VMCI: Use threaded irqs instead of tasklets

The vmci_dispatch_dgs() tasklet function calls vmci_read_data()
which uses wait_event() resulting in invalid sleep in an atomic
context (and therefore potentially in a deadlock).

Use threaded irqs to fix this issue and completely remove usage
of tasklets.

[ 20.264639] BUG: sleeping function called from invalid context at drivers/misc/vmw_vmci/vmci_guest.c:145
[ 20.264643] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 762, name: vmtoolsd
[ 20.264645] preempt_count: 101, expected: 0
[ 20.264646] RCU nest depth: 0, expected: 0
[ 20.264647] 1 lock held by vmtoolsd/762:
[ 20.264648] #0: ffff0000874ae440 (sk_lock-AF_VSOCK){+.+.}-{0:0}, at: vsock_connect+0x60/0x330 [vsock]
[ 20.264658] Preemption disabled at:
[ 20.264659] [<ffff80000151d7d8>] vmci_send_datagram+0x44/0xa0 [vmw_vmci]
[ 20.264665] CPU: 0 PID: 762 Comm: vmtoolsd Not tainted 5.19.0-0.rc8.20220727git39c3c396f813.60.fc37.aarch64 #1
[ 20.264667] Hardware name: VMware, Inc. VBSA/VBSA, BIOS VEFI 12/31/2020
[ 20.264668] Call trace:
[ 20.264669] dump_backtrace+0xc4/0x130
[ 20.264672] show_stack+0x24/0x80
[ 20.264673] dump_stack_lvl+0x88/0xb4
[ 20.264676] dump_stack+0x18/0x34
[ 20.264677] __might_resched+0x1a0/0x280
[ 20.264679] __might_sleep+0x58/0x90
[ 20.264681] vmci_read_data+0x74/0x120 [vmw_vmci]
[ 20.264683] vmci_dispatch_dgs+0x64/0x204 [vmw_vmci]
[ 20.264686] tasklet_action_common.constprop.0+0x13c/0x150
[ 20.264688] tasklet_action+0x40/0x50
[ 20.264689] __do_softirq+0x23c/0x6b4
[ 20.264690] __irq_exit_rcu+0x104/0x214
[ 20.264691] irq_exit_rcu+0x1c/0x50
[ 20.264693] el1_interrupt+0x38/0x6c
[ 20.264695] el1h_64_irq_handler+0x18/0x24
[ 20.264696] el1h_64_irq+0x68/0x6c
[ 20.264697] preempt_count_sub+0xa4/0xe0
[ 20.264698] _raw_spin_unlock_irqrestore+0x64/0xb0
[ 20.264701] vmci_send_datagram+0x7c/0xa0 [vmw_vmci]
[ 20.264703] vmci_datagram_dispatch+0x84/0x100 [vmw_vmci]
[ 20.264706] vmci_datagram_send+0x2c/0x40 [vmw_vmci]
[ 20.264709] vmci_transport_send_control_pkt+0xb8/0x120 [vmw_vsock_vmci_transport]
[ 20.264711] vmci_transport_connect+0x40/0x7c [vmw_vsock_vmci_transport]
[ 20.264713] vsock_connect+0x278/0x330 [vsock]
[ 20.264715] __sys_connect_file+0x8c/0xc0
[ 20.264718] __sys_connect+0x84/0xb4
[ 20.264720] __arm64_sys_connect+0x2c/0x3c
[ 20.264721] invoke_syscall+0x78/0x100
[ 20.264723] el0_svc_common.constprop.0+0x68/0x124
[ 20.264724] do_el0_svc+0x38/0x4c
[ 20.264725] el0_svc+0x60/0x180
[ 20.264726] el0t_64_sync_handler+0x11c/0x150
[ 20.264728] el0t_64_sync+0x190/0x194

Signed-off-by: Vishnu Dasa <[e-mail]>
Suggested-by: Zack Rusin <[e-mail]>
Reported-by: Nadav Amit <[e-mail]>
Reported-by: Nathan Chancellor <[e-mail]>
Tested-by: Nathan Chancellor <[e-mail]>
Fixes: 463713eb6164 ("VMCI: dma dg: add support for DMA datagrams receive")
Cc: <[e-mail]> # v5.18+
Cc: VMware PV-Drivers Reviewers <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Bryan Tan <[e-mail]>
Reviewed-by: Bryan Tan <[e-mail]>
Reviewed-by: Zack Rusin <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/misc/vmw_vmci/vmci_guest.c

···
 
 	bool exclusive_vectors;
 
-	struct tasklet_struct datagram_tasklet;
-	struct tasklet_struct bm_tasklet;
 	struct wait_queue_head inout_wq;
 
 	void *data_buffer;
···
  * This function assumes that it has exclusive access to the data
  * in register(s) for the duration of the call.
  */
-static void vmci_dispatch_dgs(unsigned long data)
+static void vmci_dispatch_dgs(struct vmci_guest_device *vmci_dev)
 {
-	struct vmci_guest_device *vmci_dev = (struct vmci_guest_device *)data;
 	u8 *dg_in_buffer = vmci_dev->data_buffer;
 	struct vmci_datagram *dg;
 	size_t dg_in_buffer_size = VMCI_MAX_DG_SIZE;
···
  * Scans the notification bitmap for raised flags, clears them
  * and handles the notifications.
  */
-static void vmci_process_bitmap(unsigned long data)
+static void vmci_process_bitmap(struct vmci_guest_device *dev)
 {
-	struct vmci_guest_device *dev = (struct vmci_guest_device *)data;
-
 	if (!dev->notification_bitmap) {
 		dev_dbg(dev->dev, "No bitmap present in %s\n", __func__);
 		return;
···
 	struct vmci_guest_device *dev = _dev;
 
 	/*
-	 * If we are using MSI-X with exclusive vectors then we simply schedule
-	 * the datagram tasklet, since we know the interrupt was meant for us.
+	 * If we are using MSI-X with exclusive vectors then we simply call
+	 * vmci_dispatch_dgs(), since we know the interrupt was meant for us.
 	 * Otherwise we must read the ICR to determine what to do.
 	 */
 
 	if (dev->exclusive_vectors) {
-		tasklet_schedule(&dev->datagram_tasklet);
+		vmci_dispatch_dgs(dev);
 	} else {
 		unsigned int icr;
 
···
 			return IRQ_NONE;
 
 		if (icr & VMCI_ICR_DATAGRAM) {
-			tasklet_schedule(&dev->datagram_tasklet);
+			vmci_dispatch_dgs(dev);
 			icr &= ~VMCI_ICR_DATAGRAM;
 		}
 
 		if (icr & VMCI_ICR_NOTIFICATION) {
-			tasklet_schedule(&dev->bm_tasklet);
+			vmci_process_bitmap(dev);
 			icr &= ~VMCI_ICR_NOTIFICATION;
 		}
 
···
 	struct vmci_guest_device *dev = _dev;
 
 	/* For MSI-X we can just assume it was meant for us. */
-	tasklet_schedule(&dev->bm_tasklet);
+	vmci_process_bitmap(dev);
 
 	return IRQ_HANDLED;
 }
···
 	vmci_dev->iobase = iobase;
 	vmci_dev->mmio_base = mmio_base;
 
-	tasklet_init(&vmci_dev->datagram_tasklet,
-		     vmci_dispatch_dgs, (unsigned long)vmci_dev);
-	tasklet_init(&vmci_dev->bm_tasklet,
-		     vmci_process_bitmap, (unsigned long)vmci_dev);
 	init_waitqueue_head(&vmci_dev->inout_wq);
 
 	if (mmio_base != NULL) {
···
 	 * Request IRQ for legacy or MSI interrupts, or for first
 	 * MSI-X vector.
 	 */
-	error = request_irq(pci_irq_vector(pdev, 0), vmci_interrupt,
-			    IRQF_SHARED, KBUILD_MODNAME, vmci_dev);
+	error = request_threaded_irq(pci_irq_vector(pdev, 0), NULL,
+				     vmci_interrupt, IRQF_SHARED,
+				     KBUILD_MODNAME, vmci_dev);
 	if (error) {
 		dev_err(&pdev->dev, "Irq %u in use: %d\n",
 			pci_irq_vector(pdev, 0), error);
···
 	 * between the vectors.
 	 */
 	if (vmci_dev->exclusive_vectors) {
-		error = request_irq(pci_irq_vector(pdev, 1),
-				    vmci_interrupt_bm, 0, KBUILD_MODNAME,
-				    vmci_dev);
+		error = request_threaded_irq(pci_irq_vector(pdev, 1), NULL,
+					     vmci_interrupt_bm, 0,
+					     KBUILD_MODNAME, vmci_dev);
 		if (error) {
 			dev_err(&pdev->dev,
 				"Failed to allocate irq %u: %d\n",
···
 			goto err_free_irq;
 		}
 		if (caps_in_use & VMCI_CAPS_DMA_DATAGRAM) {
-			error = request_irq(pci_irq_vector(pdev, 2),
-					    vmci_interrupt_dma_datagram,
-					    0, KBUILD_MODNAME, vmci_dev);
+			error = request_threaded_irq(pci_irq_vector(pdev, 2),
+						     NULL,
+						    vmci_interrupt_dma_datagram,
+						     0, KBUILD_MODNAME,
+						     vmci_dev);
 			if (error) {
 				dev_err(&pdev->dev,
 					"Failed to allocate irq %u: %d\n",
···
 
 err_free_irq:
 	free_irq(pci_irq_vector(pdev, 0), vmci_dev);
-	tasklet_kill(&vmci_dev->datagram_tasklet);
-	tasklet_kill(&vmci_dev->bm_tasklet);
 
 err_disable_msi:
 	pci_free_irq_vectors(pdev);
···
 	}
 	free_irq(pci_irq_vector(pdev, 0), vmci_dev);
 	pci_free_irq_vectors(pdev);
-
-	tasklet_kill(&vmci_dev->datagram_tasklet);
-	tasklet_kill(&vmci_dev->bm_tasklet);
 
 	if (vmci_dev->notification_bitmap) {
 		/*