debian/patches/extra/0002-block-io_uring-revert-Use-io_uring_register_ring_fd-.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Sam Li <faithilikerun@gmail.com>
   3 Date: Sat, 24 Sep 2022 22:48:15 +0800
   4 Subject: [PATCH] block/io_uring: revert "Use io_uring_register_ring_fd() to
   5  skip fd operations"
   6
   7 Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1193
   8
   9 The commit "Use io_uring_register_ring_fd() to skip fd operations" broke
  10 when booting a guest with iothread and io_uring. That is because the
  11 io_uring_register_ring_fd() call is made from the main thread instead of
  12 IOThread where io_uring_submit() is called. It can not be guaranteed
  13 to register the ring fd in the correct thread or unregister the same ring
  14 fd if the IOThread is disabled. This optimization is not critical so we
  15 will revert previous commit.
  16
  17 This reverts commit e2848bc574fe2715c694bf8fe9a1ba7f78a1125a
  18 and 77e3f038af1764983087e3551a0fde9951952c4d.
  19
  20 Signed-off-by: Sam Li <faithilikerun@gmail.com>
  21 ---
  22  block/io_uring.c | 13 +------------
  23  meson.build      |  1 -
  24  2 files changed, 1 insertion(+), 13 deletions(-)
  25
  26 diff --git a/block/io_uring.c b/block/io_uring.c
  27 index a1760152e0..973e15d876 100644
  28 --- a/block/io_uring.c
  29 +++ b/block/io_uring.c
  30 @@ -11,7 +11,6 @@
  31  #include "qemu/osdep.h"
  32  #include <liburing.h>
  33  #include "block/aio.h"
  34 -#include "qemu/error-report.h"
  35  #include "qemu/queue.h"
  36  #include "block/block.h"
  37  #include "block/raw-aio.h"
  38 @@ -19,7 +18,6 @@
  39  #include "qapi/error.h"
  40  #include "trace.h"
  41
  42 -
  43  /* io_uring ring size */
  44  #define MAX_ENTRIES 128
  45
  46 @@ -432,17 +430,8 @@ LuringState *luring_init(Error **errp)
  47      }
  48
  49      ioq_init(&s->io_q);
  50 -#ifdef CONFIG_LIBURING_REGISTER_RING_FD
  51 -    if (io_uring_register_ring_fd(&s->ring) < 0) {
  52 -        /*
  53 -         * Only warn about this error: we will fallback to the non-optimized
  54 -         * io_uring operations.
  55 -         */
  56 -        warn_report("failed to register linux io_uring ring file descriptor");
  57 -    }
  58 -#endif
  59 -
  60      return s;
  61 +
  62  }
  63
  64  void luring_cleanup(LuringState *s)
  65 diff --git a/meson.build b/meson.build
  66 index 20fddbd707..d5230eadd6 100644
  67 --- a/meson.build
  68 +++ b/meson.build
  69 @@ -1793,7 +1793,6 @@ config_host_data.set('CONFIG_LIBNFS', libnfs.found())
  70  config_host_data.set('CONFIG_LIBSSH', libssh.found())
  71  config_host_data.set('CONFIG_LINUX_AIO', libaio.found())
  72  config_host_data.set('CONFIG_LINUX_IO_URING', linux_io_uring.found())
  73 -config_host_data.set('CONFIG_LIBURING_REGISTER_RING_FD', cc.has_function('io_uring_register_ring_fd', prefix: '#include <liburing.h>', dependencies:linux_io_uring))
  74  config_host_data.set('CONFIG_LIBPMEM', libpmem.found())
  75  config_host_data.set('CONFIG_NUMA', numa.found())
  76  config_host_data.set('CONFIG_OPENGL', opengl.found())