xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

USB: EHCI: don't refcount QHs

Browse Source 
This patch (as1567) removes ehci-hcd's reference counting of QH
structures.  It's not necessary to refcount these things because they
always get deallocated at exactly one spot in ehci_endpoint_disable()
(except for two special QHs, ehci->async and ehci->dummy) and are
never used again.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alan Stern
2012-07-11 11:21:25 -04:00
committed by Greg Kroah-Hartman
parent 15be105b4a
commit c83e1a9ff6
5 changed files with 8 additions and 44 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/usb/host/ehci.h
View File

@@ -350,16 +350,7 @@ struct ehci_qh {
struct ehci_qtd *dummy;
struct ehci_qh *reclaim; /* next to reclaim */
struct ehci_hcd *ehci;
unsigned long unlink_time;
/*
* Do NOT use atomic operations for QH refcounting. On some CPUs
* (PPC7448 for example), atomic operations cannot be performed on
* memory that is cache-inhibited (i.e. being used for DMA).
* Spinlocks are used to protect all QH fields.
*/
u32 refcount;
unsigned stamp;
u8 needs_rescan; /* Dequeue during giveback */