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
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/*
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* Copyright (c) 2013
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* Phillip Lougher <phillip@squashfs.org.uk>
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*/
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/percpu.h>
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#include <linux/local_lock.h>
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#include "squashfs_fs.h"
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#include "squashfs_fs_sb.h"
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#include "decompressor.h"
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#include "squashfs.h"
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/*
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* This file implements multi-threaded decompression using percpu
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* variables, one thread per cpu core.
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*/
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struct squashfs_stream {
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void *stream;
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local_lock_t lock;
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};
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static void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
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void *comp_opts)
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{
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struct squashfs_stream *stream;
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struct squashfs_stream __percpu *percpu;
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int err, cpu;
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percpu = alloc_percpu(struct squashfs_stream);
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if (percpu == NULL)
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return ERR_PTR(-ENOMEM);
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for_each_possible_cpu(cpu) {
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stream = per_cpu_ptr(percpu, cpu);
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stream->stream = msblk->decompressor->init(msblk, comp_opts);
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if (IS_ERR(stream->stream)) {
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err = PTR_ERR(stream->stream);
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goto out;
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}
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local_lock_init(&stream->lock);
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}
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kfree(comp_opts);
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return (void *)(__force unsigned long) percpu;
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out:
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for_each_possible_cpu(cpu) {
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stream = per_cpu_ptr(percpu, cpu);
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if (!IS_ERR_OR_NULL(stream->stream))
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msblk->decompressor->free(stream->stream);
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}
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free_percpu(percpu);
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return ERR_PTR(err);
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}
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static void squashfs_decompressor_destroy(struct squashfs_sb_info *msblk)
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{
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struct squashfs_stream __percpu *percpu =
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(void __percpu *)(unsigned long) msblk->stream;
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struct squashfs_stream *stream;
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int cpu;
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if (msblk->stream) {
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for_each_possible_cpu(cpu) {
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stream = per_cpu_ptr(percpu, cpu);
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msblk->decompressor->free(stream->stream);
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}
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free_percpu(percpu);
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}
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}
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static int squashfs_decompress(struct squashfs_sb_info *msblk, struct bio *bio,
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int offset, int length, struct squashfs_page_actor *output)
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{
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struct squashfs_stream *stream;
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struct squashfs_stream __percpu *percpu =
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(void __percpu *)(unsigned long) msblk->stream;
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int res;
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local_lock(&percpu->lock);
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stream = this_cpu_ptr(percpu);
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res = msblk->decompressor->decompress(msblk, stream->stream, bio,
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offset, length, output);
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local_unlock(&percpu->lock);
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if (res < 0)
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ERROR("%s decompression failed, data probably corrupt\n",
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msblk->decompressor->name);
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return res;
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}
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static int squashfs_max_decompressors(void)
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{
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return num_possible_cpus();
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}
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const struct squashfs_decompressor_thread_ops squashfs_decompressor_percpu = {
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.create = squashfs_decompressor_create,
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.destroy = squashfs_decompressor_destroy,
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.decompress = squashfs_decompress,
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.max_decompressors = squashfs_max_decompressors,
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};
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