ehci-usb regression on 32-bit laptops in v4.17-rc1

[Erick Cafferata <erick@cafferata.me>]

Starting from v4.17-rc1, I've been having problems with my laptop's
webcam. Immediately after attempting to open Guvcview(or any other camera
software), the system just stops working. No response from any input and
the Caps lock LED starts blinking.
I've been following the last three -rc and no changes, so I started
testing on my own. I bisected it back to

commit 22072e83ebd510fb6a090aef9d65ccfda9b1e7e4
Author: Souptick Joarder <jrdr.linux@gmail.com>
Date:   Wed Feb 14 23:18:48 2018 +0530

    usb: host: ehci: Use dma_pool_zalloc()

    Use dma_pool_zalloc() instead of dma_pool_alloc + memset

I tried reverting it on top of -rc3 and everything worked again.
I test this bug on four machines:
- 2 hp mini 210(atom n450 and n2800, respectively)
- 1 Sony Vaio (Core 2 Duo T7250)
- 1 Thinkpad T410 (some core i7..)
The three 32-bit laptops presented the exact same bug, however the
Thinkpad did not crash (the driver didn't create the /dev/videoN at
all, I think this might be a different issue, so disregard).
And reverting this commit solved the issue in all three laptops.

Let me know if you need any further information regarding this issue.
Sincerely,
Erick Cafferata

commit d3c88476223b51d2a0a1bc2326760c0dcb6efd88
Author: Erick Cafferata <erick@cafferata.me>
Date:   Wed May 2 11:13:32 2018 -0500

    Revert "usb: host: ehci: Use dma_pool_zalloc()"
    
    This reverts commit 22072e83ebd510fb6a090aef9d65ccfda9b1e7e4.
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diff --git a/drivers/usb/host/ehci-mem.c b/drivers/usb/host/ehci-mem.c
index 4c6c08b675b5..21307d862af6 100644
--- a/drivers/usb/host/ehci-mem.c
+++ b/drivers/usb/host/ehci-mem.c
@@ -73,9 +73,10 @@ static struct ehci_qh *ehci_qh_alloc (struct ehci_hcd *ehci, gfp_t flags)
 	if (!qh)
 		goto done;
 	qh->hw = (struct ehci_qh_hw *)
-		dma_pool_zalloc(ehci->qh_pool, flags, &dma);
+		dma_pool_alloc(ehci->qh_pool, flags, &dma);
 	if (!qh->hw)
 		goto fail;
+	memset(qh->hw, 0, sizeof *qh->hw);
 	qh->qh_dma = dma;
 	// INIT_LIST_HEAD (&qh->qh_list);
 	INIT_LIST_HEAD (&qh->qtd_list);
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index 28e2a338b481..e56db44708bc 100644
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -1287,7 +1287,7 @@ itd_urb_transaction(
 		} else {
  alloc_itd:
 			spin_unlock_irqrestore(&ehci->lock, flags);
-			itd = dma_pool_zalloc(ehci->itd_pool, mem_flags,
+			itd = dma_pool_alloc(ehci->itd_pool, mem_flags,
 					&itd_dma);
 			spin_lock_irqsave(&ehci->lock, flags);
 			if (!itd) {
@@ -1297,6 +1297,7 @@ itd_urb_transaction(
 			}
 		}
 
+		memset(itd, 0, sizeof(*itd));
 		itd->itd_dma = itd_dma;
 		itd->frame = NO_FRAME;
 		list_add(&itd->itd_list, &sched->td_list);
@@ -2080,7 +2081,7 @@ sitd_urb_transaction(
 		} else {
  alloc_sitd:
 			spin_unlock_irqrestore(&ehci->lock, flags);
-			sitd = dma_pool_zalloc(ehci->sitd_pool, mem_flags,
+			sitd = dma_pool_alloc(ehci->sitd_pool, mem_flags,
 					&sitd_dma);
 			spin_lock_irqsave(&ehci->lock, flags);
 			if (!sitd) {
@@ -2090,6 +2091,7 @@ sitd_urb_transaction(
 			}
 		}
 
+		memset(sitd, 0, sizeof(*sitd));
 		sitd->sitd_dma = sitd_dma;
 		sitd->frame = NO_FRAME;
 		list_add(&sitd->sitd_list, &iso_sched->td_list);