[PATCH 5/8] null_blk: code cleaup

From: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
To: linux-block@vger.kernel.org
Cc: axboe@kernel.dk, hch@lst.de,
	Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Subject: [PATCH 5/8] null_blk: code cleaup
Date: Thu, 11 Jul 2019 10:53:25 -0700	[thread overview]
Message-ID: <20190711175328.16430-6-chaitanya.kulkarni@wdc.com> (raw)
In-Reply-To: <20190711175328.16430-1-chaitanya.kulkarni@wdc.com>

In the null_blk for different page and sector calculation we have
simple macros to make the code more redable.

Similar to that this is a purely code cleanup patch where we
introduce two new macros for calculating the page index from given
sector and index (offset) of the sector in the page.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 drivers/block/null_blk_main.c | 37 ++++++++++++++++++++---------------
 1 file changed, 21 insertions(+), 16 deletions(-)

diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index fca011a05277..d463bde001b6 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -16,6 +16,11 @@
 #define PAGE_SECTORS		(1 << PAGE_SECTORS_SHIFT)
 #define SECTOR_MASK		(PAGE_SECTORS - 1)
 
+/* Gives page index for which this sector belongs to. */
+#define PAGE_IDX_FROM_SECT(sect)	(sect >> PAGE_SECTORS_SHIFT)
+/* Gives index (offset) of the sector within page. */
+#define SECT_IDX_IN_PAGE(sect)		((sect & SECTOR_MASK) << SECTOR_SHIFT)
+
 #define FREE_BATCH		16
 
 #define TICKS_PER_SEC		50ULL
@@ -708,20 +713,20 @@ static void null_free_sector(struct nullb *nullb, sector_t sector,
 	struct radix_tree_root *root;
 
 	root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
-	idx = sector >> PAGE_SECTORS_SHIFT;
+	idx = PAGE_IDX_FROM_SECT(sector);
 	sector_bit = (sector & SECTOR_MASK);
 
 	t_page = radix_tree_lookup(root, idx);
-	if (t_page) {
-		__clear_bit(sector_bit, t_page->bitmap);
-
-		if (null_page_empty(t_page)) {
-			ret = radix_tree_delete_item(root, idx, t_page);
-			WARN_ON(ret != t_page);
-			null_free_page(ret);
-			if (is_cache)
-				nullb->dev->curr_cache -= PAGE_SIZE;
-		}
+	if (!t_page)
+		return;
+	__clear_bit(sector_bit, t_page->bitmap);
+
+	if (null_page_empty(t_page)) {
+		ret = radix_tree_delete_item(root, idx, t_page);
+		WARN_ON(ret != t_page);
+		null_free_page(ret);
+		if (is_cache)
+			nullb->dev->curr_cache -= PAGE_SIZE;
 	}
 }
 
@@ -733,11 +738,11 @@ static void null_zero_sector(struct nullb_device *d, sector_t sect,
 	unsigned int offset;
 	void *dest;
 
-	t_page = radix_tree_lookup(root, sect >> PAGE_SECTORS_SHIFT);
+	t_page = radix_tree_lookup(root, PAGE_IDX_FROM_SECT(sect));
 	if (!t_page)
 		return;
 
-	offset = (sect & SECTOR_MASK) << SECTOR_SHIFT;
+	offset = SECT_IDX_IN_PAGE(sect);
 	dest = kmap_atomic(t_page->page);
 	memset(dest + offset, 0, SECTOR_SIZE * nr_sects);
 	kunmap_atomic(dest);
@@ -797,7 +802,7 @@ static struct nullb_page *__null_lookup_page(struct nullb *nullb,
 	struct nullb_page *t_page;
 	struct radix_tree_root *root;
 
-	idx = sector >> PAGE_SECTORS_SHIFT;
+	idx = PAGE_IDX_FROM_SECT(sector);
 	sector_bit = (sector & SECTOR_MASK);
 
 	root = is_cache ? &nullb->dev->cache : &nullb->dev->data;
@@ -973,7 +978,7 @@ static int copy_to_nullb(struct nullb *nullb, struct page *source,
 		if (null_cache_active(nullb) && !is_fua)
 			null_make_cache_space(nullb, PAGE_SIZE);
 
-		offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
+		offset = SECT_IDX_IN_PAGE(sector);
 		t_page = null_insert_page(nullb, sector,
 			!null_cache_active(nullb) || is_fua);
 		if (!t_page)
@@ -1007,7 +1012,7 @@ static int copy_from_nullb(struct nullb *nullb, struct page *dest,
 	while (count < n) {
 		temp = min_t(size_t, nullb->dev->blocksize, n - count);
 
-		offset = (sector & SECTOR_MASK) << SECTOR_SHIFT;
+		offset = SECT_IDX_IN_PAGE(sector);
 		t_page = null_lookup_page(nullb, sector, false,
 			!null_cache_active(nullb));
 
-- 
2.17.0

