Messages in this thread | | | Date | Mon, 30 Jan 2023 15:07:50 -0400 | From | Jason Gunthorpe <> | Subject | Re: [PATCH v2 2/3] iommufd/device: Make hwpt_list list_add/del symmetric |
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On Mon, Jan 30, 2023 at 11:03:09AM -0800, Nicolin Chen wrote: > On Mon, Jan 30, 2023 at 10:59:32AM -0400, Jason Gunthorpe wrote: > > On Sat, Jan 28, 2023 at 01:18:10PM -0800, Nicolin Chen wrote: > > > Since the list_del() of hwpt_item is done in iommufd_device_detach(), move > > > its list_add_tail() to a similar place in iommufd_device_do_attach(). > > > > > > Also move and place the mutex outside the iommufd_device_auto_get_domain() > > > and iommufd_device_do_attach() calls, to serialize attach/detach routines. > > > This adds an additional locking protection so that the following patch can > > > safely remove devices_lock. > > > > That should be two patches then, this is just moving one line of code > > from what I can tell? > > The mutex is used to protect the list. So moving the list means > we'd need to the mutex too. What this patch does is to enlarge > the protection scope a bit to cover iommufd_device_do_attach() > and iommufd_device_auto_get_domain().
That doesn't explain why iommufd_device_auto_get_domain was changed around, it already had the lock
Jason
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