The get_user_pages_fast() may mess up the page order in @pages array, We will get the wrong DMA results in this case.
Add more commit to clarify it. Signed-off-by: Huang Shijie <sjhu...@iluvatar.ai> --- lib/scatterlist.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/lib/scatterlist.c b/lib/scatterlist.c index 739dc9fe2c55..c170afb1a25e 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -450,6 +450,9 @@ EXPORT_SYMBOL(__sg_alloc_table_from_pages); * specified by the page array. The returned sg table is released by * sg_free_table. * + * Note: Do not use get_user_pages_fast() to pin the pages for @pages array, + * it may mess up the page order, and we will get the wrong DMA results. + * Returns: * 0 on success, negative error on failure */ -- 2.17.1
