| Message ID | 20181019180030.920-1-natechancellor@gmail.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | mISDN: Fix type of switch control variable in ctrl_teimanager | expand |
From: Nathan Chancellor <natechancellor@gmail.com> Date: Fri, 19 Oct 2018 11:00:30 -0700 > Clang warns (trimmed for brevity): > > drivers/isdn/mISDN/tei.c:1193:7: warning: overflow converting case value > to switch condition type (2147764552 to 18446744071562348872) [-Wswitch] > case IMHOLD_L1: > ^ > drivers/isdn/mISDN/tei.c:1187:7: warning: overflow converting case value > to switch condition type (2147764550 to 18446744071562348870) [-Wswitch] > case IMCLEAR_L2: > ^ > 2 warnings generated. > > The root cause is that the _IOC macro can generate really large numbers, > which don't find into type int. My research into how GCC and Clang are > handling this at a low level didn't prove fruitful and surveying the > kernel tree shows that aside from here and a few places in the scsi > subsystem, everything that uses _IOC is at least of type 'unsigned int'. > Make that change here because as nothing in this function cares about > the signedness of the variable and it removes ambiguity, which is never > good when dealing with compilers. > > While we're here, remove the unnecessary local variable ret (just return > -EINVAL and 0 directly). > > Link: https://github.com/ClangBuiltLinux/linux/issues/67 > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Applied.
diff --git a/drivers/isdn/mISDN/tei.c b/drivers/isdn/mISDN/tei.c index 12d9e5f4beb1..58635b5f296f 100644 --- a/drivers/isdn/mISDN/tei.c +++ b/drivers/isdn/mISDN/tei.c @@ -1180,8 +1180,7 @@ static int ctrl_teimanager(struct manager *mgr, void *arg) { /* currently we only have one option */ - int *val = (int *)arg; - int ret = 0; + unsigned int *val = (unsigned int *)arg; switch (val[0]) { case IMCLEAR_L2: @@ -1197,9 +1196,9 @@ ctrl_teimanager(struct manager *mgr, void *arg) test_and_clear_bit(OPTION_L1_HOLD, &mgr->options); break; default: - ret = -EINVAL; + return -EINVAL; } - return ret; + return 0; } /* This function does create a L2 for fixed TEI in NT Mode */
Clang warns (trimmed for brevity): drivers/isdn/mISDN/tei.c:1193:7: warning: overflow converting case value to switch condition type (2147764552 to 18446744071562348872) [-Wswitch] case IMHOLD_L1: ^ drivers/isdn/mISDN/tei.c:1187:7: warning: overflow converting case value to switch condition type (2147764550 to 18446744071562348870) [-Wswitch] case IMCLEAR_L2: ^ 2 warnings generated. The root cause is that the _IOC macro can generate really large numbers, which don't find into type int. My research into how GCC and Clang are handling this at a low level didn't prove fruitful and surveying the kernel tree shows that aside from here and a few places in the scsi subsystem, everything that uses _IOC is at least of type 'unsigned int'. Make that change here because as nothing in this function cares about the signedness of the variable and it removes ambiguity, which is never good when dealing with compilers. While we're here, remove the unnecessary local variable ret (just return -EINVAL and 0 directly). Link: https://github.com/ClangBuiltLinux/linux/issues/67 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> --- drivers/isdn/mISDN/tei.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)