The patch titled
Subject: zram: do not lookup algorithm in backends table
has been added to the -mm mm-unstable branch. Its filename is
zram-do-not-lookup-algorithm-in-backends-table.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-do-not-lookup-algorithm-in-backends-table.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Subject: zram: do not lookup algorithm in backends table
Date: Wed, 22 Jun 2022 11:35:01 +0900
Always use crypto_has_comp() so that crypto can lookup module, call
usermodhelper to load the modules, wait for usermodhelper to finish and so
on. Otherwise crypto will do all of these steps under CPU hot-plug lock
and this looks like too much stuff to handle under the CPU hot-plug lock.
Besides this can end up in a deadlock when usermodhelper triggers a code
path that attempts to lock the CPU hot-plug lock, that zram already holds.
Link: https://lkml.kernel.org/r/20220622023501.517125-1-senozhatsky@xxxxxxxxxxxx
Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zcomp.c | 6 ------
1 file changed, 6 deletions(-)
--- a/drivers/block/zram/zcomp.c~zram-do-not-lookup-algorithm-in-backends-table
+++ a/drivers/block/zram/zcomp.c
@@ -63,12 +63,6 @@ static int zcomp_strm_init(struct zcomp_
bool zcomp_available_algorithm(const char *comp)
{
- int i;
-
- i = sysfs_match_string(backends, comp);
- if (i >= 0)
- return true;
-
/*
* Crypto does not ignore a trailing new line symbol,
* so make sure you don't supply a string containing
_
Patches currently in -mm which might be from senozhatsky@xxxxxxxxxxxx are
zram-do-not-lookup-algorithm-in-backends-table.patch
