On Thu, Aug 05, 2021 at 02:43:46PM +0200, Greg Kroah-Hartman wrote: > On Fri, Jul 30, 2021 at 02:50:13PM -0500, Bjorn Helgaas wrote: > > On Fri, Jul 30, 2021 at 07:06:26AM +0200, Greg Kroah-Hartman wrote: > > > On Thu, Jul 29, 2021 at 11:32:33PM +0000, Krzysztof Wilczyński wrote: > > > > Hello, > > > > > > > > At the moment, the dependency on iomem_get_mapping() that is currently > > > > used in the pci_create_resource_files() and pci_create_legacy_files() > > > > stops us from completely retiring the late_initcall() that is used to > > > > invoke pci_sysfs_init() when creating sysfs object for PCI devices. > > > > > > > > This dependency on iomem_get_mapping() stops us from retiring the > > > > late_initcall at the moment as when we convert dynamically added sysfs > > > > objects, that are primarily added in the pci_create_resource_files() and > > > > pci_create_legacy_files(), as these attributes are added before the VFS > > > > completes its initialisation, and since most of the PCI devices are > > > > typically enumerated in subsys_initcall this leads to a failure and an > > > > Oops related to iomem_get_mapping() access. > > > > > > > > See relevant conversations: > > > > https://lore.kernel.org/linux-pci/20210204165831.2703772-1-daniel.vetter@xxxxxxxx/ > > > > https://lore.kernel.org/linux-pci/20210313215747.GA2394467@bjorn-Precision-5520/ > > > > > > > > After some deliberation about the problem at hand, Dan Williams > > > > suggested a solution to the problem, as per: > > > > https://lore.kernel.org/linux-pci/CAPcyv4i0y_4cMGEpNVShLUyUk3nyWH203Ry3S87BqnDJE0Rmxg@xxxxxxxxxxxxxx/ > > > > > > > > The idea is to defer execution of the iomem_get_mapping() to only when > > > > the sysfs open callback is run, and thus removing the reliance of > > > > fs_initcalls to complete before any other sub-system that uses the > > > > iomem_get_mapping(). > > > > > > > > Currently, the PCI sub-system will benefit the most from this change > > > > allowing for it to complete the transition from dynamically created to > > > > static sysfs objects. > > > > > > > > This series aims to take Dan Williams' idea through the finish line. > > > > > > > > Related to: > > > > https://lore.kernel.org/linux-pci/20210527205845.GA1421476@bjorn-Precision-5520/ > > > > https://lore.kernel.org/linux-pci/20210507102706.7658-1-danijel.slivka@xxxxxxx/ > > > > https://lore.kernel.org/linux-pci/20200716110423.xtfyb3n6tn5ixedh@pali/ > > > > > > > > Krzysztof > > > > > > > > > > No objection from me on these, Bjorn, mind if I take them through my > > > driver core tree? > > > > That'd be great! > > > > Is your tree immutable? I'm hoping we can take advantage of this to > > get rid of pci_sysfs_init(), which will fix a race that people seem to > > be hitting frequently now [1]. I think Krzysztof is getting pretty > > close. > > > > [1] https://lore.kernel.org/r/m3eebg9puj.fsf@xxxxxxxxxxx > > Yes, my tree is immutable. Let me create a branch just for this that > you can pull from after it passes 0-day... Ok, here you go, a signed tag for you to pull from: The following changes since commit ff1176468d368232b684f75e82563369208bc371: Linux 5.14-rc3 (2021-07-25 15:35:14 -0700) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git tags/sysfs_defferred_iomem_get_mapping-5.15 for you to fetch changes up to f06aff924f975881a6abf91d2af0078fc8cd37bf: sysfs: Rename struct bin_attribute member to f_mapping (2021-08-05 14:47:31 +0200) ---------------------------------------------------------------- sysfs: Allow deferred execution of iomem_get_mapping() Tag for toerh trees/branches to pull from in order to have a stable base to build off of for the "Allow deferred execution of iomem_get_mapping()" set of sysfs changes Link: https://lore.kernel.org/r/20210729233235.1508920-1-kw@xxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> ---------------------------------------------------------------- Krzysztof Wilczyński (2): sysfs: Invoke iomem_get_mapping() from the sysfs open callback sysfs: Rename struct bin_attribute member to f_mapping drivers/pci/pci-sysfs.c | 6 +++--- fs/sysfs/file.c | 4 ++-- include/linux/sysfs.h | 2 +- 3 files changed, 6 insertions(+), 6 deletions(-)
