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authorJavier Martinez Canillas <javier.martinez@collabora.co.uk>2015-06-09 13:04:42 +0200
committerLee Jones <lee.jones@linaro.org>2015-06-15 13:18:19 +0100
commita841178445bb72a3d566b4e6ab9d19e9b002eb47 (patch)
treebdc857e82c9c9e8b49bd5471efa5a954673d58f0 /drivers/input
parentbb03ffb96c72418d06e75c7b74ea62e04c78d322 (diff)
downloadlinux-a841178445bb72a3d566b4e6ab9d19e9b002eb47.tar.bz2
mfd: cros_ec: Use a zero-length array for command data
Commit 1b84f2a4cd4a ("mfd: cros_ec: Use fixed size arrays to transfer data with the EC") modified the struct cros_ec_command fields to not use pointers for the input and output buffers and use fixed length arrays instead. This change was made because the cros_ec ioctl API uses that struct cros_ec_command to allow user-space to send commands to the EC and to get data from the EC. So using pointers made the API not 64-bit safe. Unfortunately this approach was not flexible enough for all the use-cases since there may be a need to send larger commands on newer versions of the EC command protocol. So to avoid to choose a constant length that it may be too big for most commands and thus wasting memory and CPU cycles on copy from and to user-space or having a size that is too small for some big commands, use a zero-length array that is both 64-bit safe and flexible. The same buffer is used for both output and input data so the maximum of these values should be used to allocate it. Suggested-by: Gwendal Grignou <gwendal@chromium.org> Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk> Tested-by: Heiko Stuebner <heiko@sntech.de> Acked-by: Lee Jones <lee.jones@linaro.org> Acked-by: Olof Johansson <olof@lixom.net> Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'drivers/input')
-rw-r--r--drivers/input/keyboard/cros_ec_keyb.c29
1 files changed, 19 insertions, 10 deletions
diff --git a/drivers/input/keyboard/cros_ec_keyb.c b/drivers/input/keyboard/cros_ec_keyb.c
index b50c5b8b8a4d..974154a74505 100644
--- a/drivers/input/keyboard/cros_ec_keyb.c
+++ b/drivers/input/keyboard/cros_ec_keyb.c
@@ -148,19 +148,28 @@ static void cros_ec_keyb_process(struct cros_ec_keyb *ckdev,
static int cros_ec_keyb_get_state(struct cros_ec_keyb *ckdev, uint8_t *kb_state)
{
- int ret;
- struct cros_ec_command msg = {
- .command = EC_CMD_MKBP_STATE,
- .insize = ckdev->cols,
- };
+ int ret = 0;
+ struct cros_ec_command *msg;
- ret = cros_ec_cmd_xfer(ckdev->ec, &msg);
- if (ret < 0)
- return ret;
+ msg = kmalloc(sizeof(*msg) + ckdev->cols, GFP_KERNEL);
+ if (!msg)
+ return -ENOMEM;
- memcpy(kb_state, msg.indata, ckdev->cols);
+ msg->version = 0;
+ msg->command = EC_CMD_MKBP_STATE;
+ msg->insize = ckdev->cols;
+ msg->outsize = 0;
- return 0;
+ ret = cros_ec_cmd_xfer(ckdev->ec, msg);
+ if (ret < 0) {
+ dev_err(ckdev->dev, "Error transferring EC message %d\n", ret);
+ goto exit;
+ }
+
+ memcpy(kb_state, msg->data, ckdev->cols);
+exit:
+ kfree(msg);
+ return ret;
}
static irqreturn_t cros_ec_keyb_irq(int irq, void *data)