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zram: unify and harden algo/priority params handling

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We have two functions that accept algo= and priority= params -
algorithm_params_store() and recompress_store().  This patch unifies and
hardens handling of those parameters.

There are 4 possible cases:

- only priority= provided [recommended]
  We need to verify that provided priority value is
  within permitted range for each particular function.

- both algo= and priority= provided
  We cannot prioritize one over another.  All we should
  do is to verify that zram is configured in the way
  that user-space expects it to be.  Namely that zram
  indeed has compressor algo= setup at given priority=.

- only algo= provided [not recommended]
  We should lookup priority in compressors list.

- none provided [not recommended]
  Just use function's defaults.

Link: https://lkml.kernel.org/r/20260311084312.1766036-7-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Suggested-by: Minchan Kim <minchan@kernel.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: gao xu <gaoxu2@honor.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Sergey Senozhatsky
2026-03-11 17:42:49 +09:00
committed by Andrew Morton
parent cedfa028b5
commit 301f392200
1 changed files with 68 additions and 42 deletions
Download Patch File Download Diff File Expand all files Collapse all files

110
drivers/block/zram/zram_drv.c
View File

@@ -1619,6 +1619,37 @@ static void zram_debugfs_register(struct zram *zram) {};
static void zram_debugfs_unregister(struct zram *zram) {};
#endif
/* Only algo parameter given, lookup by algo name */
static int lookup_algo_priority(struct zram *zram, const char *algo,
u32 min_prio)
{
s32 prio;
for (prio = min_prio; prio < ZRAM_MAX_COMPS; prio++) {
if (!zram->comp_algs[prio])
continue;
if (!strcmp(zram->comp_algs[prio], algo))
return prio;
}
return -EINVAL;
}
/* Both algo and priority parameters given, validate them */
static int validate_algo_priority(struct zram *zram, const char *algo, u32 prio)
{
if (prio >= ZRAM_MAX_COMPS)
return -EINVAL;
/* No algo at given priority */
if (!zram->comp_algs[prio])
return -EINVAL;
/* A different algo at given priority */
if (strcmp(zram->comp_algs[prio], algo))
return -EINVAL;
return 0;
}
static void comp_algorithm_set(struct zram *zram, u32 prio, const char *alg)
{
zram->comp_algs[prio] = alg;
@@ -1691,6 +1722,7 @@ static ssize_t algorithm_params_store(struct device *dev,
char *args, *param, *val, *algo = NULL, *dict_path = NULL;
struct deflate_params deflate_params;
struct zram *zram = dev_to_zram(dev);
bool prio_param = false;
int ret;
deflate_params.winbits = ZCOMP_PARAM_NOT_SET;
@@ -1703,6 +1735,7 @@ static ssize_t algorithm_params_store(struct device *dev,
return -EINVAL;
if (!strcmp(param, "priority")) {
prio_param = true;
ret = kstrtoint(val, 10, &prio);
if (ret)
return ret;
@@ -1738,24 +1771,22 @@ static ssize_t algorithm_params_store(struct device *dev,
if (init_done(zram))
return -EBUSY;
/* Lookup priority by algorithm name */
if (algo) {
s32 p;
prio = -EINVAL;
for (p = ZRAM_PRIMARY_COMP; p < ZRAM_MAX_COMPS; p++) {
if (!zram->comp_algs[p])
continue;
if (!strcmp(zram->comp_algs[p], algo)) {
prio = p;
break;
}
}
if (prio_param) {
if (prio < ZRAM_PRIMARY_COMP || prio >= ZRAM_MAX_COMPS)
return -EINVAL;
}
if (prio < ZRAM_PRIMARY_COMP || prio >= ZRAM_MAX_COMPS)
return -EINVAL;
if (algo && prio_param) {
ret = validate_algo_priority(zram, algo, prio);
if (ret)
return ret;
}
if (algo && !prio_param) {
prio = lookup_algo_priority(zram, algo, ZRAM_PRIMARY_COMP);
if (prio < 0)
return -EINVAL;
}
ret = comp_params_store(zram, prio, level, dict_path, &deflate_params);
return ret ? ret : len;
@@ -2396,9 +2427,6 @@ static int recompress_slot(struct zram *zram, u32 index, struct page *page,
void *src;
int ret = 0;
if (!zram->comps[prio])
return -EINVAL;
handle_old = get_slot_handle(zram, index);
if (!handle_old)
return -EINVAL;
@@ -2500,10 +2528,11 @@ static ssize_t recompress_store(struct device *dev,
char *args, *param, *val, *algo = NULL;
u64 num_recomp_pages = ULLONG_MAX;
struct zram_pp_ctl *ctl = NULL;
u32 prio = ZRAM_SECONDARY_COMP;
struct zram_pp_slot *pps;
s32 prio = ZRAM_SECONDARY_COMP;
u32 mode = 0, threshold = 0;
struct zram_pp_slot *pps;
struct page *page = NULL;
bool prio_param = false;
ssize_t ret;
args = skip_spaces(buf);
@@ -2551,7 +2580,8 @@ static ssize_t recompress_store(struct device *dev,
}
if (!strcmp(param, "priority")) {
ret = kstrtouint(val, 10, &prio);
prio_param = true;
ret = kstrtoint(val, 10, &prio);
if (ret)
return ret;
continue;
@@ -2565,30 +2595,26 @@ static ssize_t recompress_store(struct device *dev,
if (!init_done(zram))
return -EINVAL;
if (algo) {
bool found = false;
for (; prio < ZRAM_MAX_COMPS; prio++) {
if (!zram->comp_algs[prio])
continue;
if (!strcmp(zram->comp_algs[prio], algo)) {
found = true;
break;
}
}
if (!found) {
ret = -EINVAL;
goto out;
}
if (prio_param) {
if (prio < ZRAM_SECONDARY_COMP || prio >= ZRAM_MAX_COMPS)
return -EINVAL;
}
if (prio < ZRAM_SECONDARY_COMP || prio >= ZRAM_MAX_COMPS) {
ret = -EINVAL;
goto out;
if (algo && prio_param) {
ret = validate_algo_priority(zram, algo, prio);
if (ret)
return ret;
}
if (algo && !prio_param) {
prio = lookup_algo_priority(zram, algo, ZRAM_SECONDARY_COMP);
if (prio < 0)
return -EINVAL;
}
if (!zram->comps[prio])
return -EINVAL;
page = alloc_page(GFP_KERNEL);
if (!page) {
ret = -ENOMEM;