[Qemu-devel] [PATCH 22/34] linux-user: Remove real-time signal queuing

[Timothy E Baldwin]

As host signals are now blocked whenever guest signals are blocked, the
queue of realtime signals in now in Linux. The Qemu queue is now
redundant and removed.

Signed-off-by: Timothy Edward Baldwin <address@hidden>

Conflicts:
        linux-user/qemu.h
---
 linux-user/main.c   |  7 ------
 linux-user/qemu.h   | 11 +--------
 linux-user/signal.c | 70 ++++++++++-------------------------------------------
 3 files changed, 14 insertions(+), 74 deletions(-)

diff --git a/linux-user/main.c b/linux-user/main.c
index 349abe2..d86751a 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -3474,14 +3474,7 @@ void stop_all_tasks(void)
 /* Assumes contents are already zeroed.  */
 void init_task_state(TaskState *ts)
 {
-    int i;
- 
     ts->used = 1;
-    ts->first_free = ts->sigqueue_table;
-    for (i = 0; i < MAX_SIGQUEUE_SIZE - 1; i++) {
-        ts->sigqueue_table[i].next = &ts->sigqueue_table[i + 1];
-    }
-    ts->sigqueue_table[i].next = NULL;
 }
 
 CPUArchState *cpu_copy(CPUArchState *env)
diff --git a/linux-user/qemu.h b/linux-user/qemu.h
index f2235eb3..5f43692 100644
--- a/linux-user/qemu.h
+++ b/linux-user/qemu.h
@@ -82,16 +82,9 @@ struct vm86_saved_state {
 
 #define MAX_SIGQUEUE_SIZE 1024
 
-struct sigqueue {
-    struct sigqueue *next;
-    target_siginfo_t info;
-};
-
 struct emulated_sigtable {
     int pending; /* true if signal is pending */
-    struct sigqueue *first;
-    struct sigqueue info; /* in order to always have memory for the
-                             first signal, we put it here */
+    target_siginfo_t info;
 };
 
 /* NOTE: we force a big alignment so that the stack stored after is
@@ -131,8 +124,6 @@ typedef struct TaskState {
     struct linux_binprm *bprm;
 
     struct emulated_sigtable sigtab[TARGET_NSIG];
-    struct sigqueue sigqueue_table[MAX_SIGQUEUE_SIZE]; /* siginfo queue */
-    struct sigqueue *first_free; /* first free siginfo queue entry */
     sigset_t signal_mask;
 
     /* non zero if host signals blocked, bit 1 set if signal pending */
diff --git a/linux-user/signal.c b/linux-user/signal.c
index f57dbf5..aa08c72 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -432,27 +432,6 @@ void signal_init(void)
     }
 }
 
-/* signal queue handling */
-
-static inline struct sigqueue *alloc_sigqueue(CPUArchState *env)
-{
-    CPUState *cpu = ENV_GET_CPU(env);
-    TaskState *ts = cpu->opaque;
-    struct sigqueue *q = ts->first_free;
-    if (!q)
-        return NULL;
-    ts->first_free = q->next;
-    return q;
-}
-
-static inline void free_sigqueue(CPUArchState *env, struct sigqueue *q)
-{
-    CPUState *cpu = ENV_GET_CPU(env);
-    TaskState *ts = cpu->opaque;
-
-    q->next = ts->first_free;
-    ts->first_free = q;
-}
 
 /* abort execution with signal */
 static void QEMU_NORETURN force_sig(int target_sig)
@@ -513,7 +492,6 @@ int queue_signal(CPUArchState *env, int sig, 
target_siginfo_t *info)
     CPUState *cpu = ENV_GET_CPU(env);
     TaskState *ts = cpu->opaque;
     struct emulated_sigtable *k;
-    struct sigqueue *q, **pq;
 
 #if defined(DEBUG_SIGNAL)
     fprintf(stderr, "queue_signal: sig=%d\n",
@@ -521,32 +499,16 @@ int queue_signal(CPUArchState *env, int sig, 
target_siginfo_t *info)
 #endif
     k = &ts->sigtab[sig - 1];
 
-        pq = &k->first;
-        if (sig < TARGET_SIGRTMIN) {
-            /* if non real time signal, we queue exactly one signal */
-            if (!k->pending)
-                q = &k->info;
-            else
-                return 0;
-        } else {
-            if (!k->pending) {
-                /* first signal */
-                q = &k->info;
-            } else {
-                q = alloc_sigqueue(env);
-                if (!q)
-                    return -EAGAIN;
-                while (*pq != NULL)
-                    pq = &(*pq)->next;
-            }
-        }
-        *pq = q;
-        q->info = *info;
-        q->next = NULL;
-        k->pending = 1;
-        /* signal that a new signal is pending */
-        ts->signal_pending = 1;
-        return 1; /* indicates that the signal was queued */
+    /* we queue exactly one signal */
+    if (k->pending) {
+        return 0;
+    }
+
+    k->info = *info;
+    k->pending = 1;
+    /* signal that a new signal is pending */
+    ts->signal_pending = 1;
+    return 1; /* indicates that the signal was queued */
 }
 
 #if defined(__x86_64__)
@@ -5617,7 +5579,6 @@ void process_pending_signals(CPUArchState *cpu_env)
     target_sigset_t target_old_set;
     struct emulated_sigtable *k;
     struct target_sigaction *sa;
-    struct sigqueue *q;
     TaskState *ts = cpu->opaque;
 
 restart:
@@ -5653,10 +5614,7 @@ restart:
     fprintf(stderr, "qemu: process signal %d\n", sig);
 #endif
     /* dequeue signal */
-    q = k->first;
-    k->first = q->next;
-    if (!k->first)
-        k->pending = 0;
+    k->pending = 0;
 
     sig = gdb_handlesig(cpu, sig);
     if (!sig) {
@@ -5715,18 +5673,16 @@ restart:
         /* prepare the stack frame of the virtual CPU */
 #if defined(TARGET_ABI_MIPSN32) || defined(TARGET_ABI_MIPSN64)
         /* These targets do not have traditional signals.  */
-        setup_rt_frame(sig, sa, &q->info, &target_old_set, cpu_env);
+        setup_rt_frame(sig, sa, &k->info, &target_old_set, cpu_env);
 #else
         if (sa->sa_flags & TARGET_SA_SIGINFO)
-            setup_rt_frame(sig, sa, &q->info, &target_old_set, cpu_env);
+            setup_rt_frame(sig, sa, &k->info, &target_old_set, cpu_env);
         else
             setup_frame(sig, sa, &target_old_set, cpu_env);
 #endif
         if (sa->sa_flags & TARGET_SA_RESETHAND)
             sa->_sa_handler = TARGET_SIG_DFL;
     }
-    if (q != &k->info)
-        free_sigqueue(cpu_env, q);
 
     goto next_signal;
 }
-- 
2.1.4