tty: vgacon+sisusb, move scrolldelta to a common helper

The code is mirrorred in scrolldelta implementations of both vgacon
and sisusb. Let's move the code to a separate helper where we will
perform a common cleanup and further changes.

While we are moving the code, make it linear and save one indentation
level. This is done by returning from the "!lines" then-branch
immediatelly. This allows flushing the else-branch 1 level to the
left, obviously.

Few more new lines and comments were added too.

And do not forget to export the helper function given sisusb can be
built as module.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Thomas Winischhofer <thomas@winischhofer.net>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: <linux-fbdev@vger.kernel.org>
Cc: <linux-usb@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index a0b7576747cd5cb837be2798d9793fafab4075dc..2eab714aab67075bccd71bbc7fdb7b62f03e2c33 100644 (file)
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -4279,6 +4279,44 @@ void vcs_scr_updated(struct vc_data *vc)
        notify_update(vc);
 }
 
+void vc_scrolldelta_helper(struct vc_data *c, int lines,
+               unsigned int rolled_over, void *base, unsigned int size)
+{
+       unsigned long ubase = (unsigned long)base;
+       int margin = c->vc_size_row * 4;
+       int ul, we, p, st;
+
+       /* Turn scrollback off */
+       if (!lines) {
+               c->vc_visible_origin = c->vc_origin;
+               return;
+       }
+
+       /* Do we have already enough to allow jumping from 0 to the end? */
+       if (rolled_over > (c->vc_scr_end - ubase) + margin) {
+               ul = c->vc_scr_end - ubase;
+               we = rolled_over + c->vc_size_row;
+       } else {
+               ul = 0;
+               we = size;
+       }
+
+       p = (c->vc_visible_origin - ubase - ul + we) % we +
+               lines * c->vc_size_row;
+       st = (c->vc_origin - ubase - ul + we) % we;
+
+       /* Only a little piece would be left? Show all incl. the piece! */
+       if (st < 2 * margin)
+               margin = 0;
+       if (p < margin)
+               p = 0;
+       if (p > st - margin)
+               p = st;
+
+       c->vc_visible_origin = ubase + (p + ul) % we;
+}
+EXPORT_SYMBOL_GPL(vc_scrolldelta_helper);
+
 /*
  *     Visible symbols for modules
  */

diff --git a/drivers/usb/misc/sisusbvga/sisusb_con.c b/drivers/usb/misc/sisusbvga/sisusb_con.c
index 6331965daa0bcdf5e715b3103ebe9310979cac11..4b5777ec1501fe37a82c3bd3b23b35d8ab96ec79 100644 (file)
--- a/drivers/usb/misc/sisusbvga/sisusb_con.c
+++ b/drivers/usb/misc/sisusbvga/sisusb_con.c
@@ -686,8 +686,6 @@ static void
 sisusbcon_scrolldelta(struct vc_data *c, int lines)
 {
        struct sisusb_usb_data *sisusb;
-       int margin = c->vc_size_row * 4;
-       int ul, we, p, st;
 
        sisusb = sisusb_get_sisusb_lock_and_check(c->vc_num);
        if (!sisusb)
@@ -700,39 +698,8 @@ sisusbcon_scrolldelta(struct vc_data *c, int lines)
                return;
        }
 
-       if (!lines)             /* Turn scrollback off */
-               c->vc_visible_origin = c->vc_origin;
-       else {
-
-               if (sisusb->con_rolled_over >
-                               (c->vc_scr_end - sisusb->scrbuf) + margin) {
-
-                       ul = c->vc_scr_end - sisusb->scrbuf;
-                       we = sisusb->con_rolled_over + c->vc_size_row;
-
-               } else {
-
-                       ul = 0;
-                       we = sisusb->scrbuf_size;
-
-               }
-
-               p = (c->vc_visible_origin - sisusb->scrbuf - ul + we) % we +
-                               lines * c->vc_size_row;
-
-               st = (c->vc_origin - sisusb->scrbuf - ul + we) % we;
-
-               if (st < 2 * margin)
-                       margin = 0;
-
-               if (p < margin)
-                       p = 0;
-
-               if (p > st - margin)
-                       p = st;
-
-               c->vc_visible_origin = sisusb->scrbuf + (p + ul) % we;
-       }
+       vc_scrolldelta_helper(c, lines, sisusb->con_rolled_over,
+                       (void *)sisusb->scrbuf, sisusb->scrbuf_size);
 
        sisusbcon_set_start_address(sisusb, c);
 

diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c
index 4c54a873452ebad23207d4b94b827e5a1f3d9343..ede6a5a85ccdcbbc7c1490f8ee688e7f200c4cab 100644 (file)
--- a/drivers/video/console/vgacon.c
+++ b/drivers/video/console/vgacon.c
@@ -332,31 +332,8 @@ static void vgacon_restore_screen(struct vc_data *c)
 
 static void vgacon_scrolldelta(struct vc_data *c, int lines)
 {
-       if (!lines)             /* Turn scrollback off */
-               c->vc_visible_origin = c->vc_origin;
-       else {
-               int margin = c->vc_size_row * 4;
-               int ul, we, p, st;
-
-               if (vga_rolled_over >
-                   (c->vc_scr_end - vga_vram_base) + margin) {
-                       ul = c->vc_scr_end - vga_vram_base;
-                       we = vga_rolled_over + c->vc_size_row;
-               } else {
-                       ul = 0;
-                       we = vga_vram_size;
-               }
-               p = (c->vc_visible_origin - vga_vram_base - ul + we) % we +
-                   lines * c->vc_size_row;
-               st = (c->vc_origin - vga_vram_base - ul + we) % we;
-               if (st < 2 * margin)
-                       margin = 0;
-               if (p < margin)
-                       p = 0;
-               if (p > st - margin)
-                       p = st;
-               c->vc_visible_origin = vga_vram_base + (p + ul) % we;
-       }
+       vc_scrolldelta_helper(c, lines, vga_rolled_over, (void *)vga_vram_base,
+                       vga_vram_size);
        vga_set_mem_top(c);
 }
 #endif /* CONFIG_VGACON_SOFT_SCROLLBACK */

diff --git a/include/linux/vt_kern.h b/include/linux/vt_kern.h
index 6abd24f258bc1100e97f989714903c404ea75c42..833fdd4794a0565b1a8797c706682a93247260f1 100644 (file)
--- a/include/linux/vt_kern.h
+++ b/include/linux/vt_kern.h
@@ -191,5 +191,7 @@ extern void vt_set_led_state(int console, int leds);
 extern void vt_kbd_con_start(int console);
 extern void vt_kbd_con_stop(int console);
 
+void vc_scrolldelta_helper(struct vc_data *c, int lines,
+               unsigned int rolled_over, void *_base, unsigned int size);
 
 #endif /* _VT_KERN_H */