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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Keith Busch <kbusch@kernel.org>,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        Christoph Hellwig <hch@lst.de>,
        Johannes Thumshirn <johannes.thumshirn@wdc.com>,
        Jens Axboe <axboe@kernel.dk>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 178/779] block: fix infinite loop for invalid zone append
Date:   Mon, 15 Aug 2022 19:57:02 +0200
Message-Id: <20220815180344.875920711@linuxfoundation.org>
In-Reply-To: <20220815180337.130757997@linuxfoundation.org>
References: <20220815180337.130757997@linuxfoundation.org>
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From: Keith Busch <kbusch@kernel.org>

[ Upstream commit b82d9fa257cb3725c49d94d2aeafc4677c34448a ]

Returning 0 early from __bio_iov_append_get_pages() for the
max_append_sectors warning just creates an infinite loop since 0 means
success, and the bio will never fill from the unadvancing iov_iter. We
could turn the return into an error value, but it will already be turned
into an error value later on, so just remove the warning. Clearly no one
ever hit it anyway.

Fixes: 0512a75b98f84 ("block: Introduce REQ_OP_ZONE_APPEND")
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20220610195830.3574005-2-kbusch@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 block/bio.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index b8a8bfba714f..b117765d58c0 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1141,9 +1141,6 @@ static int __bio_iov_append_get_pages(struct bio *bio, struct iov_iter *iter)
 	size_t offset;
 	int ret = 0;
 
-	if (WARN_ON_ONCE(!max_append_sectors))
-		return 0;
-
 	/*
 	 * Move page array up in the allocated memory for the bio vecs as far as
 	 * possible so that we can start filling biovecs from the beginning
-- 
2.35.1