mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-19 02:34:01 +08:00
f268eedddf
Patch series "Squashfs: handle missing pages decompressing into page cache". This patchset enables Squashfs to handle missing pages when directly decompressing datablocks into the page cache. Previously if the full set of pages needed was not available, Squashfs would have to fall back to using an intermediate buffer (the older method), which is slower, involving a memcopy, and it introduces contention on a shared buffer. The first patch extends the "page actor" code to handle missing pages. The second patch updates Squashfs_readpage_block() to use the new functionality, and removes the code that falls back to using an intermediate buffer. This patchset is independent of the readahead work, and it is standalone. It can be merged on its own. But the readahead patch for efficiency also needs this patch-set. This patch (of 2): This patch extends the "page actor" code to handle missing pages. Previously if the full set of pages needed to decompress a Squashfs datablock was unavailable, this would cause decompression to fail on the missing pages. In this case direct decompression into the page cache could not be achieved and the code would fall back to using the older intermediate buffer method. With this patch, direct decompression into the page cache can be achieved with missing pages. For "multi-shot" decompressors (zlib, xz, zstd), the page actor will allocate a temporary buffer which is passed to the decompressor, and then freed by the page actor. For "single shot" decompressors (lz4, lzo) which decompress into a contiguous "bounce buffer", and which is then copied into the page cache, it would be pointless to allocate a temporary buffer, memcpy into it, and then free it. For these decompressors -ENOMEM is returned, which signifies that the memcpy for that page should be skipped. This also happens if the data block is uncompressed. Link: https://lkml.kernel.org/r/20220611032133.5743-1-phillip@squashfs.org.uk Link: https://lkml.kernel.org/r/20220611032133.5743-2-phillip@squashfs.org.uk Signed-off-by: Phillip Lougher <phillip@squashfs.org.uk> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Hsin-Yi Wang <hsinyi@chromium.org> Cc: Xiongwei Song <Xiongwei.Song@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
138 lines
2.8 KiB
C
138 lines
2.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* Squashfs - a compressed read only filesystem for Linux
|
|
*
|
|
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
|
|
* Phillip Lougher <phillip@squashfs.org.uk>
|
|
*
|
|
* zlib_wrapper.c
|
|
*/
|
|
|
|
|
|
#include <linux/mutex.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/zlib.h>
|
|
#include <linux/vmalloc.h>
|
|
|
|
#include "squashfs_fs.h"
|
|
#include "squashfs_fs_sb.h"
|
|
#include "squashfs.h"
|
|
#include "decompressor.h"
|
|
#include "page_actor.h"
|
|
|
|
static void *zlib_init(struct squashfs_sb_info *dummy, void *buff)
|
|
{
|
|
z_stream *stream = kmalloc(sizeof(z_stream), GFP_KERNEL);
|
|
if (stream == NULL)
|
|
goto failed;
|
|
stream->workspace = vmalloc(zlib_inflate_workspacesize());
|
|
if (stream->workspace == NULL)
|
|
goto failed;
|
|
|
|
return stream;
|
|
|
|
failed:
|
|
ERROR("Failed to allocate zlib workspace\n");
|
|
kfree(stream);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
|
|
static void zlib_free(void *strm)
|
|
{
|
|
z_stream *stream = strm;
|
|
|
|
if (stream)
|
|
vfree(stream->workspace);
|
|
kfree(stream);
|
|
}
|
|
|
|
|
|
static int zlib_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);
|
|
int zlib_init = 0, error = 0;
|
|
z_stream *stream = strm;
|
|
|
|
stream->avail_out = PAGE_SIZE;
|
|
stream->next_out = squashfs_first_page(output);
|
|
stream->avail_in = 0;
|
|
|
|
if (IS_ERR(stream->next_out)) {
|
|
error = PTR_ERR(stream->next_out);
|
|
goto finish;
|
|
}
|
|
|
|
for (;;) {
|
|
int zlib_err;
|
|
|
|
if (stream->avail_in == 0) {
|
|
const void *data;
|
|
int avail;
|
|
|
|
if (!bio_next_segment(bio, &iter_all)) {
|
|
/* Z_STREAM_END must be reached. */
|
|
error = -EIO;
|
|
break;
|
|
}
|
|
|
|
avail = min(length, ((int)bvec->bv_len) - offset);
|
|
data = bvec_virt(bvec);
|
|
length -= avail;
|
|
stream->next_in = data + offset;
|
|
stream->avail_in = avail;
|
|
offset = 0;
|
|
}
|
|
|
|
if (stream->avail_out == 0) {
|
|
stream->next_out = squashfs_next_page(output);
|
|
if (IS_ERR(stream->next_out)) {
|
|
error = PTR_ERR(stream->next_out);
|
|
break;
|
|
} else if (stream->next_out != NULL)
|
|
stream->avail_out = PAGE_SIZE;
|
|
}
|
|
|
|
if (!zlib_init) {
|
|
zlib_err = zlib_inflateInit(stream);
|
|
if (zlib_err != Z_OK) {
|
|
error = -EIO;
|
|
break;
|
|
}
|
|
zlib_init = 1;
|
|
}
|
|
|
|
zlib_err = zlib_inflate(stream, Z_SYNC_FLUSH);
|
|
if (zlib_err == Z_STREAM_END)
|
|
break;
|
|
if (zlib_err != Z_OK) {
|
|
error = -EIO;
|
|
break;
|
|
}
|
|
}
|
|
|
|
finish:
|
|
squashfs_finish_page(output);
|
|
|
|
if (!error)
|
|
if (zlib_inflateEnd(stream) != Z_OK)
|
|
error = -EIO;
|
|
|
|
return error ? error : stream->total_out;
|
|
}
|
|
|
|
const struct squashfs_decompressor squashfs_zlib_comp_ops = {
|
|
.init = zlib_init,
|
|
.free = zlib_free,
|
|
.decompress = zlib_uncompress,
|
|
.id = ZLIB_COMPRESSION,
|
|
.name = "zlib",
|
|
.alloc_buffer = 1,
|
|
.supported = 1
|
|
};
|
|
|