From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
Chandan Babu R <chandanbabu@kernel.org>,
linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
linux-xfs@vger.kernel.org
Subject: Re: [PATCH 2/5] block: add a bio_chain_and_submit helper
Date: Tue, 12 Mar 2024 22:06:05 +0100 [thread overview]
Message-ID: <20240312210605.GA1500@lst.de> (raw)
In-Reply-To: <ZfBr91m4oQS_VYFg@kbusch-mbp.mynextlight.net>
On Tue, Mar 12, 2024 at 08:51:35AM -0600, Keith Busch wrote:
> > +
> > +struct bio *blk_next_bio(struct bio *bio, struct block_device *bdev,
> > + unsigned int nr_pages, blk_opf_t opf, gfp_t gfp)
> > +{
> > + return bio_chain_and_submit(bio, bio_alloc(bdev, nr_pages, opf, gfp));
> > +}
>
> I realize you're not changing any behavior here, but I want to ask, is
> bio_alloc() always guaranteed to return a valid bio? It sure looks like
> it can return NULL under some uncommon conditions, but I can't find
> anyone checking the result. So I guess it's safe?
bio_alloc can only fail if we don't wait for allocations, that is if
__GFP_DIRECT_RECLAIM isn't set.
We could an assert here. Or work on killing the gfp_flags argument
and just add a bio_alloc_nowait for the few cases that need it.
next prev parent reply other threads:[~2024-03-12 21:06 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-12 14:45 RFCv2: fix fatal signal handling in __blkdev_issue_discard Christoph Hellwig
2024-03-12 14:45 ` [PATCH 1/5] block: move discard checks into the ioctl handler Christoph Hellwig
2024-03-12 22:12 ` Keith Busch
2024-03-12 22:31 ` Christoph Hellwig
2024-03-13 1:22 ` Keith Busch
2024-03-13 15:40 ` Keith Busch
2024-03-13 20:06 ` Christoph Hellwig
2024-03-13 20:08 ` Jens Axboe
2024-03-12 14:45 ` [PATCH 2/5] block: add a bio_chain_and_submit helper Christoph Hellwig
2024-03-12 14:51 ` Keith Busch
2024-03-12 21:06 ` Christoph Hellwig [this message]
2024-03-12 14:45 ` [PATCH 3/5] block: add a blk_alloc_discard_bio helper Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2024-03-12 14:48 RFCv2: fix fatal signal handling in __blkdev_issue_discard Christoph Hellwig
2024-03-12 14:48 ` [PATCH 2/5] block: add a bio_chain_and_submit helper Christoph Hellwig
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