block: Consolidate phys_segment and hw_segment limits

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / bio.c

diff --git a/fs/bio.c b/fs/bio.c
index 76e6713abf94a5454284d16dc125cecb90de50c2..dc17afd672e354810d4b7b2d54e21d466bf8cca8 100644 (file)
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -78,7 +78,7 @@ static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size)
 
        i = 0;
        while (i < bio_slab_nr) {
-               struct bio_slab *bslab = &bio_slabs[i];
+               bslab = &bio_slabs[i];
 
                if (!bslab->slab && entry == -1)
                        entry = i;
@@ -507,10 +507,8 @@ int bio_get_nr_vecs(struct block_device *bdev)
        int nr_pages;
 
        nr_pages = ((queue_max_sectors(q) << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT;
-       if (nr_pages > queue_max_phys_segments(q))
-               nr_pages = queue_max_phys_segments(q);
-       if (nr_pages > queue_max_hw_segments(q))
-               nr_pages = queue_max_hw_segments(q);
+       if (nr_pages > queue_max_segments(q))
+               nr_pages = queue_max_segments(q);
 
        return nr_pages;
 }
@@ -542,13 +540,18 @@ static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
 
                if (page == prev->bv_page &&
                    offset == prev->bv_offset + prev->bv_len) {
+                       unsigned int prev_bv_len = prev->bv_len;
                        prev->bv_len += len;
 
                        if (q->merge_bvec_fn) {
                                struct bvec_merge_data bvm = {
+                                       /* prev_bvec is already charged in
+                                          bi_size, discharge it in order to
+                                          simulate merging updated prev_bvec
+                                          as new bvec. */
                                        .bi_bdev = bio->bi_bdev,
                                        .bi_sector = bio->bi_sector,
-                                       .bi_size = bio->bi_size,
+                                       .bi_size = bio->bi_size - prev_bv_len,
                                        .bi_rw = bio->bi_rw,
                                };
 
@@ -570,8 +573,7 @@ static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page
         * make this too complex.
         */
 
-       while (bio->bi_phys_segments >= queue_max_phys_segments(q)
-              || bio->bi_phys_segments >= queue_max_hw_segments(q)) {
+       while (bio->bi_phys_segments >= queue_max_segments(q)) {
 
                if (retried_segments)
                        return 0;