Merge branch 'linus' into x86/boot, to resolve conflict

There's a new conflict with Linus's upstream tree, because
in the following merge conflict resolution in <asm/coco.h>:

  38b334fc767e Merge tag 'x86_sev_for_v6.9_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Linus has resolved the conflicting placement of 'cc_mask' better
than the original commit:

  1c811d403afd x86/sev: Fix position dependent variable references in startup code

... which was also done by an internal merge resolution:

  2e5fc4786b7a Merge branch 'x86/sev' into x86/boot, to resolve conflicts and to pick up dependent tree

But Linus is right in 38b334fc767e, the 'cc_mask' declaration is sufficient
within the #ifdef CONFIG_ARCH_HAS_CC_PLATFORM block.

So instead of forcing Linus to do the same resolution again, merge in Linus's
tree and follow his conflict resolution.

 Conflicts:
	arch/x86/include/asm/coco.h

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 26 insertions, 34 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 750e779c23db..8df4797c5287 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2609,15 +2609,6 @@ ssize_t filemap_read(struct kiocb *iocb, struct iov_iter *iter,
 		end_offset = min_t(loff_t, isize, iocb->ki_pos + iter->count);
 
 		/*
-		 * Pairs with a barrier in
-		 * block_write_end()->mark_buffer_dirty() or other page
-		 * dirtying routines like iomap_write_end() to ensure
-		 * changes to page contents are visible before we see
-		 * increased inode size.
-		 */
-		smp_rmb();
-
-		/*
 		 * Once we start copying data, we don't want to be touching any
 		 * cachelines that might be contended:
 		 */
@@ -4111,28 +4102,40 @@ static void filemap_cachestat(struct address_space *mapping,
 
 	rcu_read_lock();
 	xas_for_each(&xas, folio, last_index) {
+		int order;
 		unsigned long nr_pages;
 		pgoff_t folio_first_index, folio_last_index;
 
+		/*
+		 * Don't deref the folio. It is not pinned, and might
+		 * get freed (and reused) underneath us.
+		 *
+		 * We *could* pin it, but that would be expensive for
+		 * what should be a fast and lightweight syscall.
+		 *
+		 * Instead, derive all information of interest from
+		 * the rcu-protected xarray.
+		 */
+
 		if (xas_retry(&xas, folio))
 			continue;
 
+		order = xa_get_order(xas.xa, xas.xa_index);
+		nr_pages = 1 << order;
+		folio_first_index = round_down(xas.xa_index, 1 << order);
+		folio_last_index = folio_first_index + nr_pages - 1;
+
+		/* Folios might straddle the range boundaries, only count covered pages */
+		if (folio_first_index < first_index)
+			nr_pages -= first_index - folio_first_index;
+
+		if (folio_last_index > last_index)
+			nr_pages -= folio_last_index - last_index;
+
 		if (xa_is_value(folio)) {
 			/* page is evicted */
 			void *shadow = (void *)folio;
 			bool workingset; /* not used */
-			int order = xa_get_order(xas.xa, xas.xa_index);
-
-			nr_pages = 1 << order;
-			folio_first_index = round_down(xas.xa_index, 1 << order);
-			folio_last_index = folio_first_index + nr_pages - 1;
-
-			/* Folios might straddle the range boundaries, only count covered pages */
-			if (folio_first_index < first_index)
-				nr_pages -= first_index - folio_first_index;
-
-			if (folio_last_index > last_index)
-				nr_pages -= folio_last_index - last_index;
 
 			cs->nr_evicted += nr_pages;
 
@@ -4150,24 +4153,13 @@ static void filemap_cachestat(struct address_space *mapping,
 			goto resched;
 		}
 
-		nr_pages = folio_nr_pages(folio);
-		folio_first_index = folio_pgoff(folio);
-		folio_last_index = folio_first_index + nr_pages - 1;
-
-		/* Folios might straddle the range boundaries, only count covered pages */
-		if (folio_first_index < first_index)
-			nr_pages -= first_index - folio_first_index;
-
-		if (folio_last_index > last_index)
-			nr_pages -= folio_last_index - last_index;
-
 		/* page is in cache */
 		cs->nr_cache += nr_pages;
 
-		if (folio_test_dirty(folio))
+		if (xas_get_mark(&xas, PAGECACHE_TAG_DIRTY))
 			cs->nr_dirty += nr_pages;
 
-		if (folio_test_writeback(folio))
+		if (xas_get_mark(&xas, PAGECACHE_TAG_WRITEBACK))
 			cs->nr_writeback += nr_pages;
 
 resched: