zram: factor out ZRAM_SAME write

Handling of ZRAM_SAME now uses a goto to the final stages of
zram_write_page() plus it introduces a branch and flags variable, which is
not making the code any simpler.  In reality, we can handle ZRAM_SAME
immediately when we detect such pages and remove a goto and a branch.

Factor out ZRAM_SAME handling into a separate routine to simplify
zram_write_page().

Link: https://lkml.kernel.org/r/20241218063513.297475-4-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 974af83..7f7cb5b 100644 (file)
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1625,6 +1625,20 @@ static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
        return zram_read_page(zram, bvec->bv_page, index, bio);
 }
 
+static int write_same_filled_page(struct zram *zram, unsigned long fill,
+                                 u32 index)
+{
+       zram_slot_lock(zram, index);
+       zram_set_flag(zram, index, ZRAM_SAME);
+       zram_set_handle(zram, index, fill);
+       zram_slot_unlock(zram, index);
+
+       atomic64_inc(&zram->stats.same_pages);
+       atomic64_inc(&zram->stats.pages_stored);
+
+       return 0;
+}
+
 static int zram_write_page(struct zram *zram, struct page *page, u32 index)
 {
        int ret = 0;
@@ -1634,7 +1648,7 @@ static int zram_write_page(struct zram *zram, struct page *page, u32 index)
        void *src, *dst, *mem;
        struct zcomp_strm *zstrm;
        unsigned long element = 0;
-       enum zram_pageflags flags = 0;
+       bool same_filled;
 
        /* First, free memory allocated to this slot (if any) */
        zram_slot_lock(zram, index);
@@ -1642,14 +1656,10 @@ static int zram_write_page(struct zram *zram, struct page *page, u32 index)
        zram_slot_unlock(zram, index);
 
        mem = kmap_local_page(page);
-       if (page_same_filled(mem, &element)) {
-               kunmap_local(mem);
-               /* Free memory associated with this sector now. */
-               flags = ZRAM_SAME;
-               atomic64_inc(&zram->stats.same_pages);
-               goto out;
-       }
+       same_filled = page_same_filled(mem, &element);
        kunmap_local(mem);
+       if (same_filled)
+               return write_same_filled_page(zram, element, index);
 
 compress_again:
        zstrm = zcomp_stream_get(zram->comps[ZRAM_PRIMARY_COMP]);
@@ -1728,7 +1738,7 @@ compress_again:
        zcomp_stream_put(zram->comps[ZRAM_PRIMARY_COMP]);
        zs_unmap_object(zram->mem_pool, handle);
        atomic64_add(comp_len, &zram->stats.compr_data_size);
-out:
+
        zram_slot_lock(zram, index);
        if (comp_len == PAGE_SIZE) {
                zram_set_flag(zram, index, ZRAM_HUGE);
@@ -1736,13 +1746,8 @@ out:
                atomic64_inc(&zram->stats.huge_pages_since);
        }
 
-       if (flags) {
-               zram_set_flag(zram, index, flags);
-               zram_set_handle(zram, index, element);
-       }  else {
-               zram_set_handle(zram, index, handle);
-               zram_set_obj_size(zram, index, comp_len);
-       }
+       zram_set_handle(zram, index, handle);
+       zram_set_obj_size(zram, index, comp_len);
        zram_slot_unlock(zram, index);
 
        /* Update stats */