On Mon, Jan 23, 2023 at 12:37:17PM +0100, David Hildenbrand wrote: > On 17.01.23 16:58, Jason Gunthorpe wrote: > > Setting FOLL_UNLOCK allows GUP to lock/unlock the mmap lock on its own. It > > is a more explicit replacement for locked != NULL. This clears the way for > > passing in locked = 1, without intending that the lock can be unlocked. > > > > Set the flag in all cases where it is used, eg locked is present in the > > external interface or locked is used internally with locked = 0. > > > > Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx> > > --- > > include/linux/mm.h | 1 + > > mm/gup.c | 31 +++++++++++++++++++------------ > > 2 files changed, 20 insertions(+), 12 deletions(-) > > > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > index f3f196e4d66d6f..7496a5c8acede1 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -3089,6 +3089,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, > > #define FOLL_FAST_ONLY 0x80000 /* gup_fast: prevent fall-back to slow gup */ > > #define FOLL_PCI_P2PDMA 0x100000 /* allow returning PCI P2PDMA pages */ > > #define FOLL_INTERRUPTIBLE 0x200000 /* allow interrupts from generic signals */ > > +#define FOLL_UNLOCK 0x400000 /* allow unlocking the mmap lock */ > > So it's more like "FOLL_UNLOCKABLE" ? FOLL_UNLOCK sounds like an instruction > instead. Sure, I renamed it > Not that I particularly like adding new internal FOLL flags where avoidable > :P How about, I made a patch to move all the internal FOLL_ flags into mm/internal.h ? Jason
