Commit 0d4597c8 authored by Leon Romanovsky's avatar Leon Romanovsky Committed by David S. Miller
Browse files

net/rds: Track user mapped pages through special API 

Convert net/rds to use the newly introduces pin_user_pages() API,
which properly sets FOLL_PIN. Setting FOLL_PIN is now required for
code that requires tracking of pinned pages.

Note that this effectively changes the code's behavior: it now
ultimately calls set_page_dirty_lock(), instead of set_page_dirty().
This is probably more accurate.

As Christoph Hellwig put it, "set_page_dirty() is only safe if we are
dealing with a file backed page where we have reference on the inode it
hangs off." [1]

[1] https://lore.kernel.org/r/20190723153640.GB720@lst.de



Cc: Hans Westgaard Ry <hans.westgaard.ry@oracle.com>
Cc: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: default avatarLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
Acked-by: default avatarSantosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent afecdb37

net/rds/rdma.c

+12 −12
Original line number Diff line number Diff line
@@ -162,10 +162,9 @@ static int rds_pin_pages(unsigned long user_addr, unsigned int nr_pages, 
	if (write)

		gup_flags |= FOLL_WRITE;



	ret = get_user_pages_fast(user_addr, nr_pages, gup_flags, pages);

	ret = pin_user_pages_fast(user_addr, nr_pages, gup_flags, pages);

	if (ret >= 0 && ret < nr_pages) {

		while (ret--)

			put_page(pages[ret]);

		unpin_user_pages(pages, ret);

		ret = -EFAULT;

	}
@@ -300,8 +299,7 @@ static int __rds_rdma_map(struct rds_sock *rs, struct rds_get_mr_args *args, 
		 * to release anything.

		 */

		if (!need_odp) {

			for (i = 0 ; i < nents; i++)

				put_page(sg_page(&sg[i]));

			unpin_user_pages(pages, nr_pages);

			kfree(sg);

		}

		ret = PTR_ERR(trans_private);
@@ -325,7 +323,12 @@ static int __rds_rdma_map(struct rds_sock *rs, struct rds_get_mr_args *args, 
	if (cookie_ret)

		*cookie_ret = cookie;



	if (args->cookie_addr && put_user(cookie, (u64 __user *)(unsigned long) args->cookie_addr)) {

	if (args->cookie_addr &&

	    put_user(cookie, (u64 __user *)(unsigned long)args->cookie_addr)) {

		if (!need_odp) {

			unpin_user_pages(pages, nr_pages);

			kfree(sg);

		}

		ret = -EFAULT;

		goto out;

	}
@@ -496,9 +499,7 @@ void rds_rdma_free_op(struct rm_rdma_op *ro) 
			 * is the case for a RDMA_READ which copies from remote

			 * to local memory

			 */

			if (!ro->op_write)

				set_page_dirty(page);

			put_page(page);

			unpin_user_pages_dirty_lock(&page, 1, !ro->op_write);

		}

	}
@@ -515,8 +516,7 @@ void rds_atomic_free_op(struct rm_atomic_op *ao) 
	/* Mark page dirty if it was possibly modified, which

	 * is the case for a RDMA_READ which copies from remote

	 * to local memory */

	set_page_dirty(page);

	put_page(page);

	unpin_user_pages_dirty_lock(&page, 1, true);



	kfree(ao->op_notifier);

	ao->op_notifier = NULL;
@@ -944,7 +944,7 @@ int rds_cmsg_atomic(struct rds_sock *rs, struct rds_message *rm, 
	return ret;

err:

	if (page)

		put_page(page);

		unpin_user_page(page);

	rm->atomic.op_active = 0;

	kfree(rm->atomic.op_notifier);

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