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-rw-r--r--fs/bio.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/fs/bio.c b/fs/bio.c
index e56e7685af9..a5af5809f56 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1300,6 +1300,42 @@ struct bio_pair *bio_split(struct bio *bi, mempool_t *pool, int first_sectors)
return bp;
}
+/**
+ * bio_sector_offset - Find hardware sector offset in bio
+ * @bio: bio to inspect
+ * @index: bio_vec index
+ * @offset: offset in bv_page
+ *
+ * Return the number of hardware sectors between beginning of bio
+ * and an end point indicated by a bio_vec index and an offset
+ * within that vector's page.
+ */
+sector_t bio_sector_offset(struct bio *bio, unsigned short index,
+ unsigned int offset)
+{
+ unsigned int sector_sz = queue_hardsect_size(bio->bi_bdev->bd_disk->queue);
+ struct bio_vec *bv;
+ sector_t sectors;
+ int i;
+
+ sectors = 0;
+
+ if (index >= bio->bi_idx)
+ index = bio->bi_vcnt - 1;
+
+ __bio_for_each_segment(bv, bio, i, 0) {
+ if (i == index) {
+ if (offset > bv->bv_offset)
+ sectors += (offset - bv->bv_offset) / sector_sz;
+ break;
+ }
+
+ sectors += bv->bv_len / sector_sz;
+ }
+
+ return sectors;
+}
+EXPORT_SYMBOL(bio_sector_offset);
/*
* create memory pools for biovec's in a bio_set.