[ +Dan ] On 02/07/2019 08:43 AM, Björn Töpel wrote: > Den tors 7 feb. 2019 kl 06:38 skrev Davidlohr Bueso <[email protected]>: >> >> Holding mmap_sem exclusively for a gup() is an overkill. >> Lets replace the call for gup_fast() and let the mm take >> it if necessary. >> >> Cc: David S. Miller <[email protected]> >> Cc: Bjorn Topel <[email protected]> >> Cc: Magnus Karlsson <[email protected]> >> CC: [email protected] >> Signed-off-by: Davidlohr Bueso <[email protected]> >> --- >> net/xdp/xdp_umem.c | 6 ++---- >> 1 file changed, 2 insertions(+), 4 deletions(-) >> >> diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c >> index 5ab236c5c9a5..25e1e76654a8 100644 >> --- a/net/xdp/xdp_umem.c >> +++ b/net/xdp/xdp_umem.c >> @@ -265,10 +265,8 @@ static int xdp_umem_pin_pages(struct xdp_umem *umem) >> if (!umem->pgs) >> return -ENOMEM; >> >> - down_write(¤t->mm->mmap_sem); >> - npgs = get_user_pages(umem->address, umem->npgs, >> - gup_flags, &umem->pgs[0], NULL); >> - up_write(¤t->mm->mmap_sem); >> + npgs = get_user_pages_fast(umem->address, umem->npgs, >> + gup_flags, &umem->pgs[0]); >> > > Thanks for the patch! > > The lifetime of the pinning is similar to RDMA umem mapping, so isn't > gup_longterm preferred?
Seems reasonable from reading what gup_longterm seems to do. Davidlohr or Dan, any thoughts on the above? Thanks, Daniel
