[PATCH 21/38] media: dvb-ttusb-budget: don't use stack for USB transfers
From: Mauro Carvalho Chehab
Date: Wed Sep 02 2020 - 12:14:22 EST
As reported by smatch:
drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c:311 ttusb_boot_dsp() error: doing dma on the stack (b)
drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c:321 ttusb_boot_dsp() error: doing dma on the stack (b)
drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c:330 ttusb_boot_dsp() error: doing dma on the stack (b)
drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c:351 ttusb_set_channel() error: doing dma on the stack (b)
drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c:361 ttusb_del_channel() error: doing dma on the stack (b)
drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c:412 ttusb_init_controller() error: doing dma on the stack (b0)
drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c:416 ttusb_init_controller() error: doing dma on the stack (b1)
drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c:422 ttusb_init_controller() error: doing dma on the stack (b2)
drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c:425 ttusb_init_controller() error: doing dma on the stack (b3)
drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c:430 ttusb_init_controller() error: doing dma on the stack (get_version)
This driver still uses the USB stack for DMA transfers,
which is broken for a long time. I almost dropped this driver,
as there's a high chance that nobody is using it with upstream
Kernels, as we didn't receive any bug reports.
As fixing this won't be hard, I ended opting to fix.
While here, I dropped an ugly hack that implemented read via
a separate function that was just doing a memcpy().
It should be noticed that, during the init phase, there's
a "b4" register that were never initialized, as its buffer
were used just to store the results of "b3" initialization.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
---
.../media/usb/ttusb-budget/dvb-ttusb-budget.c | 83 +++++++------------
1 file changed, 30 insertions(+), 53 deletions(-)
diff --git a/drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c b/drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c
index 4e56ff83566b..2582a62184fd 100644
--- a/drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c
+++ b/drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c
@@ -72,6 +72,9 @@ DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
#define TTUSB_REV_2_2 0x22
#define TTUSB_BUDGET_NAME "ttusb_stc_fw"
+#define MAX_SEND 0x28
+#define MAX_RCV 0x20
+
/*
* since we're casting (struct ttusb*) <-> (struct dvb_demux*) around
* the dvb_demux field must be the first in struct!!
@@ -119,87 +122,72 @@ struct ttusb {
int cc; /* MuxCounter - will increment on EVERY MUX PACKET */
/* (including stuffing. yes. really.) */
- u8 last_result[32];
+ u8 send_buf[MAX_SEND];
+ u8 last_result[MAX_RCV];
int revision;
struct dvb_frontend* fe;
};
-/* ugly workaround ... don't know why it's necessary to read */
-/* all result codes. */
-
-static int ttusb_cmd(struct ttusb *ttusb,
- const u8 * data, int len, int needresult)
+static int ttusb_cmd(struct ttusb *ttusb, u8 *data, int len, int len_result)
{
int actual_len;
int err;
- int i;
-
- if (debug >= 3) {
- printk(KERN_DEBUG ">");
- for (i = 0; i < len; ++i)
- printk(KERN_CONT " %02x", data[i]);
- printk(KERN_CONT "\n");
- }
if (mutex_lock_interruptible(&ttusb->semusb) < 0)
return -EAGAIN;
+ if (debug >= 3)
+ printk(KERN_DEBUG "> %*ph\n", len, data);
+
+ memcpy(data, ttusb->send_buf, len);
+
err = usb_bulk_msg(ttusb->dev, ttusb->bulk_out_pipe,
- (u8 *) data, len, &actual_len, 1000);
+ ttusb->send_buf, len, &actual_len, 1000);
if (err != 0) {
dprintk("%s: usb_bulk_msg(send) failed, err == %i!\n",
__func__, err);
- mutex_unlock(&ttusb->semusb);
- return err;
+ goto err;
}
if (actual_len != len) {
+ err = -EIO;
dprintk("%s: only wrote %d of %d bytes\n", __func__,
actual_len, len);
- mutex_unlock(&ttusb->semusb);
- return -1;
+ goto err;
}
err = usb_bulk_msg(ttusb->dev, ttusb->bulk_in_pipe,
- ttusb->last_result, 32, &actual_len, 1000);
+ ttusb->last_result, MAX_RCV, &actual_len, 1000);
if (err != 0) {
printk("%s: failed, receive error %d\n", __func__,
err);
- mutex_unlock(&ttusb->semusb);
- return err;
+ goto err;
}
if (debug >= 3) {
actual_len = ttusb->last_result[3] + 4;
- printk(KERN_DEBUG "<");
- for (i = 0; i < actual_len; ++i)
- printk(KERN_CONT " %02x", ttusb->last_result[i]);
- printk(KERN_CONT "\n");
+ printk(KERN_DEBUG "< %*ph\n", actual_len, ttusb->last_result);
}
- if (!needresult)
- mutex_unlock(&ttusb->semusb);
- return 0;
-}
+ if (len_result)
+ memcpy(ttusb->send_buf, ttusb->last_result, len_result);
-static int ttusb_result(struct ttusb *ttusb, u8 * data, int len)
-{
- memcpy(data, ttusb->last_result, len);
+err:
mutex_unlock(&ttusb->semusb);
- return 0;
+ return err;
}
static int ttusb_i2c_msg(struct ttusb *ttusb,
u8 addr, u8 * snd_buf, u8 snd_len, u8 * rcv_buf,
u8 rcv_len)
{
- u8 b[0x28];
+ u8 b[MAX_SEND];
u8 id = ++ttusb->c;
int i, err;
- if (snd_len > 0x28 - 7 || rcv_len > 0x20 - 7)
+ if (snd_len > MAX_SEND - 7 || rcv_len > MAX_RCV - 7)
return -EINVAL;
b[0] = 0xaa;
@@ -213,13 +201,11 @@ static int ttusb_i2c_msg(struct ttusb *ttusb,
for (i = 0; i < snd_len; i++)
b[7 + i] = snd_buf[i];
- err = ttusb_cmd(ttusb, b, snd_len + 7, 1);
+ err = ttusb_cmd(ttusb, b, snd_len + 7, MAX_RCV);
if (err)
return -EREMOTEIO;
- err = ttusb_result(ttusb, b, 0x20);
-
/* check if the i2c transaction was successful */
if ((snd_len != b[5]) || (rcv_len != b[6])) return -EREMOTEIO;
@@ -400,8 +386,6 @@ static int ttusb_init_controller(struct ttusb *ttusb)
/* i2c write read: 5 bytes, addr 0x10, 0x02 bytes write, 1 bytes read. */
u8 b3[] =
{ 0xaa, ++ttusb->c, 0x31, 5, 0x10, 0x02, 0x01, 0x00, 0x1e };
- u8 b4[] =
- { 0x55, ttusb->c, 0x31, 4, 0x10, 0x02, 0x01, 0x00, 0x1e };
u8 get_version[] = { 0xaa, ++ttusb->c, 0x17, 5, 0, 0, 0, 0, 0 };
u8 get_dsp_version[0x20] =
@@ -422,15 +406,11 @@ static int ttusb_init_controller(struct ttusb *ttusb)
if ((err = ttusb_cmd(ttusb, b2, sizeof(b2), 0)))
return err;
- if ((err = ttusb_cmd(ttusb, b3, sizeof(b3), 1)))
+ if ((err = ttusb_cmd(ttusb, b3, sizeof(b3), 0)))
return err;
- err = ttusb_result(ttusb, b4, sizeof(b4));
-
- if ((err = ttusb_cmd(ttusb, get_version, sizeof(get_version), 1)))
- return err;
-
- if ((err = ttusb_result(ttusb, get_version, sizeof(get_version))))
+ if ((err = ttusb_cmd(ttusb, get_version,
+ sizeof(get_version), sizeof(get_version))))
return err;
dprintk("%s: stc-version: %c%c%c%c%c\n", __func__,
@@ -451,14 +431,11 @@ static int ttusb_init_controller(struct ttusb *ttusb)
(get_version[8] - '0');
err =
- ttusb_cmd(ttusb, get_dsp_version, sizeof(get_dsp_version), 1);
+ ttusb_cmd(ttusb, get_dsp_version,
+ sizeof(get_dsp_version), sizeof(get_dsp_version));
if (err)
return err;
- err =
- ttusb_result(ttusb, get_dsp_version, sizeof(get_dsp_version));
- if (err)
- return err;
printk("%s: dsp-version: %c%c%c\n", __func__,
get_dsp_version[4], get_dsp_version[5], get_dsp_version[6]);
return 0;
--
2.26.2