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* Use a condition variable when waiting for a syscall to be done calling.

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* Use C++ DoublyLinkedList class instead of the struct list.
* Note, this code is untested yet, but I will test it now (Qemu doesn't work
  on Haiku anymore for some reason) :-)


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34382 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler 2009-11-30 16:10:11 +00:00
parent a0973602c3
commit be62abafab
1 changed files with 34 additions and 25 deletions
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59
src/system/kernel/syscalls.cpp
View File

@ -55,19 +55,22 @@
typedef struct generic_syscall generic_syscall;
struct generic_syscall {
list_link link;
char subsystem[B_FILE_NAME_LENGTH];
syscall_hook hook;
uint32 version;
uint32 flags;
int32 use_count;
bool valid;
generic_syscall *previous;
struct generic_syscall : DoublyLinkedListLinkImpl<generic_syscall> {
char subsystem[B_FILE_NAME_LENGTH];
syscall_hook hook;
uint32 version;
uint32 flags;
int32 use_count;
bool valid;
ConditionVariable unused_condition;
generic_syscall* previous;
};
typedef DoublyLinkedList<generic_syscall> GenericSyscallList;
static mutex sGenericSyscallLock = MUTEX_INITIALIZER("generic syscall");
static struct list sGenericSyscalls;
static GenericSyscallList sGenericSyscalls;
#if SYSCALL_TRACING
@ -78,12 +81,11 @@ static int dump_syscall_tracing(int argc, char** argv);
static generic_syscall*
find_generic_syscall(const char* subsystem)
{
generic_syscall* syscall = NULL;
ASSERT_LOCKED_MUTEX(&sGenericSyscallLock);
while ((syscall = (generic_syscall*)list_get_next_item(&sGenericSyscalls,
syscall)) != NULL) {
GenericSyscallList::Iterator iterator = sGenericSyscalls.GetIterator();
while (generic_syscall* syscall = iterator.Next()) {
if (!strcmp(syscall->subsystem, subsystem))
return syscall;
}
@ -149,7 +151,9 @@ _user_generic_syscall(const char* userSubsystem, uint32 function,
= syscall->hook(subsystem, function, buffer, bufferSize);
locker.Lock();
syscall->use_count--;
if (--syscall->use_count == 0)
syscall->unused_condition.NotifyAll();
if (status != B_BAD_HANDLER)
return status;
@ -218,7 +222,7 @@ syscall_dispatcher(uint32 callIndex, void* args, uint64* _returnValue)
status_t
generic_syscall_init(void)
{
list_init(&sGenericSyscalls);
new(&sGenericSyscalls) GenericSyscallList;
#if SYSCALL_TRACING
add_debugger_command_etc("straced", &dump_syscall_tracing,
@ -257,8 +261,7 @@ register_generic_syscall(const char* subsystem, syscall_hook hook,
return B_NOT_ALLOWED;
}
generic_syscall* syscall
= (generic_syscall*)malloc(sizeof(struct generic_syscall));
generic_syscall* syscall = new(std::nothrow) generic_syscall;
if (syscall == NULL)
return B_NO_MEMORY;
@ -269,10 +272,12 @@ register_generic_syscall(const char* subsystem, syscall_hook hook,
syscall->use_count = 0;
syscall->valid = true;
syscall->previous = previous;
list_add_item(&sGenericSyscalls, syscall);
syscall->unused_condition.Init(syscall, "syscall unused");
sGenericSyscalls.Add(syscall);
if (previous != NULL)
list_remove_link(&previous->link);
sGenericSyscalls.Remove(previous);
return B_OK;
}
@ -293,19 +298,23 @@ unregister_generic_syscall(const char* subsystem, uint32 version)
syscall->valid = false;
if (syscall->use_count != 0) {
// TODO: we could use a condition variable here instead
// Wait until the syscall isn't in use anymore
ConditionVariableEntry entry;
syscall->unused_condition.Add(&entry);
locker.Unlock();
snooze(6000);
entry.Wait();
continue;
}
if (syscall->previous != NULL) {
// reestablish the old syscall
list_add_item(&sGenericSyscalls, syscall->previous);
sGenericSyscalls.Add(syscall->previous);
}
list_remove_link(&syscall->link);
free(syscall);
sGenericSyscalls.Remove(syscall);
delete syscall;
return B_OK;
}