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>
(cherry picked from commit 915e22903cb34619c1a1462ca4248add96fa41d7)

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 3ffe02ef172227daa1713d0a7ab1e3b035138541..8c1d32afe7d25e3e8cee5b7e7665bf8633aa9dfa 100644 (file)
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -1163,7 +1163,6 @@ 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;
@@ -1171,7 +1170,6 @@ 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);
@@ -1214,7 +1212,7 @@ 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++) {
@@ -1256,7 +1254,7 @@ 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);
@@ -1280,7 +1278,7 @@ 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);
@@ -1496,7 +1494,6 @@ 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;
@@ -1515,7 +1512,7 @@ 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
@@ -1792,7 +1789,6 @@ 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;
@@ -1814,7 +1810,7 @@ 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.
@@ -1924,7 +1920,7 @@ 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);
@@ -2017,7 +2013,6 @@ 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;
@@ -2041,7 +2036,7 @@ 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;
 
                        /*