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

Ilpo Järvinen
2022-06-07T14:01:05Z

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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 <jslaby@suse.cz>

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

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.