Merge tag 'asoc-v5.2' of https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound into for-linus

ASoC: Updates for v5.2

This is a pretty huge set of changes, it's been a pretty active release
all round but the big thing with this release is the Sound Open Firmware
changes from Intel, providing another DSP framework for use with the
DSPs in their SoCs.  This one works with the firmware of the same name
which is free software (unlike the previous DSP firmwares and framework)
and there has been some interest in adoption by other systems already so
hopefully we will see adoption by other vendors in the future.

Other highlights include:

 - Support for MCLK/sample rate ratio setting in the generic cards.
 - Support for pin switches in the generic cards.
 - A big set of improvements to the TLV320AIC32x4 drivers from Annaliese
   McDermond.
 - New drivers for Freescale audio mixers, several Intel machines,
   several Mediatek machines, Meson G12A, Sound Open Firmware and
   Spreadtrum compressed audio and DMA devices.

1 files changed, 27 insertions, 31 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index b3db3779a30a..2275a0ff7c30 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1081,9 +1081,14 @@ static void shmem_evict_inode(struct inode *inode)
 			}
 			spin_unlock(&sbinfo->shrinklist_lock);
 		}
-		if (!list_empty(&info->swaplist)) {
+		while (!list_empty(&info->swaplist)) {
+			/* Wait while shmem_unuse() is scanning this inode... */
+			wait_var_event(&info->stop_eviction,
+				       !atomic_read(&info->stop_eviction));
 			mutex_lock(&shmem_swaplist_mutex);
-			list_del_init(&info->swaplist);
+			/* ...but beware of the race if we peeked too early */
+			if (!atomic_read(&info->stop_eviction))
+				list_del_init(&info->swaplist);
 			mutex_unlock(&shmem_swaplist_mutex);
 		}
 	}
@@ -1099,10 +1104,11 @@ extern struct swap_info_struct *swap_info[];
 static int shmem_find_swap_entries(struct address_space *mapping,
 				   pgoff_t start, unsigned int nr_entries,
 				   struct page **entries, pgoff_t *indices,
-				   bool frontswap)
+				   unsigned int type, bool frontswap)
 {
 	XA_STATE(xas, &mapping->i_pages, start);
 	struct page *page;
+	swp_entry_t entry;
 	unsigned int ret = 0;
 
 	if (!nr_entries)
@@ -1116,13 +1122,12 @@ static int shmem_find_swap_entries(struct address_space *mapping,
 		if (!xa_is_value(page))
 			continue;
 
-		if (frontswap) {
-			swp_entry_t entry = radix_to_swp_entry(page);
-
-			if (!frontswap_test(swap_info[swp_type(entry)],
-					    swp_offset(entry)))
-				continue;
-		}
+		entry = radix_to_swp_entry(page);
+		if (swp_type(entry) != type)
+			continue;
+		if (frontswap &&
+		    !frontswap_test(swap_info[type], swp_offset(entry)))
+			continue;
 
 		indices[ret] = xas.xa_index;
 		entries[ret] = page;
@@ -1194,7 +1199,7 @@ static int shmem_unuse_inode(struct inode *inode, unsigned int type,
 
 		pvec.nr = shmem_find_swap_entries(mapping, start, nr_entries,
 						  pvec.pages, indices,
-						  frontswap);
+						  type, frontswap);
 		if (pvec.nr == 0) {
 			ret = 0;
 			break;
@@ -1227,36 +1232,27 @@ int shmem_unuse(unsigned int type, bool frontswap,
 		unsigned long *fs_pages_to_unuse)
 {
 	struct shmem_inode_info *info, *next;
-	struct inode *inode;
-	struct inode *prev_inode = NULL;
 	int error = 0;
 
 	if (list_empty(&shmem_swaplist))
 		return 0;
 
 	mutex_lock(&shmem_swaplist_mutex);
-
-	/*
-	 * The extra refcount on the inode is necessary to safely dereference
-	 * p->next after re-acquiring the lock. New shmem inodes with swap
-	 * get added to the end of the list and we will scan them all.
-	 */
 	list_for_each_entry_safe(info, next, &shmem_swaplist, swaplist) {
 		if (!info->swapped) {
 			list_del_init(&info->swaplist);
 			continue;
 		}
-
-		inode = igrab(&info->vfs_inode);
-		if (!inode)
-			continue;
-
+		/*
+		 * Drop the swaplist mutex while searching the inode for swap;
+		 * but before doing so, make sure shmem_evict_inode() will not
+		 * remove placeholder inode from swaplist, nor let it be freed
+		 * (igrab() would protect from unlink, but not from unmount).
+		 */
+		atomic_inc(&info->stop_eviction);
 		mutex_unlock(&shmem_swaplist_mutex);
-		if (prev_inode)
-			iput(prev_inode);
-		prev_inode = inode;
 
-		error = shmem_unuse_inode(inode, type, frontswap,
+		error = shmem_unuse_inode(&info->vfs_inode, type, frontswap,
 					  fs_pages_to_unuse);
 		cond_resched();
 
@@ -1264,14 +1260,13 @@ int shmem_unuse(unsigned int type, bool frontswap,
 		next = list_next_entry(info, swaplist);
 		if (!info->swapped)
 			list_del_init(&info->swaplist);
+		if (atomic_dec_and_test(&info->stop_eviction))
+			wake_up_var(&info->stop_eviction);
 		if (error)
 			break;
 	}
 	mutex_unlock(&shmem_swaplist_mutex);
 
-	if (prev_inode)
-		iput(prev_inode);
-
 	return error;
 }
 
@@ -2238,6 +2233,7 @@ static struct inode *shmem_get_inode(struct super_block *sb, const struct inode
 		info = SHMEM_I(inode);
 		memset(info, 0, (char *)inode - (char *)info);
 		spin_lock_init(&info->lock);
+		atomic_set(&info->stop_eviction, 0);
 		info->seals = F_SEAL_SEAL;
 		info->flags = flags & VM_NORESERVE;
 		INIT_LIST_HEAD(&info->shrinklist);