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// SPDX-License-Identifier: GPL-2.0-or-later
#include <linux/zlib.h>
#include "compress.h"
struct z_erofs_deflate {
struct z_erofs_deflate *next;
struct z_stream_s z;
u8 bounce[PAGE_SIZE];
};
static DEFINE_SPINLOCK(z_erofs_deflate_lock);
static unsigned int z_erofs_deflate_nstrms, z_erofs_deflate_avail_strms;
static struct z_erofs_deflate *z_erofs_deflate_head;
static DECLARE_WAIT_QUEUE_HEAD(z_erofs_deflate_wq);
module_param_named(deflate_streams, z_erofs_deflate_nstrms, uint, 0444);
static void z_erofs_deflate_exit(void)
{
/* there should be no running fs instance */
while (z_erofs_deflate_avail_strms) {
struct z_erofs_deflate *strm;
spin_lock(&z_erofs_deflate_lock);
strm = z_erofs_deflate_head;
if (!strm) {
spin_unlock(&z_erofs_deflate_lock);
continue;
}
z_erofs_deflate_head = NULL;
spin_unlock(&z_erofs_deflate_lock);
while (strm) {
struct z_erofs_deflate *n = strm->next;
vfree(strm->z.workspace);
kfree(strm);
--z_erofs_deflate_avail_strms;
strm = n;
}
}
}
static int __init z_erofs_deflate_init(void)
{
/* by default, use # of possible CPUs instead */
if (!z_erofs_deflate_nstrms)
z_erofs_deflate_nstrms = num_possible_cpus();
return 0;
}
static int z_erofs_load_deflate_config(struct super_block *sb,
struct erofs_super_block *dsb, void *data, int size)
{
struct z_erofs_deflate_cfgs *dfl = data;
static DEFINE_MUTEX(deflate_resize_mutex);
static bool inited;
if (!dfl || size < sizeof(struct z_erofs_deflate_cfgs)) {
erofs_err(sb, "invalid deflate cfgs, size=%u", size);
return -EINVAL;
}
if (dfl->windowbits > MAX_WBITS) {
erofs_err(sb, "unsupported windowbits %u", dfl->windowbits);
return -EOPNOTSUPP;
}
mutex_lock(&deflate_resize_mutex);
if (!inited) {
for (; z_erofs_deflate_avail_strms < z_erofs_deflate_nstrms;
++z_erofs_deflate_avail_strms) {
struct z_erofs_deflate *strm;
strm = kzalloc(sizeof(*strm), GFP_KERNEL);
if (!strm)
goto failed;
/* XXX: in-kernel zlib cannot customize windowbits */
strm->z.workspace = vmalloc(zlib_inflate_workspacesize());
if (!strm->z.workspace) {
kfree(strm);
goto failed;
}
spin_lock(&z_erofs_deflate_lock);
strm->next = z_erofs_deflate_head;
z_erofs_deflate_head = strm;
spin_unlock(&z_erofs_deflate_lock);
}
inited = true;
}
mutex_unlock(&deflate_resize_mutex);
erofs_info(sb, "EXPERIMENTAL DEFLATE feature in use. Use at your own risk!");
return 0;
failed:
mutex_unlock(&deflate_resize_mutex);
z_erofs_deflate_exit();
return -ENOMEM;
}
static int __z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq,
struct page **pgpl)
{
struct super_block *sb = rq->sb;
struct z_erofs_stream_dctx dctx = { .rq = rq, .no = -1, .ni = 0 };
struct z_erofs_deflate *strm;
int zerr, err;
/* 1. get the exact DEFLATE compressed size */
dctx.kin = kmap_local_page(*rq->in);
err = z_erofs_fixup_insize(rq, dctx.kin + rq->pageofs_in,
min(rq->inputsize, sb->s_blocksize - rq->pageofs_in));
if (err) {
kunmap_local(dctx.kin);
return err;
}
/* 2. get an available DEFLATE context */
again:
spin_lock(&z_erofs_deflate_lock);
strm = z_erofs_deflate_head;
if (!strm) {
spin_unlock(&z_erofs_deflate_lock);
wait_event(z_erofs_deflate_wq, READ_ONCE(z_erofs_deflate_head));
goto again;
}
z_erofs_deflate_head = strm->next;
spin_unlock(&z_erofs_deflate_lock);
/* 3. multi-call decompress */
zerr = zlib_inflateInit2(&strm->z, -MAX_WBITS);
if (zerr != Z_OK) {
err = -EIO;
goto failed_zinit;
}
rq->fillgaps = true; /* DEFLATE doesn't support NULL output buffer */
strm->z.avail_in = min(rq->inputsize, PAGE_SIZE - rq->pageofs_in);
rq->inputsize -= strm->z.avail_in;
strm->z.next_in = dctx.kin + rq->pageofs_in;
strm->z.avail_out = 0;
dctx.bounce = strm->bounce;
while (1) {
dctx.avail_out = strm->z.avail_out;
dctx.inbuf_sz = strm->z.avail_in;
err = z_erofs_stream_switch_bufs(&dctx,
(void **)&strm->z.next_out,
(void **)&strm->z.next_in, pgpl);
if (err)
break;
strm->z.avail_out = dctx.avail_out;
strm->z.avail_in = dctx.inbuf_sz;
zerr = zlib_inflate(&strm->z, Z_SYNC_FLUSH);
if (zerr != Z_OK || !(rq->outputsize + strm->z.avail_out)) {
if (zerr == Z_OK && rq->partial_decoding)
break;
if (zerr == Z_STREAM_END && !rq->outputsize)
break;
erofs_err(sb, "failed to decompress %d in[%u] out[%u]",
zerr, rq->inputsize, rq->outputsize);
err = -EFSCORRUPTED;
break;
}
}
if (zlib_inflateEnd(&strm->z) != Z_OK && !err)
err = -EIO;
if (dctx.kout)
kunmap_local(dctx.kout);
failed_zinit:
kunmap_local(dctx.kin);
/* 4. push back DEFLATE stream context to the global list */
spin_lock(&z_erofs_deflate_lock);
strm->next = z_erofs_deflate_head;
z_erofs_deflate_head = strm;
spin_unlock(&z_erofs_deflate_lock);
wake_up(&z_erofs_deflate_wq);
return err;
}
static int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq,
struct page **pgpl)
{
#ifdef CONFIG_EROFS_FS_ZIP_ACCEL
int err;
if (!rq->partial_decoding) {
err = z_erofs_crypto_decompress(rq, pgpl);
if (err != -EOPNOTSUPP)
return err;
}
#endif
return __z_erofs_deflate_decompress(rq, pgpl);
}
const struct z_erofs_decompressor z_erofs_deflate_decomp = {
.config = z_erofs_load_deflate_config,
.decompress = z_erofs_deflate_decompress,
.init = z_erofs_deflate_init,
.exit = z_erofs_deflate_exit,
.name = "deflate",
};
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