zram: Remove ZRAM_LOCK

The ZRAM_LOCK was used for locking and after the addition of spinlock_t
the bit set and cleared but there no reader of it.

Remove the ZRAM_LOCK bit.
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20240906141520.730009-3-bigeasy@linutronix.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/zram/zram_drv.c

@@ -59,23 +59,16 @@ static int zram_read_page(struct zram *zram, struct page *page, u32 index,
 
 static int zram_slot_trylock(struct zram *zram, u32 index)
 {
-	int ret;
-
-	ret = spin_trylock(&zram->table[index].lock);
-	if (ret)
-		__set_bit(ZRAM_LOCK, &zram->table[index].flags);
-	return ret;
+	return spin_trylock(&zram->table[index].lock);
 }
 
 static void zram_slot_lock(struct zram *zram, u32 index)
 {
 	spin_lock(&zram->table[index].lock);
-	__set_bit(ZRAM_LOCK, &zram->table[index].flags);
 }
 
 static void zram_slot_unlock(struct zram *zram, u32 index)
 {
-	__clear_bit(ZRAM_LOCK, &zram->table[index].flags);
 	spin_unlock(&zram->table[index].lock);
 }
 
@@ -1293,7 +1286,7 @@ static void zram_free_page(struct zram *zram, size_t index)
 	zram_set_handle(zram, index, 0);
 	zram_set_obj_size(zram, index, 0);
 	WARN_ON_ONCE(zram->table[index].flags &
-		~(1UL << ZRAM_LOCK | 1UL << ZRAM_UNDER_WB));
+		~(1UL << ZRAM_UNDER_WB));
 }
 
 /*

drivers/block/zram/zram_drv.h

@@ -45,9 +45,7 @@
 
 /* Flags for zram pages (table[page_no].flags) */
 enum zram_pageflags {
-	/* zram slot is locked */
-	ZRAM_LOCK = ZRAM_FLAG_SHIFT,
-	ZRAM_SAME,	/* Page consists the same element */
+	ZRAM_SAME = ZRAM_FLAG_SHIFT,	/* Page consists the same element */
 	ZRAM_WB,	/* page is stored on backing_device */
 	ZRAM_UNDER_WB,	/* page is under writeback */
 	ZRAM_HUGE,	/* Incompressible page */