Next patch is going to make generic_make_request() handle arbitrary
sized bios by splitting them if necessary. It makes more sense to call
blk_queue_bounce() first, partly so it's working on larger bios - but also the
code that splits bios, and __blk_recalc_rq_segments(), won't have to take into
account bouncing (as it'll already have been done).

Also, __blk_recalc_rq_segments() now doesn't have to take into account
potential bouncing - it's already been done.

Signed-off-by: Kent Overstreet <k...@daterainc.com>
Cc: Jens Axboe <ax...@kernel.dk>
Cc: Jiri Kosina <jkos...@suse.cz>
Cc: Asai Thambi S P <asamymuth...@micron.com>
---
 block/blk-core.c                  | 14 +++++++-------
 block/blk-merge.c                 | 13 ++++---------
 drivers/block/mtip32xx/mtip32xx.c |  2 --
 drivers/block/pktcdvd.c           |  2 --
 4 files changed, 11 insertions(+), 20 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index d9cab97..3c7467e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1466,13 +1466,6 @@ void blk_queue_bio(struct request_queue *q, struct bio 
*bio)
        struct request *req;
        unsigned int request_count = 0;
 
-       /*
-        * low level driver can indicate that it wants pages above a
-        * certain limit bounced to low memory (ie for highmem, or even
-        * ISA dma in theory)
-        */
-       blk_queue_bounce(q, &bio);
-
        if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
                bio_endio(bio, -EIO);
                return;
@@ -1822,6 +1815,13 @@ void generic_make_request(struct bio *bio)
        do {
                struct request_queue *q = bdev_get_queue(bio->bi_bdev);
 
+               /*
+                * low level driver can indicate that it wants pages above a
+                * certain limit bounced to low memory (ie for highmem, or even
+                * ISA dma in theory)
+                */
+               blk_queue_bounce(q, &bio);
+
                q->make_request_fn(q, bio);
 
                bio = bio_list_pop(current->bio_list);
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 953b8df..9680ec73 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -13,7 +13,7 @@ static unsigned int __blk_recalc_rq_segments(struct 
request_queue *q,
                                             struct bio *bio)
 {
        struct bio_vec bv, bvprv = { NULL };
-       int cluster, high, highprv = 1;
+       int cluster, prev = 0;
        unsigned int seg_size, nr_phys_segs;
        struct bio *fbio, *bbio;
        struct bvec_iter iter;
@@ -27,13 +27,7 @@ static unsigned int __blk_recalc_rq_segments(struct 
request_queue *q,
        nr_phys_segs = 0;
        for_each_bio(bio) {
                bio_for_each_segment(bv, bio, iter) {
-                       /*
-                        * the trick here is making sure that a high page is
-                        * never considered part of another segment, since that
-                        * might change with the bounce page.
-                        */
-                       high = page_to_pfn(bv.bv_page) > queue_bounce_pfn(q);
-                       if (!high && !highprv && cluster) {
+                       if (prev && cluster) {
                                if (seg_size + bv.bv_len
                                    > queue_max_segment_size(q))
                                        goto new_segment;
@@ -44,6 +38,7 @@ static unsigned int __blk_recalc_rq_segments(struct 
request_queue *q,
 
                                seg_size += bv.bv_len;
                                bvprv = bv;
+                               prev = 1;
                                continue;
                        }
 new_segment:
@@ -53,8 +48,8 @@ new_segment:
 
                        nr_phys_segs++;
                        bvprv = bv;
+                       prev = 1;
                        seg_size = bv.bv_len;
-                       highprv = high;
                }
                bbio = bio;
        }
diff --git a/drivers/block/mtip32xx/mtip32xx.c 
b/drivers/block/mtip32xx/mtip32xx.c
index 52b2f2a..d4c669b 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -4016,8 +4016,6 @@ static void mtip_make_request(struct request_queue 
*queue, struct bio *bio)
 
        sg = mtip_hw_get_scatterlist(dd, &tag, unaligned);
        if (likely(sg != NULL)) {
-               blk_queue_bounce(queue, &bio);
-
                if (unlikely((bio)->bi_vcnt > MTIP_MAX_SG)) {
                        dev_warn(&dd->pdev->dev,
                                "Maximum number of SGL entries exceeded\n");
diff --git a/drivers/block/pktcdvd.c b/drivers/block/pktcdvd.c
index 1bf1f22..7991cc8 100644
--- a/drivers/block/pktcdvd.c
+++ b/drivers/block/pktcdvd.c
@@ -2486,8 +2486,6 @@ static void pkt_make_request(struct request_queue *q, 
struct bio *bio)
                goto end_io;
        }
 
-       blk_queue_bounce(q, &bio);
-
        do {
                sector_t zone = get_zone(bio->bi_iter.bi_sector, pd);
                sector_t last_zone = get_zone(bio_end_sector(bio) - 1, pd);
-- 
1.8.4.rc3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to