From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- fs/squashfs/lzo_wrapper.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 123 insertions(+) create mode 100644 fs/squashfs/lzo_wrapper.c (limited to 'fs/squashfs/lzo_wrapper.c') diff --git a/fs/squashfs/lzo_wrapper.c b/fs/squashfs/lzo_wrapper.c new file mode 100644 index 000000000..be1df7a25 --- /dev/null +++ b/fs/squashfs/lzo_wrapper.c @@ -0,0 +1,123 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Squashfs - a compressed read only filesystem for Linux + * + * Copyright (c) 2010 LG Electronics + * Chan Jeong + * + * lzo_wrapper.c + */ + +#include +#include +#include +#include +#include + +#include "squashfs_fs.h" +#include "squashfs_fs_sb.h" +#include "squashfs.h" +#include "decompressor.h" +#include "page_actor.h" + +struct squashfs_lzo { + void *input; + void *output; +}; + +static void *lzo_init(struct squashfs_sb_info *msblk, void *buff) +{ + int block_size = max_t(int, msblk->block_size, SQUASHFS_METADATA_SIZE); + + struct squashfs_lzo *stream = kzalloc_obj(*stream); + if (stream == NULL) + goto failed; + stream->input = vmalloc(block_size); + if (stream->input == NULL) + goto failed; + stream->output = vmalloc(block_size); + if (stream->output == NULL) + goto failed2; + + return stream; + +failed2: + vfree(stream->input); +failed: + ERROR("Failed to allocate lzo workspace\n"); + kfree(stream); + return ERR_PTR(-ENOMEM); +} + + +static void lzo_free(void *strm) +{ + struct squashfs_lzo *stream = strm; + + if (stream) { + vfree(stream->input); + vfree(stream->output); + } + kfree(stream); +} + + +static int lzo_uncompress(struct squashfs_sb_info *msblk, void *strm, + struct bio *bio, int offset, int length, + struct squashfs_page_actor *output) +{ + struct bvec_iter_all iter_all = {}; + struct bio_vec *bvec = bvec_init_iter_all(&iter_all); + struct squashfs_lzo *stream = strm; + void *buff = stream->input, *data; + int bytes = length, res; + size_t out_len = output->length; + + while (bio_next_segment(bio, &iter_all)) { + int avail = min(bytes, ((int)bvec->bv_len) - offset); + + data = bvec_virt(bvec); + memcpy(buff, data + offset, avail); + buff += avail; + bytes -= avail; + offset = 0; + } + + res = lzo1x_decompress_safe(stream->input, (size_t)length, + stream->output, &out_len); + if (res != LZO_E_OK) + goto failed; + + res = bytes = (int)out_len; + data = squashfs_first_page(output); + buff = stream->output; + while (data) { + if (bytes <= PAGE_SIZE) { + if (!IS_ERR(data)) + memcpy(data, buff, bytes); + break; + } else { + if (!IS_ERR(data)) + memcpy(data, buff, PAGE_SIZE); + buff += PAGE_SIZE; + bytes -= PAGE_SIZE; + data = squashfs_next_page(output); + } + } + squashfs_finish_page(output); + + return res; + +failed: + return -EIO; +} + +const struct squashfs_decompressor squashfs_lzo_comp_ops = { + .init = lzo_init, + .free = lzo_free, + .decompress = lzo_uncompress, + .id = LZO_COMPRESSION, + .name = "lzo", + .alloc_buffer = 0, + .supported = 1 +}; -- cgit v1.3.1