Re: [PATCH v5] x86: Remove unnecessary kmap() from sgx_ioc_enclave_init()

From: Borislav Petkov <bp@alien8.de>
To: ira.weiny@intel.com
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org, Sean Christopherson <seanjc@google.com>,
	Jethro Beekman <jethro@fortanix.com>,
	Jarkko Sakkinen <jarkko@kernel.org>,
	Dave Hansen <dave.hansen@intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	linux-sgx@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5] x86: Remove unnecessary kmap() from sgx_ioc_enclave_init()
Date: Wed, 24 Mar 2021 10:47:20 +0100	[thread overview]
Message-ID: <20210324094720.GA5010@zn.tnic> (raw)
In-Reply-To: <20210306002058.303796-1-ira.weiny@intel.com>

On Fri, Mar 05, 2021 at 04:20:58PM -0800, ira.weiny@intel.com wrote:

> Subject: Re: [PATCH v5] x86: Remove unnecessary kmap() from  sgx_ioc_enclave_init()

The tip tree preferred format for patch subject prefixes is
'subsys/component:', e.g. 'x86/apic:', 'x86/mm/fault:', 'sched/fair:',
'genirq/core:'. Please do not use file names or complete file paths as
prefix. 'git log path/to/file' should give you a reasonable hint in most
cases.

> From: Ira Weiny <ira.weiny@intel.com>
> 
> kmap is inefficient and we are trying to reduce the usage in the kernel.

Please use passive voice in your commit message: no "we" or "I", etc,
and describe your changes in imperative mood.

Also, pls read section "2) Describe your changes" in
Documentation/process/submitting-patches.rst for more details.

Bottom line is: personal pronouns are ambiguous in text, especially with
so many parties/companies/etc developing the kernel so let's avoid them
please.

> @@ -615,11 +614,14 @@ static long sgx_ioc_enclave_init(struct sgx_encl *encl, void __user *arg)
>  	if (copy_from_user(&init_arg, arg, sizeof(init_arg)))
>  		return -EFAULT;
>  
> -	initp_page = alloc_page(GFP_KERNEL);
> -	if (!initp_page)
> +	/*
> +	 * sigstruct must be on a page boundry and token on a 512 byte boundry
> +	 * kmalloc() gives us this alignment when allocating PAGE_SIZE bytes

Please integrate scripts/checkpatch.pl into your patch creation
workflow. Some of the warnings/errors *actually* make sense.

WARNING: 'boundry' may be misspelled - perhaps 'boundary'?
#90: FILE: arch/x86/kernel/cpu/sgx/ioctl.c:618:
+        * sigstruct must be on a page boundry and token on a 512 byte boundry
                                       ^^^^^^^

WARNING: 'boundry' may be misspelled - perhaps 'boundary'?
#90: FILE: arch/x86/kernel/cpu/sgx/ioctl.c:618:
+        * sigstruct must be on a page boundry and token on a 512 byte boundry
                                                                       ^^^^^^^

Also, do you see how other comments in this file are proper sentences?
Please formulate yours this way too.

The change itself looks ok.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette