diff options
| author | Dave Penkler <dpenkler@gmail.com> | 2025-05-21 14:16:55 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-05-21 15:01:09 +0200 |
| commit | acb3dac2805d3342ded7dbbd164add32bbfdf21c (patch) | |
| tree | 3f0aa57c92f7c7fd17df548a13fb3741636192b0 | |
| parent | 3335a1bbd62417fc60a043c7f64684c99cb841a2 (diff) | |
usb: usbtmc: Fix read_stb function and get_stb ioctl
The usbtmc488_ioctl_read_stb function relied on a positive return from
usbtmc_get_stb to reset the srq condition in the driver. The
USBTMC_IOCTL_GET_STB case tested for a positive return to return the stb
to the user.
Commit: <cac01bd178d6> ("usb: usbtmc: Fix erroneous get_stb ioctl
error returns") changed the return value of usbtmc_get_stb to 0 on
success instead of returning the value of usb_control_msg which is
positive in the normal case. This change caused the function
usbtmc488_ioctl_read_stb and the USBTMC_IOCTL_GET_STB ioctl to no
longer function correctly.
Change the test in usbtmc488_ioctl_read_stb to test for failure
first and return the failure code immediately.
Change the test for the USBTMC_IOCTL_GET_STB ioctl to test for 0
instead of a positive value.
Fixes: cac01bd178d6 ("usb: usbtmc: Fix erroneous get_stb ioctl error returns")
Cc: stable@vger.kernel.org
Signed-off-by: Dave Penkler <dpenkler@gmail.com>
Link: https://lore.kernel.org/r/20250521121656.18174-3-dpenkler@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/class/usbtmc.c | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c index 740d2d2b19fb..08511442a27f 100644 --- a/drivers/usb/class/usbtmc.c +++ b/drivers/usb/class/usbtmc.c @@ -563,14 +563,15 @@ static int usbtmc488_ioctl_read_stb(struct usbtmc_file_data *file_data, rv = usbtmc_get_stb(file_data, &stb); - if (rv > 0) { - srq_asserted = atomic_xchg(&file_data->srq_asserted, - srq_asserted); - if (srq_asserted) - stb |= 0x40; /* Set RQS bit */ + if (rv < 0) + return rv; + + srq_asserted = atomic_xchg(&file_data->srq_asserted, srq_asserted); + if (srq_asserted) + stb |= 0x40; /* Set RQS bit */ + + rv = put_user(stb, (__u8 __user *)arg); - rv = put_user(stb, (__u8 __user *)arg); - } return rv; } @@ -2199,7 +2200,7 @@ static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case USBTMC_IOCTL_GET_STB: retval = usbtmc_get_stb(file_data, &tmp_byte); - if (retval > 0) + if (!retval) retval = put_user(tmp_byte, (__u8 __user *)arg); break; |