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

[Konstantin Khorenko]

The commit is pushed to "branch-rh9-5.14.vz9.1.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after ark-5.14
------>
commit fc7689e95111f37643c5493daf28d9fec4cd2e90
Author: Oleg Babin <obabin at virtuozzo.com>
Date:   Thu Sep 30 16:04:04 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>
    
    (cherry picked from vz8 commit 41eb48611eb41a923882c095b63c92455efb7b0b)
    Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko 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 ef981d3b7bb4..ff58736b8f6e 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -1144,7 +1144,7 @@ int vc_allocate(unsigned int currcons)	/* return 0 on success */
 	    vc->vc_screenbuf_size > KMALLOC_MAX_SIZE || !vc->vc_screenbuf_size)
 		goto err_free;
 	err = -ENOMEM;
-	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;
 
@@ -1160,7 +1160,7 @@ 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 err;
 }
@@ -1224,14 +1224,14 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
 
 	if (new_screen_size > KMALLOC_MAX_SIZE || !new_screen_size)
 		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;
 		}
 	}
@@ -1244,7 +1244,7 @@ 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);
 		vc_uniscr_free(new_uniscr);
 		return err;
 	}
@@ -1302,7 +1302,7 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
 	vc->vc_screenbuf = newscreen;
 	vc->vc_screenbuf_size = new_screen_size;
 	set_origin(vc);
-	kfree(oldscreen);
+	kvfree(oldscreen);
 
 	/* do part of a reset_terminal() */
 	vc->vc_top = 0;
@@ -1384,7 +1384,7 @@ struct vc_data *vc_deallocate(unsigned int currcons)
 		con_free_unimap(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;