block: Replace SG_GAPS with new queue limits mask

The SG_GAPS queue flag caused checks for bio vector alignment against
PAGE_SIZE, but the device may have different constraints. This patch
adds a queue limits so a driver with such constraints can set to allow
requests that would have been unnecessarily split. The new gaps check
takes the request_queue as a parameter to simplify the logic around
invoking this function.

This new limit makes the queue flag redundant, so removing it and
all usage. Device-mappers will inherit the correct settings through
blk_stack_limits().

Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/bio.c b/block/bio.c
index 425d6d4a2f7a42dd7bd090fc54f65dc572c94b55..b1f198f9a317b1f01d288c45e24cda56a1e1f778 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -742,8 +742,7 @@ int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page
                 * If the queue doesn't support SG gaps and adding this
                 * offset would create a gap, disallow it.
                 */
-               if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS) &&
-                   bvec_gap_to_prev(prev, offset))
+               if (bvec_gap_to_prev(q, prev, offset))
                        return 0;
        }
 

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 0027def35f5a102fd7d031b5d5ed8cdcbaa66f0b..0e0d9fd01c409a3f9351da723a0d1347e3977a9c 100644 (file)
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -82,8 +82,7 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
                 * If the queue doesn't support SG gaps and adding this
                 * offset would create a gap, disallow it.
                 */
-               if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS) &&
-                   prev && bvec_gap_to_prev(&bvprv, bv.bv_offset))
+               if (prev && bvec_gap_to_prev(q, &bvprv, bv.bv_offset))
                        goto split;
 
                if (prev && blk_queue_cluster(q)) {
@@ -484,12 +483,12 @@ static bool req_no_special_merge(struct request *req)
        return !q->mq_ops && req->special;
 }
 
-static int req_gap_to_prev(struct request *req, struct request *next)
+static int req_gap_to_prev(struct request *req, struct bio *next)
 {
        struct bio *prev = req->biotail;
 
-       return bvec_gap_to_prev(&prev->bi_io_vec[prev->bi_vcnt - 1],
-                               next->bio->bi_io_vec[0].bv_offset);
+       return bvec_gap_to_prev(req->q, &prev->bi_io_vec[prev->bi_vcnt - 1],
+                       next->bi_io_vec[1].bv_offset);
 }
 
 static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
@@ -506,8 +505,7 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
        if (req_no_special_merge(req) || req_no_special_merge(next))
                return 0;
 
-       if (test_bit(QUEUE_FLAG_SG_GAPS, &q->queue_flags) &&
-           req_gap_to_prev(req, next))
+       if (req_gap_to_prev(req, next->bio))
                return 0;
 
        /*
@@ -692,8 +690,6 @@ int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
 
 bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
 {
-       struct request_queue *q = rq->q;
-
        if (!rq_mergeable(rq) || !bio_mergeable(bio))
                return false;
 
@@ -718,13 +714,8 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
                return false;
 
        /* Only check gaps if the bio carries data */
-       if (q->queue_flags & (1 << QUEUE_FLAG_SG_GAPS) && bio_has_data(bio)) {
-               struct bio_vec *bprev;
-
-               bprev = &rq->biotail->bi_io_vec[rq->biotail->bi_vcnt - 1];
-               if (bvec_gap_to_prev(bprev, bio->bi_io_vec[0].bv_offset))
-                       return false;
-       }
+       if (bio_has_data(bio) && req_gap_to_prev(rq, bio))
+               return false;
 
        return true;
 }

diff --git a/block/blk-settings.c b/block/blk-settings.c
index d27b4e272356212530d6d5917fbb59ea2c914a25..f96c72116931e7f6ae4bacac207048490c7dcacc 100644 (file)
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -89,6 +89,7 @@ void blk_set_default_limits(struct queue_limits *lim)
        lim->max_segments = BLK_MAX_SEGMENTS;
        lim->max_integrity_segments = 0;
        lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
+       lim->virt_boundary_mask = 0;
        lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
        lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
        lim->chunk_sectors = 0;
@@ -532,6 +533,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
 
        t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask,
                                            b->seg_boundary_mask);
+       t->virt_boundary_mask = min_not_zero(t->virt_boundary_mask,
+                                           b->virt_boundary_mask);
 
        t->max_segments = min_not_zero(t->max_segments, b->max_segments);
        t->max_integrity_segments = min_not_zero(t->max_integrity_segments,
@@ -771,6 +774,17 @@ void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
 }
 EXPORT_SYMBOL(blk_queue_segment_boundary);
 
+/**
+ * blk_queue_virt_boundary - set boundary rules for bio merging
+ * @q:  the request queue for the device
+ * @mask:  the memory boundary mask
+ **/
+void blk_queue_virt_boundary(struct request_queue *q, unsigned long mask)
+{
+       q->limits.virt_boundary_mask = mask;
+}
+EXPORT_SYMBOL(blk_queue_virt_boundary);
+
 /**
  * blk_queue_dma_alignment - set dma length and memory alignment
  * @q:     the request queue for the device

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index d844ec4a2b85eead7eaf781fe52421f9ba5d9cac..2f694d78da5518e0d12a42082542bf0b5dc2b36f 100644 (file)
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -2067,7 +2067,6 @@ static void nvme_alloc_ns(struct nvme_dev *dev, unsigned nsid)
                goto out_free_ns;
        queue_flag_set_unlocked(QUEUE_FLAG_NOMERGES, ns->queue);
        queue_flag_set_unlocked(QUEUE_FLAG_NONROT, ns->queue);
-       queue_flag_set_unlocked(QUEUE_FLAG_SG_GAPS, ns->queue);
        ns->dev = dev;
        ns->queue->queuedata = ns;
 
@@ -2087,6 +2086,7 @@ static void nvme_alloc_ns(struct nvme_dev *dev, unsigned nsid)
                blk_queue_chunk_sectors(ns->queue, dev->stripe_size >> 9);
        if (dev->vwc & NVME_CTRL_VWC_PRESENT)
                blk_queue_flush(ns->queue, REQ_FLUSH | REQ_FUA);
+       blk_queue_virt_boundary(ns->queue, dev->page_size - 1);
 
        disk->major = nvme_major;
        disk->first_minor = 0;

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index afb4ad3dfeb3b1526e2d87f2b93a71f7765caa98..e76ed003769e1bc023e582df9f505c6ed9ca3fc2 100644 (file)
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1380,14 +1380,6 @@ static int queue_supports_sg_merge(struct dm_target *ti, struct dm_dev *dev,
        return q && !test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);
 }
 
-static int queue_supports_sg_gaps(struct dm_target *ti, struct dm_dev *dev,
-                                 sector_t start, sector_t len, void *data)
-{
-       struct request_queue *q = bdev_get_queue(dev->bdev);
-
-       return q && !test_bit(QUEUE_FLAG_SG_GAPS, &q->queue_flags);
-}
-
 static bool dm_table_all_devices_attribute(struct dm_table *t,
                                           iterate_devices_callout_fn func)
 {
@@ -1508,11 +1500,6 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
        else
                queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
 
-       if (dm_table_all_devices_attribute(t, queue_supports_sg_gaps))
-               queue_flag_clear_unlocked(QUEUE_FLAG_SG_GAPS, q);
-       else
-               queue_flag_set_unlocked(QUEUE_FLAG_SG_GAPS, q);
-
        dm_table_set_integrity(t);
 
        /*

diff --git a/include/linux/bio.h b/include/linux/bio.h
index ad7217458812f118f09cf70418e15013d6ad1847..b9b6e046b52ea5b9f783b69274fbdd6ac8fe5d23 100644 (file)
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -186,15 +186,6 @@ static inline void *bio_data(struct bio *bio)
 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
        __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
 
-/*
- * Check if adding a bio_vec after bprv with offset would create a gap in
- * the SG list. Most drivers don't care about this, but some do.
- */
-static inline bool bvec_gap_to_prev(struct bio_vec *bprv, unsigned int offset)
-{
-       return offset || ((bprv->bv_offset + bprv->bv_len) & (PAGE_SIZE - 1));
-}
-
 /*
  * drivers should _never_ use the all version - the bio may have been split
  * before it got to the driver and the driver won't own all of it

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index e427debc7008470602b291ba15cadc8e02a17da1..a622f270f09e78fce0bf06a73de65827ef4fddf7 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -250,6 +250,7 @@ struct blk_queue_tag {
 struct queue_limits {
        unsigned long           bounce_pfn;
        unsigned long           seg_boundary_mask;
+       unsigned long           virt_boundary_mask;
 
        unsigned int            max_hw_sectors;
        unsigned int            chunk_sectors;
@@ -479,7 +480,6 @@ struct request_queue {
 #define QUEUE_FLAG_DEAD        19      /* queue tear-down finished */
 #define QUEUE_FLAG_INIT_DONE   20      /* queue is initialized */
 #define QUEUE_FLAG_NO_SG_MERGE 21      /* don't attempt to merge SG segments*/
-#define QUEUE_FLAG_SG_GAPS     22      /* queue doesn't support SG gaps */
 
 #define QUEUE_FLAG_DEFAULT     ((1 << QUEUE_FLAG_IO_STAT) |            \
                                 (1 << QUEUE_FLAG_STACKABLE)    |       \
@@ -981,6 +981,7 @@ extern int blk_queue_dma_drain(struct request_queue *q,
                               void *buf, unsigned int size);
 extern void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn);
 extern void blk_queue_segment_boundary(struct request_queue *, unsigned long);
+extern void blk_queue_virt_boundary(struct request_queue *, unsigned long);
 extern void blk_queue_prep_rq(struct request_queue *, prep_rq_fn *pfn);
 extern void blk_queue_unprep_rq(struct request_queue *, unprep_rq_fn *ufn);
 extern void blk_queue_dma_alignment(struct request_queue *, int);
@@ -1149,6 +1150,11 @@ static inline unsigned long queue_segment_boundary(struct request_queue *q)
        return q->limits.seg_boundary_mask;
 }
 
+static inline unsigned long queue_virt_boundary(struct request_queue *q)
+{
+       return q->limits.virt_boundary_mask;
+}
+
 static inline unsigned int queue_max_sectors(struct request_queue *q)
 {
        return q->limits.max_sectors;
@@ -1349,6 +1355,19 @@ static inline void put_dev_sector(Sector p)
        page_cache_release(p.v);
 }
 
+/*
+ * Check if adding a bio_vec after bprv with offset would create a gap in
+ * the SG list. Most drivers don't care about this, but some do.
+ */
+static inline bool bvec_gap_to_prev(struct request_queue *q,
+                               struct bio_vec *bprv, unsigned int offset)
+{
+       if (!queue_virt_boundary(q))
+               return false;
+       return offset ||
+               ((bprv->bv_offset + bprv->bv_len) & queue_virt_boundary(q));
+}
+
 struct work_struct;
 int kblockd_schedule_work(struct work_struct *work);
 int kblockd_schedule_delayed_work(struct delayed_work *dwork, unsigned long delay);