IO#advise should not raise Errno::ENOSYS

As it is just a hint the kernel is free to ignore,
IO#advise already succeeds when posix_fadvise is not
available build time at all.  Following that, if posix_fadvise
was available at build time but not implemented in the running
kernel, we should also ignore it.

* io.c (do_io_advise): do not raise on ENOSYS
* test/ruby/test_io.rb (test_advise): do not skip on Errno::ENOSYS
  (test_advise_pipe): ditto
  [ruby-core:72066] [Feature #11806]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53047 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 2 insertions, 4 deletions

diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index a237fa3b87..ad9e4fa08f 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -2565,8 +2565,6 @@ End
             ret = assert_nothing_raised(lambda { os_and_fs(tf.path) }) {
               begin
                 t.advise(adv, offset, len)
-              rescue Errno::ENOSYS
-                skip
               rescue Errno::EINVAL => e
                 if /linux/ =~ RUBY_PLATFORM && (Etc.uname[:release].split('.').map(&:to_i) <=> [3,6]) < 0
                   next # [ruby-core:65355] tmpfs is not supported
@@ -3007,8 +3005,8 @@ End
     # we don't know if other platforms have a real posix_fadvise()
     with_pipe do |r,w|
       # Linux 2.6.15 and earlier returned EINVAL instead of ESPIPE
-      assert_raise(Errno::ESPIPE, Errno::EINVAL, Errno::ENOSYS) { r.advise(:willneed) }
-      assert_raise(Errno::ESPIPE, Errno::EINVAL, Errno::ENOSYS) { w.advise(:willneed) }
+      assert_raise(Errno::ESPIPE, Errno::EINVAL) { r.advise(:willneed) }
+      assert_raise(Errno::ESPIPE, Errno::EINVAL) { w.advise(:willneed) }
     end
   end if /linux/ =~ RUBY_PLATFORM