[Devel] [PATCH RHEL8 COMMIT] tty: use kvmalloc for screenbuffer allocation

[Konstantin Khorenko]

The commit is pushed to "branch-rh8-4.18.0-240.1.1.vz8.5.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh8-4.18.0-240.1.1.vz8.5.34
------>
commit 831f4d34cb809b5d7a1005b9f9e282d130e2f6fd
Author: Oleg Babin <obabin at virtuozzo.com>
Date:   Wed Jun 2 13:26:02 2021 +0300

    tty: use kvmalloc for screenbuffer allocation
    
    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 vz7 commit 472011f16561 ("tty: use kvmalloc for
    screenbuffer allocation"))
    
    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;