blob: 19e5bdeb30b6064bd442642b427dfac13c823267 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-or-later
#include <linux/module.h>
#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);
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;
}
}
}
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();
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 out_failed;
/* XXX: in-kernel zlib cannot shrink windowbits currently */
strm->z.workspace = vmalloc(zlib_inflate_workspacesize());
if (!strm->z.workspace) {
kfree(strm);
goto out_failed;
}
spin_lock(&z_erofs_deflate_lock);
strm->next = z_erofs_deflate_head;
z_erofs_deflate_head = strm;
spin_unlock(&z_erofs_deflate_lock);
}
return 0;
out_failed:
pr_err("failed to allocate zlib workspace\n");
z_erofs_deflate_exit();
return -ENOMEM;
}
int z_erofs_load_deflate_config(struct super_block *sb,
struct erofs_super_block *dsb,
struct z_erofs_deflate_cfgs *dfl, int size)
{
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;
}
erofs_info(sb, "EXPERIMENTAL DEFLATE feature in use. Use at your own risk!");
return 0;
}
int z_erofs_deflate_decompress(struct z_erofs_decompress_req *rq,
struct page **pagepool)
{
const unsigned int nrpages_out =
PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
const unsigned int nrpages_in =
PAGE_ALIGN(rq->inputsize) >> PAGE_SHIFT;
struct super_block *sb = rq->sb;
unsigned int insz, outsz, pofs;
struct z_erofs_deflate *strm;
u8 *kin, *kout = NULL;
bool bounced = false;
int no = -1, ni = 0, j = 0, zerr, err;
/* 1. get the exact DEFLATE compressed size */
kin = kmap_local_page(*rq->in);
err = z_erofs_fixup_insize(rq, kin + rq->pageofs_in,
min_t(unsigned int, rq->inputsize,
sb->s_blocksize - rq->pageofs_in));
if (err) {
kunmap_local(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 */
insz = rq->inputsize;
outsz = rq->outputsize;
zerr = zlib_inflateInit2(&strm->z, -MAX_WBITS);
if (zerr != Z_OK) {
err = -EIO;
goto failed_zinit;
}
pofs = rq->pageofs_out;
strm->z.avail_in = min_t(u32, insz, PAGE_SIZE - rq->pageofs_in);
insz -= strm->z.avail_in;
strm->z.next_in = kin + rq->pageofs_in;
strm->z.avail_out = 0;
while (1) {
if (!strm->z.avail_out) {
if (++no >= nrpages_out || !outsz) {
erofs_err(sb, "insufficient space for decompressed data");
err = -EFSCORRUPTED;
break;
}
if (kout)
kunmap_local(kout);
strm->z.avail_out = min_t(u32, outsz, PAGE_SIZE - pofs);
outsz -= strm->z.avail_out;
if (!rq->out[no]) {
rq->out[no] = erofs_allocpage(pagepool,
GFP_KERNEL | __GFP_NOFAIL);
set_page_private(rq->out[no],
Z_EROFS_SHORTLIVED_PAGE);
}
kout = kmap_local_page(rq->out[no]);
strm->z.next_out = kout + pofs;
pofs = 0;
}
if (!strm->z.avail_in && insz) {
if (++ni >= nrpages_in) {
erofs_err(sb, "invalid compressed data");
err = -EFSCORRUPTED;
break;
}
if (kout) { /* unlike kmap(), take care of the orders */
j = strm->z.next_out - kout;
kunmap_local(kout);
}
kunmap_local(kin);
strm->z.avail_in = min_t(u32, insz, PAGE_SIZE);
insz -= strm->z.avail_in;
kin = kmap_local_page(rq->in[ni]);
strm->z.next_in = kin;
bounced = false;
if (kout) {
kout = kmap_local_page(rq->out[no]);
strm->z.next_out = kout + j;
}
}
/*
* Handle overlapping: Use bounced buffer if the compressed
* data is under processing; Or use short-lived pages from the
* on-stack pagepool where pages share among the same request
* and not _all_ inplace I/O pages are needed to be doubled.
*/
if (!bounced && rq->out[no] == rq->in[ni]) {
memcpy(strm->bounce, strm->z.next_in, strm->z.avail_in);
strm->z.next_in = strm->bounce;
bounced = true;
}
for (j = ni + 1; j < nrpages_in; ++j) {
struct page *tmppage;
if (rq->out[no] != rq->in[j])
continue;
DBG_BUGON(erofs_page_is_managed(EROFS_SB(sb),
rq->in[j]));
tmppage = erofs_allocpage(pagepool,
GFP_KERNEL | __GFP_NOFAIL);
set_page_private(tmppage, Z_EROFS_SHORTLIVED_PAGE);
copy_highpage(tmppage, rq->in[j]);
rq->in[j] = tmppage;
}
zerr = zlib_inflate(&strm->z, Z_SYNC_FLUSH);
if (zerr != Z_OK || !(outsz + strm->z.avail_out)) {
if (zerr == Z_OK && rq->partial_decoding)
break;
if (zerr == Z_STREAM_END && !outsz)
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 (kout)
kunmap_local(kout);
failed_zinit:
kunmap_local(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;
}