clear-pkgs-linux-iot-lts2018/0777-kernel-VHM-Add-the-vm-owner-for-each-ioreq_client-to.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Zhao Yakui <yakui.zhao@intel.com>
Date: Tue, 18 Dec 2018 09:37:04 +0800
Subject: [PATCH] kernel/VHM: Add the vm owner for each ioreq_client to release
 vhm_vm after releasing client

Currently it will use the ioreq_client->vmid to find the corresponding vm.
But if the corresponding vmid is removed from the acrn_vm_list, it will
fail. And the lock is also acquired to get the corresponding vm from vmid.
So the vm_owner is added for ioreq_client so that it can get the
vm_owner directly for each client.

When the ioreq_client needs to be released, it will try to decrease
the refcnt of vhm_vm.

Tracked-On: projectacrn/acrn-hypervisor#2085
Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Reviewed-by: Shuo Liu <shuo.a.liu@intel.com>
Tracked-On: PKT-1617
---
 drivers/vhm/vhm_ioreq.c | 34 +++++++++-------------------------
 1 file changed, 9 insertions(+), 25 deletions(-)

diff --git a/drivers/vhm/vhm_ioreq.c b/drivers/vhm/vhm_ioreq.c
index 2f37ef958094..3f8bd4abe757 100644
--- a/drivers/vhm/vhm_ioreq.c
+++ b/drivers/vhm/vhm_ioreq.c
@@ -132,6 +132,8 @@ struct ioreq_client {
 	int pci_dev;
 	int pci_func;
 	atomic_t refcnt;
+	/* Add the vhm_vm that contains the ioreq_client */
+	struct vhm_vm *ref_vm;
 };
 
 #define MAX_CLIENT 1024
@@ -192,9 +194,11 @@ static struct ioreq_client *acrn_ioreq_get_client(int client_id)
 static void acrn_ioreq_put_client(struct ioreq_client *client)
 {
 	if (atomic_dec_and_test(&client->refcnt)) {
+		struct vhm_vm *ref_vm = client->ref_vm;
 		/* The client should be released when refcnt = 0 */
 		/* TBD: Do we need to free the other resources? */
 		kfree(client);
+		put_vm(ref_vm);
 	}
 }
 
@@ -242,6 +246,7 @@ int acrn_ioreq_create_client(unsigned long vmid, ioreq_handler_t handler,
 	}
 
 	client->vmid = vmid;
+	client->ref_vm = vm;
 	if (name)
 		strncpy(client->name, name, sizeof(client->name) - 1);
 	spin_lock_init(&client->range_lock);
@@ -380,12 +385,10 @@ static void acrn_ioreq_destroy_client_pervm(struct ioreq_client *client,
 		vm->ioreq_fallback_client = -1;
 
 	acrn_ioreq_put_client(client);
-	put_vm(vm);
 }
 
 void acrn_ioreq_destroy_client(int client_id)
 {
-	struct vhm_vm *vm;
 	struct ioreq_client *client;
 
 	if (client_id < 0 || client_id >= MAX_CLIENT) {
@@ -403,18 +406,8 @@ void acrn_ioreq_destroy_client(int client_id)
 
 	might_sleep();
 
-	vm = find_get_vm(client->vmid);
-	if (unlikely(vm == NULL)) {
-		pr_err("vhm-ioreq: failed to find vm from vmid %ld\n",
-			client->vmid);
-		acrn_ioreq_put_client(client);
-		return;
-	}
-
-	acrn_ioreq_destroy_client_pervm(client, vm);
+	acrn_ioreq_destroy_client_pervm(client, client->ref_vm);
 	acrn_ioreq_put_client(client);
-
-	put_vm(vm);
 }
 EXPORT_SYMBOL_GPL(acrn_ioreq_destroy_client);
 
@@ -552,19 +545,11 @@ struct vhm_request *acrn_ioreq_get_reqbuf(int client_id)
 		pr_err("vhm-ioreq: no client for id %d\n", client_id);
 		return NULL;
 	}
-	vm = find_get_vm(client->vmid);
-	if (unlikely(vm == NULL)) {
-		pr_err("vhm-ioreq: failed to find vm from vmid %ld\n",
-			client->vmid);
-		acrn_ioreq_put_client(client);
-		return NULL;
-	}
-
-	if (vm->req_buf == NULL) {
+	vm = client->ref_vm;
+	if (unlikely(vm == NULL || vm->req_buf == NULL)) {
 		pr_warn("vhm-ioreq: the req buf page not ready yet "
 			"for vmid %ld\n", client->vmid);
 	}
-	put_vm(vm);
 	acrn_ioreq_put_client(client);
 	return (struct vhm_request *)vm->req_buf;
 }
@@ -581,7 +566,7 @@ static int ioreq_client_thread(void *data)
 	if (!client)
 		return 0;
 
-	vm = find_get_vm(client->vmid);
+	vm = client->ref_vm;
 	if (unlikely(vm == NULL)) {
 		pr_err("vhm-ioreq: failed to find vm from vmid %ld\n",
 			client->vmid);
@@ -614,7 +599,6 @@ static int ioreq_client_thread(void *data)
 
 	set_bit(IOREQ_CLIENT_EXIT, &client->flags);
 	acrn_ioreq_put_client(client);
-	put_vm(vm);
 	return 0;
 }
 
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