RDMA/core: Ensure that rdma_user_mmap_entry_remove() is a fence

The set of entry->driver_removed is missing locking, protect it with
xa_lock() which is held by the only reader.

Otherwise readers may continue to see driver_removed = false after
rdma_user_mmap_entry_remove() returns and may continue to try and
establish new mmaps.

Fixes: 3411f9f01b ("RDMA/core: Create mmap database and cookie helper functions")
Link: https://lore.kernel.org/r/20200115202041.GA17199@ziepe.ca
Reviewed-by: Gal Pressman <galpress@amazon.com>
Acked-by: Michal Kalderon <michal.kalderon@marvell.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
This commit is contained in:
Jason Gunthorpe 2020-01-15 20:20:44 +00:00
parent e8b3a426fb
commit 6b3712c024

View file

@ -232,7 +232,9 @@ void rdma_user_mmap_entry_remove(struct rdma_user_mmap_entry *entry)
if (!entry)
return;
xa_lock(&entry->ucontext->mmap_xa);
entry->driver_removed = true;
xa_unlock(&entry->ucontext->mmap_xa);
kref_put(&entry->ref, rdma_user_mmap_entry_free);
}
EXPORT_SYMBOL(rdma_user_mmap_entry_remove);