2022-06-23 06:56:17

by Lv qian

Subject: [PATCH] vmalloc:Merge multiple if conditional sentences

Merge multiple if statements to improve code readability

Signed-off-by: Lv qian <[email protected]>
---
mm/vmalloc.c | 66 ++++++++++++++--------------------------------------
1 file changed, 18 insertions(+), 48 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index effd1ff6a4b4..6902a180f8f7 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -135,22 +135,12 @@ static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int max_page_shift)
{
- if (max_page_shift < PMD_SHIFT)
- return 0;
-
- if (!arch_vmap_pmd_supported(prot))
- return 0;
-
- if ((end - addr) != PMD_SIZE)
- return 0;
-
- if (!IS_ALIGNED(addr, PMD_SIZE))
- return 0;
-
- if (!IS_ALIGNED(phys_addr, PMD_SIZE))
- return 0;
-
- if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr))
+ if (max_page_shift < PMD_SHIFT ||
+ !arch_vmap_pmd_supported(prot) ||
+ (end - addr) != PMD_SIZE ||
+ !IS_ALIGNED(addr, PMD_SIZE) ||
+ !IS_ALIGNED(phys_addr, PMD_SIZE) ||
+ (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr)))
return 0;

return pmd_set_huge(pmd, phys_addr, prot);
@@ -185,22 +175,12 @@ static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int max_page_shift)
{
- if (max_page_shift < PUD_SHIFT)
- return 0;
-
- if (!arch_vmap_pud_supported(prot))
- return 0;
-
- if ((end - addr) != PUD_SIZE)
- return 0;
-
- if (!IS_ALIGNED(addr, PUD_SIZE))
- return 0;
-
- if (!IS_ALIGNED(phys_addr, PUD_SIZE))
- return 0;
-
- if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
+ if (max_page_shift < PUD_SHIFT ||
+ !arch_vmap_pud_supported(prot) ||
+ (end - addr) != PUD_SIZE ||
+ !IS_ALIGNED(addr, PUD_SIZE) ||
+ !IS_ALIGNED(phys_addr, PUD_SIZE) ||
+ (pud_present(*pud) && !pud_free_pmd_page(pud, addr)))
return 0;

return pud_set_huge(pud, phys_addr, prot);
@@ -236,22 +216,12 @@ static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
phys_addr_t phys_addr, pgprot_t prot,
unsigned int max_page_shift)
{
- if (max_page_shift < P4D_SHIFT)
- return 0;
-
- if (!arch_vmap_p4d_supported(prot))
- return 0;
-
- if ((end - addr) != P4D_SIZE)
- return 0;
-
- if (!IS_ALIGNED(addr, P4D_SIZE))
- return 0;
-
- if (!IS_ALIGNED(phys_addr, P4D_SIZE))
- return 0;
-
- if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
+ if (max_page_shift < P4D_SHIFT ||
+ !arch_vmap_p4d_supported(prot) ||
+ (end - addr) != P4D_SIZE ||
+ !IS_ALIGNED(addr, P4D_SIZE) ||
+ !IS_ALIGNED(phys_addr, P4D_SIZE) ||
+ (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr)))
return 0;

return p4d_set_huge(p4d, phys_addr, prot);
--
2.18.2

2022-06-23 07:49:29

by Muchun Song

Subject: Re: [PATCH] vmalloc:Merge multiple if conditional sentences

On Thu, Jun 23, 2022 at 02:45:27PM +0800, Lv qian wrote:
> Merge multiple if statements to improve code readability
>

Hi Lv qian,

Why do you think it is more readable? For me, the original one
is more readable than yours.

Thanks.

> Signed-off-by: Lv qian <[email protected]>
> ---
> mm/vmalloc.c | 66 ++++++++++++++--------------------------------------
> 1 file changed, 18 insertions(+), 48 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index effd1ff6a4b4..6902a180f8f7 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -135,22 +135,12 @@ static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
> phys_addr_t phys_addr, pgprot_t prot,
> unsigned int max_page_shift)
> {
> - if (max_page_shift < PMD_SHIFT)
> - return 0;
> -
> - if (!arch_vmap_pmd_supported(prot))
> - return 0;
> -
> - if ((end - addr) != PMD_SIZE)
> - return 0;
> -
> - if (!IS_ALIGNED(addr, PMD_SIZE))
> - return 0;
> -
> - if (!IS_ALIGNED(phys_addr, PMD_SIZE))
> - return 0;
> -
> - if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr))
> + if (max_page_shift < PMD_SHIFT ||
> + !arch_vmap_pmd_supported(prot) ||
> + (end - addr) != PMD_SIZE ||
> + !IS_ALIGNED(addr, PMD_SIZE) ||
> + !IS_ALIGNED(phys_addr, PMD_SIZE) ||
> + (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr)))
> return 0;
>
> return pmd_set_huge(pmd, phys_addr, prot);
> @@ -185,22 +175,12 @@ static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
> phys_addr_t phys_addr, pgprot_t prot,
> unsigned int max_page_shift)
> {
> - if (max_page_shift < PUD_SHIFT)
> - return 0;
> -
> - if (!arch_vmap_pud_supported(prot))
> - return 0;
> -
> - if ((end - addr) != PUD_SIZE)
> - return 0;
> -
> - if (!IS_ALIGNED(addr, PUD_SIZE))
> - return 0;
> -
> - if (!IS_ALIGNED(phys_addr, PUD_SIZE))
> - return 0;
> -
> - if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
> + if (max_page_shift < PUD_SHIFT ||
> + !arch_vmap_pud_supported(prot) ||
> + (end - addr) != PUD_SIZE ||
> + !IS_ALIGNED(addr, PUD_SIZE) ||
> + !IS_ALIGNED(phys_addr, PUD_SIZE) ||
> + (pud_present(*pud) && !pud_free_pmd_page(pud, addr)))
> return 0;
>
> return pud_set_huge(pud, phys_addr, prot);
> @@ -236,22 +216,12 @@ static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
> phys_addr_t phys_addr, pgprot_t prot,
> unsigned int max_page_shift)
> {
> - if (max_page_shift < P4D_SHIFT)
> - return 0;
> -
> - if (!arch_vmap_p4d_supported(prot))
> - return 0;
> -
> - if ((end - addr) != P4D_SIZE)
> - return 0;
> -
> - if (!IS_ALIGNED(addr, P4D_SIZE))
> - return 0;
> -
> - if (!IS_ALIGNED(phys_addr, P4D_SIZE))
> - return 0;
> -
> - if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
> + if (max_page_shift < P4D_SHIFT ||
> + !arch_vmap_p4d_supported(prot) ||
> + (end - addr) != P4D_SIZE ||
> + !IS_ALIGNED(addr, P4D_SIZE) ||
> + !IS_ALIGNED(phys_addr, P4D_SIZE) ||
> + (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr)))
> return 0;
>
> return p4d_set_huge(p4d, phys_addr, prot);
> --
> 2.18.2
>
>

2022-06-23 08:47:27

by Christophe Leroy

Subject: Re: [PATCH] vmalloc:Merge multiple if conditional sentences

Le 23/06/2022 à 08:45, Lv qian a écrit :
> Merge multiple if statements to improve code readability

Your change reduces the code readability, it doesn't increase it.

>
> Signed-off-by: Lv qian <[email protected]>
> ---
> mm/vmalloc.c | 66 ++++++++++++++--------------------------------------
> 1 file changed, 18 insertions(+), 48 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index effd1ff6a4b4..6902a180f8f7 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -135,22 +135,12 @@ static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
> phys_addr_t phys_addr, pgprot_t prot,
> unsigned int max_page_shift)
> {
> - if (max_page_shift < PMD_SHIFT)
> - return 0;
> -
> - if (!arch_vmap_pmd_supported(prot))
> - return 0;
> -
> - if ((end - addr) != PMD_SIZE)
> - return 0;
> -
> - if (!IS_ALIGNED(addr, PMD_SIZE))
> - return 0;
> -
> - if (!IS_ALIGNED(phys_addr, PMD_SIZE))
> - return 0;
> -
> - if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr))
> + if (max_page_shift < PMD_SHIFT ||
> + !arch_vmap_pmd_supported(prot) ||
> + (end - addr) != PMD_SIZE ||
> + !IS_ALIGNED(addr, PMD_SIZE) ||
> + !IS_ALIGNED(phys_addr, PMD_SIZE) ||
> + (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr)))
> return 0;
>
> return pmd_set_huge(pmd, phys_addr, prot);
> @@ -185,22 +175,12 @@ static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
> phys_addr_t phys_addr, pgprot_t prot,
> unsigned int max_page_shift)
> {
> - if (max_page_shift < PUD_SHIFT)
> - return 0;
> -
> - if (!arch_vmap_pud_supported(prot))
> - return 0;
> -
> - if ((end - addr) != PUD_SIZE)
> - return 0;
> -
> - if (!IS_ALIGNED(addr, PUD_SIZE))
> - return 0;
> -
> - if (!IS_ALIGNED(phys_addr, PUD_SIZE))
> - return 0;
> -
> - if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
> + if (max_page_shift < PUD_SHIFT ||
> + !arch_vmap_pud_supported(prot) ||
> + (end - addr) != PUD_SIZE ||
> + !IS_ALIGNED(addr, PUD_SIZE) ||
> + !IS_ALIGNED(phys_addr, PUD_SIZE) ||
> + (pud_present(*pud) && !pud_free_pmd_page(pud, addr)))
> return 0;
>
> return pud_set_huge(pud, phys_addr, prot);
> @@ -236,22 +216,12 @@ static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
> phys_addr_t phys_addr, pgprot_t prot,
> unsigned int max_page_shift)
> {
> - if (max_page_shift < P4D_SHIFT)
> - return 0;
> -
> - if (!arch_vmap_p4d_supported(prot))
> - return 0;
> -
> - if ((end - addr) != P4D_SIZE)
> - return 0;
> -
> - if (!IS_ALIGNED(addr, P4D_SIZE))
> - return 0;
> -
> - if (!IS_ALIGNED(phys_addr, P4D_SIZE))
> - return 0;
> -
> - if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
> + if (max_page_shift < P4D_SHIFT ||
> + !arch_vmap_p4d_supported(prot) ||
> + (end - addr) != P4D_SIZE ||
> + !IS_ALIGNED(addr, P4D_SIZE) ||
> + !IS_ALIGNED(phys_addr, P4D_SIZE) ||
> + (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr)))
> return 0;
>
> return p4d_set_huge(p4d, phys_addr, prot);
> --
> 2.18.2
>
>

2022-06-23 19:34:36

by Uladzislau Rezki (Sony)

Subject: Re: [PATCH] vmalloc:Merge multiple if conditional sentences

> Merge multiple if statements to improve code readability
>
> Signed-off-by: Lv qian <[email protected]>
> ---
> mm/vmalloc.c | 66 ++++++++++++++--------------------------------------
> 1 file changed, 18 insertions(+), 48 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index effd1ff6a4b4..6902a180f8f7 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -135,22 +135,12 @@ static int vmap_try_huge_pmd(pmd_t *pmd, unsigned long addr, unsigned long end,
> phys_addr_t phys_addr, pgprot_t prot,
> unsigned int max_page_shift)
> {
> - if (max_page_shift < PMD_SHIFT)
> - return 0;
> -
> - if (!arch_vmap_pmd_supported(prot))
> - return 0;
> -
> - if ((end - addr) != PMD_SIZE)
> - return 0;
> -
> - if (!IS_ALIGNED(addr, PMD_SIZE))
> - return 0;
> -
> - if (!IS_ALIGNED(phys_addr, PMD_SIZE))
> - return 0;
> -
> - if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr))
> + if (max_page_shift < PMD_SHIFT ||
> + !arch_vmap_pmd_supported(prot) ||
> + (end - addr) != PMD_SIZE ||
> + !IS_ALIGNED(addr, PMD_SIZE) ||
> + !IS_ALIGNED(phys_addr, PMD_SIZE) ||
> + (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr)))
> return 0;
>
> return pmd_set_huge(pmd, phys_addr, prot);
> @@ -185,22 +175,12 @@ static int vmap_try_huge_pud(pud_t *pud, unsigned long addr, unsigned long end,
> phys_addr_t phys_addr, pgprot_t prot,
> unsigned int max_page_shift)
> {
> - if (max_page_shift < PUD_SHIFT)
> - return 0;
> -
> - if (!arch_vmap_pud_supported(prot))
> - return 0;
> -
> - if ((end - addr) != PUD_SIZE)
> - return 0;
> -
> - if (!IS_ALIGNED(addr, PUD_SIZE))
> - return 0;
> -
> - if (!IS_ALIGNED(phys_addr, PUD_SIZE))
> - return 0;
> -
> - if (pud_present(*pud) && !pud_free_pmd_page(pud, addr))
> + if (max_page_shift < PUD_SHIFT ||
> + !arch_vmap_pud_supported(prot) ||
> + (end - addr) != PUD_SIZE ||
> + !IS_ALIGNED(addr, PUD_SIZE) ||
> + !IS_ALIGNED(phys_addr, PUD_SIZE) ||
> + (pud_present(*pud) && !pud_free_pmd_page(pud, addr)))
> return 0;
>
> return pud_set_huge(pud, phys_addr, prot);
> @@ -236,22 +216,12 @@ static int vmap_try_huge_p4d(p4d_t *p4d, unsigned long addr, unsigned long end,
> phys_addr_t phys_addr, pgprot_t prot,
> unsigned int max_page_shift)
> {
> - if (max_page_shift < P4D_SHIFT)
> - return 0;
> -
> - if (!arch_vmap_p4d_supported(prot))
> - return 0;
> -
> - if ((end - addr) != P4D_SIZE)
> - return 0;
> -
> - if (!IS_ALIGNED(addr, P4D_SIZE))
> - return 0;
> -
> - if (!IS_ALIGNED(phys_addr, P4D_SIZE))
> - return 0;
> -
> - if (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr))
> + if (max_page_shift < P4D_SHIFT ||
> + !arch_vmap_p4d_supported(prot) ||
> + (end - addr) != P4D_SIZE ||
> + !IS_ALIGNED(addr, P4D_SIZE) ||
> + !IS_ALIGNED(phys_addr, P4D_SIZE) ||
> + (p4d_present(*p4d) && !p4d_free_pud_page(p4d, addr)))
> return 0;
>
> return p4d_set_huge(p4d, phys_addr, prot);
> --
> 2.18.2
>
IMO, it is more complicated to understand.

--
Uladzsislau Rezki