From: Luis Chamberlain <mcgrof@kernel.org>
To: akpm@linux-foundation.org, ziy@nvidia.com, linux-mm@kvack.org
Cc: fstests@vger.kernel.org, linux-xfs@vger.kernel.org,
linux-kernel@vger.kernel.org, willy@infradead.org, hare@suse.de,
john.g.garry@oracle.com, p.raghav@samsung.com,
da.gomez@samsung.com, mcgrof@kernel.org
Subject: [PATCH 2/2] mm/huge_memory: cap max length on debugfs file entry folio split
Date: Wed, 24 Apr 2024 15:54:49 -0700 [thread overview]
Message-ID: <20240424225449.1498244-3-mcgrof@kernel.org> (raw)
In-Reply-To: <20240424225449.1498244-1-mcgrof@kernel.org>
Don't allow to query beyond a mapped file's length. Since this is just
a debugfs interface allow userspace to be lazy and use a large value so
we can just use the entire file.
Without this we can end up wasting cycles looking for folios which
just don't exist for no good reason.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
mm/huge_memory.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 8386d24a163e..86a8c7b3b8dc 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3535,7 +3535,7 @@ static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start,
struct file *candidate;
struct address_space *mapping;
int ret = -EINVAL;
- pgoff_t index;
+ pgoff_t index, fsize;
int nr_pages = 1;
unsigned long total = 0, split = 0;
@@ -3547,11 +3547,14 @@ static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start,
if (IS_ERR(candidate))
goto out;
+ mapping = candidate->f_mapping;
+ fsize = i_size_read(mapping->host);
+ if (off_end > fsize)
+ off_end = fsize;
+
pr_debug("split file-backed THPs in file: %s, page offset: [0x%lx - 0x%lx]\n",
file_path, off_start, off_end);
- mapping = candidate->f_mapping;
-
for (index = off_start; index < off_end; index += nr_pages) {
struct folio *folio = filemap_get_folio(mapping, index);
--
2.43.0
next prev parent reply other threads:[~2024-04-24 22:54 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-24 22:54 [PATCH 0/2] mm/huge_memory: couple fixes and one cleanup Luis Chamberlain
2024-04-24 22:54 ` [PATCH 1/2] mm/huge_memory: skip invalid debugfs file entry for folio split Luis Chamberlain
2024-04-25 1:03 ` Zi Yan
2024-04-25 22:40 ` Luis Chamberlain
2024-04-25 21:01 ` Andrew Morton
2024-04-29 4:04 ` Luis Chamberlain
2024-04-29 16:23 ` Andrew Morton
2024-05-07 0:30 ` Luis Chamberlain
2024-04-24 22:54 ` Luis Chamberlain [this message]
2024-04-25 1:05 ` [PATCH 2/2] mm/huge_memory: cap max length on debugfs file entry " Zi Yan
2024-04-24 22:55 ` [PATCH 0/2] mm/huge_memory: couple fixes and one cleanup Luis Chamberlain
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