Logan, Am 21.02.2017 um 06:00 schrieb Logan Gunthorpe: > Hello, > > Our story for this patch-set begins with a new driver I wrote and am in > the process of submitting upstream. That driver creates a fairly > standard char device and the code for it was copied from a similar > instance in device-dax. However, upon review, Greg Kroah-Hartman > noticed [1] a suspicious line that assigned to the parent field of > the underlying kobject for the char device. > > I removed that from my code and endeavoured to remove it from the > code I copied as well. However, Dan Williams pointed out [2] that this > code is necessary for correct reference counting of the underlying > structures. This prompted me to do a fair bit more research and > investigation into whats going on and I found it to be a common pattern. > (Although misleading and though required to be correct, frequently > forgotten.) This pattern is used in at least 15 places in the kernel > and probably should have been used in at least 5 more. > > This patch-set aims to correct this and hopefully prevent future > developers from wasting their time on it. The first patch introduces > a new helper API as originally proposed by Dan Williams [3]. Please > see the commit message for that patch for a longer description of the > problem and history. > > The subsequent patches either update correct instances to use the > new API or fix incorrect usages to ensure the cdev correctly takes > a reference count using the new API (this is noted in those patches). > > This moves all except four of the cdev.kobj.parent usages into the one > cdev function, the remaining four are in the infiniband subsystem and > I've left alone because that subsystem seems to make use of kobjects > directly (instead of struct devices). These are noted in patch 7 of > this series. > > This series is based on v4.10 with the exception of the last patch > which is for my new driver which, as yet, has not been accepted > upstream. > > @Dan the first patch in this series will need your sign-off. > > Thanks, > > Logan > > [1] https://lkml.org/lkml/2017/2/10/370 > [2] https://lkml.org/lkml/2017/2/10/607 > [3] https://lkml.org/lkml/2017/2/13/700 > > Logan Gunthorpe (14): > chardev: add helper function to register char devs with a struct > device > device-dax: utilize new device_add_cdev helper function > input: utilize new device_add_cdev helper function > gpiolib: utilize new device_add_cdev helper function > tpm-chip: utilize new device_add_cdev helper function > platform/chrome: utilize new device_add_cdev helper function > infiniband: utilize new device_add_cdev helper function > iio:core: utilize new device_add_cdev helper function > media: utilize new device_add_cdev helper function > mtd: utilize new device_add_cdev helper function > rapidio: utilize new device_add_cdev helper function > rtc: utilize new device_add_cdev helper function > scsi: utilize new device_add_cdev helper function > switchtec: utilize new device_add_cdev helper function > > drivers/char/tpm/tpm-chip.c | 3 +-- > drivers/dax/dax.c | 5 ++--- > drivers/gpio/gpiolib.c | 3 +-- > drivers/iio/industrialio-core.c | 3 +-- > drivers/infiniband/core/ucm.c | 8 +++++--- > drivers/input/evdev.c | 3 +-- > drivers/input/joydev.c | 3 +-- > drivers/input/mousedev.c | 3 +-- > drivers/media/cec/cec-core.c | 3 +-- > drivers/media/media-devnode.c | 3 +-- > drivers/mtd/ubi/build.c | 8 +++++--- > drivers/mtd/ubi/vmt.c | 10 +++++----- > drivers/pci/switch/switchtec.c | 3 +-- > drivers/platform/chrome/cros_ec_dev.c | 6 ++---- > drivers/rapidio/devices/rio_mport_cdev.c | 9 ++++++--- > drivers/rtc/rtc-dev.c | 3 +-- > drivers/scsi/osd/osd_uld.c | 9 +++++---- > fs/char_dev.c | 24 ++++++++++++++++++++++++ > include/linux/cdev.h | 1 + > 19 files changed, 65 insertions(+), 45 deletions(-)
Do you have a git tree where I can pull from? Thanks, //richard _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm
