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From: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
To: Trond Myklebust <trond.myklebust@hammerspace.com>,
	Anna Schumaker <anna@kernel.org>, Jens Axboe <axboe@kernel.dk>,
	Chaitanya Kulkarni <kch@nvidia.com>,
	Kees Cook <keescook@chromium.org>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	Chuck Lever <chuck.lever@oracle.com>,
	Baptiste Lepers <baptiste.lepers@gmail.com>,
	linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>,
	Ira Weiny <ira.weiny@intel.com>
Subject: [PATCH] nfs: Replace kmap() with kmap_local_page()
Date: Tue, 28 Jun 2022 20:24:26 +0200	[thread overview]
Message-ID: <20220628182426.944-1-fmdefrancesco@gmail.com> (raw)

The use of kmap() is being deprecated in favor of kmap_local_page().

With kmap_local_page(), the mapping is per thread, CPU local and not
globally visible. Furthermore, the mapping can be acquired from any context
(including interrupts).

Therefore, use kmap_local_page() in nfs_do_filldir() because this mapping
is per thread, CPU local, and not globally visible.

Suggested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
---

I cannot test this patch for several reasons. While these changes seem safe
and trivial, I would feel better if people familiar with NFS could take the
time to properly test this patch. Thank you.

 fs/nfs/dir.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 0c4e8dd6aa96..8b89f10d8899 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1084,7 +1084,7 @@ static void nfs_do_filldir(struct nfs_readdir_descriptor *desc,
 	struct nfs_cache_array *array;
 	unsigned int i;
 
-	array = kmap(desc->page);
+	array = kmap_local_page(desc->page);
 	for (i = desc->cache_entry_index; i < array->size; i++) {
 		struct nfs_cache_array_entry *ent;
 
@@ -1110,7 +1110,7 @@ static void nfs_do_filldir(struct nfs_readdir_descriptor *desc,
 	if (array->page_is_eof)
 		desc->eof = !desc->eob;
 
-	kunmap(desc->page);
+	kunmap_local(array);
 	dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %llu\n",
 			(unsigned long long)desc->dir_cookie);
 }
-- 
2.36.1


             reply	other threads:[~2022-06-28 18:24 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-28 18:24 Fabio M. De Francesco [this message]
2022-07-01 18:54 ` [PATCH] nfs: Replace kmap() with kmap_local_page() Ira Weiny

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