btrfs: use rbio->nr_pages to reduce calculation

We can use rbio->stripe_npages to reduce unnecessary calculation in
many code place.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 7 insertions, 12 deletions

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index c435fe0f86e4..719dbc0d3080 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -1174,7 +1174,6 @@ static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
 {
         struct btrfs_bio *bbio = rbio->bbio;
         void *pointers[rbio->real_stripes];
-        int stripe_len = rbio->stripe_len;
         int nr_data = rbio->nr_data;
         int stripe;
         int pagenr;
@@ -1182,7 +1181,6 @@ static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
         int q_stripe = -1;
         struct bio_list bio_list;
         struct bio *bio;
-        int pages_per_stripe = stripe_len >> PAGE_CACHE_SHIFT;
         int ret;
 
         bio_list_init(&bio_list);
@@ -1225,7 +1223,7 @@ static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
         else
                 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
 
-        for (pagenr = 0; pagenr < pages_per_stripe; pagenr++) {
+        for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
                 struct page *p;
                 /* first collect one page from each data stripe */
                 for (stripe = 0; stripe < nr_data; stripe++) {
@@ -1267,7 +1265,7 @@ static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
          * everything else.
          */
         for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
-                for (pagenr = 0; pagenr < pages_per_stripe; pagenr++) {
+                for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
                         struct page *page;
                         if (stripe < rbio->nr_data) {
                                 page = page_in_rbio(rbio, stripe, pagenr, 1);
@@ -1291,7 +1289,7 @@ static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
                 if (!bbio->tgtdev_map[stripe])
                         continue;
 
-                for (pagenr = 0; pagenr < pages_per_stripe; pagenr++) {
+                for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
                         struct page *page;
                         if (stripe < rbio->nr_data) {
                                 page = page_in_rbio(rbio, stripe, pagenr, 1);
@@ -1505,7 +1503,6 @@ static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio)
         int bios_to_read = 0;
         struct bio_list bio_list;
         int ret;
-        int nr_pages = DIV_ROUND_UP(rbio->stripe_len, PAGE_CACHE_SIZE);
         int pagenr;
         int stripe;
         struct bio *bio;
@@ -1524,7 +1521,7 @@ static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio)
          * stripe
          */
         for (stripe = 0; stripe < rbio->nr_data; stripe++) {
-                for (pagenr = 0; pagenr < nr_pages; pagenr++) {
+                for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
                         struct page *page;
                         /*
                          * we want to find all the pages missing from
@@ -1800,7 +1797,6 @@ static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
         int pagenr, stripe;
         void **pointers;
         int faila = -1, failb = -1;
-        int nr_pages = DIV_ROUND_UP(rbio->stripe_len, PAGE_CACHE_SIZE);
         struct page *page;
         int err;
         int i;
@@ -1823,7 +1819,7 @@ static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
 
         index_rbio_pages(rbio);
 
-        for (pagenr = 0; pagenr < nr_pages; pagenr++) {
+        for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
                 /*
                  * Now we just use bitmap to mark the horizontal stripes in
                  * which we have data when doing parity scrub.
@@ -1934,7 +1930,7 @@ pstripe:
                  * other endio functions will fiddle the uptodate bits
                  */
                 if (rbio->operation == BTRFS_RBIO_WRITE) {
-                        for (i = 0;  i < nr_pages; i++) {
+                        for (i = 0;  i < rbio->stripe_npages; i++) {
                                 if (faila != -1) {
                                         page = rbio_stripe_page(rbio, faila, i);
                                         SetPageUptodate(page);
@@ -2030,7 +2026,6 @@ static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
         int bios_to_read = 0;
         struct bio_list bio_list;
         int ret;
-        int nr_pages = DIV_ROUND_UP(rbio->stripe_len, PAGE_CACHE_SIZE);
         int pagenr;
         int stripe;
         struct bio *bio;
@@ -2054,7 +2049,7 @@ static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
                         continue;
                 }
 
-                for (pagenr = 0; pagenr < nr_pages; pagenr++) {
+                for (pagenr = 0; pagenr < rbio->stripe_npages; pagenr++) {
                         struct page *p;
 
                         /*