zram: add support for dict comp config

Handle dict=path algorithm param so that we can read a pre-trained
compression algorithm dictionary which we then pass to the backend
configuration.

Link: https://lkml.kernel.org/r/20240902105656.1383858-17-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nick Terrell <terrelln@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index e29e952b99c3d2baa894d92479f0c179b4397ce4..9b29f9e6cb503ed391774f0610d47b367ed40d38 100644 (file)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -33,6 +33,7 @@
 #include <linux/debugfs.h>
 #include <linux/cpuhotplug.h>
 #include <linux/part_stat.h>
+#include <linux/kernel_read_file.h>
 
 #include "zram_drv.h"
 
@@ -998,8 +999,34 @@ static int __comp_algorithm_store(struct zram *zram, u32 prio, const char *buf)
        return 0;
 }
 
-static int comp_params_store(struct zram *zram, u32 prio, s32 level)
+static void comp_params_reset(struct zram *zram, u32 prio)
 {
+       struct zcomp_params *params = &zram->params[prio];
+
+       vfree(params->dict);
+       params->level = ZCOMP_PARAM_NO_LEVEL;
+       params->dict_sz = 0;
+       params->dict = NULL;
+}
+
+static int comp_params_store(struct zram *zram, u32 prio, s32 level,
+                            const char *dict_path)
+{
+       ssize_t sz = 0;
+
+       comp_params_reset(zram, prio);
+
+       if (dict_path) {
+               sz = kernel_read_file_from_path(dict_path, 0,
+                                               &zram->params[prio].dict,
+                                               INT_MAX,
+                                               NULL,
+                                               READING_POLICY);
+               if (sz < 0)
+                       return -EINVAL;
+       }
+
+       zram->params[prio].dict_sz = sz;
        zram->params[prio].level = level;
        return 0;
 }
@@ -1010,7 +1037,7 @@ static ssize_t algorithm_params_store(struct device *dev,
                                      size_t len)
 {
        s32 prio = ZRAM_PRIMARY_COMP, level = ZCOMP_PARAM_NO_LEVEL;
-       char *args, *param, *val, *algo = NULL;
+       char *args, *param, *val, *algo = NULL, *dict_path = NULL;
        struct zram *zram = dev_to_zram(dev);
        int ret;
 
@@ -1039,6 +1066,11 @@ static ssize_t algorithm_params_store(struct device *dev,
                        algo = val;
                        continue;
                }
+
+               if (!strcmp(param, "dict")) {
+                       dict_path = val;
+                       continue;
+               }
        }
 
        /* Lookup priority by algorithm name */
@@ -1060,7 +1092,7 @@ static ssize_t algorithm_params_store(struct device *dev,
        if (prio < ZRAM_PRIMARY_COMP || prio >= ZRAM_MAX_COMPS)
                return -EINVAL;
 
-       ret = comp_params_store(zram, prio, level);
+       ret = comp_params_store(zram, prio, level, dict_path);
        return ret ? ret : len;
 }
 
@@ -2050,12 +2082,7 @@ static void zram_comp_params_reset(struct zram *zram)
        u32 prio;
 
        for (prio = ZRAM_PRIMARY_COMP; prio < ZRAM_MAX_COMPS; prio++) {
-               struct zcomp_params *params = &zram->params[prio];
-
-               vfree(params->dict);
-               params->level = ZCOMP_PARAM_NO_LEVEL;
-               params->dict_sz = 0;
-               params->dict = NULL;
+               comp_params_reset(zram, prio);
        }
 }