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From: Jarkko Sakkinen <jarkko@kernel.org>
To: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Sean Christopherson <seanjc@google.com>,
	Shuah Khan <shuah@kernel.org>,
	x86@kernel.org, linux-sgx@vger.kernel.org,
	linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jia Zhang <zhang.jia@linux.alibaba.com>
Subject: Re: [PATCH v3 5/5] x86/sgx: Remove redundant if conditions in sgx_encl_create
Date: Sat, 30 Jan 2021 16:33:16 +0200	[thread overview]
Message-ID: <YBVuLFriVAm5EiEc@kernel.org> (raw)
In-Reply-To: <20210124062907.88229-6-tianjia.zhang@linux.alibaba.com>

On Sun, Jan 24, 2021 at 02:29:07PM +0800, Tianjia Zhang wrote:
> In this scenario, there is no case where va_page is NULL, and
> the error has been checked. The if condition statement here is
> redundant, so remove the condition detection.
> 
> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
> ---
>  arch/x86/kernel/cpu/sgx/ioctl.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
> index 1c6ecf9fbeff..b0b829f1b761 100644
> --- a/arch/x86/kernel/cpu/sgx/ioctl.c
> +++ b/arch/x86/kernel/cpu/sgx/ioctl.c
> @@ -66,9 +66,11 @@ static int sgx_encl_create(struct sgx_encl *encl, struct sgx_secs *secs)
>  	va_page = sgx_encl_grow(encl);
>  	if (IS_ERR(va_page))
>  		return PTR_ERR(va_page);
> -	else if (va_page)
> -		list_add(&va_page->list, &encl->va_pages);
> -	/* else the tail page of the VA page list had free slots. */

This is fine. The check does not make sense.

> +
> +	if (WARN_ONCE(!va_page, "non-empty VA page list before ECREATE"))
> +		return -EIO;

No need for this WARN_ONCE().

> +
> +	list_add(&va_page->list, &encl->va_pages);

This is fine.

>  
>  	/* The extra page goes to SECS. */
>  	encl_size = secs->size + PAGE_SIZE;
> -- 
> 2.19.1.3.ge56e4f7
> 
> 

/Jarkko

  parent reply	other threads:[~2021-01-30 16:29 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-24  6:29 [PATCH v3 0/5] Some optimizations related to sgx Tianjia Zhang
2021-01-24  6:29 ` [PATCH v3 1/5] selftests/x86: Simplify the code to get vdso base address in sgx Tianjia Zhang
2021-01-24  6:29 ` [PATCH v3 2/5] x86/sgx: Optimize the locking range in sgx_sanitize_section() Tianjia Zhang
2021-01-30 13:24   ` Jarkko Sakkinen
2021-01-24  6:29 ` [PATCH v3 3/5] x86/sgx: Optimize the free_cnt count in sgx_epc_section Tianjia Zhang
2021-01-27 17:40   ` Jarkko Sakkinen
2021-02-11  6:04     ` Tianjia Zhang
2021-02-12 12:19       ` Jarkko Sakkinen
2021-02-16  3:30         ` Tianjia Zhang
2021-01-24  6:29 ` [PATCH v3 4/5] x86/sgx: Allows ioctl PROVISION to execute before CREATE Tianjia Zhang
2021-01-30 13:26   ` Jarkko Sakkinen
2021-02-01 12:55     ` Tianjia Zhang
2021-01-24  6:29 ` [PATCH v3 5/5] x86/sgx: Remove redundant if conditions in sgx_encl_create Tianjia Zhang
2021-01-24  8:20   ` Greg KH
2021-01-25 18:46     ` Sean Christopherson
2021-01-30 14:33   ` Jarkko Sakkinen [this message]
2021-02-01 12:37     ` Tianjia Zhang
2021-01-25 17:22 ` [PATCH v3 0/5] Some optimizations related to sgx Jarkko Sakkinen

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