2022-01-03 18:34:55

by Walt Drummond

[permalink] [raw]
Subject: [RFC PATCH 5/8] signals: Better support cases where _NSIG_WORDS is greater than 2

Directly handle the now more common cases where _NSIG_WORDS could be 3
or 4.

Signed-off-by: Walt Drummond <[email protected]>
---
fs/proc/array.c | 3 +-
include/linux/signal.h | 74 +++++++++++++++++++++++++++---------------
kernel/signal.c | 5 +++
3 files changed, 55 insertions(+), 27 deletions(-)

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 49be8c8ef555..f37c03077b58 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -223,7 +223,8 @@ void render_sigset_t(struct seq_file *m, const char *header,

seq_puts(m, header);

- i = _NSIG;
+ /* Round up when _NSIG isn't a multiple of 4 */
+ i = (_NSIG + 3) & ~0x03;
do {
int x = 0;

diff --git a/include/linux/signal.h b/include/linux/signal.h
index eaf7991fffee..4084b765a6cc 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -168,18 +168,22 @@ do { \
static inline int sigequalsets(const sigset_t *set1, const sigset_t *set2)
{
switch (_NSIG_WORDS) {
+ default:
+ return memcmp(set1, set2, sizeof(sigset_t)) == 0;
case 4:
return (set1->sig[3] == set2->sig[3]) &&
(set1->sig[2] == set2->sig[2]) &&
(set1->sig[1] == set2->sig[1]) &&
(set1->sig[0] == set2->sig[0]);
+ case 3:
+ return (set1->sig[2] == set2->sig[2]) &&
+ (set1->sig[1] == set2->sig[1]) &&
+ (set1->sig[0] == set2->sig[0]);
case 2:
return (set1->sig[1] == set2->sig[1]) &&
(set1->sig[0] == set2->sig[0]);
case 1:
return set1->sig[0] == set2->sig[0];
- default:
- return memcmp(set1, set2, sizeof(sigset_t)) == 0;
}
return 0;
}
@@ -197,27 +201,24 @@ static inline int sigisemptyset(sigset_t *set)
#define _SIG_SET_BINOP(name, op) \
static inline void name(sigset_t *r, const sigset_t *a, const sigset_t *b) \
{ \
- unsigned long a0, a1, a2, a3, b0, b1, b2, b3; \
int i; \
\
switch (_NSIG_WORDS) { \
+ default: \
+ for (i = 0; i < _NSIG_WORDS; i++) \
+ r->sig[i] = op(a->sig[i], b->sig[i]); \
+ break; \
case 4: \
- a3 = a->sig[3]; a2 = a->sig[2]; \
- b3 = b->sig[3]; b2 = b->sig[2]; \
- r->sig[3] = op(a3, b3); \
- r->sig[2] = op(a2, b2); \
+ r->sig[3] = op(a->sig[3], b->sig[3]); \
+ fallthrough; \
+ case 3: \
+ r->sig[2] = op(a->sig[2], b->sig[2]); \
fallthrough; \
case 2: \
- a1 = a->sig[1]; b1 = b->sig[1]; \
- r->sig[1] = op(a1, b1); \
+ r->sig[1] = op(a->sig[1], b->sig[1]); \
fallthrough; \
case 1: \
- a0 = a->sig[0]; b0 = b->sig[0]; \
- r->sig[0] = op(a0, b0); \
- break; \
- default: \
- for (i = 0; i < _NSIG_WORDS; i++) \
- r->sig[i] = op(a->sig[i], b->sig[i]); \
+ r->sig[0] = op(a->sig[0], b->sig[0]); \
break; \
} \
}
@@ -242,17 +243,22 @@ static inline void name(sigset_t *set) \
int i; \
\
switch (_NSIG_WORDS) { \
- case 4: set->sig[3] = op(set->sig[3]); \
- set->sig[2] = op(set->sig[2]); \
- fallthrough; \
- case 2: set->sig[1] = op(set->sig[1]); \
- fallthrough; \
- case 1: set->sig[0] = op(set->sig[0]); \
- break; \
default: \
for (i = 0; i < _NSIG_WORDS; i++) \
set->sig[i] = op(set->sig[i]); \
break; \
+ case 4: \
+ set->sig[3] = op(set->sig[3]); \
+ fallthrough; \
+ case 3: \
+ set->sig[2] = op(set->sig[2]); \
+ fallthrough; \
+ case 2: \
+ set->sig[1] = op(set->sig[1]); \
+ fallthrough; \
+ case 1: \
+ set->sig[0] = op(set->sig[0]); \
+ break; \
} \
}

@@ -268,9 +274,17 @@ static inline void sigemptyset(sigset_t *set)
default:
memset(set, 0, sizeof(sigset_t));
break;
- case 2: set->sig[1] = 0;
+ case 4:
+ set->sig[3] = 0;
+ fallthrough;
+ case 3:
+ set->sig[2] = 0;
fallthrough;
- case 1: set->sig[0] = 0;
+ case 2:
+ set->sig[1] = 0;
+ fallthrough;
+ case 1:
+ set->sig[0] = 0;
break;
}
}
@@ -281,9 +295,17 @@ static inline void sigfillset(sigset_t *set)
default:
memset(set, -1, sizeof(sigset_t));
break;
- case 2: set->sig[1] = -1;
+ case 4:
+ set->sig[3] = -1;
fallthrough;
- case 1: set->sig[0] = -1;
+ case 3:
+ set->sig[2] = -1;
+ fallthrough;
+ case 2:
+ set->sig[1] = -1;
+ fallthrough;
+ case 1:
+ set->sig[0] = -1;
break;
}
}
diff --git a/kernel/signal.c b/kernel/signal.c
index 9421f1112b20..9c846a017201 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -143,6 +143,11 @@ static inline bool has_pending_signals(sigset_t *signal, sigset_t *blocked)
ready |= signal->sig[0] &~ blocked->sig[0];
break;

+ case 3: ready = signal->sig[2] &~ blocked->sig[2];
+ ready |= signal->sig[1] &~ blocked->sig[1];
+ ready |= signal->sig[0] &~ blocked->sig[0];
+ break;
+
case 2: ready = signal->sig[1] &~ blocked->sig[1];
ready |= signal->sig[0] &~ blocked->sig[0];
break;
--
2.30.2