| Message ID | 20210118133358.99311-1-tianjia.zhang@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | x86/sgx: Remove redundant if conditions in sgx_encl_create | expand |
On Mon, Jan 18, 2021, 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. > > Reported-by: Jia Zhang <zhang.jia@linux.alibaba.com> > Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com> > --- > arch/x86/kernel/cpu/sgx/ioctl.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c > index 90a5caf76939..f45957c05f69 100644 > --- a/arch/x86/kernel/cpu/sgx/ioctl.c > +++ b/arch/x86/kernel/cpu/sgx/ioctl.c > @@ -66,9 +66,8 @@ 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. */ > + > + list_add(&va_page->list, &encl->va_pages); Maybe add a WARN_ONCE to document/enforce the behavior? va_page = sgx_encl_grow(encl); if (IS_ERR(va_page)) return PTR_ERR(va_page); if (WARN_ONCE(!va_page, "clever comment goes here)) return -EIO; list_add(&va_page->list, &encl->va_pages); > > /* The extra page goes to SECS. */ > encl_size = secs->size + PAGE_SIZE; > -- > 2.19.1.3.ge56e4f7 >
On Mon, Jan 18, 2021 at 09:33:58PM +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. > > Reported-by: Jia Zhang <zhang.jia@linux.alibaba.com> > Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com> What do we gain with this change and why is it reported as a regression? /Jarkko > --- > arch/x86/kernel/cpu/sgx/ioctl.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c > index 90a5caf76939..f45957c05f69 100644 > --- a/arch/x86/kernel/cpu/sgx/ioctl.c > +++ b/arch/x86/kernel/cpu/sgx/ioctl.c > @@ -66,9 +66,8 @@ 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. */ > + > + list_add(&va_page->list, &encl->va_pages); > > /* The extra page goes to SECS. */ > encl_size = secs->size + PAGE_SIZE; > -- > 2.19.1.3.ge56e4f7 > >
diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c index 90a5caf76939..f45957c05f69 100644 --- a/arch/x86/kernel/cpu/sgx/ioctl.c +++ b/arch/x86/kernel/cpu/sgx/ioctl.c @@ -66,9 +66,8 @@ 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. */ + + list_add(&va_page->list, &encl->va_pages); /* The extra page goes to SECS. */ encl_size = secs->size + PAGE_SIZE;
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. Reported-by: Jia Zhang <zhang.jia@linux.alibaba.com> Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com> --- arch/x86/kernel/cpu/sgx/ioctl.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)