Update `IO::Buffer` read/write to use rb_thread_io_blocking_region. (#6438)

common.mk

@@ -7675,6 +7675,7 @@ io_buffer.$(OBJEXT): $(top_srcdir)/internal/compilers.h
 io_buffer.$(OBJEXT): $(top_srcdir)/internal/error.h
 io_buffer.$(OBJEXT): $(top_srcdir)/internal/static_assert.h
 io_buffer.$(OBJEXT): $(top_srcdir)/internal/string.h
+io_buffer.$(OBJEXT): $(top_srcdir)/internal/thread.h
 io_buffer.$(OBJEXT): {$(VPATH)}assert.h
 io_buffer.$(OBJEXT): {$(VPATH)}backward/2/assume.h
 io_buffer.$(OBJEXT): {$(VPATH)}backward/2/attributes.h

io_buffer.c

@@ -6,15 +6,16 @@
 
 **********************************************************************/
 
-#include "internal/array.h"
 #include "ruby/io.h"
 #include "ruby/io/buffer.h"
 #include "ruby/fiber/scheduler.h"
 
 #include "internal.h"
-#include "internal/string.h"
+#include "internal/array.h"
 #include "internal/bits.h"
 #include "internal/error.h"
+#include "internal/string.h"
+#include "internal/thread.h"
 
 VALUE rb_cIOBuffer;
 VALUE rb_eIOBufferLockedError;
@@ -2281,6 +2282,20 @@ io_buffer_default_size(size_t page_size)
     return platform_agnostic_default_size;
 }
 
+struct io_buffer_read_internal_argument {
+    int descriptor;
+    void *base;
+    size_t size;
+};
+
+static VALUE
+io_buffer_read_internal(void *_argument)
+{
+    struct io_buffer_read_internal_argument *argument = _argument;
+    ssize_t result = read(argument->descriptor, argument->base, argument->size);
+    return rb_fiber_scheduler_io_result(result, errno);
+}
+
 VALUE
 rb_io_buffer_read(VALUE self, VALUE io, size_t length)
 {
@@ -2304,9 +2319,13 @@ rb_io_buffer_read(VALUE self, VALUE io, size_t length)
     size_t size;
     io_buffer_get_bytes_for_writing(data, &base, &size);
 
-    ssize_t result = read(descriptor, base, size);
+    struct io_buffer_read_internal_argument argument = {
+        .descriptor = descriptor,
+        .base = base,
+        .size = length,
+    };
 
-    return rb_fiber_scheduler_io_result(result, errno);
+    return rb_thread_io_blocking_region(io_buffer_read_internal, &argument, descriptor);
 }
 
 static VALUE
@@ -2315,6 +2334,38 @@ io_buffer_read(VALUE self, VALUE io, VALUE length)
     return rb_io_buffer_read(self, io, RB_NUM2SIZE(length));
 }
 
+struct io_buffer_pread_internal_argument {
+    int descriptor;
+    void *base;
+    size_t size;
+    off_t offset;
+};
+
+static VALUE
+io_buffer_pread_internal(void *_argument)
+{
+    struct io_buffer_pread_internal_argument *argument = _argument;
+
+#if defined(HAVE_PREAD)
+    ssize_t result = pread(argument->descriptor, argument->base, argument->size, argument->offset);
+#else
+    // This emulation is not thread safe.
+    rb_off_t offset = lseek(argument->descriptor, 0, SEEK_CUR);
+    if (offset == (rb_off_t)-1)
+        return rb_fiber_scheduler_io_result(-1, errno);
+
+    if (lseek(argument->descriptor, argument->offset, SEEK_SET) == (rb_off_t)-1)
+        return rb_fiber_scheduler_io_result(-1, errno);
+
+    ssize_t result = read(argument->descriptor, argument->base, argument->size);
+
+    if (lseek(argument->descriptor, offset, SEEK_SET) == (rb_off_t)-1)
+        return rb_fiber_scheduler_io_result(-1, errno);
+#endif
+
+    return rb_fiber_scheduler_io_result(result, errno);
+}
+
 VALUE
 rb_io_buffer_pread(VALUE self, VALUE io, size_t length, rb_off_t offset)
 {
@@ -2338,24 +2389,14 @@ rb_io_buffer_pread(VALUE self, VALUE io, size_t length, rb_off_t offset)
     size_t size;
     io_buffer_get_bytes_for_writing(data, &base, &size);
 
-#if defined(HAVE_PREAD)
-    ssize_t result = pread(descriptor, base, size, offset);
-#else
-    // This emulation is not thread safe, but the GVL means it's unlikely to be a problem.
-    rb_off_t current_offset = lseek(descriptor, 0, SEEK_CUR);
-    if (current_offset == (rb_off_t)-1)
-        return rb_fiber_scheduler_io_result(-1, errno);
+    struct io_buffer_pread_internal_argument argument = {
+        .descriptor = descriptor,
+        .base = base,
+        .size = length,
+        .offset = offset,
+    };
 
-    if (lseek(descriptor, offset, SEEK_SET) == (rb_off_t)-1)
-        return rb_fiber_scheduler_io_result(-1, errno);
-
-    ssize_t result = read(descriptor, base, size);
-
-    if (lseek(descriptor, current_offset, SEEK_SET) == (rb_off_t)-1)
-        return rb_fiber_scheduler_io_result(-1, errno);
-#endif
-
-    return rb_fiber_scheduler_io_result(result, errno);
+    return rb_thread_io_blocking_region(io_buffer_pread_internal, &argument, descriptor);
 }
 
 static VALUE
@@ -2364,6 +2405,20 @@ io_buffer_pread(VALUE self, VALUE io, VALUE length, VALUE offset)
     return rb_io_buffer_pread(self, io, RB_NUM2SIZE(length), NUM2OFFT(offset));
 }
 
+struct io_buffer_write_internal_argument {
+    int descriptor;
+    const void *base;
+    size_t size;
+};
+
+static VALUE
+io_buffer_write_internal(void *_argument)
+{
+    struct io_buffer_write_internal_argument *argument = _argument;
+    ssize_t result = write(argument->descriptor, argument->base, argument->size);
+    return rb_fiber_scheduler_io_result(result, errno);
+}
+
 VALUE
 rb_io_buffer_write(VALUE self, VALUE io, size_t length)
 {
@@ -2387,9 +2442,13 @@ rb_io_buffer_write(VALUE self, VALUE io, size_t length)
     size_t size;
     io_buffer_get_bytes_for_reading(data, &base, &size);
 
-    ssize_t result = write(descriptor, base, length);
+    struct io_buffer_write_internal_argument argument = {
+        .descriptor = descriptor,
+        .base = base,
+        .size = length,
+    };
 
-    return rb_fiber_scheduler_io_result(result, errno);
+    return rb_thread_io_blocking_region(io_buffer_write_internal, &argument, descriptor);
 }
 
 static VALUE
@@ -2398,6 +2457,38 @@ io_buffer_write(VALUE self, VALUE io, VALUE length)
     return rb_io_buffer_write(self, io, RB_NUM2SIZE(length));
 }
 
+struct io_buffer_pwrite_internal_argument {
+    int descriptor;
+    const void *base;
+    size_t size;
+    off_t offset;
+};
+
+static VALUE
+io_buffer_pwrite_internal(void *_argument)
+{
+    struct io_buffer_pwrite_internal_argument *argument = _argument;
+
+#if defined(HAVE_PWRITE)
+    ssize_t result = pwrite(argument->descriptor, argument->base, argument->size, argument->offset);
+#else
+    // This emulation is not thread safe.
+    rb_off_t offset = lseek(argument->descriptor, 0, SEEK_CUR);
+    if (offset == (rb_off_t)-1)
+        return rb_fiber_scheduler_io_result(-1, errno);
+
+    if (lseek(argument->descriptor, argument->offset, SEEK_SET) == (rb_off_t)-1)
+        return rb_fiber_scheduler_io_result(-1, errno);
+
+    ssize_t result = write(argument->descriptor, argument->base, argument->size);
+
+    if (lseek(argument->descriptor, offset, SEEK_SET) == (rb_off_t)-1)
+        return rb_fiber_scheduler_io_result(-1, errno);
+#endif
+
+    return rb_fiber_scheduler_io_result(result, errno);
+}
+
 VALUE
 rb_io_buffer_pwrite(VALUE self, VALUE io, size_t length, rb_off_t offset)
 {
@@ -2421,24 +2512,14 @@ rb_io_buffer_pwrite(VALUE self, VALUE io, size_t length, rb_off_t offset)
     size_t size;
     io_buffer_get_bytes_for_reading(data, &base, &size);
 
-#if defined(HAVE_PWRITE)
-    ssize_t result = pwrite(descriptor, base, length, offset);
-#else
-    // This emulation is not thread safe, but the GVL means it's unlikely to be a problem.
-    rb_off_t current_offset = lseek(descriptor, 0, SEEK_CUR);
-    if (current_offset == (rb_off_t)-1)
-        return rb_fiber_scheduler_io_result(-1, errno);
+    struct io_buffer_pwrite_internal_argument argument = {
+        .descriptor = descriptor,
+        .base = base,
+        .size = length,
+        .offset = offset,
+    };
 
-    if (lseek(descriptor, offset, SEEK_SET) == (rb_off_t)-1)
-        return rb_fiber_scheduler_io_result(-1, errno);
-
-    ssize_t result = write(descriptor, base, length);
-
-    if (lseek(descriptor, current_offset, SEEK_SET) == (rb_off_t)-1)
-        return rb_fiber_scheduler_io_result(-1, errno);
-#endif
-
-    return rb_fiber_scheduler_io_result(result, errno);
+    return rb_thread_io_blocking_region(io_buffer_pwrite_internal, &argument, descriptor);
 }
 
 static VALUE