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-rw-r--r--include/linux/bio.h34
1 files changed, 33 insertions, 1 deletions
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 5349e6816cbb..6b7481f62218 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -41,7 +41,7 @@
#endif
#define BIO_MAX_PAGES 256
-#define BIO_MAX_SIZE (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
+#define BIO_MAX_SIZE (BIO_MAX_PAGES << PAGE_SHIFT)
#define BIO_MAX_SECTORS (BIO_MAX_SIZE >> 9)
/*
@@ -310,6 +310,38 @@ static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
bio->bi_flags &= ~(1U << bit);
}
+static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
+{
+ *bv = bio_iovec(bio);
+}
+
+static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
+{
+ struct bvec_iter iter = bio->bi_iter;
+ int idx;
+
+ if (unlikely(!bio_multiple_segments(bio))) {
+ *bv = bio_iovec(bio);
+ return;
+ }
+
+ bio_advance_iter(bio, &iter, iter.bi_size);
+
+ if (!iter.bi_bvec_done)
+ idx = iter.bi_idx - 1;
+ else /* in the middle of bvec */
+ idx = iter.bi_idx;
+
+ *bv = bio->bi_io_vec[idx];
+
+ /*
+ * iter.bi_bvec_done records actual length of the last bvec
+ * if this bio ends in the middle of one io vector
+ */
+ if (iter.bi_bvec_done)
+ bv->bv_len = iter.bi_bvec_done;
+}
+
enum bip_flags {
BIP_BLOCK_INTEGRITY = 1 << 0, /* block layer owns integrity data */
BIP_MAPPED_INTEGRITY = 1 << 1, /* ref tag has been remapped */
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