block: Declare several function pointer arguments 'const'

Commit Message

Bart Van Assche July 1, 2019, 3:48 p.m. UTC

Make it clear to the compiler and also to humans that the functions
that query request queue properties do not modify any member of the
request_queue data structure.

Signed-off-by: Bart Van Assche <[e-mail]>
---
 block/blk-merge.c      |  7 ++++---
 include/linux/blkdev.h | 32 ++++++++++++++++----------------
 2 files changed, 20 insertions(+), 19 deletions(-)

Patch

diff --git a/block/blk-merge.c b/block/blk-merge.c
index ca45eb51c669..4e2d94a50884 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -144,7 +144,7 @@  static inline unsigned get_max_io_size(struct request_queue *q,
 	return sectors;
 }
 
-static unsigned get_max_segment_size(struct request_queue *q,
+static unsigned get_max_segment_size(const struct request_queue *q,
 				     unsigned offset)
 {
 	unsigned long mask = queue_segment_boundary(q);
@@ -161,8 +161,9 @@  static unsigned get_max_segment_size(struct request_queue *q,
  * Split the bvec @bv into segments, and update all kinds of
  * variables.
  */
-static bool bvec_split_segs(struct request_queue *q, struct bio_vec *bv,
-		unsigned *nsegs, unsigned *sectors, unsigned max_segs)
+static bool bvec_split_segs(const struct request_queue *q,
+			    const struct bio_vec *bv, unsigned *nsegs,
+			    unsigned *sectors, unsigned max_segs)
 {
 	unsigned len = bv->bv_len;
 	unsigned total_len = 0;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index de32c10a6ea4..1e9253aa39b1 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1238,42 +1238,42 @@  enum blk_default_limits {
 	BLK_SEG_BOUNDARY_MASK	= 0xFFFFFFFFUL,
 };
 
-static inline unsigned long queue_segment_boundary(struct request_queue *q)
+static inline unsigned long queue_segment_boundary(const struct request_queue *q)
 {
 	return q->limits.seg_boundary_mask;
 }
 
-static inline unsigned long queue_virt_boundary(struct request_queue *q)
+static inline unsigned long queue_virt_boundary(const struct request_queue *q)
 {
 	return q->limits.virt_boundary_mask;
 }
 
-static inline unsigned int queue_max_sectors(struct request_queue *q)
+static inline unsigned int queue_max_sectors(const struct request_queue *q)
 {
 	return q->limits.max_sectors;
 }
 
-static inline unsigned int queue_max_hw_sectors(struct request_queue *q)
+static inline unsigned int queue_max_hw_sectors(const struct request_queue *q)
 {
 	return q->limits.max_hw_sectors;
 }
 
-static inline unsigned short queue_max_segments(struct request_queue *q)
+static inline unsigned short queue_max_segments(const struct request_queue *q)
 {
 	return q->limits.max_segments;
 }
 
-static inline unsigned short queue_max_discard_segments(struct request_queue *q)
+static inline unsigned short queue_max_discard_segments(const struct request_queue *q)
 {
 	return q->limits.max_discard_segments;
 }
 
-static inline unsigned int queue_max_segment_size(struct request_queue *q)
+static inline unsigned int queue_max_segment_size(const struct request_queue *q)
 {
 	return q->limits.max_segment_size;
 }
 
-static inline unsigned short queue_logical_block_size(struct request_queue *q)
+static inline unsigned short queue_logical_block_size(const struct request_queue *q)
 {
 	int retval = 512;
 
@@ -1288,7 +1288,7 @@  static inline unsigned short bdev_logical_block_size(struct block_device *bdev)
 	return queue_logical_block_size(bdev_get_queue(bdev));
 }
 
-static inline unsigned int queue_physical_block_size(struct request_queue *q)
+static inline unsigned int queue_physical_block_size(const struct request_queue *q)
 {
 	return q->limits.physical_block_size;
 }
@@ -1298,7 +1298,7 @@  static inline unsigned int bdev_physical_block_size(struct block_device *bdev)
 	return queue_physical_block_size(bdev_get_queue(bdev));
 }
 
-static inline unsigned int queue_io_min(struct request_queue *q)
+static inline unsigned int queue_io_min(const struct request_queue *q)
 {
 	return q->limits.io_min;
 }
@@ -1308,7 +1308,7 @@  static inline int bdev_io_min(struct block_device *bdev)
 	return queue_io_min(bdev_get_queue(bdev));
 }
 
-static inline unsigned int queue_io_opt(struct request_queue *q)
+static inline unsigned int queue_io_opt(const struct request_queue *q)
 {
 	return q->limits.io_opt;
 }
@@ -1318,7 +1318,7 @@  static inline int bdev_io_opt(struct block_device *bdev)
 	return queue_io_opt(bdev_get_queue(bdev));
 }
 
-static inline int queue_alignment_offset(struct request_queue *q)
+static inline int queue_alignment_offset(const struct request_queue *q)
 {
 	if (q->limits.misaligned)
 		return -1;
@@ -1348,7 +1348,7 @@  static inline int bdev_alignment_offset(struct block_device *bdev)
 	return q->limits.alignment_offset;
 }
 
-static inline int queue_discard_alignment(struct request_queue *q)
+static inline int queue_discard_alignment(const struct request_queue *q)
 {
 	if (q->limits.discard_misaligned)
 		return -1;
@@ -1438,7 +1438,7 @@  static inline unsigned int bdev_zone_sectors(struct block_device *bdev)
 	return 0;
 }
 
-static inline int queue_dma_alignment(struct request_queue *q)
+static inline int queue_dma_alignment(const struct request_queue *q)
 {
 	return q ? q->dma_alignment : 511;
 }
@@ -1549,7 +1549,7 @@  static inline void blk_queue_max_integrity_segments(struct request_queue *q,
 }
 
 static inline unsigned short
-queue_max_integrity_segments(struct request_queue *q)
+queue_max_integrity_segments(const struct request_queue *q)
 {
 	return q->limits.max_integrity_segments;
 }
@@ -1632,7 +1632,7 @@  static inline void blk_queue_max_integrity_segments(struct request_queue *q,
 						    unsigned int segs)
 {
 }
-static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
+static inline unsigned short queue_max_integrity_segments(const struct request_queue *q)
 {
 	return 0;
 }