Commit 5c2a380a authored by Mathias Nyman's avatar Mathias Nyman Committed by Greg Kroah-Hartman
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xhci: Allocate separate command structures for each LPM command 



Every lpm commmand, both for USB 2 and USB 3 devies used the same
xhci->lpm_command structure to change max exit latency.

xhci->lpm_command is only protected by a hcd->bandwidth mutex, which is
not enoungh as USB 2 and USB 3 devices are behind separate HCDs.

Simplify code and avoid unnecessary locking risks by allocating
separate command structures for each lpm command, just like with
all other commands.

Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220216095153.1303105-7-mathias.nyman@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e1ec140f

drivers/usb/host/xhci-mem.c

+0 −7
Original line number Diff line number Diff line
@@ -1846,9 +1846,6 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci) 
	xhci->event_ring = NULL;

	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Freed event ring");



	if (xhci->lpm_command)

		xhci_free_command(xhci, xhci->lpm_command);

	xhci->lpm_command = NULL;

	if (xhci->cmd_ring)

		xhci_ring_free(xhci, xhci->cmd_ring);

	xhci->cmd_ring = NULL;
@@ -2488,10 +2485,6 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags) 
			"// Setting command ring address to 0x%016llx", val_64);

	xhci_write_64(xhci, val_64, &xhci->op_regs->cmd_ring);



	xhci->lpm_command = xhci_alloc_command_with_ctx(xhci, true, flags);

	if (!xhci->lpm_command)

		goto fail;



	/* Reserve one command ring TRB for disabling LPM.

	 * Since the USB core grabs the shared usb_bus bandwidth mutex before

	 * disabling LPM, we only need to reserve one TRB for all devices.

drivers/usb/host/xhci.c

+8 −13
Original line number Diff line number Diff line
@@ -4344,6 +4344,10 @@ static int __maybe_unused xhci_change_max_exit_latency(struct xhci_hcd *xhci, 
	unsigned long flags;

	int ret;



	command = xhci_alloc_command_with_ctx(xhci, true, GFP_KERNEL);

	if (!command)

		return -ENOMEM;



	spin_lock_irqsave(&xhci->lock, flags);



	virt_dev = xhci->devs[udev->slot_id];
@@ -4360,10 +4364,10 @@ static int __maybe_unused xhci_change_max_exit_latency(struct xhci_hcd *xhci, 
	}



	/* Attempt to issue an Evaluate Context command to change the MEL. */

	command = xhci->lpm_command;

	ctrl_ctx = xhci_get_input_control_ctx(command->in_ctx);

	if (!ctrl_ctx) {

		spin_unlock_irqrestore(&xhci->lock, flags);

		xhci_free_command(xhci, command);

		xhci_warn(xhci, "%s: Could not get input context, bad type.\n",

				__func__);

		return -ENOMEM;
@@ -4390,6 +4394,9 @@ static int __maybe_unused xhci_change_max_exit_latency(struct xhci_hcd *xhci, 
		virt_dev->current_mel = max_exit_latency;

		spin_unlock_irqrestore(&xhci->lock, flags);

	}



	xhci_free_command(xhci, command);



	return ret;

}
@@ -4510,18 +4517,8 @@ static int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd, 
			exit_latency = xhci_besl_encoding[hird];

			spin_unlock_irqrestore(&xhci->lock, flags);



			/* USB 3.0 code dedicate one xhci->lpm_command->in_ctx

			 * input context for link powermanagement evaluate

			 * context commands. It is protected by hcd->bandwidth

			 * mutex and is shared by all devices. We need to set

			 * the max ext latency in USB 2 BESL LPM as well, so

			 * use the same mutex and xhci_change_max_exit_latency()

			 */

			mutex_lock(hcd->bandwidth_mutex);

			ret = xhci_change_max_exit_latency(xhci, udev,

							   exit_latency);

			mutex_unlock(hcd->bandwidth_mutex);



			if (ret < 0)

				return ret;

			spin_lock_irqsave(&xhci->lock, flags);
@@ -4549,9 +4546,7 @@ static int xhci_set_usb2_hardware_lpm(struct usb_hcd *hcd, 
		readl(pm_addr);

		if (udev->usb2_hw_lpm_besl_capable) {

			spin_unlock_irqrestore(&xhci->lock, flags);

			mutex_lock(hcd->bandwidth_mutex);

			xhci_change_max_exit_latency(xhci, udev, 0);

			mutex_unlock(hcd->bandwidth_mutex);

			readl_poll_timeout(ports[port_num]->addr, pm_val,

					   (pm_val & PORT_PLS_MASK) == XDEV_U0,

					   100, 10000);

drivers/usb/host/xhci.h

+0 −2
Original line number Diff line number Diff line
@@ -1812,8 +1812,6 @@ struct xhci_hcd { 
	/* slot enabling and address device helpers */

	/* these are not thread safe so use mutex */

	struct mutex mutex;

	/* For USB 3.0 LPM enable/disable. */

	struct xhci_command		*lpm_command;

	/* Internal mirror of the HW's dcbaa */

	struct xhci_virt_device	*devs[MAX_HC_SLOTS];

	/* For keeping track of bandwidth domains per roothub. */