[Devel] [PATCH RHEL7 COMMIT] tty: use kvmalloc for screenbuffer allocation

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-693.21.1.vz7.47.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.21.1.vz7.47.6
------>
commit f3595823918c2e2ef7864b31f4ebf6350f18e580
Author: Oleg Babin <obabin at virtuozzo.com>
Date:   Wed May 16 11:09:25 2018 +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>
---
 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 b49abe57b05f..bedf467b3e46 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;
@@ -873,7 +873,7 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
 
 	if (new_screen_size > (4 << 20))
 		return -EINVAL;
-	newscreen = kmalloc(new_screen_size, GFP_USER);
+	newscreen = kvmalloc(new_screen_size, GFP_USER);
 	if (!newscreen)
 		return -ENOMEM;
 
@@ -882,7 +882,7 @@ 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;
 	}
 
@@ -929,7 +929,7 @@ 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);
@@ -1012,7 +1012,7 @@ 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;