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	id E60F467373; Fri,  2 May 2025 09:05:37 +0200 (CEST)
Date: Fri, 2 May 2025 09:05:37 +0200
From: Christoph Hellwig <hch@lst.de>
To: Damien Le Moal <dlemoal@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org,
	"Md. Haris Iqbal" <haris.iqbal@ionos.com>,
	Jack Wang <jinpu.wang@ionos.com>, Coly Li <colyli@kernel.org>,
	Kent Overstreet <kent.overstreet@linux.dev>,
	Mike Snitzer <snitzer@kernel.org>,
	Mikulas Patocka <mpatocka@redhat.com>, Chris Mason <clm@fb.com>,
	Josef Bacik <josef@toxicpanda.com>, David Sterba <dsterba@suse.com>,
	Andreas Gruenbacher <agruenba@redhat.com>,
	Carlos Maiolino <cem@kernel.org>,
	Naohiro Aota <naohiro.aota@wdc.com>,
	Johannes Thumshirn <jth@kernel.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Pavel Machek <pavel@kernel.org>, slava@dubeyko.com,
	glaubitz@physik.fu-berlin.de, frank.li@vivo.com,
	linux-bcache@vger.kernel.org, dm-devel@lists.linux.dev,
	linux-btrfs@vger.kernel.org, gfs2@lists.linux.dev,
	linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org,
	linux-pm@vger.kernel.org
Subject: Re: [PATCH 07/19] block: simplify bio_map_kern
Message-ID: <20250502070537.GA8402@lst.de>
References: <20250430212159.2865803-1-hch@lst.de> <20250430212159.2865803-8-hch@lst.de> <282b0a35-cc60-4d61-a3b7-9b565c57b8bf@kernel.org>
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On Fri, May 02, 2025 at 03:56:08AM +0900, Damien Le Moal wrote:
> > -	unsigned long kaddr = (unsigned long)data;
> > -	unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
> > -	unsigned long start = kaddr >> PAGE_SHIFT;
> > -	const int nr_pages = end - start;
> > -	bool is_vmalloc = is_vmalloc_addr(data);
> > -	struct page *page;
> > -	int offset, i;
> > +	unsigned int nr_vecs = bio_add_max_vecs(data, len);
> >  	struct bio *bio;
> >  
> > -	bio = bio_kmalloc(nr_pages, gfp_mask);
> > +	bio = bio_kmalloc(nr_vecs, gfp_mask);
> 
> This may also fail if nr_vecs is larger than UIO_MAXIOV, in which case, the
> ENOMEM error may not really be appropriate. I guess we can sort this out
> separately though.

Yeah.  It's also existing behavior, so no real change here.