[Devel] [PATCH 6/6] tty: use kvmalloc for screenbuffer allocation

[Alexander Mikhalitsyn]

From: Oleg Babin <obabin at virtuozzo.com>

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>
[VvS RHEL7.8 rebase] context changes
(cherry picked from commit 472011f165617f88833d61a14456198610a1632b)

VZ 8 rebase part https://jira.sw.ru/browse/PSBM-127798

Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn at virtuozzo.com>
---
 drivers/tty/vt/vt.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index b530605cbc2d..30f2f9c8dd2e 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -968,7 +968,7 @@ int vc_allocate(unsigned int currcons)	/* return 0 on success */
 	if (!*vc->vc_uni_pagedir_loc)
 		con_set_default_unimap(vc);
 
-	vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_KERNEL);
+	vc->vc_screenbuf = kvzalloc(vc->vc_screenbuf_size, GFP_KERNEL);
 	if (!vc->vc_screenbuf)
 		goto err_free;
 
@@ -984,7 +984,7 @@ int vc_allocate(unsigned int currcons)	/* return 0 on success */
 	return 0;
 err_free:
 	visual_deinit(vc);
-	kfree(vc);
+	kvfree(vc);
 	vc_cons[currcons].d = NULL;
 	return -ENOMEM;
 }
@@ -1057,14 +1057,14 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
 
 	if (new_screen_size > (4 << 20))
 		return -EINVAL;
-	newscreen = kzalloc(new_screen_size, GFP_USER);
+	newscreen = kvzalloc(new_screen_size, GFP_USER);
 	if (!newscreen)
 		return -ENOMEM;
 
 	if (get_vc_uniscr(vc)) {
 		new_uniscr = vc_uniscr_alloc(new_cols, new_rows);
 		if (!new_uniscr) {
-			kfree(newscreen);
+			kvfree(newscreen);
 			return -ENOMEM;
 		}
 	}
@@ -1077,7 +1077,7 @@ 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);
 		kfree(new_uniscr);
 		return err;
 	}
@@ -1131,7 +1131,7 @@ 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);
@@ -1214,7 +1214,7 @@ struct vc_data *vc_deallocate(unsigned int currcons)
 		visual_deinit(vc);
 		put_pid(vc->vt_pid);
 		vc_uniscr_set(vc, NULL);
-		kfree(vc->vc_screenbuf);
+		kvfree(vc->vc_screenbuf);
 		vc_cons[currcons].d = NULL;
 	}
 	return vc;
-- 
2.28.0