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

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

The patch titled
     Subject: zram: return errors from read_from_bdev_sync
has been added to the -mm mm-unstable branch.  Its filename is
     zram-return-errors-from-read_from_bdev_sync.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-return-errors-from-read_from_bdev_sync.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: return errors from read_from_bdev_sync
Date: Thu, 6 Apr 2023 16:41:02 +0200

Propagate read errors to the caller instead of dropping them on the floor,
and stop returning the somewhat dangerous 1 on success from
read_from_bdev*.

Link: https://lkml.kernel.org/r/20230406144102.149231-17-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/block/zram/zram_drv.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/drivers/block/zram/zram_drv.c~zram-return-errors-from-read_from_bdev_sync
+++ a/drivers/block/zram/zram_drv.c
@@ -770,6 +770,7 @@ struct zram_work {
 	struct zram *zram;
 	unsigned long entry;
 	struct page *page;
+	int error;
 };
 
 static void zram_sync_read(struct work_struct *work)
@@ -781,7 +782,7 @@ static void zram_sync_read(struct work_s
 	bio_init(&bio, zw->zram->bdev, &bv, 1, REQ_OP_READ);
 	bio.bi_iter.bi_sector = zw->entry * (PAGE_SIZE >> 9);
 	__bio_add_page(&bio, zw->page, PAGE_SIZE, 0);
-	submit_bio_wait(&bio);
+	zw->error = submit_bio_wait(&bio);
 }
 
 /*
@@ -803,7 +804,7 @@ static int read_from_bdev_sync(struct zr
 	flush_work(&work.work);
 	destroy_work_on_stack(&work.work);
 
-	return 1;
+	return work.error;
 }
 #else
 static int read_from_bdev_sync(struct zram *zram, struct page *page,
@@ -821,7 +822,7 @@ static int read_from_bdev(struct zram *z
 	if (!parent)
 		return read_from_bdev_sync(zram, page, entry);
 	read_from_bdev_async(zram, page, entry, parent);
-	return 1;
+	return 0;
 }
 #else
 static inline void reset_bdev(struct zram *zram) {};
_

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