[merged mm-stable] zram-permit-reclaim-in-zstd-custom-allocator.patch removed from -mm tree

[merged mm-stable] zram-permit-reclaim-in-zstd-custom-allocator.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: zram: permit reclaim in zstd custom allocator
has been removed from the -mm tree.  Its filename was
     zram-permit-reclaim-in-zstd-custom-allocator.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Subject: zram: permit reclaim in zstd custom allocator
Date: Mon, 3 Mar 2025 11:03:25 +0900

When configured with pre-trained compression/decompression dictionary
support, zstd requires custom memory allocator, which it calls internally
from compression()/decompression() routines.  That means allocation from
atomic context (either under entry spin-lock, or per-CPU local-lock or
both).  Now, with non-atomic zram read()/write(), those limitations are
relaxed and we can allow direct and indirect reclaim.

Link: https://lkml.kernel.org/r/20250303022425.285971-17-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Yosry Ahmed <yosry.ahmed@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/block/zram/backend_zstd.c |   11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

--- a/drivers/block/zram/backend_zstd.c~zram-permit-reclaim-in-zstd-custom-allocator
+++ a/drivers/block/zram/backend_zstd.c
@@ -24,19 +24,10 @@ struct zstd_params {
 /*
  * For C/D dictionaries we need to provide zstd with zstd_custom_mem,
  * which zstd uses internally to allocate/free memory when needed.
- *
- * This means that allocator.customAlloc() can be called from zcomp_compress()
- * under local-lock (per-CPU compression stream), in which case we must use
- * GFP_ATOMIC.
- *
- * Another complication here is that we can be configured as a swap device.
  */
 static void *zstd_custom_alloc(void *opaque, size_t size)
 {
-	if (!preemptible())
-		return kvzalloc(size, GFP_ATOMIC);
-
-	return kvzalloc(size, __GFP_KSWAPD_RECLAIM | __GFP_NOWARN);
+	return kvzalloc(size, GFP_NOIO | __GFP_NOWARN);
 }
 
 static void zstd_custom_free(void *opaque, void *address)
_

Patches currently in -mm which might be from senozhatsky@chromium.org are