mirror of
https://github.com/torvalds/linux.git
synced 2024-11-25 13:41:51 +00:00
2a1eb111d2
When strict percpu address space checks are enabled, then current direct casts between the percpu address space and the generic address space fail the compilation on x86_64 with: decompressor_multi_percpu.c: In function `squashfs_decompressor_create': decompressor_multi_percpu.c:49:16: error: cast to generic address space pointer from disjoint `__seg_gs' address space pointer decompressor_multi_percpu.c: In function `squashfs_decompressor_destroy': decompressor_multi_percpu.c:64:25: error: cast to `__seg_gs' address space pointer from disjoint generic address space pointer decompressor_multi_percpu.c: In function `squashfs_decompress': decompressor_multi_percpu.c:82:25: error: cast to `__seg_gs' address space pointer from disjoint generic address space pointer Add intermediate casts to unsigned long, as advised in [1] and [2]. Side note: sparse still requires __force when casting from the percpu address space, although the documentation [2] allows casts to unsigned long without __force attribute. Found by GCC's named address space checks. There were no changes in the resulting object file. [1] https://gcc.gnu.org/onlinedocs/gcc/Named-Address-Spaces.html#x86-Named-Address-Spaces [2] https://sparse.docs.kernel.org/en/latest/annotations.html#address-space-name Link: https://lkml.kernel.org/r/20240830091104.13049-1-ubizjak@gmail.com Signed-off-by: Uros Bizjak <ubizjak@gmail.com> Cc: Phillip Lougher <phillip@squashfs.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
111 lines
2.6 KiB
C
111 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Copyright (c) 2013
|
|
* Phillip Lougher <phillip@squashfs.org.uk>
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/percpu.h>
|
|
#include <linux/local_lock.h>
|
|
|
|
#include "squashfs_fs.h"
|
|
#include "squashfs_fs_sb.h"
|
|
#include "decompressor.h"
|
|
#include "squashfs.h"
|
|
|
|
/*
|
|
* This file implements multi-threaded decompression using percpu
|
|
* variables, one thread per cpu core.
|
|
*/
|
|
|
|
struct squashfs_stream {
|
|
void *stream;
|
|
local_lock_t lock;
|
|
};
|
|
|
|
static void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
|
|
void *comp_opts)
|
|
{
|
|
struct squashfs_stream *stream;
|
|
struct squashfs_stream __percpu *percpu;
|
|
int err, cpu;
|
|
|
|
percpu = alloc_percpu(struct squashfs_stream);
|
|
if (percpu == NULL)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
stream = per_cpu_ptr(percpu, cpu);
|
|
stream->stream = msblk->decompressor->init(msblk, comp_opts);
|
|
if (IS_ERR(stream->stream)) {
|
|
err = PTR_ERR(stream->stream);
|
|
goto out;
|
|
}
|
|
local_lock_init(&stream->lock);
|
|
}
|
|
|
|
kfree(comp_opts);
|
|
return (void *)(__force unsigned long) percpu;
|
|
|
|
out:
|
|
for_each_possible_cpu(cpu) {
|
|
stream = per_cpu_ptr(percpu, cpu);
|
|
if (!IS_ERR_OR_NULL(stream->stream))
|
|
msblk->decompressor->free(stream->stream);
|
|
}
|
|
free_percpu(percpu);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
static void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
|
|
{
|
|
struct squashfs_stream __percpu *percpu =
|
|
(void __percpu *)(unsigned long) msblk->stream;
|
|
struct squashfs_stream *stream;
|
|
int cpu;
|
|
|
|
if (msblk->stream) {
|
|
for_each_possible_cpu(cpu) {
|
|
stream = per_cpu_ptr(percpu, cpu);
|
|
msblk->decompressor->free(stream->stream);
|
|
}
|
|
free_percpu(percpu);
|
|
}
|
|
}
|
|
|
|
static int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
|
|
int offset, int length, struct squashfs_page_actor *output)
|
|
{
|
|
struct squashfs_stream *stream;
|
|
struct squashfs_stream __percpu *percpu =
|
|
(void __percpu *)(unsigned long) msblk->stream;
|
|
int res;
|
|
|
|
local_lock(&percpu->lock);
|
|
stream = this_cpu_ptr(percpu);
|
|
|
|
res = msblk->decompressor->decompress(msblk, stream->stream, bio,
|
|
offset, length, output);
|
|
|
|
local_unlock(&percpu->lock);
|
|
|
|
if (res < 0)
|
|
ERROR("%s decompression failed, data probably corrupt\n",
|
|
msblk->decompressor->name);
|
|
|
|
return res;
|
|
}
|
|
|
|
static int squashfs_max_decompressors(void)
|
|
{
|
|
return num_possible_cpus();
|
|
}
|
|
|
|
const struct squashfs_decompressor_thread_ops squashfs_decompressor_percpu = {
|
|
.create = squashfs_decompressor_create,
|
|
.destroy = squashfs_decompressor_destroy,
|
|
.decompress = squashfs_decompress,
|
|
.max_decompressors = squashfs_max_decompressors,
|
|
};
|