The patch titled
Subject: zram: limit max recompress prio to num_active_comps
has been added to the -mm mm-unstable branch. Its filename is
zram-limit-max-recompress-prio-to-num_active_comps.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-limit-max-recompress-prio-to-num_active_comps.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Subject: zram: limit max recompress prio to num_active_comps
Date: Sat, 22 Feb 2025 07:25:38 +0900
Use the actual number of algorithms zram was configure with instead of
theoretical limit of ZRAM_MAX_COMPS.
Also make sure that min prio is not above max prio.
Link: https://lkml.kernel.org/r/20250221222958.2225035-8-senozhatsky@xxxxxxxxxxxx
Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Hillf Danton <hdanton@xxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Yosry Ahmed <yosry.ahmed@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
--- a/drivers/block/zram/zram_drv.c~zram-limit-max-recompress-prio-to-num_active_comps
+++ a/drivers/block/zram/zram_drv.c
@@ -2031,16 +2031,19 @@ static ssize_t recompress_store(struct d
struct device_attribute *attr,
const char *buf, size_t len)
{
- u32 prio = ZRAM_SECONDARY_COMP, prio_max = ZRAM_MAX_COMPS;
struct zram *zram = dev_to_zram(dev);
char *args, *param, *val, *algo = NULL;
u64 num_recomp_pages = ULLONG_MAX;
struct zram_pp_ctl *ctl = NULL;
struct zram_pp_slot *pps;
u32 mode = 0, threshold = 0;
+ u32 prio, prio_max;
struct page *page;
ssize_t ret;
+ prio = ZRAM_SECONDARY_COMP;
+ prio_max = zram->num_active_comps;
+
args = skip_spaces(buf);
while (*args) {
args = next_arg(args, ¶m, &val);
@@ -2093,7 +2096,7 @@ static ssize_t recompress_store(struct d
if (prio == ZRAM_PRIMARY_COMP)
prio = ZRAM_SECONDARY_COMP;
- prio_max = min(prio + 1, ZRAM_MAX_COMPS);
+ prio_max = prio + 1;
continue;
}
}
@@ -2121,7 +2124,7 @@ static ssize_t recompress_store(struct d
continue;
if (!strcmp(zram->comp_algs[prio], algo)) {
- prio_max = min(prio + 1, ZRAM_MAX_COMPS);
+ prio_max = prio + 1;
found = true;
break;
}
@@ -2133,6 +2136,12 @@ static ssize_t recompress_store(struct d
}
}
+ prio_max = min(prio_max, (u32)zram->num_active_comps);
+ if (prio >= prio_max) {
+ ret = -EINVAL;
+ goto release_init_lock;
+ }
+
page = alloc_page(GFP_KERNEL);
if (!page) {
ret = -ENOMEM;
_
Patches currently in -mm which might be from senozhatsky@xxxxxxxxxxxx are
zram-sleepable-entry-locking.patch
zram-permit-preemption-with-active-compression-stream.patch
zram-remove-unused-crypto-include.patch
zram-remove-max_comp_streams-device-attr.patch
zram-remove-second-stage-of-handle-allocation.patch
zram-remove-writestall-zram_stats-member.patch
zram-limit-max-recompress-prio-to-num_active_comps.patch
zram-filter-out-recomp-targets-based-on-priority.patch
zram-rework-recompression-loop.patch
zsmalloc-rename-pool-lock.patch
zsmalloc-make-zspage-lock-preemptible.patch
zsmalloc-introduce-new-object-mapping-api.patch
zram-switch-to-new-zsmalloc-object-mapping-api.patch
zram-permit-reclaim-in-zstd-custom-allocator.patch
zram-do-not-leak-page-on-recompress_store-error-path.patch
zram-do-not-leak-page-on-writeback_store-error-path.patch
zram-add-might_sleep-to-zcomp-api.patch
zsmalloc-zram-there-be-preemption.patch
