On (09/18/15 14:19), Joonsoo Kim wrote:
[..]
> -static struct zcomp_backend *find_backend(const char *compress)
> +static const char *find_backend(const char *compress)
> {
> int i = 0;
> while (backends[i]) {
> - if (sysfs_streq(compress, backends[i]->name))
> + if (sysfs_streq(compress, backends[i]) &&
> + crypto_has_comp(compress, 0, 0))
ok, just for note. zcomp does sysfs_streq(), because sysfs data
usually contain a trailing new line, crypto_has_comp() does strcmp().
> int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm,
> - const unsigned char *src, size_t *dst_len)
> + const unsigned char *src, unsigned int *dst_len)
> {
> - return comp->backend->compress(src, zstrm->buffer, dst_len,
> - zstrm->private);
> + *dst_len = PAGE_SIZE << 1;
> +
hm... wouldn't it be better to say crypto api that we have a PAGE_SIZE
buffer instead of PAGE_SIZE << 1, so in case of buffer overrun (or
whatever is the correct term here) it will stop compression earlier
(well, possibly)? zram will drop compressed data larger than PAGE_SIZE
anyway, so if passing a smaller buffer size can save us CPU time then
let's do it.
> + return crypto_comp_compress(zstrm->tfm, src, PAGE_SIZE,
> + zstrm->buffer, dst_len);
> }
>
> int zcomp_decompress(struct zcomp *comp, struct zcomp_strm *zstrm,
> const unsigned char *src,
> - size_t src_len, unsigned char *dst)
> + unsigned int src_len, unsigned char *dst)
> {
> - return comp->backend->decompress(src, src_len, dst);
> + unsigned int size = PAGE_SIZE;
> +
> + return crypto_comp_decompress(zstrm->tfm, src, src_len, dst, &size);
^^^^^^^^ tab?
> }
>
> void zcomp_destroy(struct zcomp *comp)
> @@ -359,7 +365,7 @@ void zcomp_destroy(struct zcomp *comp)
> struct zcomp *zcomp_create(const char *compress, int max_strm)
> {
> struct zcomp *comp;
> - struct zcomp_backend *backend;
> + const char *backend;
rebase against the current linux-next. this and the next patch do not
apply cleanly. the function was touched recently: '+int error'.
>
> backend = find_backend(compress);
> if (!backend)
> diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h
> index 4c09c01..4f9df8e 100644
> --- a/drivers/block/zram/zcomp.h
> +++ b/drivers/block/zram/zcomp.h
> @@ -11,38 +11,22 @@
> #define _ZCOMP_H_
>
> #include <linux/mutex.h>
> +#include <linux/crypto.h>
>
> struct zcomp_strm {
> + struct crypto_comp *tfm;
> +
> /* compression/decompression buffer */
> void *buffer;
> - /*
> - * The private data of the compression stream, only compression
> - * stream backend can touch this (e.g. compression algorithm
> - * working memory)
> - */
> - void *private;
> +
> /* used in multi stream backend, protected by backend strm_lock */
> struct list_head list;
> };
>
> -/* static compression backend */
> -struct zcomp_backend {
> - int (*compress)(const unsigned char *src, unsigned char *dst,
> - size_t *dst_len, void *private);
> -
> - int (*decompress)(const unsigned char *src, size_t src_len,
> - unsigned char *dst);
> -
> - void *(*create)(void);
> - void (*destroy)(void *private);
> -
> - const char *name;
> -};
> -
> /* dynamic per-device compression frontend */
> struct zcomp {
> void *stream;
> - struct zcomp_backend *backend;
> + const char *backend;
^^ what for?
-ss
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