diff --git a/include/spdk/env.h b/include/spdk/env.h
index 830825687..921e32329 100644
--- a/include/spdk/env.h
+++ b/include/spdk/env.h
@@ -345,6 +345,20 @@ struct spdk_pci_id spdk_pci_device_get_id(struct spdk_pci_device *dev);
 int spdk_pci_device_get_socket_id(struct spdk_pci_device *dev);
 
 int spdk_pci_device_get_serial_number(struct spdk_pci_device *dev, char *sn, size_t len);
+
+/**
+ * Claim a PCI device for exclusive SPDK userspace access.
+ *
+ * Uses F_SETLK on a shared memory file with the PCI address embedded in its name.
+ *  As long as this file remains open with the lock acquired, other processes will
+ *  not be able to successfully call this function on the same PCI device.
+ *
+ * \param pci_addr PCI address of the device to claim
+ *
+ * \return -1 if the device has already been claimed, an fd otherwise.  This fd
+ *	   should be closed when the application no longer needs access to the
+ *	   PCI device (including when it is hot removed).
+ */
 int spdk_pci_device_claim(const struct spdk_pci_addr *pci_addr);
 void spdk_pci_device_detach(struct spdk_pci_device *device);
 
diff --git a/lib/bdev/nvme/bdev_nvme.c b/lib/bdev/nvme/bdev_nvme.c
index 8d099ea5b..d4fa82a54 100644
--- a/lib/bdev/nvme/bdev_nvme.c
+++ b/lib/bdev/nvme/bdev_nvme.c
@@ -742,7 +742,7 @@ probe_cb(void *cb_ctx, const struct spdk_nvme_transport_id *trid,
 			return false;
 		}
 
-		if (spdk_pci_device_claim(&pci_addr) != 0) {
+		if (spdk_pci_device_claim(&pci_addr) < 0) {
 			return false;
 		}
 	}
diff --git a/lib/copy/ioat/copy_engine_ioat.c b/lib/copy/ioat/copy_engine_ioat.c
index e0d0e8aeb..0e85c9033 100644
--- a/lib/copy/ioat/copy_engine_ioat.c
+++ b/lib/copy/ioat/copy_engine_ioat.c
@@ -248,7 +248,7 @@ probe_cb(void *cb_ctx, struct spdk_pci_device *pci_dev)
 	}
 
 	/* Claim the device in case conflict with other process */
-	if (spdk_pci_device_claim(&pci_addr) != 0) {
+	if (spdk_pci_device_claim(&pci_addr) < 0) {
 		return false;
 	}
 
diff --git a/lib/env_dpdk/pci.c b/lib/env_dpdk/pci.c
index df2f289f8..144bd7798 100644
--- a/lib/env_dpdk/pci.c
+++ b/lib/env_dpdk/pci.c
@@ -495,7 +495,7 @@ spdk_pci_device_claim(const struct spdk_pci_addr *pci_addr)
 	*(int *)dev_map = (int)getpid();
 	munmap(dev_map, sizeof(int));
 	/* Keep dev_fd open to maintain the lock. */
-	return 0;
+	return dev_fd;
 }
 #endif /* __linux__ */
 
diff --git a/test/lib/env/pci/pci_ut.c b/test/lib/env/pci/pci_ut.c
index 48a98c462..873f67aed 100644
--- a/test/lib/env/pci/pci_ut.c
+++ b/test/lib/env/pci/pci_ut.c
@@ -51,7 +51,7 @@ pci_test(void)
 	pci_addr.func = 1;
 
 	rc = spdk_pci_device_claim(&pci_addr);
-	CU_ASSERT(rc == 0);
+	CU_ASSERT(rc >= 0);
 
 	childPid = fork();
 	CU_ASSERT(childPid >= 0);