[merged mm-stable] zram-dont-use-highmem-for-the-bounce-buffer-in-zram_bvec_readwrite.patch removed from -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

The quilt patch titled
     Subject: zram: don't use highmem for the bounce buffer in zram_bvec_{read,write}
has been removed from the -mm tree.  Its filename was
     zram-dont-use-highmem-for-the-bounce-buffer-in-zram_bvec_readwrite.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: Christoph Hellwig <hch@lst.de>
Subject: zram: don't use highmem for the bounce buffer in zram_bvec_{read,write}
Date: Tue, 11 Apr 2023 19:14:50 +0200

There is no point in allocation a highmem page when we instantly need to
copy from it.

Link: https://lkml.kernel.org/r/20230411171459.567614-9-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/block/zram/zram_drv.c |   17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

--- a/drivers/block/zram/zram_drv.c~zram-dont-use-highmem-for-the-bounce-buffer-in-zram_bvec_readwrite
+++ a/drivers/block/zram/zram_drv.c
@@ -1431,7 +1431,7 @@ static int zram_bvec_read(struct zram *z
 	page = bvec->bv_page;
 	if (is_partial_io(bvec)) {
 		/* Use a temporary buffer to decompress the page */
-		page = alloc_page(GFP_NOIO|__GFP_HIGHMEM);
+		page = alloc_page(GFP_NOIO);
 		if (!page)
 			return -ENOMEM;
 	}
@@ -1440,12 +1440,8 @@ static int zram_bvec_read(struct zram *z
 	if (unlikely(ret))
 		goto out;
 
-	if (is_partial_io(bvec)) {
-		void *src = kmap_atomic(page);
-
-		memcpy_to_bvec(bvec, src + offset);
-		kunmap_atomic(src);
-	}
+	if (is_partial_io(bvec))
+		memcpy_to_bvec(bvec, page_address(page) + offset);
 out:
 	if (is_partial_io(bvec))
 		__free_page(page);
@@ -1589,12 +1585,11 @@ static int zram_bvec_write(struct zram *
 
 	vec = *bvec;
 	if (is_partial_io(bvec)) {
-		void *dst;
 		/*
 		 * This is a partial IO. We need to read the full page
 		 * before to write the changes.
 		 */
-		page = alloc_page(GFP_NOIO|__GFP_HIGHMEM);
+		page = alloc_page(GFP_NOIO);
 		if (!page)
 			return -ENOMEM;
 
@@ -1602,9 +1597,7 @@ static int zram_bvec_write(struct zram *
 		if (ret)
 			goto out;
 
-		dst = kmap_atomic(page);
-		memcpy_from_bvec(dst + offset, bvec);
-		kunmap_atomic(dst);
+		memcpy_from_bvec(page_address(page) + offset, bvec);
 
 		bvec_set_page(&vec, page, PAGE_SIZE, 0);
 	}
_

Patches currently in -mm which might be from hch@lst.de are

zram-rename-__zram_bvec_read-to-zram_read_page.patch
zram-directly-call-zram_read_page-in-writeback_store.patch
zram-refactor-zram_bdev_read.patch
zram-dont-pass-a-bvec-to-__zram_bvec_write.patch
zram-refactor-zram_bdev_write.patch
zram-pass-a-page-to-read_from_bdev.patch
zram-dont-return-errors-from-read_from_bdev_async.patch
zram-fix-synchronous-reads.patch
zram-return-errors-from-read_from_bdev_sync.patch