linux-kernel - Re: [PATCH bpf v2] lib/buildid: use __kernel

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Message-ID: <aUSUe9jHnYJ577Gh@casper.infradead.org>
Date: Thu, 18 Dec 2025 23:55:39 +0000
From: Matthew Wilcox <willy@...radead.org>
To: Shakeel Butt <shakeel.butt@...ux.dev>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
	Andrii Nakryiko <andrii@...nel.org>,
	Shaurya Rane <ssrane_b23@...vjti.ac.in>,
	"Darrick J . Wong" <djwong@...nel.org>,
	Christoph Hellwig <hch@...radead.org>,
	Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Meta kernel team <kernel-team@...a.com>, bpf@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	syzbot+09b7d050e4806540153d@...kaller.appspotmail.com,
	Christoph Hellwig <hch@....de>
Subject: Re: [PATCH bpf v2] lib/buildid: use __kernel_read() for sleepable
 context

On Thu, Dec 18, 2025 at 12:55:05PM -0800, Shakeel Butt wrote:
> +	do {
> +		ret = __kernel_read(r->file, buf, sz, &pos);
> +		if (ret <= 0) {
> +			r->err = ret ?: -EIO;
> +			return NULL;
> +		}
> +		buf += ret;
> +		sz -= ret;
> +	} while (sz > 0);

Why are you doing a loop around __kernel_read()?  eg kernel_read() does
not do a read around __kernel_read().  The callers of kernel_read()
don't do a loop either.  So what makes you think it needs to have a loop
around it?