--- /dev/null
+// 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;
+}
projects / linux-2.6-block.git / commitdiff