diff options
Diffstat (limited to 'drivers/block/zram/backend_zstd.c')
| -rw-r--r-- | drivers/block/zram/backend_zstd.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/drivers/block/zram/backend_zstd.c b/drivers/block/zram/backend_zstd.c new file mode 100644 index 000000000000..1184c0036f44 --- /dev/null +++ b/drivers/block/zram/backend_zstd.c @@ -0,0 +1,226 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> +#include <linux/zstd.h> + +#include "backend_zstd.h" + +struct zstd_ctx { + zstd_cctx *cctx; + zstd_dctx *dctx; + void *cctx_mem; + void *dctx_mem; +}; + +struct zstd_params { + zstd_custom_mem custom_mem; + zstd_cdict *cdict; + zstd_ddict *ddict; + zstd_parameters cprm; +}; + +/* + * For C/D dictionaries we need to provide zstd with zstd_custom_mem, + * which zstd uses internally to allocate/free memory when needed. + * + * This means that allocator.customAlloc() can be called from zcomp_compress() + * under local-lock (per-CPU compression stream), in which case we must use + * GFP_ATOMIC. + * + * Another complication here is that we can be configured as a swap device. + */ +static void *zstd_custom_alloc(void *opaque, size_t size) +{ + if (!preemptible()) + return kvzalloc(size, GFP_ATOMIC); + + return kvzalloc(size, __GFP_KSWAPD_RECLAIM | __GFP_NOWARN); +} + +static void zstd_custom_free(void *opaque, void *address) +{ + kvfree(address); +} + +static void zstd_release_params(struct zcomp_params *params) +{ + struct zstd_params *zp = params->drv_data; + + params->drv_data = NULL; + if (!zp) + return; + + zstd_free_cdict(zp->cdict); + zstd_free_ddict(zp->ddict); + kfree(zp); +} + +static int zstd_setup_params(struct zcomp_params *params) +{ + zstd_compression_parameters prm; + struct zstd_params *zp; + + zp = kzalloc(sizeof(*zp), GFP_KERNEL); + if (!zp) + return -ENOMEM; + + params->drv_data = zp; + if (params->level == ZCOMP_PARAM_NO_LEVEL) + params->level = zstd_default_clevel(); + + zp->cprm = zstd_get_params(params->level, PAGE_SIZE); + + zp->custom_mem.customAlloc = zstd_custom_alloc; + zp->custom_mem.customFree = zstd_custom_free; + + prm = zstd_get_cparams(params->level, PAGE_SIZE, + params->dict_sz); + + zp->cdict = zstd_create_cdict_byreference(params->dict, + params->dict_sz, + prm, + zp->custom_mem); + if (!zp->cdict) + goto error; + + zp->ddict = zstd_create_ddict_byreference(params->dict, + params->dict_sz, + zp->custom_mem); + if (!zp->ddict) + goto error; + + return 0; + +error: + zstd_release_params(params); + return -EINVAL; +} + +static void zstd_destroy(struct zcomp_ctx *ctx) +{ + struct zstd_ctx *zctx = ctx->context; + + if (!zctx) + return; + + /* + * If ->cctx_mem and ->dctx_mem were allocated then we didn't use + * C/D dictionary and ->cctx / ->dctx were "embedded" into these + * buffers. + * + * If otherwise then we need to explicitly release ->cctx / ->dctx. + */ + if (zctx->cctx_mem) + vfree(zctx->cctx_mem); + else + zstd_free_cctx(zctx->cctx); + + if (zctx->dctx_mem) + vfree(zctx->dctx_mem); + else + zstd_free_dctx(zctx->dctx); + + kfree(zctx); +} + +static int zstd_create(struct zcomp_params *params, struct zcomp_ctx *ctx) +{ + struct zstd_ctx *zctx; + zstd_parameters prm; + size_t sz; + + zctx = kzalloc(sizeof(*zctx), GFP_KERNEL); + if (!zctx) + return -ENOMEM; + + ctx->context = zctx; + if (params->dict_sz == 0) { + prm = zstd_get_params(params->level, PAGE_SIZE); + sz = zstd_cctx_workspace_bound(&prm.cParams); + zctx->cctx_mem = vzalloc(sz); + if (!zctx->cctx_mem) + goto error; + + zctx->cctx = zstd_init_cctx(zctx->cctx_mem, sz); + if (!zctx->cctx) + goto error; + + sz = zstd_dctx_workspace_bound(); + zctx->dctx_mem = vzalloc(sz); + if (!zctx->dctx_mem) + goto error; + + zctx->dctx = zstd_init_dctx(zctx->dctx_mem, sz); + if (!zctx->dctx) + goto error; + } else { + struct zstd_params *zp = params->drv_data; + + zctx->cctx = zstd_create_cctx_advanced(zp->custom_mem); + if (!zctx->cctx) + goto error; + + zctx->dctx = zstd_create_dctx_advanced(zp->custom_mem); + if (!zctx->dctx) + goto error; + } + + return 0; + +error: + zstd_release_params(params); + zstd_destroy(ctx); + return -EINVAL; +} + +static int zstd_compress(struct zcomp_params *params, struct zcomp_ctx *ctx, + struct zcomp_req *req) +{ + struct zstd_params *zp = params->drv_data; + struct zstd_ctx *zctx = ctx->context; + size_t ret; + + if (params->dict_sz == 0) + ret = zstd_compress_cctx(zctx->cctx, req->dst, req->dst_len, + req->src, req->src_len, &zp->cprm); + else + ret = zstd_compress_using_cdict(zctx->cctx, req->dst, + req->dst_len, req->src, + req->src_len, + zp->cdict); + if (zstd_is_error(ret)) + return -EINVAL; + req->dst_len = ret; + return 0; +} + +static int zstd_decompress(struct zcomp_params *params, struct zcomp_ctx *ctx, + struct zcomp_req *req) +{ + struct zstd_params *zp = params->drv_data; + struct zstd_ctx *zctx = ctx->context; + size_t ret; + + if (params->dict_sz == 0) + ret = zstd_decompress_dctx(zctx->dctx, req->dst, req->dst_len, + req->src, req->src_len); + else + ret = zstd_decompress_using_ddict(zctx->dctx, req->dst, + req->dst_len, req->src, + req->src_len, zp->ddict); + if (zstd_is_error(ret)) + return -EINVAL; + return 0; +} + +const struct zcomp_ops backend_zstd = { + .compress = zstd_compress, + .decompress = zstd_decompress, + .create_ctx = zstd_create, + .destroy_ctx = zstd_destroy, + .setup_params = zstd_setup_params, + .release_params = zstd_release_params, + .name = "zstd", +}; 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