This is a note to let you know that I've just added the patch titled
Subject: USB: fix race in autosuspend reschedule
to my gregkh-2.6 tree. Its filename is
usb-fix-race-in-autosuspend-reschedule.patch
This tree can be found at
http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/
>From [email protected] Thu Oct 11 13:47:47 2007
From: Alan Stern <[email protected]>
Date: Thu, 11 Oct 2007 16:47:36 -0400 (EDT)
Subject: USB: fix race in autosuspend reschedule
To: Greg KH <[email protected]>
Cc: USB development list <[email protected]>
Message-ID: <[email protected]>
This patch (as1002) fixes a small race which can occur when a driver
expects usbcore to reschedule an autosuspend request. If the request
arrives too late, it won't be rescheduled. The patch adds an extra
argument to autosuspend_check(), indicating that a reschedule is
needed no matter how much time has elapsed.
It also tries to avoid letting asynchronous changes to the value of
jiffies cause a delay to become negative, by caching a local copy of
the current time.
Signed-off-by: Alan Stern <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/usb/core/driver.c | 32 ++++++++++++++++----------------
1 file changed, 16 insertions(+), 16 deletions(-)
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -935,11 +935,11 @@ done:
#ifdef CONFIG_USB_SUSPEND
/* Internal routine to check whether we may autosuspend a device. */
-static int autosuspend_check(struct usb_device *udev)
+static int autosuspend_check(struct usb_device *udev, int reschedule)
{
int i;
struct usb_interface *intf;
- unsigned long suspend_time;
+ unsigned long suspend_time, j;
/* For autosuspend, fail fast if anything is in use or autosuspend
* is disabled. Also fail if any interfaces require remote wakeup
@@ -981,20 +981,20 @@ static int autosuspend_check(struct usb_
}
/* If everything is okay but the device hasn't been idle for long
- * enough, queue a delayed autosuspend request.
+ * enough, queue a delayed autosuspend request. If the device
+ * _has_ been idle for long enough and the reschedule flag is set,
+ * likewise queue a delayed (1 second) autosuspend request.
*/
- if (time_after(suspend_time, jiffies)) {
+ j = jiffies;
+ if (time_before(j, suspend_time))
+ reschedule = 1;
+ else
+ suspend_time = j + HZ;
+ if (reschedule) {
if (!timer_pending(&udev->autosuspend.timer)) {
-
- /* The value of jiffies may change between the
- * time_after() comparison above and the subtraction
- * below. That's okay; the system behaves sanely
- * when a timer is registered for the present moment
- * or for the past.
- */
queue_delayed_work(ksuspend_usb_wq, &udev->autosuspend,
- round_jiffies_relative(suspend_time - jiffies));
- }
+ round_jiffies_relative(suspend_time - j));
+ }
return -EAGAIN;
}
return 0;
@@ -1002,7 +1002,7 @@ static int autosuspend_check(struct usb_
#else
-static inline int autosuspend_check(struct usb_device *udev)
+static inline int autosuspend_check(struct usb_device *udev, int reschedule)
{
return 0;
}
@@ -1059,7 +1059,7 @@ static int usb_suspend_both(struct usb_d
udev->do_remote_wakeup = device_may_wakeup(&udev->dev);
if (udev->auto_pm) {
- status = autosuspend_check(udev);
+ status = autosuspend_check(udev, 0);
if (status < 0)
goto done;
}
@@ -1085,7 +1085,7 @@ static int usb_suspend_both(struct usb_d
/* Try another autosuspend when the interfaces aren't busy */
if (udev->auto_pm)
- autosuspend_check(udev);
+ autosuspend_check(udev, status == -EBUSY);
/* If the suspend succeeded then prevent any more URB submissions,
* flush any outstanding URBs, and propagate the suspend up the tree.
Patches currently in gregkh-2.6 which might be from [email protected] are
driver/sysfs-remove-first-pass-at-shadow-directory-support.patch
driver/sysfs-fix-i_mutex-locking-in-sysfs_get_dentry.patch
driver/sysfs-in-sysfs_lookup-don-t-open-code-sysfs_find_dirent.patch
driver/sysfs-cosmetic-changes-in-sysfs_lookup.patch
driver/sysfs-make-sysfs_add-remove_one-call-link-unlink_sibling-implictly.patch
driver/sysfs-make-sysfs_add_one-automatically-check-for-duplicate-entry.patch
driver/sysfs-make-sysfs_addrm_finish-return-void.patch
driver/sysfs-simplify-sysfs_rename_dir.patch
driver/sysfs-introduce-sysfs_rename_mutex.patch
driver/sysfs-clean-up-header-files.patch
driver/sysfs-make-sysfs_mount-static.patch
driver/sysfs-remove-s_dentry.patch
driver/sysfs-remove-sysfs_instantiate.patch
driver/sysfs-rewrite-rename-in-terms-of-sysfs-dirents.patch
driver/sysfs-move-all-of-inode-initialization-into-sysfs_init_inode.patch
driver/sysfs-rewrite-sysfs_drop_dentry.patch
driver/sysfs-rewrite-sysfs_move_dir-in-terms-of-sysfs-dirents.patch
driver/sysfs-simplify-readdir.patch
driver/sysfs-simply-sysfs_get_dentry.patch
driver/sysfs-use-kill_anon_super.patch
driver/sysfs-fix-comments-of-sysfs_add-remove_one.patch
driver/sysfs-fix-sysfs_chmod_file-such-that-it-updates-sd-s_mode-too.patch
driver/sysfs-implement-sysfs_open_dirent.patch
driver/sysfs-kill-sysfs_update_file.patch
driver/sysfs-kill-unnecessary-null-pointer-check-in-sysfs_release.patch
driver/sysfs-kill-unnecessary-sysfs_get-in-open-paths.patch
driver/sysfs-make-bin-attr-open-get-active-reference-of-parent-too.patch
driver/sysfs-make-s_elem-an-anonymous-union.patch
driver/sysfs-make-sysfs_root-a-regular-directory-dirent.patch
driver/sysfs-move-sysfs-file-poll-implementation-to-sysfs_open_dirent.patch
driver/sysfs-move-sysfs_dirent-s_children-into-sysfs_dirent-s_dir.patch
driver/sysfs-open-code-sysfs_attach_dentry.patch
driver/sysfs-reposition-sysfs_dirent-s_mode.patch
driver/pm-acquire-device-locks-prior-to-suspending.patch
driver/pm-merge-device-power-management-source-files.patch
driver/sysfs-add-copyrights.patch
usb/usb-add-ep-enable.patch
usb/usb-avoid-the-donelist-after-an-error-in-ohci-hcd.patch
usb/usb-add-direction-bit-to-urb-transfer_flags.patch
usb/usb-add-urb-ep.patch
usb/usb-address-0-handling-during-device-initialization.patch
usb/usb-avoid-urb-pipe-in-usbfs.patch
usb/usb-avoid-urb-pipe-in-usbmon.patch
usb/usb-avoid-using-urb-pipe-in-usbcore.patch
usb/usb-cleanup-for-previous-patches.patch
usb/usb-gadget-file-storage-gadget-cleanups.patch
usb/usb-separate-out-endpoint-queue-management-and-dma-mapping-routines.patch
usb/usb-update-spinlock-usage-for-root-hub-urbs.patch
usb/usb-fix-mistake-in-usb_hcd_giveback_urb.patch
usb/usb-less-restrictive-command-checking-in-g-file-storage.patch
usb/usb-reorganize-urb-status-use-in-dummy-hcd.patch
usb/usb-reorganize-urb-status-use-in-ehci-hcd.patch
usb/usb-reorganize-urb-status-use-in-ohci-hcd.patch
usb/usb-reorganize-urb-status-use-in-r8a66597-hcd.patch
usb/usb-reorganize-urb-status-use-in-sl811-hcd.patch
usb/usb-reorganize-urb-status-use-in-usbmon.patch
usb/usb-eliminate-urb-status-usage.patch
usb/usb-cleanups-for-g_file_storage.patch
usb/usb-don-t-touch-sysfs-stuff-when-altsetting-is-unchanged.patch
usb/usb-make-hcds-responsible-for-managing-endpoint-queues.patch
usb/usb-get-rid-of-urb-lock.patch
usb/usb-remove-traces-of-urb-status-from-usbcore.patch
usb/usb-usbmon-doc-update-mention-new-wildcard-bus.patch
usb/usbmon-update-pipe-removal-to-suit-my-taste.patch
usb/usb-break-apart-flush_endpoint-and-disable_endpoint.patch
usb/usb-fix-location-of-statement-label-in-dummy-hcd.patch
usb/usb-flush-outstanding-urbs-when-suspending.patch
usb/usb-get-rid-of-annoying-endpoint-release-message.patch
usb/usb-move-decision-to-ignore-freeze-events.patch
usb/usb-remove-unnecessary-tests-in-isp116x-and-sl811.patch
usb/usb-add-urb-unlinked-field.patch
usb/usb-centralize-eremoteio-handling.patch
usb/usb-driver-for-ch341-usb-serial-adaptor.patch
usb/usb-minor-fixes-for-r8a66597-driver.patch
usb/usb-remove-iso-status-value-in-uhci-hcd.patch
usb/usb-fix-double-frees-in-error-code-paths-of-ipaq-driver.patch
usb/usb-fix-limited_power-setting-mistake-in-hub.c.patch
usb/usb-don-t-propagate-freeze-or-prethaw-suspends.patch
usb/usb-remove-usb_quirk_no_autosuspend.patch
usb/usb-unusual_devs-modification-for-nikon-d200.patch
usb/usb-unusual_devs-update-for-nokia-6131.patch
usb/usb-unusual_devs-entry-for-nikon-dsc-d2xs.patch
usb/usb-storage-always-set-the-allow_restart-flag.patch
usb/usb-mutual-exclusion-for-ehci-init-and-port-resets.patch
usb/usb-documentation-for-usb-power-management.patch
usb/usb-serial-core-should-respect-driver-requirements.patch
usb/usb-skip-autosuspended-devices-during-system-resume.patch
usb/usb-fix-race-in-autosuspend-reschedule.patch
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