Input: mousedev - fix implicit conversion warning

commit dae1a432ab1fe79ae53129ededeaece35a2dc14d upstream.

Clang warns:

drivers/input/mousedev.c:653:63: error: implicit conversion from 'int'
to 'signed char' changes value from 200 to -56
[-Wconstant-conversion]
  client->ps2[1] = 0x60; client->ps2[2] = 3; client->ps2[3] = 200;
                                                            ~ ^~~
As the PS2 data is really a stream of bytes, let's switch to using u8 type
for it, which silences this warning.

Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/input/mousedev.c b/drivers/input/mousedev.c
index b604564dec5c9a5d8d154ac18a61c02341f77e5d..30328e57fddae69aea599b7636bf00f9e862902c 100644 (file)
--- a/drivers/input/mousedev.c
+++ b/drivers/input/mousedev.c
@@ -15,6 +15,7 @@
 #define MOUSEDEV_MINORS                31
 #define MOUSEDEV_MIX           63
 
+#include <linux/bitops.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/poll.h>
@@ -103,7 +104,7 @@ struct mousedev_client {
        spinlock_t packet_lock;
        int pos_x, pos_y;
 
-       signed char ps2[6];
+       u8 ps2[6];
        unsigned char ready, buffer, bufsiz;
        unsigned char imexseq, impsseq;
        enum mousedev_emul mode;
@@ -291,11 +292,10 @@ static void mousedev_notify_readers(struct mousedev *mousedev,
                }
 
                client->pos_x += packet->dx;
-               client->pos_x = client->pos_x < 0 ?
-                       0 : (client->pos_x >= xres ? xres : client->pos_x);
+               client->pos_x = clamp_val(client->pos_x, 0, xres);
+
                client->pos_y += packet->dy;
-               client->pos_y = client->pos_y < 0 ?
-                       0 : (client->pos_y >= yres ? yres : client->pos_y);
+               client->pos_y = clamp_val(client->pos_y, 0, yres);
 
                p->dx += packet->dx;
                p->dy += packet->dy;
@@ -571,44 +571,50 @@ static int mousedev_open(struct inode *inode, struct file *file)
        return error;
 }
 
-static inline int mousedev_limit_delta(int delta, int limit)
-{
-       return delta > limit ? limit : (delta < -limit ? -limit : delta);
-}
-
-static void mousedev_packet(struct mousedev_client *client,
-                           signed char *ps2_data)
+static void mousedev_packet(struct mousedev_client *client, u8 *ps2_data)
 {
        struct mousedev_motion *p = &client->packets[client->tail];
+       s8 dx, dy, dz;
+
+       dx = clamp_val(p->dx, -127, 127);
+       p->dx -= dx;
+
+       dy = clamp_val(p->dy, -127, 127);
+       p->dy -= dy;
 
-       ps2_data[0] = 0x08 |
-               ((p->dx < 0) << 4) | ((p->dy < 0) << 5) | (p->buttons & 0x07);
-       ps2_data[1] = mousedev_limit_delta(p->dx, 127);
-       ps2_data[2] = mousedev_limit_delta(p->dy, 127);
-       p->dx -= ps2_data[1];
-       p->dy -= ps2_data[2];
+       ps2_data[0] = BIT(3);
+       ps2_data[0] |= ((dx & BIT(7)) >> 3) | ((dy & BIT(7)) >> 2);
+       ps2_data[0] |= p->buttons & 0x07;
+       ps2_data[1] = dx;
+       ps2_data[2] = dy;
 
        switch (client->mode) {
        case MOUSEDEV_EMUL_EXPS:
-               ps2_data[3] = mousedev_limit_delta(p->dz, 7);
-               p->dz -= ps2_data[3];
-               ps2_data[3] = (ps2_data[3] & 0x0f) | ((p->buttons & 0x18) << 1);
+               dz = clamp_val(p->dz, -7, 7);
+               p->dz -= dz;
+
+               ps2_data[3] = (dz & 0x0f) | ((p->buttons & 0x18) << 1);
                client->bufsiz = 4;
                break;
 
        case MOUSEDEV_EMUL_IMPS:
-               ps2_data[0] |=
-                       ((p->buttons & 0x10) >> 3) | ((p->buttons & 0x08) >> 1);
-               ps2_data[3] = mousedev_limit_delta(p->dz, 127);
-               p->dz -= ps2_data[3];
+               dz = clamp_val(p->dz, -127, 127);
+               p->dz -= dz;
+
+               ps2_data[0] |= ((p->buttons & 0x10) >> 3) |
+                              ((p->buttons & 0x08) >> 1);
+               ps2_data[3] = dz;
+
                client->bufsiz = 4;
                break;
 
        case MOUSEDEV_EMUL_PS2:
        default:
-               ps2_data[0] |=
-                       ((p->buttons & 0x10) >> 3) | ((p->buttons & 0x08) >> 1);
                p->dz = 0;
+
+               ps2_data[0] |= ((p->buttons & 0x10) >> 3) |
+                              ((p->buttons & 0x08) >> 1);
+
                client->bufsiz = 3;
                break;
        }
@@ -714,7 +720,7 @@ static ssize_t mousedev_read(struct file *file, char __user *buffer,
 {
        struct mousedev_client *client = file->private_data;
        struct mousedev *mousedev = client->mousedev;
-       signed char data[sizeof(client->ps2)];
+       u8 data[sizeof(client->ps2)];
        int retval = 0;
 
        if (!client->ready && !client->buffer && mousedev->exist &&