null_blk: single kmap per bio segment

Rather than kmap the the request bio segment for each sector, do
the mapping just once.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Tested-by: Hans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 2f64cd713584b0044f22b0b6c3abf335248a9360..ea3fc4241f82cd11b01ec3adf6b7e8108d23bfd0 100644 (file)
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -1129,8 +1129,8 @@ again:
        return 0;
 }
 
-static blk_status_t copy_to_nullb(struct nullb *nullb, struct page *source,
-       unsigned int off, sector_t sector, size_t n, bool is_fua)
+static blk_status_t copy_to_nullb(struct nullb *nullb, void *source,
+                                 sector_t sector, size_t n, bool is_fua)
 {
        size_t temp, count = 0;
        unsigned int offset;
@@ -1148,7 +1148,7 @@ static blk_status_t copy_to_nullb(struct nullb *nullb, struct page *source,
                if (!t_page)
                        return BLK_STS_NOSPC;
 
-               memcpy_page(t_page->page, offset, source, off + count, temp);
+               memcpy_to_page(t_page->page, offset, source + count, temp);
 
                __set_bit(sector & SECTOR_MASK, t_page->bitmap);
 
@@ -1161,8 +1161,8 @@ static blk_status_t copy_to_nullb(struct nullb *nullb, struct page *source,
        return BLK_STS_OK;
 }
 
-static void copy_from_nullb(struct nullb *nullb, struct page *dest,
-       unsigned int off, sector_t sector, size_t n)
+static void copy_from_nullb(struct nullb *nullb, void *dest, sector_t sector,
+                           size_t n)
 {
        size_t temp, count = 0;
        unsigned int offset;
@@ -1176,22 +1176,16 @@ static void copy_from_nullb(struct nullb *nullb, struct page *dest,
                        !null_cache_active(nullb));
 
                if (t_page)
-                       memcpy_page(dest, off + count, t_page->page, offset,
-                                   temp);
+                       memcpy_from_page(dest + count, t_page->page, offset,
+                                        temp);
                else
-                       memzero_page(dest, off + count, temp);
+                       memset(dest + count, 0, temp);
 
                count += temp;
                sector += temp >> SECTOR_SHIFT;
        }
 }
 
-static void nullb_fill_pattern(struct nullb *nullb, struct page *page,
-                              unsigned int len, unsigned int off)
-{
-       memset_page(page, off, 0xff, len);
-}
-
 blk_status_t null_handle_discard(struct nullb_device *dev,
                                 sector_t sector, sector_t nr_sectors)
 {
@@ -1240,27 +1234,29 @@ static blk_status_t null_transfer(struct nullb *nullb, struct page *page,
        struct nullb_device *dev = nullb->dev;
        blk_status_t err = BLK_STS_OK;
        unsigned int valid_len = len;
+       void *p;
 
+       p = kmap_local_page(page) + off;
        if (!is_write) {
                if (dev->zoned)
                        valid_len = null_zone_valid_read_len(nullb,
                                sector, len);
 
                if (valid_len) {
-                       copy_from_nullb(nullb, page, off, sector,
-                                       valid_len);
+                       copy_from_nullb(nullb, p, sector, valid_len);
                        off += valid_len;
                        len -= valid_len;
                }
 
                if (len)
-                       nullb_fill_pattern(nullb, page, len, off);
+                       memset(p + valid_len, 0xff, len);
                flush_dcache_page(page);
        } else {
                flush_dcache_page(page);
-               err = copy_to_nullb(nullb, page, off, sector, len, is_fua);
+               err = copy_to_nullb(nullb, p, sector, len, is_fua);
        }
 
+       kunmap_local(p);
        return err;
 }