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mISDN: Fix type of switch control variable in ctrl_teimanager

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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>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Nathan Chancellor 2018-10-19 11:00:30 -07:00 committed by David S. Miller
parent 988f3f1603
commit aeb5e02aca
1 changed files with 3 additions and 4 deletions
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7
drivers/isdn/mISDN/tei.c
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@ -1180,8 +1180,7 @@ static int
ctrl_teimanager(struct manager *mgr, void *arg) ctrl_teimanager(struct manager *mgr, void *arg)
{ {
/* currently we only have one option */ /* currently we only have one option */
int *val = (int *)arg; unsigned int *val = (unsigned int *)arg;
int ret = 0;
switch (val[0]) { switch (val[0]) {
case IMCLEAR_L2: case IMCLEAR_L2:
@ -1197,9 +1196,9 @@ ctrl_teimanager(struct manager *mgr, void *arg)
test_and_clear_bit(OPTION_L1_HOLD, &mgr->options); test_and_clear_bit(OPTION_L1_HOLD, &mgr->options);
break; break;
default: default:
ret = -EINVAL; return -EINVAL;
} }
return ret; return 0;
} }
/* This function does create a L2 for fixed TEI in NT Mode */ /* This function does create a L2 for fixed TEI in NT Mode */