+ zram-dont-return-errors-from-read_from_bdev_async.patch added to mm-unstable branch

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

The patch titled
     Subject: zram: don't return errors from read_from_bdev_async
has been added to the -mm mm-unstable branch.  Its filename is
     zram-dont-return-errors-from-read_from_bdev_async.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-dont-return-errors-from-read_from_bdev_async.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: don't return errors from read_from_bdev_async
Date: Tue, 11 Apr 2023 19:14:57 +0200

bio_alloc will never return a NULL bio when it is allowed to sleep, and
adding a single page to bio with a single vector also can't fail, so
switch to the asserting __bio_add_page variant and drop the error returns.

Link: https://lkml.kernel.org/r/20230411171459.567614-16-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 |   16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

--- a/drivers/block/zram/zram_drv.c~zram-dont-return-errors-from-read_from_bdev_async
+++ a/drivers/block/zram/zram_drv.c
@@ -585,24 +585,16 @@ static void zram_page_end_io(struct bio
 	bio_put(bio);
 }
 
-/*
- * Returns 1 if the submission is successful.
- */
-static int read_from_bdev_async(struct zram *zram, struct page *page,
+static void read_from_bdev_async(struct zram *zram, struct page *page,
 			unsigned long entry, struct bio *parent)
 {
 	struct bio *bio;
 
 	bio = bio_alloc(zram->bdev, 1, parent ? parent->bi_opf : REQ_OP_READ,
 			GFP_NOIO);
-	if (!bio)
-		return -ENOMEM;
 
 	bio->bi_iter.bi_sector = entry * (PAGE_SIZE >> 9);
-	if (!bio_add_page(bio, page, PAGE_SIZE, 0)) {
-		bio_put(bio);
-		return -EIO;
-	}
+	__bio_add_page(bio, page, PAGE_SIZE, 0);
 
 	if (!parent)
 		bio->bi_end_io = zram_page_end_io;
@@ -610,7 +602,6 @@ static int read_from_bdev_async(struct z
 		bio_chain(bio, parent);
 
 	submit_bio(bio);
-	return 1;
 }
 
 #define PAGE_WB_SIG "page_index="
@@ -840,7 +831,8 @@ static int read_from_bdev(struct zram *z
 			return -EIO;
 		return read_from_bdev_sync(zram, page, entry, parent);
 	}
-	return read_from_bdev_async(zram, page, entry, parent);
+	read_from_bdev_async(zram, page, entry, parent);
+	return 1;
 }
 #else
 static inline void reset_bdev(struct zram *zram) {};
_

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

zram-always-compile-read_from_bdev_sync.patch
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