Re: [PATCH 4/4] vc_screen: replace __get_free_pages() with kmalloc()

[Jiri Slaby <jirislaby@kernel.org>]

On 28. 05. 26, 12:24, Mike Rapoport (Microsoft) wrote:
> vcs_read() and vcs_write() allocate staging buffers with
> __get_free_pages().
> 
> These buffers can be allocated with kmalloc() as there's nothing special
> about them to go directly to the page allocator.
> 
> kmalloc() provides a better API that does not require ugly casts and it's a
> modern way of saying "I need a page-sized buffer"
> 
> Replace use of __get_free_page() with kmalloc() and drop unused now
> DEFINE_FREE(free_page_ptr ...)
> 
> Link: https://lore.kernel.org/all/700c5a5f-3128-4671-99aa-827ca73f5cdf@kernel.org
> Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> ---
>   drivers/tty/vt/vc_screen.c | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/tty/vt/vc_screen.c b/drivers/tty/vt/vc_screen.c
> index 4d2d46c95fef..386c80efc672 100644
> --- a/drivers/tty/vt/vc_screen.c
> +++ b/drivers/tty/vt/vc_screen.c
> @@ -53,8 +53,6 @@
>   #define HEADER_SIZE	4u
>   #define CON_BUF_SIZE (IS_ENABLED(CONFIG_BASE_SMALL) ? 256 : PAGE_SIZE)
>   
> -DEFINE_FREE(free_page_ptr, void *, if (_T) free_page((unsigned long)_T));
> -

Indeed, I don't know why I came up with this in the first place :P.

Reviewed-by: Jiri Slaby <jirislaby@kernel.org>

> @@ -371,7 +369,7 @@ vcs_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
>   	loff_t pos;
>   	bool viewed, attr, uni_mode;
>   
> -	char *con_buf __free(free_page_ptr) = (char *)__get_free_page(GFP_KERNEL);
> +	char *con_buf __free(kfree) = kmalloc(PAGE_SIZE, GFP_KERNEL);
>   	if (!con_buf)
>   		return -ENOMEM;
>   
> @@ -596,7 +594,7 @@ vcs_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
>   	if (use_unicode(inode))
>   		return -EOPNOTSUPP;
>   
> -	char *con_buf __free(free_page_ptr) = (char *)__get_free_page(GFP_KERNEL);
> +	char *con_buf __free(kfree) = kmalloc(PAGE_SIZE, GFP_KERNEL);
>   	if (!con_buf)
>   		return -ENOMEM;
>   
> 


-- 
js
suse labs