I recently posted an intended replacement[1] for iov_iter_get_pages*() which, instead of always just getting a ref on the pages it extracts from the iterator it is given, will pin them or leave them unaltered (but still in the list) as appropriate. However, Christoph objected[2] to my using EXPORT_SYMBOL() with it on the basis that: get_user_pages_fast, pin_user_pages_fast are very intentionally EXPORT_SYMBOL_GPL, which should not be bypassed by an iov_* wrapper. but iov_iter_get_pages*() is EXPORT_SYMBOL(), so it's already possible to bypass this restriction. He has also raised other objections[3]. Should we then convert this to EXPORT_SYMBOL_GPL(), as per the attached patch? Link: https://lore.kernel.org/r/166920902005.1461876.2786264600108839814.stgit@xxxxxxxxxxxxxxxxxxxxxx/ [1] Link: https://lore.kernel.org/r/Y3zFzdWnWlEJ8X8/@infradead.org/ [2] Link: https://lore.kernel.org/lkml/20221025154143.GA25128@xxxxxx/ [3] --- iov_iter: Mark iov_iter_get_pages2*() as EXPORT_SYMBOL_GPL() iov_iter_get_pages2*() should be marked EXPORT_SYMBOL_GPL() as the use get_user_pages_fast()[1]. Reported-by: Christoph Hellwig <hch@xxxxxx> Signed-off-by: David Howells <dhowells@xxxxxxxxxx> cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> cc: linux-mm@xxxxxxxxx cc: linux-fsdevel@xxxxxxxxxxxxxxx Link: https://lore.kernel.org/r/Y3zFzdWnWlEJ8X8/@infradead.org/ [1] --- iov_iter.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 612fc9bf9881..02b02a5fece4 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1502,7 +1502,7 @@ ssize_t iov_iter_get_pages2(struct iov_iter *i, return __iov_iter_get_pages_alloc(i, &pages, maxsize, maxpages, start); } -EXPORT_SYMBOL(iov_iter_get_pages2); +EXPORT_SYMBOL_GPL(iov_iter_get_pages2); ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, struct page ***pages, size_t maxsize, @@ -1519,7 +1519,7 @@ ssize_t iov_iter_get_pages_alloc2(struct iov_iter *i, } return len; } -EXPORT_SYMBOL(iov_iter_get_pages_alloc2); +EXPORT_SYMBOL_GPL(iov_iter_get_pages_alloc2); size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i)
