linux-kernel - [PATCH 1/2] tomoyo: Convert get_user_pages*() to pin_user

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Date:   Sat,  7 Nov 2020 13:54:10 +0530
From:   Souptick Joarder <jrdr.linux@...il.com>
To:     takedakn@...data.co.jp, penguin-kernel@...ove.SAKURA.ne.jp,
        jmorris@...ei.org, serge@...lyn.com
Cc:     linux-security-module@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Souptick Joarder <jrdr.linux@...il.com>,
        John Hubbard <jhubbard@...dia.com>
Subject: [PATCH 1/2] tomoyo: Convert get_user_pages*() to pin_user_pages*()

In 2019, we introduced pin_user_pages*() and now we are converting
get_user_pages*() to the new API as appropriate. [1] & [2] could
be referred for more information. This is case 5 as per document [1].

[1] Documentation/core-api/pin_user_pages.rst

[2] "Explicit pinning of user-space pages":
        https://lwn.net/Articles/807108/

Signed-off-by: Souptick Joarder <jrdr.linux@...il.com>
Cc: John Hubbard <jhubbard@...dia.com>
---
 security/tomoyo/domain.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c
index dc4ecc0..bd748be 100644
--- a/security/tomoyo/domain.c
+++ b/security/tomoyo/domain.c
@@ -914,7 +914,7 @@ bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos,
 	 * (represented by bprm).  'current' is the process doing
 	 * the execve().
 	 */
-	if (get_user_pages_remote(bprm->mm, pos, 1,
+	if (pin_user_pages_remote(bprm->mm, pos, 1,
 				FOLL_FORCE, &page, NULL, NULL) <= 0)
 		return false;
 #else
@@ -936,7 +936,7 @@ bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos,
 	}
 	/* Same with put_arg_page(page) in fs/exec.c */
 #ifdef CONFIG_MMU
-	put_page(page);
+	unpin_user_page(page);
 #endif
 	return true;
 }
-- 
1.9.1