From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3EE9E521234; Mon, 7 Sep 2026 20:06:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788811594; cv=none; b=WNRcB2UD4lyAm5e5UqR/ZvisGCVyv4E2Bo0sa74OiTSsV9GkpkvkrENproplqRSjKmbVK5W/HwxEmkS5F0NpnQl28Epwmbp4GU540zBDNUPiejdb9/iTj0mmx0kiBvRQv2wY0p7xqsRDeyAZ0oih9kthwWtOyJKOtZS6J+iFvDw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788811594; c=relaxed/simple; bh=6z+DKIAYLJkOjTbCElZ17IsPYuMv4G48gys7vG2ZGtY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ieXhQlcmlPo/+sqla4ZeZCjfQS+BcHJ7bUCG05FCSmsWX75zdqoaaRpmdXZxaFBtOl0tCnfig9bks3c7osw3OmYH51UV7piBtZYmSxwnwilrC52TtIdOWWHSwRvBnBxFVTMww34y1t9YcJrjKB1P+GD9ODaSwdMpT69f9xuY6W4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=itj8IO6W; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="itj8IO6W" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E356D1F00A3A; Mon, 7 Sep 2026 20:06:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788811590; bh=8iZFtkM4l1pBZzM0aft9DJRPxcvPbB47sa2kHkN4CLw=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=itj8IO6WuGDUlG4fV19yF3V4rKpQ14rYl9UeIVKDmHnSJolv7EFD8UQxFlCdkBVGK ws9Vqsg1Z5r3sQcqqF/wAeIxdjJpCuEOH8c/snnX01Cix6RsOz8HMTuSuIxyouMrEX N9Ho7R/MyeVcbXscY7gENbyUtymnAzjTKk4/z1IDjAsYrtk1M77rWloHCt2hqKJLKo RJGm+RXuXyXLJDPqMwjCCESNFKNgKuiECjrFBmLVzhKAvOx6SXB7UFw/iN06DxwGtd PXj/TdTFDuHpUbKZBcLTJzspv/NQjcVuLM3gTFfWwF/b6764/khZWF7e+zmsWaTxUO tAY1Bek0OCNgg== Message-ID: Date: Mon, 7 Sep 2026 22:06:22 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH bpf-next v5 1/7] mm: Add copy_remote_mm_str() To: Anastasios Papagiannis , bpf@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, andrii@kernel.org, ast@kernel.org, brauner@kernel.org, daniel@iogearbox.net, eddyz87@gmail.com, kpsingh@kernel.org, ljs@kernel.org, matt@bobrowski.net, memxor@gmail.com, song@kernel.org, sun.jian.kdev@gmail.com, utilityemal77@gmail.com, viro@zeniv.linux.org.uk References: <20260907165220.52431-1-tasos.papagiannnis@gmail.com> <20260907165220.52431-2-tasos.papagiannnis@gmail.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/7/26 18:52, Anastasios Papagiannis wrote: > copy_remote_vm_str() gets the target address space from a struct > task_struct. This does not work for an address space that exists but is > not yet associated with a task_struct, such as the mm held by struct > linux_binprm during exec. > > Add copy_remote_mm_str(), which operates directly on a struct mm_struct. > > Use a common internal interface for the MMU and NOMMU implementations > and define both public wrappers in mm/util.c. Preserve the existing > copy_remote_vm_str() behavior, including handling zero-length requests > before acquiring the task's mm. > > Signed-off-by: Anastasios Papagiannis > --- > include/linux/mm.h | 2 ++ > mm/internal.h | 5 ++++ > mm/memory.c | 41 ++---------------------------- > mm/nommu.c | 41 ++---------------------------- > mm/util.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++ > 5 files changed, 73 insertions(+), 78 deletions(-) Almost looks like a cleanup now ;) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index dd09c438fa23..d5bde1f71a97 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -3326,6 +3326,8 @@ extern int access_remote_vm(struct mm_struct *mm, unsigned long addr, > void *buf, int len, unsigned int gup_flags); > > #ifdef CONFIG_BPF_SYSCALL > +extern int copy_remote_mm_str(struct mm_struct *mm, unsigned long addr, > + void *buf, int len, unsigned int gup_flags); > extern int copy_remote_vm_str(struct task_struct *tsk, unsigned long addr, > void *buf, int len, unsigned int gup_flags); Ah, no new "extern" and best to drop the "extern" from the other involved function while at it. Also, you can just drop the ifdef; the linker will complain either way later. > #endif > diff --git a/mm/internal.h b/mm/internal.h > index 38b1165212c9..8264a346d18a 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -25,6 +25,11 @@ > struct folio_batch; > struct hstate; > > +#ifdef CONFIG_BPF_SYSCALL > +int __copy_remote_mm_str(struct mm_struct *mm, unsigned long addr, > + void *buf, int len, unsigned int gup_flags); > +#endif > + Same here, the linker will complain, so no need for the ifdef. Apart from that LGTM, thanks! -- Cheers, David