+ zram-do-not-forget-to-endio-for-partial-discard-requests.patch added to mm-new branch

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

The patch titled
     Subject: zram: do not forget to endio for partial discard requests
has been added to the -mm mm-new branch.  Its filename is
     zram-do-not-forget-to-endio-for-partial-discard-requests.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-do-not-forget-to-endio-for-partial-discard-requests.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Subject: zram: do not forget to endio for partial discard requests
Date: Tue, 31 Mar 2026 16:42:44 +0900

As reported by Qu Wenruo and Avinesh Kumar, the following

 getconf PAGESIZE
 65536
 blkdiscard -p 4k /dev/zram0

takes literally forever to complete.  zram doesn't support partial
discards and just returns immediately w/o doing any discard work in such
cases.  The problem is that we forget to endio on our way out, so
blkdiscard sleeps forever in submit_bio_wait().  Fix this by jumping to
end_bio label, which does bio_endio().

Link: https://lkml.kernel.org/r/20260331074255.777019-1-senozhatsky@chromium.org
Fixes: 0120dd6e4e202 ("zram: make zram_bio_discard more self-contained")
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reported-by: Qu Wenruo <wqu@suse.com>
Closes: https://lore.kernel.org/linux-block/92361cd3-fb8b-482e-bc89-15ff1acb9a59@suse.com
Tested-by: Qu Wenruo <wqu@suse.com>
Reported-by: Avinesh Kumar <avinesh.kumar@suse.com>
Closes: https://bugzilla.suse.com/show_bug.cgi?id=1256530
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/block/zram/zram_drv.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/block/zram/zram_drv.c~zram-do-not-forget-to-endio-for-partial-discard-requests
+++ a/drivers/block/zram/zram_drv.c
@@ -2678,7 +2678,7 @@ static void zram_bio_discard(struct zram
 	 */
 	if (offset) {
 		if (n <= (PAGE_SIZE - offset))
-			return;
+			goto end_bio;
 
 		n -= (PAGE_SIZE - offset);
 		index++;
@@ -2693,6 +2693,7 @@ static void zram_bio_discard(struct zram
 		n -= PAGE_SIZE;
 	}
 
+end_bio:
 	bio_endio(bio);
 }
 
_

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

zram-do-not-forget-to-endio-for-partial-discard-requests.patch