linux/drivers/usb/core/sysfs.c, branch v4.9

usb: no locking for reading descriptors in sysfs

2016-02-03T21:29:12Z

Quting the relevant thread: > In fact, I suspect the locking added by the kernel 3.13 commit for > read_descriptors() is invalid because read_descriptors() performs no USB > activity; read_descriptors() just reads information from an allocated > memory structure. This structure is protected as the structure is > existing before and after the sysfs vfs descriptors entry is created or > destroyed. You're right. For some reason I thought that usb_deauthorize_device() would destroy the rawdescriptor structures (as mentioned in that commit's Changelog), but it doesn't. The locking in read_descriptors() is unnecessary. > The information is only written at the time of enumeration > and does not change. At least that is my understanding. > > It is noted that in our testing of kernel 3.8 on ARM, that sysfs > read_descriptors() was non-blocking because the kernel 3.13 comment was > not there. > > The pre-kernel 3.13 sysfs read_descriptors() seemed to work OK. > > Proposal: > ========= > > Remove the usb_lock_device(udev) and usb_unlock_device(udev) from > devices/usb/core/sysfs.c in read_descriptors() that was added by the > kernel 3.13 commit > "232275a USB: fix substandard locking for the sysfs files" > > Any comments to this proposal ? It seems okay to me. Please submit a patch. So this removes the locking making the point about -EINTR in the first path moot. Signed-off-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman

usb: sysfs: make locking interruptible

2016-02-03T21:29:12Z

232275a USB: fix substandard locking for the sysfs files introduced needed locking into sysfs operations on USB devices It, however, uses uninterruptible sleep and if the error handling is on extreme cases of sleep lengths of 10s of seconds are possible. Unless we are removing the device we should use interruptible sleep. Signed-off-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman

usb: show speed "10000" in sysfs for USB 3.1 SuperSpeedPlus devices

2016-01-25T04:16:52Z

The same way as SuperSpeed devices show "5000" as device speed we wan't to show "10000" as the default speed for SuperSpeedPlus devices in sysfs. Signed-off-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman

usb: core: lpm: fix usb3_hardware_lpm sysfs node

2015-12-01T22:58:18Z

Commit 655fe4effe0f ("usbcore: add sysfs support to xHCI usb3 hardware LPM") introduced usb3_hardware_lpm sysfs node. This doesn't show the correct status of USB3 U1 and U2 LPM status. This patch fixes this by replacing usb3_hardware_lpm with two nodes, usb3_hardware_lpm_u1 (for U1) and usb3_hardware_lpm_u2 (for U2), and recording the U1/U2 LPM status in right places. This patch should be back-ported to kernels as old as 4.3, that contains Commit 655fe4effe0f ("usbcore: add sysfs support to xHCI usb3 hardware LPM"). Cc: stable@vger.kernel.org Signed-off-by: Lu Baolu Signed-off-by: Greg Kroah-Hartman

usb: interface authorization: SysFS part of USB interface authorization

2015-09-22T19:08:40Z

This introduces an attribute for each interface to authorize (1) or deauthorize (0) it: /sys/bus/usb/devices/INTERFACE/authorized Signed-off-by: Stefan Koch Signed-off-by: Greg Kroah-Hartman

Revert "usb: interface authorization: SysFS part of USB interface authorization"

2015-08-18T16:57:43Z

This reverts commit 187b3d75bbfba45a38b5d1d3656c0f11f6f6f2d0 as the signed-off-by address is invalid. Cc: Stefan Koch Signed-off-by: Greg Kroah-Hartman

usb: interface authorization: SysFS part of USB interface authorization

2015-08-14T23:55:54Z

This introduces an attribute for each interface to authorize (1) or deauthorize (0) it: /sys/bus/usb/devices/INTERFACE/authorized Signed-off-by: Stefan Koch Signed-off-by: Greg Kroah-Hartman

usbcore: add sysfs support to xHCI usb3 hardware LPM

2015-07-22T22:45:03Z

Add a sysfs node to make it easier to verify if LPM is supported and being enabled for USB 3.0 devices. Signed-off-by: Kevin Strasser Signed-off-by: Greg Kroah-Hartman

USB / PM: Drop CONFIG_PM_RUNTIME from the USB core

2014-12-03T23:51:54Z

After commit b2b49ccbdd54 (PM: Kconfig: Set PM_RUNTIME if PM_SLEEP is selected) PM_RUNTIME is always set if PM is set, so quite a few depend on CONFIG_PM (or even dropped in some cases). Replace CONFIG_PM_RUNTIME with CONFIG_PM in the USB core code and documentation. Signed-off-by: Rafael J. Wysocki Acked-by: Alan Stern Acked-by: Greg Kroah-Hartman

USB: core: correct spelling mistakes in comments and warning

2014-01-08T00:17:40Z

Signed-off-by: Rahul Bedarkar Acked-by: Randy Dunlap Signed-off-by: Greg Kroah-Hartman