[Devel] [PATCH vz7 1/2] tty/vt: use kvmalloc for screenbuffer allocation

[Oleg Babin]

Console driver allocates a screenbuffer with kmalloc(). The
size of the buffer can be up to 32768 bytes which is the 3rd
memory order.

Use kvmalloc() for screenbuffer allocation to fallback to vmalloc()
in case of high order page is not available at the moment.

https://jira.sw.ru/browse/HCI-53
Signed-off-by: Oleg Babin <obabin at virtuozzo.com>
---
 drivers/tty/vt/vt.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index fbc6290..9408a69 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -787,7 +787,7 @@ int vc_allocate(unsigned int currcons)	/* return 0 on success */
 	    visual_init(vc, currcons, 1);
 	    if (!*vc->vc_uni_pagedir_loc)
 		con_set_default_unimap(vc);
-	    vc->vc_screenbuf = kmalloc(vc->vc_screenbuf_size, GFP_KERNEL);
+	    vc->vc_screenbuf = kvmalloc(vc->vc_screenbuf_size, GFP_KERNEL);
 	    if (!vc->vc_screenbuf) {
 		kfree(vc);
 		vc_cons[currcons].d = NULL;
@@ -871,7 +871,7 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
 	if (new_cols == vc->vc_cols && new_rows == vc->vc_rows)
 		return 0;
 
-	newscreen = kmalloc(new_screen_size, GFP_USER);
+	newscreen = kvmalloc(new_screen_size, GFP_USER);
 	if (!newscreen)
 		return -ENOMEM;
 
@@ -880,7 +880,7 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
 
 	err = resize_screen(vc, new_cols, new_rows, user);
 	if (err) {
-		kfree(newscreen);
+		kvfree(newscreen);
 		return err;
 	}
 
@@ -927,7 +927,7 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
 	if (new_scr_end > new_origin)
 		scr_memsetw((void *)new_origin, vc->vc_video_erase_char,
 			    new_scr_end - new_origin);
-	kfree(vc->vc_screenbuf);
+	kvfree(vc->vc_screenbuf);
 	vc->vc_screenbuf = newscreen;
 	vc->vc_screenbuf_size = new_screen_size;
 	set_origin(vc);
@@ -1010,7 +1010,7 @@ struct vc_data *vc_deallocate(unsigned int currcons)
 		vc->vc_sw->con_deinit(vc);
 		put_pid(vc->vt_pid);
 		module_put(vc->vc_sw->owner);
-		kfree(vc->vc_screenbuf);
+		kvfree(vc->vc_screenbuf);
 		vc_cons[currcons].d = NULL;
 	}
 	return vc;
-- 
1.8.3.1