Merge branch 'akpm' (patchbomb from Andrew Morton)

Merge incoming from Andrew Morton:
 - Various misc things.
 - arch/sh updates.
 - Part of ocfs2.  Review is slow.
 - Slab updates.
 - Most of -mm.
 - printk updates.
 - lib/ updates.
 - checkpatch updates.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (226 commits)
  checkpatch: update $declaration_macros, add uninitialized_var
  checkpatch: warn on missing spaces in broken up quoted
  checkpatch: fix false positives for --strict "space after cast" test
  checkpatch: fix false positive MISSING_BREAK warnings with --file
  checkpatch: add test for native c90 types in unusual order
  checkpatch: add signed generic types
  checkpatch: add short int to c variable types
  checkpatch: add for_each tests to indentation and brace tests
  checkpatch: fix brace style misuses of else and while
  checkpatch: add --fix option for a couple OPEN_BRACE misuses
  checkpatch: use the correct indentation for which()
  checkpatch: add fix_insert_line and fix_delete_line helpers
  checkpatch: add ability to insert and delete lines to patch/file
  checkpatch: add an index variable for fixed lines
  checkpatch: warn on break after goto or return with same tab indentation
  checkpatch: emit a warning on file add/move/delete
  checkpatch: add test for commit id formatting style in commit log
  checkpatch: emit fewer kmalloc_array/kcalloc conversion warnings
  checkpatch: improve "no space after cast" test
  checkpatch: allow multiple const * types
  ...

1 files changed, 43 insertions, 28 deletions

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 36e54be402df..dfa4024c448a 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -183,19 +183,32 @@ static ssize_t comp_algorithm_store(struct device *dev,
 static int zram_test_flag(struct zram_meta *meta, u32 index,
 			enum zram_pageflags flag)
 {
-	return meta->table[index].flags & BIT(flag);
+	return meta->table[index].value & BIT(flag);
 }
 
 static void zram_set_flag(struct zram_meta *meta, u32 index,
 			enum zram_pageflags flag)
 {
-	meta->table[index].flags |= BIT(flag);
+	meta->table[index].value |= BIT(flag);
 }
 
 static void zram_clear_flag(struct zram_meta *meta, u32 index,
 			enum zram_pageflags flag)
 {
-	meta->table[index].flags &= ~BIT(flag);
+	meta->table[index].value &= ~BIT(flag);
+}
+
+static size_t zram_get_obj_size(struct zram_meta *meta, u32 index)
+{
+	return meta->table[index].value & (BIT(ZRAM_FLAG_SHIFT) - 1);
+}
+
+static void zram_set_obj_size(struct zram_meta *meta,
+					u32 index, size_t size)
+{
+	unsigned long flags = meta->table[index].value >> ZRAM_FLAG_SHIFT;
+
+	meta->table[index].value = (flags << ZRAM_FLAG_SHIFT) | size;
 }
 
 static inline int is_partial_io(struct bio_vec *bvec)
@@ -255,7 +268,6 @@ static struct zram_meta *zram_meta_alloc(u64 disksize)
 		goto free_table;
 	}
 
-	rwlock_init(&meta->tb_lock);
 	return meta;
 
 free_table:
@@ -304,7 +316,12 @@ static void handle_zero_page(struct bio_vec *bvec)
 	flush_dcache_page(page);
 }
 
-/* NOTE: caller should hold meta->tb_lock with write-side */
+
+/*
+ * To protect concurrent access to the same index entry,
+ * caller should hold this table index entry's bit_spinlock to
+ * indicate this index entry is accessing.
+ */
 static void zram_free_page(struct zram *zram, size_t index)
 {
 	struct zram_meta *meta = zram->meta;
@@ -324,11 +341,12 @@ static void zram_free_page(struct zram *zram, size_t index)
 
 	zs_free(meta->mem_pool, handle);
 
-	atomic64_sub(meta->table[index].size, &zram->stats.compr_data_size);
+	atomic64_sub(zram_get_obj_size(meta, index),
+			&zram->stats.compr_data_size);
 	atomic64_dec(&zram->stats.pages_stored);
 
 	meta->table[index].handle = 0;
-	meta->table[index].size = 0;
+	zram_set_obj_size(meta, index, 0);
 }
 
 static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
@@ -337,14 +355,14 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
 	unsigned char *cmem;
 	struct zram_meta *meta = zram->meta;
 	unsigned long handle;
-	u16 size;
+	size_t size;
 
-	read_lock(&meta->tb_lock);
+	bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
 	handle = meta->table[index].handle;
-	size = meta->table[index].size;
+	size = zram_get_obj_size(meta, index);
 
 	if (!handle || zram_test_flag(meta, index, ZRAM_ZERO)) {
-		read_unlock(&meta->tb_lock);
+		bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
 		clear_page(mem);
 		return 0;
 	}
@@ -355,7 +373,7 @@ static int zram_decompress_page(struct zram *zram, char *mem, u32 index)
 	else
 		ret = zcomp_decompress(zram->comp, cmem, size, mem);
 	zs_unmap_object(meta->mem_pool, handle);
-	read_unlock(&meta->tb_lock);
+	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
 
 	/* Should NEVER happen. Return bio error if it does. */
 	if (unlikely(ret)) {
@@ -376,14 +394,14 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
 	struct zram_meta *meta = zram->meta;
 	page = bvec->bv_page;
 
-	read_lock(&meta->tb_lock);
+	bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
 	if (unlikely(!meta->table[index].handle) ||
 			zram_test_flag(meta, index, ZRAM_ZERO)) {
-		read_unlock(&meta->tb_lock);
+		bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
 		handle_zero_page(bvec);
 		return 0;
 	}
-	read_unlock(&meta->tb_lock);
+	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
 
 	if (is_partial_io(bvec))
 		/* Use  a temporary buffer to decompress the page */
@@ -461,10 +479,10 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 	if (page_zero_filled(uncmem)) {
 		kunmap_atomic(user_mem);
 		/* Free memory associated with this sector now. */
-		write_lock(&zram->meta->tb_lock);
+		bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
 		zram_free_page(zram, index);
 		zram_set_flag(meta, index, ZRAM_ZERO);
-		write_unlock(&zram->meta->tb_lock);
+		bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
 
 		atomic64_inc(&zram->stats.zero_pages);
 		ret = 0;
@@ -514,12 +532,12 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 	 * Free memory associated with this sector
 	 * before overwriting unused sectors.
 	 */
-	write_lock(&zram->meta->tb_lock);
+	bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
 	zram_free_page(zram, index);
 
 	meta->table[index].handle = handle;
-	meta->table[index].size = clen;
-	write_unlock(&zram->meta->tb_lock);
+	zram_set_obj_size(meta, index, clen);
+	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
 
 	/* Update stats */
 	atomic64_add(clen, &zram->stats.compr_data_size);
@@ -560,6 +578,7 @@ static void zram_bio_discard(struct zram *zram, u32 index,
 			     int offset, struct bio *bio)
 {
 	size_t n = bio->bi_iter.bi_size;
+	struct zram_meta *meta = zram->meta;
 
 	/*
 	 * zram manages data in physical block size units. Because logical block
@@ -580,13 +599,9 @@ static void zram_bio_discard(struct zram *zram, u32 index,
 	}
 
 	while (n >= PAGE_SIZE) {
-		/*
-		 * Discard request can be large so the lock hold times could be
-		 * lengthy.  So take the lock once per page.
-		 */
-		write_lock(&zram->meta->tb_lock);
+		bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
 		zram_free_page(zram, index);
-		write_unlock(&zram->meta->tb_lock);
+		bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
 		index++;
 		n -= PAGE_SIZE;
 	}
@@ -821,9 +836,9 @@ static void zram_slot_free_notify(struct block_device *bdev,
 	zram = bdev->bd_disk->private_data;
 	meta = zram->meta;
 
-	write_lock(&meta->tb_lock);
+	bit_spin_lock(ZRAM_ACCESS, &meta->table[index].value);
 	zram_free_page(zram, index);
-	write_unlock(&meta->tb_lock);
+	bit_spin_unlock(ZRAM_ACCESS, &meta->table[index].value);
 	atomic64_inc(&zram->stats.notify_free);
 }