linux-kernel - [PATCH] usbip: vhci_hcd: slighly simplify code in 'vhci_urb

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Message-Id: <20200321152938.19580-1-christophe.jaillet@wanadoo.fr>
Date:   Sat, 21 Mar 2020 16:29:38 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     valentina.manea.m@...il.com, shuah@...nel.org,
        gregkh@...uxfoundation.org
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH] usbip: vhci_hcd: slighly simplify code in 'vhci_urb_dequeue()'

The allocation of 'unlink' can be moved before a spin_lock.
This slighly simplifies the error handling if the memory allocation fails,
aligns the code structure with what is done in 'vhci_tx_urb()' and reduces
potential lock contention.

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
 drivers/usb/usbip/vhci_hcd.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/usbip/vhci_hcd.c b/drivers/usb/usbip/vhci_hcd.c
index 65850e9c7190..b909a634260c 100644
--- a/drivers/usb/usbip/vhci_hcd.c
+++ b/drivers/usb/usbip/vhci_hcd.c
@@ -905,17 +905,16 @@ static int vhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 		/* tcp connection is alive */
 		struct vhci_unlink *unlink;
 
-		spin_lock(&vdev->priv_lock);
-
 		/* setup CMD_UNLINK pdu */
 		unlink = kzalloc(sizeof(struct vhci_unlink), GFP_ATOMIC);
 		if (!unlink) {
-			spin_unlock(&vdev->priv_lock);
 			spin_unlock_irqrestore(&vhci->lock, flags);
 			usbip_event_add(&vdev->ud, VDEV_EVENT_ERROR_MALLOC);
 			return -ENOMEM;
 		}
 
+		spin_lock(&vdev->priv_lock);
+
 		unlink->seqnum = atomic_inc_return(&vhci_hcd->seqnum);
 		if (unlink->seqnum == 0xffff)
 			pr_info("seqnum max\n");
-- 
2.20.1