vduse: take out allocations from vduse_dev_alloc_coherent

The function vduse_dev_alloc_coherent will be called under rwlock in
next patches.  Make it out of the lock to avoid increasing its fail
rate.

Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20260119143306.1818855-10-eperezma@redhat.com>

Author: eugpermar

drivers/vdpa/vdpa_user/iova_domain.c

@@ -493,17 +493,15 @@ void vduse_domain_unmap_page(struct vduse_iova_domain *domain,
 	vduse_domain_free_iova(iovad, dma_addr, size);
 }
 
-void *vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
-				  size_t size, dma_addr_t *dma_addr,
-				  gfp_t flag)
+dma_addr_t vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
+				       size_t size, void *orig)
 {
 	struct iova_domain *iovad = &domain->consistent_iovad;
 	unsigned long limit = domain->iova_limit;
 	dma_addr_t iova = vduse_domain_alloc_iova(iovad, size, limit);
-	void *orig = alloc_pages_exact(size, flag);
 
-	if (!iova || !orig)
-		goto err;
+	if (!iova)
+		return DMA_MAPPING_ERROR;
 
 	spin_lock(&domain->iotlb_lock);
 	if (vduse_iotlb_add_range(domain, (u64)iova, (u64)iova + size - 1,
@@ -514,17 +512,12 @@ void *vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
 	}
 	spin_unlock(&domain->iotlb_lock);
 
-	*dma_addr = iova;
+	return iova;
 
-	return orig;
 err:
-	*dma_addr = DMA_MAPPING_ERROR;
-	if (orig)
-		free_pages_exact(orig, size);
-	if (iova)
-		vduse_domain_free_iova(iovad, iova, size);
+	vduse_domain_free_iova(iovad, iova, size);
 
-	return NULL;
+	return DMA_MAPPING_ERROR;
 }
 
 void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
@@ -533,7 +526,6 @@ void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
 	struct iova_domain *iovad = &domain->consistent_iovad;
 	struct vhost_iotlb_map *map;
 	struct vdpa_map_file *map_file;
-	phys_addr_t pa;
 
 	spin_lock(&domain->iotlb_lock);
 	map = vhost_iotlb_itree_first(domain->iotlb, (u64)dma_addr,
@@ -545,12 +537,10 @@ void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
 	map_file = (struct vdpa_map_file *)map->opaque;
 	fput(map_file->file);
 	kfree(map_file);
-	pa = map->addr;
 	vhost_iotlb_map_free(domain->iotlb, map);
 	spin_unlock(&domain->iotlb_lock);
 
 	vduse_domain_free_iova(iovad, dma_addr, size);
-	free_pages_exact(phys_to_virt(pa), size);
 }
 
 static vm_fault_t vduse_domain_mmap_fault(struct vm_fault *vmf)

drivers/vdpa/vdpa_user/iova_domain.h

@@ -65,9 +65,8 @@ void vduse_domain_unmap_page(struct vduse_iova_domain *domain,
 			     dma_addr_t dma_addr, size_t size,
 			     enum dma_data_direction dir, unsigned long attrs);
 
-void *vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
-				  size_t size, dma_addr_t *dma_addr,
-				  gfp_t flag);
+dma_addr_t vduse_domain_alloc_coherent(struct vduse_iova_domain *domain,
+				       size_t size, void *orig);
 
 void vduse_domain_free_coherent(struct vduse_iova_domain *domain, size_t size,
 				dma_addr_t dma_addr, unsigned long attrs);

drivers/vdpa/vdpa_user/vduse_dev.c

@@ -916,23 +916,27 @@ static void *vduse_dev_alloc_coherent(union virtio_map token, size_t size,
 {
 	struct vduse_dev *vdev;
 	struct vduse_iova_domain *domain;
-	unsigned long iova;
 	void *addr;
 
 	*dma_addr = DMA_MAPPING_ERROR;
 	if (!token.group)
 		return NULL;
 
-	vdev = token.group->dev;
-	domain = vdev->domain;
-	addr = vduse_domain_alloc_coherent(domain, size,
-					   (dma_addr_t *)&iova, flag);
+	addr = alloc_pages_exact(size, flag);
 	if (!addr)
 		return NULL;
 
-	*dma_addr = (dma_addr_t)iova;
+	vdev = token.group->dev;
+	domain = vdev->domain;
+	*dma_addr = vduse_domain_alloc_coherent(domain, size, addr);
+	if (*dma_addr == DMA_MAPPING_ERROR)
+		goto err;
 
 	return addr;
+
+err:
+	free_pages_exact(addr, size);
+	return NULL;
 }
 
 static void vduse_dev_free_coherent(union virtio_map token, size_t size,
@@ -949,6 +953,7 @@ static void vduse_dev_free_coherent(union virtio_map token, size_t size,
 	domain = vdev->domain;
 
 	vduse_domain_free_coherent(domain, size, dma_addr, attrs);
+	free_pages_exact(vaddr, size);
 }
 
 static bool vduse_dev_need_sync(union virtio_map token, dma_addr_t dma_addr)