[SCSI] sg and st unmap_user_pages allow PageReserved

2.6.15-rc1 made sg's st_unmap_user_pages and st's sgl_unmap_user_pages BUG on a PageReserved page. But that's wrong: they could be unmapping the ZERO_PAGE, which is marked PG_reserved; and perhaps others (while get_user_pages is still permitted on VM_PFNMAP areas - that may change). More change is needed here: sg claims to dirty even pages written from, and st claims not to dirty even pages read into; and SetPageDirty is not adequate for this nowadays. Fixes to those follow in a later patch: for the moment just fix the 2.6.15 regression. Signed-off-by: Hugh Dickins <[email protected]> Acked-by: Nick Piggin <[email protected]> Signed-off-by: James Bottomley <[email protected]>
chewitt · Dec 2, 2005 · 032c09d · 032c09d
1 parent 6bc733e
commit 032c09d
Show file tree

Hide file tree

Showing 2 changed files with 0 additions and 4 deletions.
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
@@ -1878,8 +1878,6 @@ st_unmap_user_pages(struct scatterlist *sgl, const unsigned int nr_pages,
 	for (i=0; i < nr_pages; i++) {
 		struct page *page = sgl[i].page;
 
-		/* XXX: just for debug. Remove when PageReserved is removed */
-		BUG_ON(PageReserved(page));
 		if (dirtied)
 			SetPageDirty(page);
 		/* unlock_page(page); */

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
@@ -4525,8 +4525,6 @@ static int sgl_unmap_user_pages(struct scatterlist *sgl, const unsigned int nr_p
 	for (i=0; i < nr_pages; i++) {
 		struct page *page = sgl[i].page;
 
-		/* XXX: just for debug. Remove when PageReserved is removed */
-		BUG_ON(PageReserved(page));
 		if (dirtied)
 			SetPageDirty(page);
 		/* FIXME: cache flush missing for rw==READ