diff options
| -rw-r--r-- | arch/x86/include/asm/io.h | 3 | ||||
| -rw-r--r-- | block/blk-merge.c | 51 | ||||
| -rw-r--r-- | drivers/xen/biomerge.c | 8 | ||||
| -rw-r--r-- | include/linux/blkdev.h | 1 |
4 files changed, 63 insertions, 0 deletions
diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index 34f69cb9350a..4799845e325f 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -335,6 +335,9 @@ extern bool is_early_ioremap_ptep(pte_t *ptep); #include <xen/xen.h> struct bio_vec; +extern bool xen_page_phys_mergeable(const struct page *p1, + const struct page *p2); + extern bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, const struct bio_vec *vec2); diff --git a/block/blk-merge.c b/block/blk-merge.c index 067c946cdcb0..09f6bac65769 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -9,6 +9,57 @@ #include "blk.h" +static unsigned int __blk_max_segment(struct request_queue *q, struct bio_vec *bv) +{ + unsigned len = bv->bv_len; + + len = min_t(unsigned, len, blk_queue_cluster(q) + ? queue_max_segment_size(q) + : PAGE_SIZE); + + len = min_t(unsigned, len, + queue_segment_boundary(q) + 1 - + (bvec_to_phys(bv) & queue_segment_boundary(q))); + + return len; +} + +#ifdef CONFIG_XEN +unsigned int blk_max_segment(struct request_queue *q, struct bio_vec *bv) +{ + unsigned len = __blk_max_segment(q, bv); + unsigned ret; + struct page *next, *prev; + + if (!xen_domain()) + return len; + + ret = min_t(unsigned, len, PAGE_SIZE - bv->bv_offset); + prev = bv->bv_page; + + while (ret < len) { + next = nth_page(prev, 1); + + if (!xen_page_phys_mergeable(prev, next)) + break; + + ret += min_t(unsigned, len - ret, PAGE_SIZE); + prev = next; + } + + return ret; +} + +#else + +unsigned int blk_max_segment(struct request_queue *q, struct bio_vec *bv) +{ + return __blk_max_segment(q, bv); +} + +#endif +EXPORT_SYMBOL(blk_max_segment); + static struct bio *blk_bio_discard_split(struct request_queue *q, struct bio *bio, struct bio_set *bs) diff --git a/drivers/xen/biomerge.c b/drivers/xen/biomerge.c index 0edb91c0de6b..d9fb59864f0b 100644 --- a/drivers/xen/biomerge.c +++ b/drivers/xen/biomerge.c @@ -3,6 +3,14 @@ #include <linux/export.h> #include <xen/page.h> +bool xen_page_phys_mergeable(const struct page *p1, const struct page *p2) +{ + unsigned long mfn1 = pfn_to_mfn(page_to_pfn(p1)); + unsigned long mfn2 = pfn_to_mfn(page_to_pfn(p2)); + + return mfn1 + 1 == mfn2; +} + bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, const struct bio_vec *vec2) { diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 05e3d6e77119..ff90dcf761be 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -775,6 +775,7 @@ extern int blk_insert_cloned_request(struct request_queue *q, extern void blk_delay_queue(struct request_queue *, unsigned long); extern void blk_queue_split(struct request_queue *, struct bio **, struct bio_set *); +extern unsigned int blk_max_segment(struct request_queue *, struct bio_vec *); extern void blk_recount_segments(struct request_queue *, struct bio *); extern int scsi_verify_blk_ioctl(struct block_device *, unsigned int); extern int scsi_cmd_blk_ioctl(struct block_device *, fmode_t, |