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xhci: Allocate separate command structures for each LPM command

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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: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220216095153.1303105-7-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mathias Nyman 2022-02-16 11:51:50 +02:00 committed by Greg Kroah-Hartman
parent e1ec140f27
commit 5c2a380a5a
3 changed files with 8 additions and 22 deletions
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7
drivers/usb/host/xhci-mem.c
View File

@ -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.

21
drivers/usb/host/xhci.c
View File

@ -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);

2
drivers/usb/host/xhci.h
View File

@ -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. */