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bh=iZeD7ZRu9tfSGLuTP62t6auaUEfXlLmcKZ7Z2/qHEMQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=NKpoyy+Yq6eqQbNYmjxqL2awnOyyHtD9l6JPyLyvHjgVoziqxs+++3YxXj1ILg3s7 fThj6+7nxfFmT1cgl4T8Z52FbVv3E1+An1mGocVyxA8KAphD8aJqEfobzBt3Jhc7l5 zcR20po358bnNrXE8ln3SnUEFC/KX/yu2Asz1XdU= Date: Tue, 4 Apr 2023 12:31:31 -0700 From: Andrew Morton To: Christoph Hellwig Cc: Pankaj Raghav , axboe@kernel.dk, minchan@kernel.org, martin@omnibond.com, hubcap@omnibond.com, brauner@kernel.org, viro@zeniv.linux.org.uk, senozhatsky@chromium.org, willy@infradead.org, hch@lst.de, devel@lists.orangefs.org, mcgrof@kernel.org, linux-block@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, gost.dev@samsung.com, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2 1/5] zram: always chain bio to the parent in read_from_bdev_async Message-Id: <20230404123131.6e8fca22b0a484c8c152492a@linux-foundation.org> In-Reply-To: References: <20230403132221.94921-1-p.raghav@samsung.com> <20230403132221.94921-2-p.raghav@samsung.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: BFC84C0020 X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: gy4pqdh53ipi1kc93qzmj6gyptsgmbq9 X-HE-Tag: 1680636693-337543 X-HE-Meta: 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 mc9iTo4u EwFnzPLFpQ7+EjDsqCYMLucr1HX6bJs5Xcw1LiI9CTD7cTAu9U2rwdb1gSBGfEV6q+5PeqwN7XOCsiUbaXVrQj5WZz+we211idQ+GdjIs8653SmjRPVcQdQQUSBe10EwQ06Qnk5C4rP1/H0HYf6m6sHTzFvosePC5iQKLB+sSJ9bH7itGoJ0QrvIB241fEzl/ITDDlIZJj94wZZ7BC/WF6M+JtoTdLAruProvry8lNW/FIp+vMrVi2Ue9hWgHnL2nNFUHBjdEcRY3pLIAtj1tCzvH+PNoEIa4OHx+pTc7y6RkfleX7+xUlCEQDxOei6T2YogqLP/Ua6MFoQNsHD+oO70N3plsetmRWiGxbL5CmM1fIGa9YbkBDDoM7iz3Jn2K5RMtcHR4Itp8O734t4CfUSFPX9NPshtOtobrB7DUieY0SSATFmc6UzyFAiUesytY9k+JIOYIfGRaKWs= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, 4 Apr 2023 08:06:55 -0700 Christoph Hellwig wrote: > On Mon, Apr 03, 2023 at 03:22:17PM +0200, Pankaj Raghav wrote: > > zram_bvec_read() is called with the bio set to NULL only in > > writeback_store() function. When a writeback is triggered, > > zram_bvec_read() is called only if ZRAM_WB flag is not set. That will > > result only calling zram_read_from_zspool() in __zram_bvec_read(). > > > > rw_page callback used to call read_from_bdev_async with a NULL parent > > bio but that has been removed since commit 3222d8c2a7f8 > > ("block: remove ->rw_page"). > > > > We can now safely always call bio_chain() as read_from_bdev_async() will > > be called with a parent bio set. A WARN_ON_ONCE is added if this function > > is called with parent set to NULL. > > I'm pretty sure this is wrong. Thanks, I'll drop this v2 series. > I've now sent a series to untangle > and fix up the zram I/O path, which should address the underlying > issue here. I can't find that series. > It will obviously conflict with this patch, so maybe the best thing is > to get the other page_endio removals into their respective maintainer > trees, and then just do the final removal of the unused function after > -rc1.