Revert fwalk/sfp locking to fix concurrent reads
The locking can fail in a couple of ways:
- A concurrent fread from an unbuffered or line-buffered file flushes
the output of other line-buffered files, and if _fwalk locks every
file, then the fread blocks until other file reads have completed.
- __sfp can initialize a file lock while _fwalk is locking/unlocking it.
For now, revert to the behavior Bionic had in previous releases. This
commit reverts the file locking parts of commit
468efc80da2504f4ae7de8b5e137426d44dda9d7.
Bug: http://b/131251441
Bug: http://b/130189834
Test: bionic unit tests
Change-Id: I9e20b9cd8ccd14e7962f7308e174f08af72b56c6
diff --git a/libc/stdio/local.h b/libc/stdio/local.h
index d306a21..1ecf122 100644
--- a/libc/stdio/local.h
+++ b/libc/stdio/local.h
@@ -204,6 +204,7 @@
__LIBC32_LEGACY_PUBLIC__ int _fwalk(int (*)(FILE*));
off64_t __sseek64(void*, off64_t, int);
+int __sflush_locked(FILE*);
int __swhatbuf(FILE*, size_t*, int*);
wint_t __fgetwc_unlock(FILE*);
wint_t __ungetwc(wint_t, FILE*);