When we care about pagecache maintenance, we need to make sure that both f_mapping and i_mapping point at the right mapping.
But for iomem mappings we only care about the virtual/pte side of things, so f_mapping is enough. Also setting inode->i_mapping was confusing me as a driver maintainer, since in e.g. drivers/gpu we don't do that. Per Dan this seems to be copypasta from places which do care about pagecache consistency, but not needed. Hence remove it for slightly less confusion.
Signed-off-by: Daniel Vetter daniel.vetter@intel.com Cc: Jason Gunthorpe jgg@ziepe.ca Cc: Kees Cook keescook@chromium.org Cc: Dan Williams dan.j.williams@intel.com Cc: Andrew Morton akpm@linux-foundation.org Cc: John Hubbard jhubbard@nvidia.com Cc: Jérôme Glisse jglisse@redhat.com Cc: Jan Kara jack@suse.cz Cc: Dan Williams dan.j.williams@intel.com Cc: linux-mm@kvack.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-samsung-soc@vger.kernel.org Cc: linux-media@vger.kernel.org Reviewed-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Daniel Vetter daniel.vetter@ffwll.ch --- drivers/char/mem.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index abd4ffdc8cde..5502f56f3655 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -864,7 +864,6 @@ static int open_port(struct inode *inode, struct file *filp) * revocations when drivers want to take over a /dev/mem mapped * range. */ - inode->i_mapping = devmem_inode->i_mapping; filp->f_mapping = inode->i_mapping;
return 0;