On Sat, 29 Sep 2018, Jia-Ju Bai wrote: > >> picolcd_send_and_wait (acquire a spinlock) > >> hid_hw_request > >> __hid_request > >> hid_alloc_report_buf(GFP_KERNEL) > >> > >> picolcd_reset (acquire a spinlock) > >> hid_hw_request > >> __hid_request > >> hid_alloc_report_buf(GFP_KERNEL) > >> > >> lg4ff_play (acquire a spinlock) > >> hid_hw_request > >> __hid_request > >> hid_alloc_report_buf(GFP_KERNEL) > >> > >> lg4ff_set_autocenter_ffex (acquire a spinlock) > >> hid_hw_request > >> __hid_request > >> hid_alloc_report_buf(GFP_KERNEL) > > Hm, so it's always drivers calling out into core in atomic context. So > > either we take this, and put our bets on being able to allocate the buffer > > without sleeping, > > In my opinion, I prefer this way.
Why? Forcing all the report buffer to be limited to be non-sleeping allocations just because of two drivers, looks like an overkill, and actually calls for more issues (as GFP_ATOMIC is of course in principle less likely to succeed). -- Jiri Kosina SUSE Labs
