linux-kernel - [PATCH mm-unstable v1 10/20] RDMA/umem: remove FOLL

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20221116102659.70287-11-david@redhat.com>
Date:   Wed, 16 Nov 2022 11:26:49 +0100
From:   David Hildenbrand <david@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     x86@...nel.org, linux-alpha@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-ia64@...r.kernel.org,
        linux-mips@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        sparclinux@...r.kernel.org, linux-um@...ts.infradead.org,
        etnaviv@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-samsung-soc@...r.kernel.org, linux-rdma@...r.kernel.org,
        linux-media@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-mm@...ck.org, linux-perf-users@...r.kernel.org,
        linux-security-module@...r.kernel.org,
        linux-kselftest@...r.kernel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Jason Gunthorpe <jgg@...pe.ca>,
        John Hubbard <jhubbard@...dia.com>,
        Peter Xu <peterx@...hat.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Hugh Dickins <hughd@...gle.com>, Nadav Amit <namit@...are.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Matthew Wilcox <willy@...radead.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Muchun Song <songmuchun@...edance.com>,
        Shuah Khan <shuah@...nel.org>,
        Lucas Stach <l.stach@...gutronix.de>,
        David Airlie <airlied@...il.com>,
        Oded Gabbay <ogabbay@...nel.org>,
        Arnd Bergmann <arnd@...db.de>,
        Christoph Hellwig <hch@...radead.org>,
        Alex Williamson <alex.williamson@...hat.com>,
        David Hildenbrand <david@...hat.com>,
        Leon Romanovsky <leonro@...dia.com>,
        Leon Romanovsky <leon@...nel.org>
Subject: [PATCH mm-unstable v1 10/20] RDMA/umem: remove FOLL_FORCE usage

GUP now supports reliable R/O long-term pinning in COW mappings, such
that we break COW early. MAP_SHARED VMAs only use the shared zeropage so
far in one corner case (DAXFS file with holes), which can be ignored
because GUP does not support long-term pinning in fsdax (see
check_vma_flags()).

Consequently, FOLL_FORCE | FOLL_WRITE | FOLL_LONGTERM is no longer required
for reliable R/O long-term pinning: FOLL_LONGTERM is sufficient. So stop
using FOLL_FORCE, which is really only for ptrace access.

Tested-by: Leon Romanovsky <leonro@...dia.com> # Over mlx4 and mlx5.
Cc: Jason Gunthorpe <jgg@...pe.ca>
Cc: Leon Romanovsky <leon@...nel.org>
Signed-off-by: David Hildenbrand <david@...hat.com>
---
 drivers/infiniband/core/umem.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index 86d479772fbc..755a9c57db6f 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -156,7 +156,7 @@ struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr,
 	struct mm_struct *mm;
 	unsigned long npages;
 	int pinned, ret;
-	unsigned int gup_flags = FOLL_WRITE;
+	unsigned int gup_flags = FOLL_LONGTERM;
 
 	/*
 	 * If the combination of the addr and size requested for this memory
@@ -210,8 +210,8 @@ struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr,
 
 	cur_base = addr & PAGE_MASK;
 
-	if (!umem->writable)
-		gup_flags |= FOLL_FORCE;
+	if (umem->writable)
+		gup_flags |= FOLL_WRITE;
 
 	while (npages) {
 		cond_resched();
@@ -219,7 +219,7 @@ struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr,
 					  min_t(unsigned long, npages,
 						PAGE_SIZE /
 						sizeof(struct page *)),
-					  gup_flags | FOLL_LONGTERM, page_list);
+					  gup_flags, page_list);
 		if (pinned < 0) {
 			ret = pinned;
 			goto umem_release;
-- 
2.38.1