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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: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Leon Romanovsky 2020-02-11 19:03:55 -08:00 committed by David S. Miller
parent afecdb376b
commit 0d4597c8c5
1 changed files with 12 additions and 12 deletions
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24
net/rds/rdma.c
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@ -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);