Commit e451eb51 authored Feb 11, 2019 by Davidlohr Bueso Committed by Daniel Borkmann Feb 11, 2019

xsk: share the mmap_sem for page pinning

Holding mmap_sem exclusively for a gup() is an overkill. Lets
share the lock and replace the gup call for gup_longterm(), as
it is better suited for the lifetime of the pinning.

Fixes: c0c77d8f ("xsk: add user memory registration support sockopt")
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: David S. Miller <davem@davemloft.net>
Cc: Bjorn Topel <bjorn.topel@intel.com>
Cc: Magnus Karlsson <magnus.karlsson@intel.com>
CC: netdev@vger.kernel.org
Acked-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

parent 3defaf2f

net/xdp/xdp_umem.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -259,10 +259,10 @@ static int xdp_umem_pin_pages(struct xdp_umem *umem)
		if (!umem->pgs)
		return -ENOMEM;

		down_write(&current->mm->mmap_sem);
		npgs = get_user_pages(umem->address, umem->npgs,
		down_read(&current->mm->mmap_sem);
		npgs = get_user_pages_longterm(umem->address, umem->npgs,
		gup_flags, &umem->pgs[0], NULL);
		up_write(&current->mm->mmap_sem);
		up_read(&current->mm->mmap_sem);

		if (npgs != umem->npgs) {
		if (npgs >= 0) {

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