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authorRich Felker <dalias@aerifal.cx>2011-03-24 23:16:52 -0400
committerRich Felker <dalias@aerifal.cx>2011-03-24 23:16:52 -0400
commita37452430f93700aeb122d693959ad79d8e43ada (patch)
tree6ed8879bddb17c2b0db8c8bbd4778e11912f0767 /src/stdio
parentd8dc2faf1033e134e3a8f39bdf15c065f4d234be (diff)
downloadmusl-a37452430f93700aeb122d693959ad79d8e43ada.tar.gz
simplify and optimize FILE lock handling
Diffstat (limited to 'src/stdio')
-rw-r--r--src/stdio/__lockfile.c13
-rw-r--r--src/stdio/ftrylockfile.c6
-rw-r--r--src/stdio/vsnprintf.c2
-rw-r--r--src/stdio/vswprintf.c2
4 files changed, 12 insertions, 11 deletions
diff --git a/src/stdio/__lockfile.c b/src/stdio/__lockfile.c
index e4320f05..93c94867 100644
--- a/src/stdio/__lockfile.c
+++ b/src/stdio/__lockfile.c
@@ -3,17 +3,18 @@
void __lockfile(FILE *f)
{
- int spins;
- if (f->owner < 0) return;
- if (f->owner && f->owner == __pthread_self()->tid) {
+ int spins=100000;
+ int tid;
+
+ if (f->lock < 0) return;
+ tid = __pthread_self()->tid;
+ if (f->lock == tid) {
while (f->lockcount == INT_MAX);
f->lockcount++;
return;
}
- spins = 100000;
- while (a_swap(&f->lock, 1))
+ while (f->lock || a_cas(&f->lock, 0, tid))
if (spins) spins--, a_spin();
else syscall(SYS_sched_yield);
- f->owner = __pthread_self()->tid;
f->lockcount = 1;
}
diff --git a/src/stdio/ftrylockfile.c b/src/stdio/ftrylockfile.c
index 1d0a1ff8..67f4b6a0 100644
--- a/src/stdio/ftrylockfile.c
+++ b/src/stdio/ftrylockfile.c
@@ -3,16 +3,16 @@
int ftrylockfile(FILE *f)
{
+ int tid = pthread_self()->tid;
if (!libc.lockfile) libc.lockfile = __lockfile;
- if (f->owner && f->owner == pthread_self()->tid) {
+ if (f->lock == tid) {
if (f->lockcount == INT_MAX)
return -1;
f->lockcount++;
return 0;
}
- if (a_swap(&f->lock, 1))
+ if (f->lock || a_cas(&f->lock, 0, tid))
return -1;
- f->owner = pthread_self()->tid;
f->lockcount = 1;
return 0;
}
diff --git a/src/stdio/vsnprintf.c b/src/stdio/vsnprintf.c
index ff792e17..5d3f0c5f 100644
--- a/src/stdio/vsnprintf.c
+++ b/src/stdio/vsnprintf.c
@@ -17,7 +17,7 @@ int vsnprintf(char *s, size_t n, const char *fmt, va_list ap)
f.write = sn_write;
f.buf_size = 1;
f.buf = buf;
- f.owner = -1;
+ f.lock = -1;
if (n > INT_MAX) {
errno = EOVERFLOW;
return -1;
diff --git a/src/stdio/vswprintf.c b/src/stdio/vswprintf.c
index 4ad581fb..31ea1875 100644
--- a/src/stdio/vswprintf.c
+++ b/src/stdio/vswprintf.c
@@ -32,7 +32,7 @@ int vswprintf(wchar_t *s, size_t n, const wchar_t *fmt, va_list ap)
f.write = sw_write;
f.buf_size = sizeof buf;
f.buf = buf;
- f.owner = -1;
+ f.lock = -1;
f.cookie = &c;
if (!n) {
return -1;