diff options
Diffstat (limited to 'fs/erofs/decompressor_deflate.c')
| -rw-r--r-- | fs/erofs/decompressor_deflate.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/fs/erofs/decompressor_deflate.c b/fs/erofs/decompressor_deflate.c new file mode 100644 index 000000000000..19e5bdeb30b6 --- /dev/null +++ b/fs/erofs/decompressor_deflate.c @@ -0,0 +1,247 @@ +// 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; +} |