Blame SOURCES/kvm-qxl-replace-pipe-signaling-with-bottom-half.patch

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From bf9b8d36996ecbe78f1561404a355af6f7c5d4f6 Mon Sep 17 00:00:00 2001
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From: Gerd Hoffmann <kraxel@redhat.com>
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Date: Tue, 21 Jan 2014 11:25:17 -0500
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Subject: [PATCH 6/6] qxl: replace pipe signaling with bottom half
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Message-id: <1390303517-20167-3-git-send-email-kraxel@redhat.com>
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Patchwork-id: 56865
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O-Subject: [RHEL-7 qemu-kvm PATCH 2/2] qxl: replace pipe signaling with bottom half
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Bugzilla: 1009297
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RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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qxl creates a pipe, then writes something to it to wake up the iothread
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from the spice server thread to raise an irq.  These days qemu bottom
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halves can be scheduled from threads and signals, so there is no reason
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to do this any more.  Time to clean it up.
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Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
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(cherry picked from commit 4a46c99c8118586f19894fe66fc6e353f159d4d9)
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---
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 hw/display/qxl.c | 33 +++------------------------------
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 hw/display/qxl.h |  3 +--
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 2 files changed, 4 insertions(+), 32 deletions(-)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 hw/display/qxl.c | 33 +++------------------------------
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 hw/display/qxl.h |  3 +--
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 2 files changed, 4 insertions(+), 32 deletions(-)
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diff --git a/hw/display/qxl.c b/hw/display/qxl.c
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index 830b3c5..4381d97 100644
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--- a/hw/display/qxl.c
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+++ b/hw/display/qxl.c
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@@ -1702,15 +1702,9 @@ static const MemoryRegionOps qxl_io_ops = {
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     },
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 };
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-static void pipe_read(void *opaque)
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+static void qxl_update_irq_bh(void *opaque)
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 {
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     PCIQXLDevice *d = opaque;
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-    char dummy;
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-    int len;
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-
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-    do {
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-        len = read(d->pipe[0], &dummy, sizeof(dummy));
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-    } while (len == sizeof(dummy));
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     qxl_update_irq(d);
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 }
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@@ -1731,28 +1725,7 @@ static void qxl_send_events(PCIQXLDevice *d, uint32_t events)
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     if ((old_pending & le_events) == le_events) {
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         return;
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     }
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-    if (qemu_thread_is_self(&d->main)) {
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-        qxl_update_irq(d);
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-    } else {
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-        if (write(d->pipe[1], d, 1) != 1) {
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-            dprint(d, 1, "%s: write to pipe failed\n", __func__);
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-        }
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-    }
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-}
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-
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-static void init_pipe_signaling(PCIQXLDevice *d)
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-{
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-    if (pipe(d->pipe) < 0) {
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-        fprintf(stderr, "%s:%s: qxl pipe creation failed\n",
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-                __FILE__, __func__);
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-        exit(1);
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-    }
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-    fcntl(d->pipe[0], F_SETFL, O_NONBLOCK);
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-    fcntl(d->pipe[1], F_SETFL, O_NONBLOCK);
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-    fcntl(d->pipe[0], F_SETOWN, getpid());
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-
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-    qemu_thread_get_self(&d->main);
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-    qemu_set_fd_handler(d->pipe[0], pipe_read, NULL, d);
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+    qemu_bh_schedule(d->update_irq);
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 }
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 /* graphics console */
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@@ -2044,7 +2017,7 @@ static int qxl_init_common(PCIQXLDevice *qxl)
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     }
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     qemu_add_vm_change_state_handler(qxl_vm_change_state_handler, qxl);
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-    init_pipe_signaling(qxl);
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+    qxl->update_irq = qemu_bh_new(qxl_update_irq_bh, qxl);
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     qxl_reset_state(qxl);
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     qxl->update_area_bh = qemu_bh_new(qxl_render_update_area_bh, qxl);
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diff --git a/hw/display/qxl.h b/hw/display/qxl.h
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index 8e9b0c2..5da33e2 100644
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--- a/hw/display/qxl.h
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+++ b/hw/display/qxl.h
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@@ -78,8 +78,7 @@ typedef struct PCIQXLDevice {
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     QemuMutex          track_lock;
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     /* thread signaling */
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-    QemuThread         main;
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-    int                pipe[2];
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+    QEMUBH             *update_irq;
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     /* ram pci bar */
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     QXLRam             *ram;
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-- 
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1.8.3.1
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