[Spice-commits] server/red_worker.c

[Christophe Fergau]

 server/red_worker.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

New commits:
commit 6a200503521c4187fe9d3c3413283ce3c17f02f4
Author: Christophe Fergeau <cfergeau at redhat.com>
Date:   Mon Sep 19 16:14:48 2011 +0200

    replace warning with comment in glz_usr_free_image
    
    When running some xinerama tests, I got several
    glz_usr_free_image: error
    messages. Looking at the code, this error is reported when this
    function is called from a different DisplayChannelClient than the
    one which created the glz compressed image.
    When this happens, the backtrace is
        at glz_encoder_dictionary.c:362
        0x7fff940b6670) at glz_encoder_dictionary.c:449
        image_type=LZ_IMAGE_TYPE_RGB32, image_width=512, image_height=256, image_stride=2048, first_lines=0x0,
        num_first_lines=0, usr_image_context=0x7fff7420da40, image_head_dist=0x7fff9b2a3194)
        at glz_encoder_dictionary.c:570
        top_down=4, lines=0x0, num_lines=0, stride=2048, io_ptr=0x7fff740ea7c0 "  ZL", num_io_bytes=65536, usr_context=
        0x7fff7420da40, o_enc_dict_context=0x7fff7420da60) at glz_encoder.c:255
        drawable=0x7fff9b46bc08, o_comp_data=0x7fff9b2a3350) at red_worker.c:5753
        0x7fff9b46bc08, can_lossy=0, o_comp_data=0x7fff9b2a3350) at red_worker.c:6211
        0x7fff9b46bc08, can_lossy=0) at red_worker.c:6344
        0x7fff74085c50, dpi=0x7fff7445b890, src_allowed_lossy=0) at red_worker.c:7046
        0x7fff7445b890) at red_worker.c:7720
        at red_worker.c:7964
        at red_worker.c:8431
    
    Since the glz dictionary is shared between all the
    DisplayChannelClient instances that belong to the same client, it can
    happen that the glz dictionary code decides to free an image from one
    thread while it was added from another thread (thread ==
    DisplayChannelClient), so the error message that is printed is not an
    actual error. This commit removes this message and adds a comment
    explaining what's going on.

diff --git a/server/red_worker.c b/server/red_worker.c
index 3278824..7af715d 100644
--- a/server/red_worker.c
+++ b/server/red_worker.c
@@ -5482,7 +5482,13 @@ static void glz_usr_free_image(GlzEncoderUsrContext *usr, GlzUsrImageContext *im
     if (this_cc == drawable_cc) {
         red_display_free_glz_drawable_instance(drawable_cc, glz_drawable_instance);
     } else {
-        red_printf("error");
+        /* The glz dictionary is shared between all DisplayChannelClient
+         * instances that belong to the same client, and glz_usr_free_image
+         * can be called by the dictionary code
+         * (glz_dictionary_window_remove_head). Thus this function can be
+         * called from any DisplayChannelClient thread, hence the need for
+         * this check.
+         */
         pthread_mutex_lock(&drawable_cc->glz_drawables_inst_to_free_lock);
         ring_add_before(&glz_drawable_instance->free_link,
                         &drawable_cc->glz_drawables_inst_to_free);