Re: [PATCH v2 11/11] backends/iommufd: Make iommufd_backend_*() return bool

[Cédric Le Goater]

On 5/7/24 08:42, Zhenzhong Duan wrote:

This is to follow the coding standand to return bool if 'Error **'
is used to pass error.

The changed functions include:

iommufd_backend_connect
iommufd_backend_alloc_ioas

By this chance, simplify the functions a bit by avoiding duplicate
recordings, e.g., log through either error interface or trace, not
both.

Suggested-by: Cédric Le Goater <c...@redhat.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.d...@intel.com>

Reviewed-by: Cédric Le Goater <c...@redhat.com>

Thanks,

C.

---
  include/sysemu/iommufd.h |  6 +++---
  backends/iommufd.c       | 29 +++++++++++++----------------
  hw/vfio/iommufd.c        |  5 ++---
  backends/trace-events    |  4 ++--
  4 files changed, 20 insertions(+), 24 deletions(-)

diff --git a/include/sysemu/iommufd.h b/include/sysemu/iommufd.h
index 9af27ebd6c..293bfbe967 100644
--- a/include/sysemu/iommufd.h
+++ b/include/sysemu/iommufd.h
@@ -23,11 +23,11 @@ struct IOMMUFDBackend {
      /*< public >*/
  };

-int iommufd_backend_connect(IOMMUFDBackend *be, Error **errp);

+bool iommufd_backend_connect(IOMMUFDBackend *be, Error **errp);
  void iommufd_backend_disconnect(IOMMUFDBackend *be);

-int iommufd_backend_alloc_ioas(IOMMUFDBackend *be, uint32_t *ioas_id,

-                               Error **errp);
+bool iommufd_backend_alloc_ioas(IOMMUFDBackend *be, uint32_t *ioas_id,
+                                Error **errp);
  void iommufd_backend_free_id(IOMMUFDBackend *be, uint32_t id);
  int iommufd_backend_map_dma(IOMMUFDBackend *be, uint32_t ioas_id, hwaddr iova,
                              ram_addr_t size, void *vaddr, bool readonly);
diff --git a/backends/iommufd.c b/backends/iommufd.c
index 76a0204852..c506afbdac 100644
--- a/backends/iommufd.c
+++ b/backends/iommufd.c
@@ -72,24 +72,22 @@ static void iommufd_backend_class_init(ObjectClass *oc, 
void *data)
      object_class_property_add_str(oc, "fd", NULL, iommufd_backend_set_fd);
  }

-int iommufd_backend_connect(IOMMUFDBackend *be, Error **errp)

+bool iommufd_backend_connect(IOMMUFDBackend *be, Error **errp)
  {
-    int fd, ret = 0;
+    int fd;

if (be->owned && !be->users) {

          fd = qemu_open_old("/dev/iommu", O_RDWR);
          if (fd < 0) {
              error_setg_errno(errp, errno, "/dev/iommu opening failed");
-            ret = fd;
-            goto out;
+            return false;
          }
          be->fd = fd;
      }
      be->users++;
-out:
-    trace_iommufd_backend_connect(be->fd, be->owned,
-                                  be->users, ret);
-    return ret;
+
+    trace_iommufd_backend_connect(be->fd, be->owned, be->users);
+    return true;
  }

void iommufd_backend_disconnect(IOMMUFDBackend *be)

@@ -106,25 +104,24 @@ out:
      trace_iommufd_backend_disconnect(be->fd, be->users);
  }

-int iommufd_backend_alloc_ioas(IOMMUFDBackend *be, uint32_t *ioas_id,

-                               Error **errp)
+bool iommufd_backend_alloc_ioas(IOMMUFDBackend *be, uint32_t *ioas_id,
+                                Error **errp)
  {
-    int ret, fd = be->fd;
+    int fd = be->fd;
      struct iommu_ioas_alloc alloc_data  = {
          .size = sizeof(alloc_data),
          .flags = 0,
      };

- ret = ioctl(fd, IOMMU_IOAS_ALLOC, &alloc_data);

-    if (ret) {
+    if (ioctl(fd, IOMMU_IOAS_ALLOC, &alloc_data)) {
          error_setg_errno(errp, errno, "Failed to allocate ioas");
-        return ret;
+        return false;
      }

*ioas_id = alloc_data.out_ioas_id;

-    trace_iommufd_backend_alloc_ioas(fd, *ioas_id, ret);
+    trace_iommufd_backend_alloc_ioas(fd, *ioas_id);

- return ret;

+    return true;
  }

void iommufd_backend_free_id(IOMMUFDBackend *be, uint32_t id)

diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index 6a446b16dc..554f9a6292 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -71,7 +71,7 @@ static bool iommufd_cdev_connect_and_bind(VFIODevice 
*vbasedev, Error **errp)
          .flags = 0,
      };

- if (iommufd_backend_connect(iommufd, errp)) {

+    if (!iommufd_backend_connect(iommufd, errp)) {
          return false;
      }

@@ -346,8 +346,7 @@ static bool iommufd_cdev_attach(const char *name, VFIODevice *vbasedev,

      }

/* Need to allocate a new dedicated container */

-    ret = iommufd_backend_alloc_ioas(vbasedev->iommufd, &ioas_id, errp);
-    if (ret < 0) {
+    if (!iommufd_backend_alloc_ioas(vbasedev->iommufd, &ioas_id, errp)) {
          goto err_alloc_ioas;
      }

diff --git a/backends/trace-events b/backends/trace-events

index d45c6e31a6..211e6f374a 100644
--- a/backends/trace-events
+++ b/backends/trace-events
@@ -7,11 +7,11 @@ dbus_vmstate_loading(const char *id) "id: %s"
  dbus_vmstate_saving(const char *id) "id: %s"

# iommufd.c

-iommufd_backend_connect(int fd, bool owned, uint32_t users, int ret) "fd=%d 
owned=%d users=%d (%d)"
+iommufd_backend_connect(int fd, bool owned, uint32_t users) "fd=%d owned=%d 
users=%d"
  iommufd_backend_disconnect(int fd, uint32_t users) "fd=%d users=%d"
  iommu_backend_set_fd(int fd) "pre-opened /dev/iommu fd=%d"
  iommufd_backend_map_dma(int iommufd, uint32_t ioas, uint64_t iova, uint64_t size, void *vaddr, bool 
readonly, int ret) " iommufd=%d ioas=%d iova=0x%"PRIx64" size=0x%"PRIx64" addr=%p 
readonly=%d (%d)"
  iommufd_backend_unmap_dma_non_exist(int iommufd, uint32_t ioas, uint64_t iova, uint64_t size, int ret) 
" Unmap nonexistent mapping: iommufd=%d ioas=%d iova=0x%"PRIx64" size=0x%"PRIx64" 
(%d)"
  iommufd_backend_unmap_dma(int iommufd, uint32_t ioas, uint64_t iova, uint64_t size, int ret) " 
iommufd=%d ioas=%d iova=0x%"PRIx64" size=0x%"PRIx64" (%d)"
-iommufd_backend_alloc_ioas(int iommufd, uint32_t ioas, int ret) " iommufd=%d 
ioas=%d (%d)"
+iommufd_backend_alloc_ioas(int iommufd, uint32_t ioas) " iommufd=%d ioas=%d"
  iommufd_backend_free_id(int iommufd, uint32_t id, int ret) " iommufd=%d id=%d 
(%d)"