2022-06-08 03:34:56

by Jiri Slaby

Subject: [PATCH 12/36] tty/vt: consolemap: use sizeof(*pointer) instead of sizeof(type)

It is preferred to use sizeof(*pointer) instead of sizeof(type). First,
the type of the variable can change and one needs not change the former
(unlike the latter). Second, the latter is error-prone due to (u16),
(u16 *), and (u16 **) mixture here.

Signed-off-by: Jiri Slaby <[email protected]>
---
drivers/tty/vt/consolemap.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
index 097ab7d01f8b..79a62dcca046 100644
--- a/drivers/tty/vt/consolemap.c
+++ b/drivers/tty/vt/consolemap.c
@@ -251,12 +251,12 @@ static void set_inverse_trans_unicode(struct vc_data *conp,
return;
q = p->inverse_trans_unicode;
if (!q) {
- q = p->inverse_trans_unicode =
- kmalloc_array(MAX_GLYPH, sizeof(u16), GFP_KERNEL);
+ q = p->inverse_trans_unicode = kmalloc_array(MAX_GLYPH,
+ sizeof(*q), GFP_KERNEL);
if (!q)
return;
}
- memset(q, 0, MAX_GLYPH * sizeof(u16));
+ memset(q, 0, MAX_GLYPH * sizeof(*q));

for (i = 0; i < UNI_DIRS; i++) {
p1 = p->uni_pgdir[i];
@@ -478,8 +478,8 @@ static int con_unify_unimap(struct vc_data *conp, struct uni_pagedict *p)
continue;
if (!p1[k] || !q1[k])
break;
- if (memcmp(p1[k], q1[k],
- UNI_ROW_GLYPHS * sizeof(u16)))
+ if (memcmp(p1[k], q1[k], UNI_ROW_GLYPHS *
+ sizeof(*p1[k])))
break;
}
if (k < UNI_DIR_ROWS)
@@ -505,7 +505,7 @@ con_insert_unipair(struct uni_pagedict *p, u_short unicode, u_short fontpos)
n = UNI_DIR(unicode);
p1 = p->uni_pgdir[n];
if (!p1) {
- p1 = p->uni_pgdir[n] = kcalloc(UNI_DIR_ROWS, sizeof(u16 *),
+ p1 = p->uni_pgdir[n] = kcalloc(UNI_DIR_ROWS, sizeof(*p1),
GFP_KERNEL);
if (!p1)
return -ENOMEM;
@@ -514,11 +514,12 @@ con_insert_unipair(struct uni_pagedict *p, u_short unicode, u_short fontpos)
n = UNI_ROW(unicode);
p2 = p1[n];
if (!p2) {
- p2 = p1[n] = kmalloc_array(UNI_ROW_GLYPHS, sizeof(u16), GFP_KERNEL);
+ p2 = p1[n] = kmalloc_array(UNI_ROW_GLYPHS, sizeof(*p2),
+ GFP_KERNEL);
if (!p2)
return -ENOMEM;
/* No glyphs for the characters (yet) */
- memset(p2, 0xff, UNI_ROW_GLYPHS * sizeof(u16));
+ memset(p2, 0xff, UNI_ROW_GLYPHS * sizeof(*p2));
}

p2[UNI_GLYPH(unicode)] = fontpos;
@@ -571,7 +572,7 @@ int con_set_unimap(struct vc_data *vc, ushort ct, struct unipair __user *list)
if (!ct)
return 0;

- unilist = vmemdup_user(list, array_size(sizeof(struct unipair), ct));
+ unilist = vmemdup_user(list, array_size(sizeof(*unilist), ct));
if (IS_ERR(unilist))
return PTR_ERR(unilist);

@@ -771,7 +772,7 @@ int con_get_unimap(struct vc_data *vc, ushort ct, ushort __user *uct, struct uni
struct uni_pagedict *p;
struct unipair *unilist;

- unilist = kvmalloc_array(ct, sizeof(struct unipair), GFP_KERNEL);
+ unilist = kvmalloc_array(ct, sizeof(*unilist), GFP_KERNEL);
if (!unilist)
return -ENOMEM;

@@ -800,7 +801,7 @@ int con_get_unimap(struct vc_data *vc, ushort ct, ushort __user *uct, struct uni
}
}
console_unlock();
- if (copy_to_user(list, unilist, min(ect, ct) * sizeof(struct unipair)))
+ if (copy_to_user(list, unilist, min(ect, ct) * sizeof(*unilist)))
ret = -EFAULT;
put_user(ect, uct);
kvfree(unilist);
--
2.36.1

2022-06-08 04:37:37

by Ilpo Järvinen

Subject: Re: [PATCH 12/36] tty/vt: consolemap: use sizeof(*pointer) instead of sizeof(type)

On Tue, 7 Jun 2022, Jiri Slaby wrote:

> It is preferred to use sizeof(*pointer) instead of sizeof(type). First,
> the type of the variable can change and one needs not change the former
> (unlike the latter). Second, the latter is error-prone due to (u16),
> (u16 *), and (u16 **) mixture here.
>
> Signed-off-by: Jiri Slaby <[email protected]>

Reviewed-by: Ilpo J?rvinen <[email protected]>

This seems fine but see the comments below which are not directly related
to the change itself.

> ---
> drivers/tty/vt/consolemap.c | 23 ++++++++++++-----------
> 1 file changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
> index 097ab7d01f8b..79a62dcca046 100644
> --- a/drivers/tty/vt/consolemap.c
> +++ b/drivers/tty/vt/consolemap.c
> @@ -251,12 +251,12 @@ static void set_inverse_trans_unicode(struct vc_data *conp,
> return;
> q = p->inverse_trans_unicode;
> if (!q) {
> - q = p->inverse_trans_unicode =
> - kmalloc_array(MAX_GLYPH, sizeof(u16), GFP_KERNEL);
> + q = p->inverse_trans_unicode = kmalloc_array(MAX_GLYPH,
> + sizeof(*q), GFP_KERNEL);
> if (!q)
> return;
> }
> - memset(q, 0, MAX_GLYPH * sizeof(u16));
> + memset(q, 0, MAX_GLYPH * sizeof(*q));

Convert kmalloc_array into kcalloc and place memset() into else branch?

> for (i = 0; i < UNI_DIRS; i++) {
> p1 = p->uni_pgdir[i];
> @@ -478,8 +478,8 @@ static int con_unify_unimap(struct vc_data *conp, struct uni_pagedict *p)
> continue;
> if (!p1[k] || !q1[k])
> break;
> - if (memcmp(p1[k], q1[k],
> - UNI_ROW_GLYPHS * sizeof(u16)))
> + if (memcmp(p1[k], q1[k], UNI_ROW_GLYPHS *
> + sizeof(*p1[k])))
> break;
> }
> if (k < UNI_DIR_ROWS)
> @@ -505,7 +505,7 @@ con_insert_unipair(struct uni_pagedict *p, u_short unicode, u_short fontpos)
> n = UNI_DIR(unicode);
> p1 = p->uni_pgdir[n];
> if (!p1) {
> - p1 = p->uni_pgdir[n] = kcalloc(UNI_DIR_ROWS, sizeof(u16 *),
> + p1 = p->uni_pgdir[n] = kcalloc(UNI_DIR_ROWS, sizeof(*p1),
> GFP_KERNEL);
> if (!p1)
> return -ENOMEM;
> @@ -514,11 +514,12 @@ con_insert_unipair(struct uni_pagedict *p, u_short unicode, u_short fontpos)
> n = UNI_ROW(unicode);
> p2 = p1[n];
> if (!p2) {
> - p2 = p1[n] = kmalloc_array(UNI_ROW_GLYPHS, sizeof(u16), GFP_KERNEL);
> + p2 = p1[n] = kmalloc_array(UNI_ROW_GLYPHS, sizeof(*p2),
> + GFP_KERNEL);
> if (!p2)
> return -ENOMEM;
> /* No glyphs for the characters (yet) */
> - memset(p2, 0xff, UNI_ROW_GLYPHS * sizeof(u16));
> + memset(p2, 0xff, UNI_ROW_GLYPHS * sizeof(*p2));

This could have been kcalloc'ed.


--
i.