+ zram-refactor-zram_bdev_read.patch added to mm-unstable branch

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

The patch titled
     Subject: zram: refactor zram_bdev_read
has been added to the -mm mm-unstable branch.  Its filename is
     zram-refactor-zram_bdev_read.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-refactor-zram_bdev_read.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: Christoph Hellwig <hch@lst.de>
Subject: zram: refactor zram_bdev_read
Date: Thu, 6 Apr 2023 16:40:56 +0200

Split the partial read into a separate helper.

Link: https://lkml.kernel.org/r/20230406144102.149231-11-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 |   40 ++++++++++++++++----------------
 1 file changed, 20 insertions(+), 20 deletions(-)

--- a/drivers/block/zram/zram_drv.c~zram-refactor-zram_bdev_read
+++ a/drivers/block/zram/zram_drv.c
@@ -1422,33 +1422,33 @@ static int zram_read_page(struct zram *z
 	return ret;
 }
 
-static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
-			  u32 index, int offset, struct bio *bio)
+/*
+ * Use a temporary buffer to decompress the page, as the decompressor
+ * always expects a full page for the output.
+ */
+static int zram_bvec_read_partial(struct zram *zram, struct bio_vec *bvec,
+				  u32 index, int offset, struct bio *bio)
 {
+	struct page *page = alloc_page(GFP_NOIO);
 	int ret;
-	struct page *page;
-
-	page = bvec->bv_page;
-	if (is_partial_io(bvec)) {
-		/* Use a temporary buffer to decompress the page */
-		page = alloc_page(GFP_NOIO);
-		if (!page)
-			return -ENOMEM;
-	}
-
-	ret = zram_read_page(zram, page, index, bio, is_partial_io(bvec));
-	if (unlikely(ret))
-		goto out;
 
-	if (is_partial_io(bvec))
+	if (!page)
+		return -ENOMEM;
+	ret = zram_read_page(zram, page, index, bio, true);
+	if (likely(!ret))
 		memcpy_to_bvec(bvec, page_address(page) + offset);
-out:
-	if (is_partial_io(bvec))
-		__free_page(page);
-
+	__free_page(page);
 	return ret;
 }
 
+static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
+			  u32 index, int offset, struct bio *bio)
+{
+	if (is_partial_io(bvec))
+		return zram_bvec_read_partial(zram, bvec, index, offset, bio);
+	return zram_read_page(zram, bvec->bv_page, index, bio, false);
+}
+
 static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
 				u32 index, struct bio *bio)
 {
_

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

zram-remove-valid_io_request.patch
zram-make-zram_bio_discard-more-self-contained.patch
zram-simplify-bvec-iteration-in-__zram_make_request.patch
zram-move-discard-handling-to-zram_submit_bio.patch
zram-return-early-on-error-in-zram_bvec_rw.patch
zram-refactor-highlevel-read-and-write-handling.patch
zram-dont-use-highmem-for-the-bounce-buffer-in-zram_bvec_readwrite.patch
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