Merge tag 'mm-hotfixes-stable-2023-06-20-12-31' of...

Merge tag 'mm-hotfixes-stable-2023-06-20-12-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull hotfixes from Andrew Morton:
 "19 hotfixes.  8 of these are cc:stable.

  This includes a wholesale reversion of the post-6.4 series 'make slab
  shrink lockless'. After input from Dave Chinner it has been decided
  that we should go a different way [1]"

Link: https://lkml.kernel.org/r/ZH6K0McWBeCjaf16@dread.disaster.area [1]

* tag 'mm-hotfixes-stable-2023-06-20-12-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  selftests/mm: fix cross compilation with LLVM
  mailmap: add entries for Ben Dooks
  nilfs2: prevent general protection fault in nilfs_clear_dirty_page()
  Revert "mm: vmscan: make global slab shrink lockless"
  Revert "mm: vmscan: make memcg slab shrink lockless"
  Revert "mm: vmscan: add shrinker_srcu_generation"
  Revert "mm: shrinkers: make count and scan in shrinker debugfs lockless"
  Revert "mm: vmscan: hold write lock to reparent shrinker nr_deferred"
  Revert "mm: vmscan: remove shrinker_rwsem from synchronize_shrinkers()"
  Revert "mm: shrinkers: convert shrinker_rwsem to mutex"
  nilfs2: fix buffer corruption due to concurrent device reads
  scripts/gdb: fix SB_* constants parsing
  scripts: fix the gfp flags header path in gfp-translate
  udmabuf: revert 'Add support for mapping hugepages (v4)'
  mm/khugepaged: fix iteration in collapse_file
  memfd: check for non-NULL file_seals in memfd_create() syscall
  mm/vmalloc: do not output a spurious warning when huge vmalloc() fails
  mm/mprotect: fix do_mprotect_pkey() limit check
  writeback: fix dereferencing NULL mapping->host on writeback_page_template

.mailmap

@@ -70,6 +70,8 @@ Baolin Wang <baolin.wang@linux.alibaba.com> <baolin.wang@unisoc.com>
 Baolin Wang <baolin.wang@linux.alibaba.com> <baolin.wang7@gmail.com>
 Bart Van Assche <bvanassche@acm.org> <bart.vanassche@sandisk.com>
 Bart Van Assche <bvanassche@acm.org> <bart.vanassche@wdc.com>
+Ben Dooks <ben-linux@fluff.org> <ben.dooks@simtec.co.uk>
+Ben Dooks <ben-linux@fluff.org> <ben.dooks@sifive.com>
 Ben Gardner <bgardner@wabtec.com>
 Ben M Cahill <ben.m.cahill@intel.com>
 Ben Widawsky <bwidawsk@kernel.org> <ben@bwidawsk.net>

drivers/dma-buf/udmabuf.c

@@ -12,7 +12,6 @@
 #include <linux/shmem_fs.h>
 #include <linux/slab.h>
 #include <linux/udmabuf.h>
-#include <linux/hugetlb.h>
 #include <linux/vmalloc.h>
 #include <linux/iosys-map.h>
 
@@ -207,9 +206,7 @@ static long udmabuf_create(struct miscdevice *device,
 	struct udmabuf *ubuf;
 	struct dma_buf *buf;
 	pgoff_t pgoff, pgcnt, pgidx, pgbuf = 0, pglimit;
-	struct page *page, *hpage = NULL;
-	pgoff_t subpgoff, maxsubpgs;
-	struct hstate *hpstate;
+	struct page *page;
 	int seals, ret = -EINVAL;
 	u32 i, flags;
 
@@ -245,7 +242,7 @@ static long udmabuf_create(struct miscdevice *device,
 		if (!memfd)
 			goto err;
 		mapping = memfd->f_mapping;
-		if (!shmem_mapping(mapping) && !is_file_hugepages(memfd))
+		if (!shmem_mapping(mapping))
 			goto err;
 		seals = memfd_fcntl(memfd, F_GET_SEALS, 0);
 		if (seals == -EINVAL)
@@ -256,48 +253,16 @@ static long udmabuf_create(struct miscdevice *device,
 			goto err;
 		pgoff = list[i].offset >> PAGE_SHIFT;
 		pgcnt = list[i].size   >> PAGE_SHIFT;
-		if (is_file_hugepages(memfd)) {
-			hpstate = hstate_file(memfd);
-			pgoff = list[i].offset >> huge_page_shift(hpstate);
-			subpgoff = (list[i].offset &
-				    ~huge_page_mask(hpstate)) >> PAGE_SHIFT;
-			maxsubpgs = huge_page_size(hpstate) >> PAGE_SHIFT;
-		}
 		for (pgidx = 0; pgidx < pgcnt; pgidx++) {
-			if (is_file_hugepages(memfd)) {
-				if (!hpage) {
-					hpage = find_get_page_flags(mapping, pgoff,
-								    FGP_ACCESSED);
-					if (!hpage) {
-						ret = -EINVAL;
-						goto err;
-					}
-				}
-				page = hpage + subpgoff;
-				get_page(page);
-				subpgoff++;
-				if (subpgoff == maxsubpgs) {
-					put_page(hpage);
-					hpage = NULL;
-					subpgoff = 0;
-					pgoff++;
-				}
-			} else {
-				page = shmem_read_mapping_page(mapping,
-							       pgoff + pgidx);
+			page = shmem_read_mapping_page(mapping, pgoff + pgidx);
 			if (IS_ERR(page)) {
 				ret = PTR_ERR(page);
 				goto err;
 			}
-			}
 			ubuf->pages[pgbuf++] = page;
 		}
 		fput(memfd);
 		memfd = NULL;
-		if (hpage) {
-			put_page(hpage);
-			hpage = NULL;
-		}
 	}
 
 	exp_info.ops  = &udmabuf_ops;

drivers/md/dm-cache-metadata.c

@@ -1828,7 +1828,7 @@ int dm_cache_metadata_abort(struct dm_cache_metadata *cmd)
 	 * Replacement block manager (new_bm) is created and old_bm destroyed outside of
 	 * cmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of
 	 * shrinker associated with the block manager's bufio client vs cmd root_lock).
-	 * - must take shrinker_mutex without holding cmd->root_lock
+	 * - must take shrinker_rwsem without holding cmd->root_lock
 	 */
 	new_bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
 					 CACHE_MAX_CONCURRENT_LOCKS);

drivers/md/dm-thin-metadata.c

@@ -1891,7 +1891,7 @@ int dm_pool_abort_metadata(struct dm_pool_metadata *pmd)
 	 * Replacement block manager (new_bm) is created and old_bm destroyed outside of
 	 * pmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of
 	 * shrinker associated with the block manager's bufio client vs pmd root_lock).
-	 * - must take shrinker_mutex without holding pmd->root_lock
+	 * - must take shrinker_rwsem without holding pmd->root_lock
 	 */
 	new_bm = dm_block_manager_create(pmd->bdev, THIN_METADATA_BLOCK_SIZE << SECTOR_SHIFT,
 					 THIN_MAX_CONCURRENT_LOCKS);

fs/nilfs2/page.c

@@ -370,7 +370,15 @@ void nilfs_clear_dirty_pages(struct address_space *mapping, bool silent)
 			struct folio *folio = fbatch.folios[i];
 
 			folio_lock(folio);
+
+			/*
+			 * This folio may have been removed from the address
+			 * space by truncation or invalidation when the lock
+			 * was acquired.  Skip processing in that case.
+			 */
+			if (likely(folio->mapping == mapping))
 				nilfs_clear_dirty_page(&folio->page, silent);
+
 			folio_unlock(folio);
 		}
 		folio_batch_release(&fbatch);

fs/nilfs2/segbuf.c

@@ -101,6 +101,12 @@ int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *segbuf)
 	if (unlikely(!bh))
 		return -ENOMEM;
 
+	lock_buffer(bh);
+	if (!buffer_uptodate(bh)) {
+		memset(bh->b_data, 0, bh->b_size);
+		set_buffer_uptodate(bh);
+	}
+	unlock_buffer(bh);
 	nilfs_segbuf_add_segsum_buffer(segbuf, bh);
 	return 0;
 }

fs/nilfs2/segment.c

@@ -981,10 +981,13 @@ static void nilfs_segctor_fill_in_super_root(struct nilfs_sc_info *sci,
 	unsigned int isz, srsz;
 
 	bh_sr = NILFS_LAST_SEGBUF(&sci->sc_segbufs)->sb_super_root;
+
+	lock_buffer(bh_sr);
 	raw_sr = (struct nilfs_super_root *)bh_sr->b_data;
 	isz = nilfs->ns_inode_size;
 	srsz = NILFS_SR_BYTES(isz);
 
+	raw_sr->sr_sum = 0;  /* Ensure initialization within this update */
 	raw_sr->sr_bytes = cpu_to_le16(srsz);
 	raw_sr->sr_nongc_ctime
 		= cpu_to_le64(nilfs_doing_gc() ?
@@ -998,6 +1001,8 @@ static void nilfs_segctor_fill_in_super_root(struct nilfs_sc_info *sci,
 	nilfs_write_inode_common(nilfs->ns_sufile, (void *)raw_sr +
 				 NILFS_SR_SUFILE_OFFSET(isz), 1);
 	memset((void *)raw_sr + srsz, 0, nilfs->ns_blocksize - srsz);
+	set_buffer_uptodate(bh_sr);
+	unlock_buffer(bh_sr);
 }
 
 static void nilfs_redirty_inodes(struct list_head *head)
@@ -1780,6 +1785,7 @@ static void nilfs_abort_logs(struct list_head *logs, int err)
 	list_for_each_entry(segbuf, logs, sb_list) {
 		list_for_each_entry(bh, &segbuf->sb_segsum_buffers,
 				    b_assoc_buffers) {
+			clear_buffer_uptodate(bh);
 			if (bh->b_page != bd_page) {
 				if (bd_page)
 					end_page_writeback(bd_page);
@@ -1791,6 +1797,7 @@ static void nilfs_abort_logs(struct list_head *logs, int err)
 				    b_assoc_buffers) {
 			clear_buffer_async_write(bh);
 			if (bh == segbuf->sb_super_root) {
+				clear_buffer_uptodate(bh);
 				if (bh->b_page != bd_page) {
 					end_page_writeback(bd_page);
 					bd_page = bh->b_page;

fs/nilfs2/super.c

@@ -372,10 +372,31 @@ static int nilfs_move_2nd_super(struct super_block *sb, loff_t sb2off)
 		goto out;
 	}
 	nsbp = (void *)nsbh->b_data + offset;
-	memset(nsbp, 0, nilfs->ns_blocksize);
 
+	lock_buffer(nsbh);
 	if (sb2i >= 0) {
+		/*
+		 * The position of the second superblock only changes by 4KiB,
+		 * which is larger than the maximum superblock data size
+		 * (= 1KiB), so there is no need to use memmove() to allow
+		 * overlap between source and destination.
+		 */
 		memcpy(nsbp, nilfs->ns_sbp[sb2i], nilfs->ns_sbsize);
+
+		/*
+		 * Zero fill after copy to avoid overwriting in case of move
+		 * within the same block.
+		 */
+		memset(nsbh->b_data, 0, offset);
+		memset((void *)nsbp + nilfs->ns_sbsize, 0,
+		       nsbh->b_size - offset - nilfs->ns_sbsize);
+	} else {
+		memset(nsbh->b_data, 0, nsbh->b_size);
+	}
+	set_buffer_uptodate(nsbh);
+	unlock_buffer(nsbh);
+
+	if (sb2i >= 0) {
 		brelse(nilfs->ns_sbh[sb2i]);
 		nilfs->ns_sbh[sb2i] = nsbh;
 		nilfs->ns_sbp[sb2i] = nsbp;

fs/super.c

@@ -54,7 +54,7 @@ static char *sb_writers_name[SB_FREEZE_LEVELS] = {
  * One thing we have to be careful of with a per-sb shrinker is that we don't
  * drop the last active reference to the superblock from within the shrinker.
  * If that happens we could trigger unregistering the shrinker from within the
- * shrinker path and that leads to deadlock on the shrinker_mutex. Hence we
+ * shrinker path and that leads to deadlock on the shrinker_rwsem. Hence we
  * take a passive reference to the superblock to avoid this from occurring.
  */
 static unsigned long super_cache_scan(struct shrinker *shrink,

include/trace/events/writeback.h

@@ -68,7 +68,7 @@ DECLARE_EVENT_CLASS(writeback_folio_template,
 		strscpy_pad(__entry->name,
 			    bdi_dev_name(mapping ? inode_to_bdi(mapping->host) :
 					 NULL), 32);
-		__entry->ino = mapping ? mapping->host->i_ino : 0;
+		__entry->ino = (mapping && mapping->host) ? mapping->host->i_ino : 0;
 		__entry->index = folio->index;
 	),
 

mm/khugepaged.c

@@ -2070,7 +2070,6 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr,
 					TTU_IGNORE_MLOCK | TTU_BATCH_FLUSH);
 
 		xas_lock_irq(&xas);
-		xas_set(&xas, index);
 
 		VM_BUG_ON_PAGE(page != xas_load(&xas), page);
 

mm/memfd.c

@@ -371,11 +371,14 @@ SYSCALL_DEFINE2(memfd_create,
 
 		inode->i_mode &= ~0111;
 		file_seals = memfd_file_seals_ptr(file);
+		if (file_seals) {
 			*file_seals &= ~F_SEAL_SEAL;
 			*file_seals |= F_SEAL_EXEC;
+		}
 	} else if (flags & MFD_ALLOW_SEALING) {
 		/* MFD_EXEC and MFD_ALLOW_SEALING are set */
 		file_seals = memfd_file_seals_ptr(file);
+		if (file_seals)
 			*file_seals &= ~F_SEAL_SEAL;
 	}
 

mm/mprotect.c

@@ -867,7 +867,7 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
 	}
 	tlb_finish_mmu(&tlb);
 
-	if (!error && vma_iter_end(&vmi) < end)
+	if (!error && tmp < end)
 		error = -ENOMEM;
 
 out:

mm/shrinker_debug.c

@@ -5,12 +5,10 @@
 #include <linux/seq_file.h>
 #include <linux/shrinker.h>
 #include <linux/memcontrol.h>
-#include <linux/srcu.h>
 
 /* defined in vmscan.c */
-extern struct mutex shrinker_mutex;
+extern struct rw_semaphore shrinker_rwsem;
 extern struct list_head shrinker_list;
-extern struct srcu_struct shrinker_srcu;
 
 static DEFINE_IDA(shrinker_debugfs_ida);
 static struct dentry *shrinker_debugfs_root;
@@ -51,13 +49,18 @@ static int shrinker_debugfs_count_show(struct seq_file *m, void *v)
 	struct mem_cgroup *memcg;
 	unsigned long total;
 	bool memcg_aware;
-	int ret = 0, nid, srcu_idx;
+	int ret, nid;
 
 	count_per_node = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
 	if (!count_per_node)
 		return -ENOMEM;
 
-	srcu_idx = srcu_read_lock(&shrinker_srcu);
+	ret = down_read_killable(&shrinker_rwsem);
+	if (ret) {
+		kfree(count_per_node);
+		return ret;
+	}
+	rcu_read_lock();
 
 	memcg_aware = shrinker->flags & SHRINKER_MEMCG_AWARE;
 
@@ -88,7 +91,8 @@ static int shrinker_debugfs_count_show(struct seq_file *m, void *v)
 		}
 	} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
 
-	srcu_read_unlock(&shrinker_srcu, srcu_idx);
+	rcu_read_unlock();
+	up_read(&shrinker_rwsem);
 
 	kfree(count_per_node);
 	return ret;
@@ -111,8 +115,9 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file,
 		.gfp_mask = GFP_KERNEL,
 	};
 	struct mem_cgroup *memcg = NULL;
-	int nid, srcu_idx;
+	int nid;
 	char kbuf[72];
+	ssize_t ret;
 
 	read_len = size < (sizeof(kbuf) - 1) ? size : (sizeof(kbuf) - 1);
 	if (copy_from_user(kbuf, buf, read_len))
@@ -141,7 +146,11 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file,
 		return -EINVAL;
 	}
 
-	srcu_idx = srcu_read_lock(&shrinker_srcu);
+	ret = down_read_killable(&shrinker_rwsem);
+	if (ret) {
+		mem_cgroup_put(memcg);
+		return ret;
+	}
 
 	sc.nid = nid;
 	sc.memcg = memcg;
@@ -150,7 +159,7 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file,
 
 	shrinker->scan_objects(shrinker, &sc);
 
-	srcu_read_unlock(&shrinker_srcu, srcu_idx);
+	up_read(&shrinker_rwsem);
 	mem_cgroup_put(memcg);
 
 	return size;
@@ -168,7 +177,7 @@ int shrinker_debugfs_add(struct shrinker *shrinker)
 	char buf[128];
 	int id;
 
-	lockdep_assert_held(&shrinker_mutex);
+	lockdep_assert_held(&shrinker_rwsem);
 
 	/* debugfs isn't initialized yet, add debugfs entries later. */
 	if (!shrinker_debugfs_root)
@@ -211,7 +220,7 @@ int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...)
 	if (!new)
 		return -ENOMEM;
 
-	mutex_lock(&shrinker_mutex);
+	down_write(&shrinker_rwsem);
 
 	old = shrinker->name;
 	shrinker->name = new;
@@ -229,7 +238,7 @@ int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...)
 			shrinker->debugfs_entry = entry;
 	}
 
-	mutex_unlock(&shrinker_mutex);
+	up_write(&shrinker_rwsem);
 
 	kfree_const(old);
 
@@ -242,7 +251,7 @@ struct dentry *shrinker_debugfs_detach(struct shrinker *shrinker,
 {
 	struct dentry *entry = shrinker->debugfs_entry;
 
-	lockdep_assert_held(&shrinker_mutex);
+	lockdep_assert_held(&shrinker_rwsem);
 
 	kfree_const(shrinker->name);
 	shrinker->name = NULL;
@@ -271,14 +280,14 @@ static int __init shrinker_debugfs_init(void)
 	shrinker_debugfs_root = dentry;
 
 	/* Create debugfs entries for shrinkers registered at boot */
-	mutex_lock(&shrinker_mutex);
+	down_write(&shrinker_rwsem);
 	list_for_each_entry(shrinker, &shrinker_list, list)
 		if (!shrinker->debugfs_entry) {
 			ret = shrinker_debugfs_add(shrinker);
 			if (ret)
 				break;
 		}
-	mutex_unlock(&shrinker_mutex);
+	up_write(&shrinker_rwsem);
 
 	return ret;
 }

mm/vmalloc.c

@@ -3098,11 +3098,20 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 	 * allocation request, free them via vfree() if any.
 	 */
 	if (area->nr_pages != nr_small_pages) {
-		/* vm_area_alloc_pages() can also fail due to a fatal signal */
-		if (!fatal_signal_pending(current))
+		/*
+		 * vm_area_alloc_pages() can fail due to insufficient memory but
+		 * also:-
+		 *
+		 * - a pending fatal signal
+		 * - insufficient huge page-order pages
+		 *
+		 * Since we always retry allocations at order-0 in the huge page
+		 * case a warning for either is spurious.
+		 */
+		if (!fatal_signal_pending(current) && page_order == 0)
 			warn_alloc(gfp_mask, NULL,
-				"vmalloc error: size %lu, page order %u, failed to allocate pages",
-				area->nr_pages * PAGE_SIZE, page_order);
+				"vmalloc error: size %lu, failed to allocate pages",
+				area->nr_pages * PAGE_SIZE);
 		goto fail;
 	}
 

mm/vmscan.c

@@ -35,7 +35,7 @@
 #include <linux/cpuset.h>
 #include <linux/compaction.h>
 #include <linux/notifier.h>
-#include <linux/mutex.h>
+#include <linux/rwsem.h>
 #include <linux/delay.h>
 #include <linux/kthread.h>
 #include <linux/freezer.h>
@@ -57,7 +57,6 @@
 #include <linux/khugepaged.h>
 #include <linux/rculist_nulls.h>
 #include <linux/random.h>
-#include <linux/srcu.h>
 
 #include <asm/tlbflush.h>
 #include <asm/div64.h>
@@ -190,9 +189,7 @@ struct scan_control {
 int vm_swappiness = 60;
 
 LIST_HEAD(shrinker_list);
-DEFINE_MUTEX(shrinker_mutex);
-DEFINE_SRCU(shrinker_srcu);
-static atomic_t shrinker_srcu_generation = ATOMIC_INIT(0);
+DECLARE_RWSEM(shrinker_rwsem);
 
 #ifdef CONFIG_MEMCG
 static int shrinker_nr_max;
@@ -211,21 +208,8 @@ static inline int shrinker_defer_size(int nr_items)
 static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg,
 						     int nid)
 {
-	return srcu_dereference_check(memcg->nodeinfo[nid]->shrinker_info,
-				      &shrinker_srcu,
-				      lockdep_is_held(&shrinker_mutex));
-}
-
-static struct shrinker_info *shrinker_info_srcu(struct mem_cgroup *memcg,
-						     int nid)
-{
-	return srcu_dereference(memcg->nodeinfo[nid]->shrinker_info,
-				&shrinker_srcu);
-}
-
-static void free_shrinker_info_rcu(struct rcu_head *head)
-{
-	kvfree(container_of(head, struct shrinker_info, rcu));
+	return rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info,
+					 lockdep_is_held(&shrinker_rwsem));
 }
 
 static int expand_one_shrinker_info(struct mem_cgroup *memcg,
@@ -266,7 +250,7 @@ static int expand_one_shrinker_info(struct mem_cgroup *memcg,
 		       defer_size - old_defer_size);
 
 		rcu_assign_pointer(pn->shrinker_info, new);
-		call_srcu(&shrinker_srcu, &old->rcu, free_shrinker_info_rcu);
+		kvfree_rcu(old, rcu);
 	}
 
 	return 0;
@@ -292,7 +276,7 @@ int alloc_shrinker_info(struct mem_cgroup *memcg)
 	int nid, size, ret = 0;
 	int map_size, defer_size = 0;
 
-	mutex_lock(&shrinker_mutex);
+	down_write(&shrinker_rwsem);
 	map_size = shrinker_map_size(shrinker_nr_max);
 	defer_size = shrinker_defer_size(shrinker_nr_max);
 	size = map_size + defer_size;
@@ -308,7 +292,7 @@ int alloc_shrinker_info(struct mem_cgroup *memcg)
 		info->map_nr_max = shrinker_nr_max;
 		rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info);
 	}
-	mutex_unlock(&shrinker_mutex);
+	up_write(&shrinker_rwsem);
 
 	return ret;
 }
@@ -324,7 +308,7 @@ static int expand_shrinker_info(int new_id)
 	if (!root_mem_cgroup)
 		goto out;
 
-	lockdep_assert_held(&shrinker_mutex);
+	lockdep_assert_held(&shrinker_rwsem);
 
 	map_size = shrinker_map_size(new_nr_max);
 	defer_size = shrinker_defer_size(new_nr_max);
@@ -352,16 +336,15 @@ void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id)
 {
 	if (shrinker_id >= 0 && memcg && !mem_cgroup_is_root(memcg)) {
 		struct shrinker_info *info;
-		int srcu_idx;
 
-		srcu_idx = srcu_read_lock(&shrinker_srcu);
-		info = shrinker_info_srcu(memcg, nid);
+		rcu_read_lock();
+		info = rcu_dereference(memcg->nodeinfo[nid]->shrinker_info);
 		if (!WARN_ON_ONCE(shrinker_id >= info->map_nr_max)) {
 			/* Pairs with smp mb in shrink_slab() */
 			smp_mb__before_atomic();
 			set_bit(shrinker_id, info->map);
 		}
-		srcu_read_unlock(&shrinker_srcu, srcu_idx);
+		rcu_read_unlock();
 	}
 }
 
@@ -374,7 +357,8 @@ static int prealloc_memcg_shrinker(struct shrinker *shrinker)
 	if (mem_cgroup_disabled())
 		return -ENOSYS;
 
-	mutex_lock(&shrinker_mutex);
+	down_write(&shrinker_rwsem);
+	/* This may call shrinker, so it must use down_read_trylock() */
 	id = idr_alloc(&shrinker_idr, shrinker, 0, 0, GFP_KERNEL);
 	if (id < 0)
 		goto unlock;
@@ -388,7 +372,7 @@ static int prealloc_memcg_shrinker(struct shrinker *shrinker)
 	shrinker->id = id;
 	ret = 0;
 unlock:
-	mutex_unlock(&shrinker_mutex);
+	up_write(&shrinker_rwsem);
 	return ret;
 }
 
@@ -398,7 +382,7 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker)
 
 	BUG_ON(id < 0);
 
-	lockdep_assert_held(&shrinker_mutex);
+	lockdep_assert_held(&shrinker_rwsem);
 
 	idr_remove(&shrinker_idr, id);
 }
@@ -408,7 +392,7 @@ static long xchg_nr_deferred_memcg(int nid, struct shrinker *shrinker,
 {
 	struct shrinker_info *info;
 
-	info = shrinker_info_srcu(memcg, nid);
+	info = shrinker_info_protected(memcg, nid);
 	return atomic_long_xchg(&info->nr_deferred[shrinker->id], 0);
 }
 
@@ -417,7 +401,7 @@ static long add_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker,
 {
 	struct shrinker_info *info;
 
-	info = shrinker_info_srcu(memcg, nid);
+	info = shrinker_info_protected(memcg, nid);
 	return atomic_long_add_return(nr, &info->nr_deferred[shrinker->id]);
 }
 
@@ -433,7 +417,7 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg)
 		parent = root_mem_cgroup;
 
 	/* Prevent from concurrent shrinker_info expand */
-	mutex_lock(&shrinker_mutex);
+	down_read(&shrinker_rwsem);
 	for_each_node(nid) {
 		child_info = shrinker_info_protected(memcg, nid);
 		parent_info = shrinker_info_protected(parent, nid);
@@ -442,7 +426,7 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg)
 			atomic_long_add(nr, &parent_info->nr_deferred[i]);
 		}
 	}
-	mutex_unlock(&shrinker_mutex);
+	up_read(&shrinker_rwsem);
 }
 
 static bool cgroup_reclaim(struct scan_control *sc)
@@ -743,9 +727,9 @@ void free_prealloced_shrinker(struct shrinker *shrinker)
 	shrinker->name = NULL;
 #endif
 	if (shrinker->flags & SHRINKER_MEMCG_AWARE) {
-		mutex_lock(&shrinker_mutex);
+		down_write(&shrinker_rwsem);
 		unregister_memcg_shrinker(shrinker);
-		mutex_unlock(&shrinker_mutex);
+		up_write(&shrinker_rwsem);
 		return;
 	}
 
@@ -755,11 +739,11 @@ void free_prealloced_shrinker(struct shrinker *shrinker)
 
 void register_shrinker_prepared(struct shrinker *shrinker)
 {
-	mutex_lock(&shrinker_mutex);
-	list_add_tail_rcu(&shrinker->list, &shrinker_list);
+	down_write(&shrinker_rwsem);
+	list_add_tail(&shrinker->list, &shrinker_list);
 	shrinker->flags |= SHRINKER_REGISTERED;
 	shrinker_debugfs_add(shrinker);
-	mutex_unlock(&shrinker_mutex);
+	up_write(&shrinker_rwsem);
 }
 
 static int __register_shrinker(struct shrinker *shrinker)
@@ -810,16 +794,13 @@ void unregister_shrinker(struct shrinker *shrinker)
 	if (!(shrinker->flags & SHRINKER_REGISTERED))
 		return;
 
-	mutex_lock(&shrinker_mutex);
-	list_del_rcu(&shrinker->list);
+	down_write(&shrinker_rwsem);
+	list_del(&shrinker->list);
 	shrinker->flags &= ~SHRINKER_REGISTERED;
 	if (shrinker->flags & SHRINKER_MEMCG_AWARE)
 		unregister_memcg_shrinker(shrinker);
 	debugfs_entry = shrinker_debugfs_detach(shrinker, &debugfs_id);
-	mutex_unlock(&shrinker_mutex);
-
-	atomic_inc(&shrinker_srcu_generation);
-	synchronize_srcu(&shrinker_srcu);
+	up_write(&shrinker_rwsem);
 
 	shrinker_debugfs_remove(debugfs_entry, debugfs_id);
 
@@ -831,13 +812,15 @@ EXPORT_SYMBOL(unregister_shrinker);
 /**
  * synchronize_shrinkers - Wait for all running shrinkers to complete.
  *
- * This is useful to guarantee that all shrinker invocations have seen an
- * update, before freeing memory.
+ * This is equivalent to calling unregister_shrink() and register_shrinker(),
+ * but atomically and with less overhead. This is useful to guarantee that all
+ * shrinker invocations have seen an update, before freeing memory, similar to
+ * rcu.
  */
 void synchronize_shrinkers(void)
 {
-	atomic_inc(&shrinker_srcu_generation);
-	synchronize_srcu(&shrinker_srcu);
+	down_write(&shrinker_rwsem);
+	up_write(&shrinker_rwsem);
 }
 EXPORT_SYMBOL(synchronize_shrinkers);
 
@@ -946,20 +929,19 @@ static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid,
 {
 	struct shrinker_info *info;
 	unsigned long ret, freed = 0;
-	int srcu_idx, generation;
-	int i = 0;
+	int i;
 
 	if (!mem_cgroup_online(memcg))
 		return 0;
 
-again:
-	srcu_idx = srcu_read_lock(&shrinker_srcu);
-	info = shrinker_info_srcu(memcg, nid);
+	if (!down_read_trylock(&shrinker_rwsem))
+		return 0;
+
+	info = shrinker_info_protected(memcg, nid);
 	if (unlikely(!info))
 		goto unlock;
 
-	generation = atomic_read(&shrinker_srcu_generation);
-	for_each_set_bit_from(i, info->map, info->map_nr_max) {
+	for_each_set_bit(i, info->map, info->map_nr_max) {
 		struct shrink_control sc = {
 			.gfp_mask = gfp_mask,
 			.nid = nid,
@@ -1005,14 +987,14 @@ static unsigned long shrink_slab_memcg(gfp_t gfp_mask, int nid,
 				set_shrinker_bit(memcg, nid, i);
 		}
 		freed += ret;
-		if (atomic_read(&shrinker_srcu_generation) != generation) {
-			srcu_read_unlock(&shrinker_srcu, srcu_idx);
-			i++;
-			goto again;
+
+		if (rwsem_is_contended(&shrinker_rwsem)) {
+			freed = freed ? : 1;
+			break;
 		}
 	}
 unlock:
-	srcu_read_unlock(&shrinker_srcu, srcu_idx);
+	up_read(&shrinker_rwsem);
 	return freed;
 }
 #else /* CONFIG_MEMCG */
@@ -1049,7 +1031,6 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
 {
 	unsigned long ret, freed = 0;
 	struct shrinker *shrinker;
-	int srcu_idx, generation;
 
 	/*
 	 * The root memcg might be allocated even though memcg is disabled
@@ -1061,11 +1042,10 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
 	if (!mem_cgroup_disabled() && !mem_cgroup_is_root(memcg))
 		return shrink_slab_memcg(gfp_mask, nid, memcg, priority);
 
-	srcu_idx = srcu_read_lock(&shrinker_srcu);
+	if (!down_read_trylock(&shrinker_rwsem))
+		goto out;
 
-	generation = atomic_read(&shrinker_srcu_generation);
-	list_for_each_entry_srcu(shrinker, &shrinker_list, list,
-				 srcu_read_lock_held(&shrinker_srcu)) {
+	list_for_each_entry(shrinker, &shrinker_list, list) {
 		struct shrink_control sc = {
 			.gfp_mask = gfp_mask,
 			.nid = nid,
@@ -1076,14 +1056,19 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
 		if (ret == SHRINK_EMPTY)
 			ret = 0;
 		freed += ret;
-
-		if (atomic_read(&shrinker_srcu_generation) != generation) {
+		/*
+		 * Bail out if someone want to register a new shrinker to
+		 * prevent the registration from being stalled for long periods
+		 * by parallel ongoing shrinking.
+		 */
+		if (rwsem_is_contended(&shrinker_rwsem)) {
 			freed = freed ? : 1;
 			break;
 		}
 	}
 
-	srcu_read_unlock(&shrinker_srcu, srcu_idx);
+	up_read(&shrinker_rwsem);
+out:
 	cond_resched();
 	return freed;
 }

scripts/gdb/linux/constants.py.in

@@ -48,12 +48,12 @@ if IS_BUILTIN(CONFIG_COMMON_CLK):
     LX_GDBPARSED(CLK_GET_RATE_NOCACHE)
 
 /* linux/fs.h */
-LX_VALUE(SB_RDONLY)
-LX_VALUE(SB_SYNCHRONOUS)
-LX_VALUE(SB_MANDLOCK)
-LX_VALUE(SB_DIRSYNC)
-LX_VALUE(SB_NOATIME)
-LX_VALUE(SB_NODIRATIME)
+LX_GDBPARSED(SB_RDONLY)
+LX_GDBPARSED(SB_SYNCHRONOUS)
+LX_GDBPARSED(SB_MANDLOCK)
+LX_GDBPARSED(SB_DIRSYNC)
+LX_GDBPARSED(SB_NOATIME)
+LX_GDBPARSED(SB_NODIRATIME)
 
 /* linux/htimer.h */
 LX_GDBPARSED(hrtimer_resolution)

scripts/gfp-translate

@@ -63,11 +63,11 @@ fi
 
 # Extract GFP flags from the kernel source
 TMPFILE=`mktemp -t gfptranslate-XXXXXX` || exit 1
-grep -q ___GFP $SOURCE/include/linux/gfp.h
+grep -q ___GFP $SOURCE/include/linux/gfp_types.h
 if [ $? -eq 0 ]; then
-	grep "^#define ___GFP" $SOURCE/include/linux/gfp.h | sed -e 's/u$//' | grep -v GFP_BITS > $TMPFILE
+	grep "^#define ___GFP" $SOURCE/include/linux/gfp_types.h | sed -e 's/u$//' | grep -v GFP_BITS > $TMPFILE
 else
-	grep "^#define __GFP" $SOURCE/include/linux/gfp.h | sed -e 's/(__force gfp_t)//' | sed -e 's/u)/)/' | grep -v GFP_BITS | sed -e 's/)\//) \//' > $TMPFILE
+	grep "^#define __GFP" $SOURCE/include/linux/gfp_types.h | sed -e 's/(__force gfp_t)//' | sed -e 's/u)/)/' | grep -v GFP_BITS | sed -e 's/)\//) \//' > $TMPFILE
 fi
 
 # Parse the flags

tools/testing/selftests/mm/Makefile

@@ -5,12 +5,15 @@ LOCAL_HDRS += $(selfdir)/mm/local_config.h $(top_srcdir)/mm/gup_test.h
 
 include local_config.mk
 
+ifeq ($(ARCH),)
+
 ifeq ($(CROSS_COMPILE),)
 uname_M := $(shell uname -m 2>/dev/null || echo not)
 else
 uname_M := $(shell echo $(CROSS_COMPILE) | grep -o '^[a-z0-9]\+')
 endif
-MACHINE ?= $(shell echo $(uname_M) | sed -e 's/aarch64.*/arm64/' -e 's/ppc64.*/ppc64/')
+ARCH ?= $(shell echo $(uname_M) | sed -e 's/aarch64.*/arm64/' -e 's/ppc64.*/ppc64/')
+endif
 
 # Without this, failed build products remain, with up-to-date timestamps,
 # thus tricking Make (and you!) into believing that All Is Well, in subsequent
@@ -65,7 +68,7 @@ TEST_GEN_PROGS += ksm_tests
 TEST_GEN_PROGS += ksm_functional_tests
 TEST_GEN_PROGS += mdwe_test
 
-ifeq ($(MACHINE),x86_64)
+ifeq ($(ARCH),x86_64)
 CAN_BUILD_I386 := $(shell ./../x86/check_cc.sh "$(CC)" ../x86/trivial_32bit_program.c -m32)
 CAN_BUILD_X86_64 := $(shell ./../x86/check_cc.sh "$(CC)" ../x86/trivial_64bit_program.c)
 CAN_BUILD_WITH_NOPIE := $(shell ./../x86/check_cc.sh "$(CC)" ../x86/trivial_program.c -no-pie)
@@ -87,13 +90,13 @@ TEST_GEN_PROGS += $(BINARIES_64)
 endif
 else
 
-ifneq (,$(findstring $(MACHINE),ppc64))
+ifneq (,$(findstring $(ARCH),ppc64))
 TEST_GEN_PROGS += protection_keys
 endif
 
 endif
 
-ifneq (,$(filter $(MACHINE),arm64 ia64 mips64 parisc64 ppc64 riscv64 s390x sparc64 x86_64))
+ifneq (,$(filter $(ARCH),arm64 ia64 mips64 parisc64 ppc64 riscv64 s390x sparc64 x86_64))
 TEST_GEN_PROGS += va_high_addr_switch
 TEST_GEN_PROGS += virtual_address_range
 TEST_GEN_PROGS += write_to_hugetlbfs
@@ -112,7 +115,7 @@ $(TEST_GEN_PROGS): vm_util.c
 $(OUTPUT)/uffd-stress: uffd-common.c
 $(OUTPUT)/uffd-unit-tests: uffd-common.c
 
-ifeq ($(MACHINE),x86_64)
+ifeq ($(ARCH),x86_64)
 BINARIES_32 := $(patsubst %,$(OUTPUT)/%,$(BINARIES_32))
 BINARIES_64 := $(patsubst %,$(OUTPUT)/%,$(BINARIES_64))