linux-kernel - [PATCH v3 12/41] genwqe: convert put_page() to put_user

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Message-Id: <20190807013340.9706-13-jhubbard@nvidia.com>
Date:   Tue,  6 Aug 2019 18:33:11 -0700
From:   john.hubbard@...il.com
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Christoph Hellwig <hch@...radead.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Dave Chinner <david@...morbit.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Ira Weiny <ira.weiny@...el.com>, Jan Kara <jack@...e.cz>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Jérôme Glisse <jglisse@...hat.com>,
        LKML <linux-kernel@...r.kernel.org>,
        amd-gfx@...ts.freedesktop.org, ceph-devel@...r.kernel.org,
        devel@...verdev.osuosl.org, devel@...ts.orangefs.org,
        dri-devel@...ts.freedesktop.org, intel-gfx@...ts.freedesktop.org,
        kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-block@...r.kernel.org, linux-crypto@...r.kernel.org,
        linux-fbdev@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-media@...r.kernel.org, linux-mm@...ck.org,
        linux-nfs@...r.kernel.org, linux-rdma@...r.kernel.org,
        linux-rpi-kernel@...ts.infradead.org, linux-xfs@...r.kernel.org,
        netdev@...r.kernel.org, rds-devel@....oracle.com,
        sparclinux@...r.kernel.org, x86@...nel.org,
        xen-devel@...ts.xenproject.org, John Hubbard <jhubbard@...dia.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Frank Haverkamp <haver@...ux.vnet.ibm.com>,
        "Guilherme G . Piccoli" <gpiccoli@...ux.vnet.ibm.com>,
        Arnd Bergmann <arnd@...db.de>
Subject: [PATCH v3 12/41] genwqe: convert put_page() to put_user_page*()

From: John Hubbard <jhubbard@...dia.com>

For pages that were retained via get_user_pages*(), release those pages
via the new put_user_page*() routines, instead of via put_page() or
release_pages().

This is part a tree-wide conversion, as described in commit fc1d8e7cca2d
("mm: introduce put_user_page*(), placeholder versions").

This changes the release code slightly, because each page slot in the
page_list[] array is no longer checked for NULL. However, that check
was wrong anyway, because the get_user_pages() pattern of usage here
never allowed for NULL entries within a range of pinned pages.

Acked-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

Cc: Frank Haverkamp <haver@...ux.vnet.ibm.com>
Cc: Guilherme G. Piccoli <gpiccoli@...ux.vnet.ibm.com>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: John Hubbard <jhubbard@...dia.com>
---
 drivers/misc/genwqe/card_utils.c | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/misc/genwqe/card_utils.c b/drivers/misc/genwqe/card_utils.c
index 2e1c4d2905e8..2a888f31d2c5 100644
--- a/drivers/misc/genwqe/card_utils.c
+++ b/drivers/misc/genwqe/card_utils.c
@@ -517,24 +517,13 @@ int genwqe_free_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl)
 /**
  * genwqe_free_user_pages() - Give pinned pages back
  *
- * Documentation of get_user_pages is in mm/gup.c:
- *
- * If the page is written to, set_page_dirty (or set_page_dirty_lock,
- * as appropriate) must be called after the page is finished with, and
- * before put_page is called.
+ * The pages may have been written to, so we call put_user_pages_dirty_lock(),
+ * rather than put_user_pages().
  */
 static int genwqe_free_user_pages(struct page **page_list,
 			unsigned int nr_pages, int dirty)
 {
-	unsigned int i;
-
-	for (i = 0; i < nr_pages; i++) {
-		if (page_list[i] != NULL) {
-			if (dirty)
-				set_page_dirty_lock(page_list[i]);
-			put_page(page_list[i]);
-		}
-	}
+	put_user_pages_dirty_lock(page_list, nr_pages, dirty);
 	return 0;
 }
 
-- 
2.22.0