
* of @p without the following rmb.
|
|
|
|
*/
|
|
|
|
smp_rmb();
|
|
|
|
|
|
|
|
/*
|
|
|
|
* For correctness, we need a test which is guaranteed to trigger
|
|
|
|
* if curr_nr + #allocated == min_nr. Testing curr_nr < min_nr
|
|
|
|
* without locking achieves that and refilling as soon as possible
|
|
|
|
* is desirable.
|
|
|
|
*
|
|
|
|
* Because curr_nr visible here is always a value after the
|
|
|
|
* allocation of @element, any task which decremented curr_nr below
|
|
|
|
* min_nr is guaranteed to see curr_nr < min_nr unless curr_nr gets
|
|
|
|
* incremented to min_nr afterwards. If curr_nr gets incremented
|
|
|
|
* to min_nr after the allocation of @element, the elements
|
|
|
|
* allocated after that are subject to the same guarantee.
|
|
|
|
*
|
|
|
|
* Waiters happen iff curr_nr is 0 and the above guarantee also
|
|
|
|
* ensures that there will be frees which return elements to the
|
|
|
|
* pool waking up the waiters.
|
|
|
|
*/
|
2020-08-15 00:31:44 +00:00
|
|
|
if (unlikely(READ_ONCE(pool->curr_nr) < pool->min_nr)) {
|
2005-04-16 22:20:36 +00:00
|
|
|
spin_lock_irqsave(&pool->lock, flags);
|
2014-04-07 22:37:35 +00:00
|
|
|
if (likely(pool->curr_nr < pool->min_nr)) {
|
2005-04-16 22:20:36 +00:00
|
|
|
add_element(pool, element);
|
|
|
|
spin_unlock_irqrestore(&pool->lock, flags);
|
|
|
|
wake_up(&pool->wait);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
spin_unlock_irqrestore(&pool->lock, flags);
|
|
|
|
}
|
|
|
|
pool->free(element, pool->pool_data);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(mempool_free);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* A commonly used alloc and free fn.
|
|
|
|
*/
|
2005-10-07 06:46:04 +00:00
|
|
|
void *mempool_alloc_slab(gfp_t gfp_mask, void *pool_data)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2006-03-22 08:08:13 +00:00
|
|
|
struct kmem_cache *mem = pool_data;
|
2015-04-15 23:14:14 +00:00
|
|
|
VM_BUG_ON(mem->ctor);
|
2005-04-16 22:20:36 +00:00
|
|
|
return kmem_cache_alloc(mem, gfp_mask);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(mempool_alloc_slab);
|
|
|
|
|
|
|
|
void mempool_free_slab(void *element, void *pool_data)
|
|
|
|
{
|
2006-03-22 08:08:13 +00:00
|
|
|
struct kmem_cache *mem = pool_data;
|
2005-04-16 22:20:36 +00:00
|
|
|
kmem_cache_free(mem, element);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(mempool_free_slab);
|
2006-03-26 09:37:44 +00:00
|
|
|
|
2006-03-26 09:37:46 +00:00
|
|
|
/*
|
|
|
|
* A commonly used alloc and free fn that kmalloc/kfrees the amount of memory
|
2007-10-19 23:27:18 +00:00
|
|
|
* specified by pool_data
|
2006-03-26 09:37:46 +00:00
|
|
|
*/
|
|
|
|
void *mempool_kmalloc(gfp_t gfp_mask, void *pool_data)
|
|
|
|
{
|
2009-08-08 13:01:22 +00:00
|
|
|
size_t size = (size_t)pool_data;
|
2006-03-26 09:37:46 +00:00
|
|
|
return kmalloc(size, gfp_mask);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(mempool_kmalloc);
|
|
|
|
|
|
|
|
void mempool_kfree(void *element, void *pool_data)
|
|
|
|
{
|
|
|
|
kfree(element);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(mempool_kfree);
|
|
|
|
|
2006-03-26 09:37:44 +00:00
|
|
|
/*
|
|
|
|
* A simple mempool-backed page allocator that allocates pages
|
|
|
|
* of the order specified by pool_data.
|
|
|
|
*/
|
|
|
|
void *mempool_alloc_pages(gfp_t gfp_mask, void *pool_data)
|
|
|
|
{
|
|
|
|
int order = (int)(long)pool_data;
|
|
|
|
return alloc_pages(gfp_mask, order);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(mempool_alloc_pages);
|
|
|
|
|
|
|
|
void mempool_free_pages(void *element, void *pool_data)
|
|
|
|
{
|
|
|
|
int order = (int)(long)pool_data;
|
|
|
|
__free_pages(element, order);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(mempool_free_pages);
|