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| author | David Hildenbrand <david@redhat.com> | 2025-09-01 17:03:45 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-09-21 14:22:06 -0700 |
| commit | 80e7bb74d4ff24725f0ddb1c72d8de45a3d975f6 (patch) | |
| tree | 33bc0d3e966f6a54c909be8221d2f95ac87db75d /mm/util.c | |
| parent | a16c46c2402026162111ed9fd1fc28d25223443e (diff) | |
| download | linux-80e7bb74d4ff24725f0ddb1c72d8de45a3d975f6.tar.gz | |
scatterlist: disallow non-contigous page ranges in a single SG entry
The expectation is that there is currently no user that would pass in
non-contigous page ranges: no allocator, not even VMA, will hand these
out.
The only problematic part would be if someone would provide a range
obtained directly from memblock, or manually merge problematic ranges. If
we find such cases, we should fix them to create separate SG entries.
Let's check in sg_set_page() that this is really the case. No need to
check in sg_set_folio(), as pages in a folio are guaranteed to be
contiguous. As sg_set_page() gets inlined into modules, we have to export
the page_range_contiguous() helper -- use EXPORT_SYMBOL, there is nothing
special about this helper such that we would want to enforce GPL-only
modules.
We can now drop the nth_page() usage in sg_page_iter_page().
Link: https://lkml.kernel.org/r/20250901150359.867252-25-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/util.c')
| -rw-r--r-- | mm/util.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/util.c b/mm/util.c index 4b9d40c7128681..e29d3310e26bb6 100644 --- a/mm/util.c +++ b/mm/util.c @@ -1315,4 +1315,5 @@ bool page_range_contiguous(const struct page *page, unsigned long nr_pages) return false; return true; } +EXPORT_SYMBOL(page_range_contiguous); #endif |