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Commit a49049ea authored by Björn Töpel's avatar Björn Töpel Committed by Daniel Borkmann
Browse files

xsk: simplified umem setup 



As suggested by Daniel Borkmann, the umem setup code was a too
defensive and complex. Here, we reduce the number of checks. Also, the
memory pinning is now folded into the umem creation, and we do correct
locking.

Signed-off-by: default avatarBjörn Töpel <bjorn.topel@intel.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 37b07693

net/xdp/xdp_umem.c

+38 −41
Original line number Diff line number Diff line
@@ -16,21 +16,10 @@ 


#define XDP_UMEM_MIN_FRAME_SIZE 2048



int xdp_umem_create(struct xdp_umem **umem)

{

	*umem = kzalloc(sizeof(**umem), GFP_KERNEL);



	if (!*umem)

		return -ENOMEM;



	return 0;

}



static void xdp_umem_unpin_pages(struct xdp_umem *umem)

{

	unsigned int i;



	if (umem->pgs) {

	for (i = 0; i < umem->npgs; i++) {

		struct page *page = umem->pgs[i];
@@ -41,15 +30,12 @@ static void xdp_umem_unpin_pages(struct xdp_umem *umem) 
	kfree(umem->pgs);

	umem->pgs = NULL;

}

}



static void xdp_umem_unaccount_pages(struct xdp_umem *umem)

{

	if (umem->user) {

	atomic_long_sub(umem->npgs, &umem->user->locked_vm);

	free_uid(umem->user);

}

}



static void xdp_umem_release(struct xdp_umem *umem)

{
@@ -66,7 +52,6 @@ static void xdp_umem_release(struct xdp_umem *umem) 
		umem->cq = NULL;

	}



	if (umem->pgs) {

	xdp_umem_unpin_pages(umem);



	task = get_pid_task(umem->pid, PIDTYPE_PID);
@@ -79,9 +64,6 @@ static void xdp_umem_release(struct xdp_umem *umem) 
		goto out;



	mmput(mm);

		umem->pgs = NULL;

	}



	xdp_umem_unaccount_pages(umem);

out:

	kfree(umem);
@@ -167,16 +149,13 @@ static int xdp_umem_account_pages(struct xdp_umem *umem) 
	return 0;

}



int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)

static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)

{

	u32 frame_size = mr->frame_size, frame_headroom = mr->frame_headroom;

	u64 addr = mr->addr, size = mr->len;

	unsigned int nframes, nfpp;

	int size_chk, err;



	if (!umem)

		return -EINVAL;



	if (frame_size < XDP_UMEM_MIN_FRAME_SIZE || frame_size > PAGE_SIZE) {

		/* Strictly speaking we could support this, if:

		 * - huge pages, or*
@@ -245,6 +224,24 @@ int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr) 
	return err;

}



struct xdp_umem *xdp_umem_create(struct xdp_umem_reg *mr)

{

	struct xdp_umem *umem;

	int err;



	umem = kzalloc(sizeof(*umem), GFP_KERNEL);

	if (!umem)

		return ERR_PTR(-ENOMEM);



	err = xdp_umem_reg(umem, mr);

	if (err) {

		kfree(umem);

		return ERR_PTR(err);

	}



	return umem;

}



bool xdp_umem_validate_queues(struct xdp_umem *umem)

{

	return umem->fq && umem->cq;

net/xdp/xdp_umem.h

+1 −2
Original line number Diff line number Diff line
@@ -50,9 +50,8 @@ static inline char *xdp_umem_get_data_with_headroom(struct xdp_umem *umem, 
}



bool xdp_umem_validate_queues(struct xdp_umem *umem);

int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr);

void xdp_get_umem(struct xdp_umem *umem);

void xdp_put_umem(struct xdp_umem *umem);

int xdp_umem_create(struct xdp_umem **umem);

struct xdp_umem *xdp_umem_create(struct xdp_umem_reg *mr);



#endif /* XDP_UMEM_H_ */

net/xdp/xsk.c

+12 −12
Original line number Diff line number Diff line
@@ -406,25 +406,23 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname, 
		struct xdp_umem_reg mr;

		struct xdp_umem *umem;



		if (xs->umem)

			return -EBUSY;



		if (copy_from_user(&mr, optval, sizeof(mr)))

			return -EFAULT;



		mutex_lock(&xs->mutex);

		err = xdp_umem_create(&umem);

		if (xs->umem) {

			mutex_unlock(&xs->mutex);

			return -EBUSY;

		}



		err = xdp_umem_reg(umem, &mr);

		if (err) {

			kfree(umem);

		umem = xdp_umem_create(&mr);

		if (IS_ERR(umem)) {

			mutex_unlock(&xs->mutex);

			return err;

			return PTR_ERR(umem);

		}



		/* Make sure umem is ready before it can be seen by others */

		smp_wmb();



		xs->umem = umem;

		mutex_unlock(&xs->mutex);

		return 0;
@@ -435,13 +433,15 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname, 
		struct xsk_queue **q;

		int entries;



		if (!xs->umem)

			return -EINVAL;



		if (copy_from_user(&entries, optval, sizeof(entries)))

			return -EFAULT;



		mutex_lock(&xs->mutex);

		if (!xs->umem) {

			mutex_unlock(&xs->mutex);

			return -EINVAL;

		}



		q = (optname == XDP_UMEM_FILL_RING) ? &xs->umem->fq :

			&xs->umem->cq;

		err = xsk_init_queue(entries, q, true);