lib/sbitmap: make sbitmap_get_shallow() internal

Because it's only used in sbitmap.c

Signed-off-by: Yu Kuai <[e-mail]>
Reviewed-by: Damien Le Moal <[e-mail]>
Reviewed-by: Jan Kara <[e-mail]>
Reviewed-by: Bart Van Assche <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

include/linux/sbitmap.h

···
 int sbitmap_get(struct sbitmap *sb);
 
 /**
- * sbitmap_get_shallow() - Try to allocate a free bit from a &struct sbitmap,
- * limiting the depth used from each word.
- * @sb: Bitmap to allocate from.
- * @shallow_depth: The maximum number of bits to allocate from the bitmap.
- *
- * This rather specific operation allows for having multiple users with
- * different allocation limits. E.g., there can be a high-priority class that
- * uses sbitmap_get() and a low-priority class that uses sbitmap_get_shallow()
- * with a @shallow_depth of (sb->depth >> 1). Then, the low-priority
- * class can only allocate half of the total bits in the bitmap, preventing it
- * from starving out the high-priority class.
- *
- * Return: Non-negative allocated bit number if successful, -1 otherwise.
- */
-int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth);
-
-/**
  * sbitmap_any_bit_set() - Check for a set bit in a &struct sbitmap.
  * @sb: Bitmap to check.
  *

lib/sbitmap.c

···
 	return sbitmap_find_bit(sb, shallow_depth, index, alloc_hint, true);
 }
 
-int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth)
+/**
+ * sbitmap_get_shallow() - Try to allocate a free bit from a &struct sbitmap,
+ * limiting the depth used from each word.
+ * @sb: Bitmap to allocate from.
+ * @shallow_depth: The maximum number of bits to allocate from the bitmap.
+ *
+ * This rather specific operation allows for having multiple users with
+ * different allocation limits. E.g., there can be a high-priority class that
+ * uses sbitmap_get() and a low-priority class that uses sbitmap_get_shallow()
+ * with a @shallow_depth of (sb->depth >> 1). Then, the low-priority
+ * class can only allocate half of the total bits in the bitmap, preventing it
+ * from starving out the high-priority class.
+ *
+ * Return: Non-negative allocated bit number if successful, -1 otherwise.
+ */
+static int sbitmap_get_shallow(struct sbitmap *sb, unsigned long shallow_depth)
 {
 	int nr;
 	unsigned int hint, depth;
···
 
 	return nr;
 }
-EXPORT_SYMBOL_GPL(sbitmap_get_shallow);
 
 bool sbitmap_any_bit_set(const struct sbitmap *sb)
 {