simplify and optimize FILE lock handling

diff --git a/src/internal/stdio_impl.h b/src/internal/stdio_impl.h
index 4e6d3503c2d39393157e6407dd4f1256dd170018..b977df6829013714e1bb52e753ade4f9abadc12f 100644 (file)
--- a/src/internal/stdio_impl.h
+++ b/src/internal/stdio_impl.h
@@ -23,8 +23,8 @@
 
 #define UNGET 4
 
-#define FLOCK(f) ((libc.lockfile && (f)->owner>=0) ? (libc.lockfile((f)),0) : 0)
-#define FUNLOCK(f) ((f)->lockcount && (--(f)->lockcount || ((f)->owner=(f)->lock=0)))
+#define FLOCK(f) ((libc.lockfile && (f)->lock>=0) ? (libc.lockfile((f)),0) : 0)
+#define FUNLOCK(f) ((f)->lockcount && (--(f)->lockcount || ((f)->lock=0)))
 
 #define F_PERM 1
 #define F_NORD 4
@@ -59,7 +59,6 @@ struct __FILE_s {
        off_t (*seek)(FILE *, off_t, int);
        int mode;
        int (*close)(FILE *);
-       int owner;
 };
 
 size_t __stdio_read(FILE *, unsigned char *, size_t);

diff --git a/src/stdio/__lockfile.c b/src/stdio/__lockfile.c
index e4320f050c9f85fd83d1f0e06a32b05cddb40b9f..93c94867868801c4d4df7dd8d3e9fb0f90648b18 100644 (file)
--- 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 1d0a1ff8662baad6ce8593348c4179530b70ca4e..67f4b6a070ca2c1c833c8d92401e6f8ac75c251f 100644 (file)
--- 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 ff792e1717223c0dd51f2d46433961a5aa6677f1..5d3f0c5f1977cd23cb95abd21f529d73beb08258 100644 (file)
--- 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 4ad581fb4c400d592b6a980791c9ad1b26d397f4..31ea1875c3cdcd7e0e77dc05bde39760f4ef5881 100644 (file)
--- 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;