Re: [PATCH 2/2] MIPS/c-r4k: do no use mmap_sem for gup_fast()

On Thu, 07 Feb 2019, Paul Burton wrote: Hi Davidlohr, On Wed, Feb 06, 2019 at 09:37:40PM -0800, Davidlohr Bueso wrote: It is well known that because the mm can internally call the regular gup_unlocked if the lockless approach fails and take the sem there, the caller must not hold the mmap_sem

Re: [PATCH 2/2] MIPS/c-r4k: do no use mmap_sem for gup_fast()

Hi Davidlohr, On Wed, Feb 06, 2019 at 09:37:40PM -0800, Davidlohr Bueso wrote: > It is well known that because the mm can internally > call the regular gup_unlocked if the lockless approach > fails and take the sem there, the caller must not hold > the mmap_sem already. > > Fixes: e523f289fe4d

[PATCH 2/2] MIPS/c-r4k: do no use mmap_sem for gup_fast()

It is well known that because the mm can internally call the regular gup_unlocked if the lockless approach fails and take the sem there, the caller must not hold the mmap_sem already. Fixes: e523f289fe4d (MIPS: c-r4k: Fix sigtramp SMP call to use kmap) Cc: Ralf Baechle Cc: Paul Burton Cc: James