backends/iommufd: Make iommufd_backend_*() return bool

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 <clg@redhat.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>

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)

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)"

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;
     }
 

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);