2019-09-10 09:20:30

by Pasha Tatashin

Subject: [PATCH v4 05/17] arm64: hibernate: remove gotos in create_safe_exec_page

Usually, gotos are used to handle cleanup after exception, but
in case of create_safe_exec_page there are no clean-ups. So,
simply return the errors directly.

Signed-off-by: Pavel Tatashin <[email protected]>
Reviewed-by: James Morse <[email protected]>
---
arch/arm64/kernel/hibernate.c | 34 +++++++++++-----------------------
1 file changed, 11 insertions(+), 23 deletions(-)

diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
index 47a861e0cb0c..7bbeb33c700d 100644
--- a/arch/arm64/kernel/hibernate.c
+++ b/arch/arm64/kernel/hibernate.c
@@ -198,7 +198,6 @@ static int create_safe_exec_page(void *src_start, size_t length,
unsigned long dst_addr,
phys_addr_t *phys_dst_addr)
{
- int rc = 0;
pgd_t *trans_pgd;
pgd_t *pgdp;
pud_t *pudp;
@@ -206,47 +205,37 @@ static int create_safe_exec_page(void *src_start, size_t length,
pte_t *ptep;
unsigned long dst = get_safe_page(GFP_ATOMIC);

- if (!dst) {
- rc = -ENOMEM;
- goto out;
- }
+ if (!dst)
+ return -ENOMEM;

memcpy((void *)dst, src_start, length);
__flush_icache_range(dst, dst + length);

trans_pgd = (void *)get_safe_page(GFP_ATOMIC);
- if (!trans_pgd) {
- rc = -ENOMEM;
- goto out;
- }
+ if (!trans_pgd)
+ return -ENOMEM;

pgdp = pgd_offset_raw(trans_pgd, dst_addr);
if (pgd_none(READ_ONCE(*pgdp))) {
pudp = (void *)get_safe_page(GFP_ATOMIC);
- if (!pudp) {
- rc = -ENOMEM;
- goto out;
- }
+ if (!pudp)
+ return -ENOMEM;
pgd_populate(&init_mm, pgdp, pudp);
}

pudp = pud_offset(pgdp, dst_addr);
if (pud_none(READ_ONCE(*pudp))) {
pmdp = (void *)get_safe_page(GFP_ATOMIC);
- if (!pmdp) {
- rc = -ENOMEM;
- goto out;
- }
+ if (!pmdp)
+ return -ENOMEM;
pud_populate(&init_mm, pudp, pmdp);
}

pmdp = pmd_offset(pudp, dst_addr);
if (pmd_none(READ_ONCE(*pmdp))) {
ptep = (void *)get_safe_page(GFP_ATOMIC);
- if (!ptep) {
- rc = -ENOMEM;
- goto out;
- }
+ if (!ptep)
+ return -ENOMEM;
pmd_populate_kernel(&init_mm, pmdp, ptep);
}

@@ -272,8 +261,7 @@ static int create_safe_exec_page(void *src_start, size_t length,

*phys_dst_addr = virt_to_phys((void *)dst);

-out:
- return rc;
+ return 0;
}

#define dcache_clean_range(start, end) __flush_dcache_area(start, (end - start))
--
2.23.0

2019-09-10 11:50:03

by Matthias Brugger

Subject: Re: [PATCH v4 05/17] arm64: hibernate: remove gotos in create_safe_exec_page

On 09/09/2019 20:12, Pavel Tatashin wrote:
> Usually, gotos are used to handle cleanup after exception, but
> in case of create_safe_exec_page there are no clean-ups. So,
> simply return the errors directly.
>

While at it, how about also cleaning up swsusp_arch_resume() which has the same
issue.

Regards,
Matthias

> Signed-off-by: Pavel Tatashin <[email protected]>
> Reviewed-by: James Morse <[email protected]>
> ---
> arch/arm64/kernel/hibernate.c | 34 +++++++++++-----------------------
> 1 file changed, 11 insertions(+), 23 deletions(-)
>
> diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
> index 47a861e0cb0c..7bbeb33c700d 100644
> --- a/arch/arm64/kernel/hibernate.c
> +++ b/arch/arm64/kernel/hibernate.c
> @@ -198,7 +198,6 @@ static int create_safe_exec_page(void *src_start, size_t length,
> unsigned long dst_addr,
> phys_addr_t *phys_dst_addr)
> {
> - int rc = 0;
> pgd_t *trans_pgd;
> pgd_t *pgdp;
> pud_t *pudp;
> @@ -206,47 +205,37 @@ static int create_safe_exec_page(void *src_start, size_t length,
> pte_t *ptep;
> unsigned long dst = get_safe_page(GFP_ATOMIC);
>
> - if (!dst) {
> - rc = -ENOMEM;
> - goto out;
> - }
> + if (!dst)
> + return -ENOMEM;
>
> memcpy((void *)dst, src_start, length);
> __flush_icache_range(dst, dst + length);
>
> trans_pgd = (void *)get_safe_page(GFP_ATOMIC);
> - if (!trans_pgd) {
> - rc = -ENOMEM;
> - goto out;
> - }
> + if (!trans_pgd)
> + return -ENOMEM;
>
> pgdp = pgd_offset_raw(trans_pgd, dst_addr);
> if (pgd_none(READ_ONCE(*pgdp))) {
> pudp = (void *)get_safe_page(GFP_ATOMIC);
> - if (!pudp) {
> - rc = -ENOMEM;
> - goto out;
> - }
> + if (!pudp)
> + return -ENOMEM;
> pgd_populate(&init_mm, pgdp, pudp);
> }
>
> pudp = pud_offset(pgdp, dst_addr);
> if (pud_none(READ_ONCE(*pudp))) {
> pmdp = (void *)get_safe_page(GFP_ATOMIC);
> - if (!pmdp) {
> - rc = -ENOMEM;
> - goto out;
> - }
> + if (!pmdp)
> + return -ENOMEM;
> pud_populate(&init_mm, pudp, pmdp);
> }
>
> pmdp = pmd_offset(pudp, dst_addr);
> if (pmd_none(READ_ONCE(*pmdp))) {
> ptep = (void *)get_safe_page(GFP_ATOMIC);
> - if (!ptep) {
> - rc = -ENOMEM;
> - goto out;
> - }
> + if (!ptep)
> + return -ENOMEM;
> pmd_populate_kernel(&init_mm, pmdp, ptep);
> }
>
> @@ -272,8 +261,7 @@ static int create_safe_exec_page(void *src_start, size_t length,
>
> *phys_dst_addr = virt_to_phys((void *)dst);
>
> -out:
> - return rc;
> + return 0;
> }
>
> #define dcache_clean_range(start, end) __flush_dcache_area(start, (end - start))
>

2019-09-10 18:53:06

by Pasha Tatashin

Subject: Re: [PATCH v4 05/17] arm64: hibernate: remove gotos in create_safe_exec_page

> On 09/09/2019 20:12, Pavel Tatashin wrote:
> > Usually, gotos are used to handle cleanup after exception, but
> > in case of create_safe_exec_page there are no clean-ups. So,
> > simply return the errors directly.
> >
>
> While at it, how about also cleaning up swsusp_arch_resume() which has the same
> issue.

Thank you for suggestion. I will do cleanups in swsusp_arch_resume() as well.

Pasha

>
> Regards,
> Matthias
>
> > Signed-off-by: Pavel Tatashin <[email protected]>
> > Reviewed-by: James Morse <[email protected]>
> > ---
> > arch/arm64/kernel/hibernate.c | 34 +++++++++++-----------------------
> > 1 file changed, 11 insertions(+), 23 deletions(-)
> >
> > diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
> > index 47a861e0cb0c..7bbeb33c700d 100644
> > --- a/arch/arm64/kernel/hibernate.c
> > +++ b/arch/arm64/kernel/hibernate.c
> > @@ -198,7 +198,6 @@ static int create_safe_exec_page(void *src_start, size_t length,
> > unsigned long dst_addr,
> > phys_addr_t *phys_dst_addr)
> > {
> > - int rc = 0;
> > pgd_t *trans_pgd;
> > pgd_t *pgdp;
> > pud_t *pudp;
> > @@ -206,47 +205,37 @@ static int create_safe_exec_page(void *src_start, size_t length,
> > pte_t *ptep;
> > unsigned long dst = get_safe_page(GFP_ATOMIC);
> >
> > - if (!dst) {
> > - rc = -ENOMEM;
> > - goto out;
> > - }
> > + if (!dst)
> > + return -ENOMEM;
> >
> > memcpy((void *)dst, src_start, length);
> > __flush_icache_range(dst, dst + length);
> >
> > trans_pgd = (void *)get_safe_page(GFP_ATOMIC);
> > - if (!trans_pgd) {
> > - rc = -ENOMEM;
> > - goto out;
> > - }
> > + if (!trans_pgd)
> > + return -ENOMEM;
> >
> > pgdp = pgd_offset_raw(trans_pgd, dst_addr);
> > if (pgd_none(READ_ONCE(*pgdp))) {
> > pudp = (void *)get_safe_page(GFP_ATOMIC);
> > - if (!pudp) {
> > - rc = -ENOMEM;
> > - goto out;
> > - }
> > + if (!pudp)
> > + return -ENOMEM;
> > pgd_populate(&init_mm, pgdp, pudp);
> > }
> >
> > pudp = pud_offset(pgdp, dst_addr);
> > if (pud_none(READ_ONCE(*pudp))) {
> > pmdp = (void *)get_safe_page(GFP_ATOMIC);
> > - if (!pmdp) {
> > - rc = -ENOMEM;
> > - goto out;
> > - }
> > + if (!pmdp)
> > + return -ENOMEM;
> > pud_populate(&init_mm, pudp, pmdp);
> > }
> >
> > pmdp = pmd_offset(pudp, dst_addr);
> > if (pmd_none(READ_ONCE(*pmdp))) {
> > ptep = (void *)get_safe_page(GFP_ATOMIC);
> > - if (!ptep) {
> > - rc = -ENOMEM;
> > - goto out;
> > - }
> > + if (!ptep)
> > + return -ENOMEM;
> > pmd_populate_kernel(&init_mm, pmdp, ptep);
> > }
> >
> > @@ -272,8 +261,7 @@ static int create_safe_exec_page(void *src_start, size_t length,
> >
> > *phys_dst_addr = virt_to_phys((void *)dst);
> >
> > -out:
> > - return rc;
> > + return 0;
> > }
> >
> > #define dcache_clean_range(start, end) __flush_dcache_area(start, (end - start))
> >