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-rw-r--r--include/linux/blk_types.h8
-rw-r--r--include/linux/bvec.h29
2 files changed, 28 insertions, 9 deletions
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index d59553324a84..397602606f74 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -273,7 +273,13 @@ struct bio {
* Everything starting with bi_max_vecs will be preserved by bio_reset()
*/
- unsigned short bi_max_vecs; /* max bvl_vecs we can hold */
+ /*
+ * Number of elements in `bi_io_vec` that were allocated for this bio.
+ * Only used by the bio submitter to make `bio_add_page` fail once full
+ * and to free the `bi_io_vec` allocation. Must not be used in drivers
+ * and does not hold a useful value for cloned bios.
+ */
+ unsigned short bi_max_vecs;
atomic_t __bi_cnt; /* pin count */
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index 3fc0efa0825b..06fb60471aaf 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -75,14 +75,27 @@ static inline void bvec_set_virt(struct bio_vec *bv, void *vaddr,
}
struct bvec_iter {
- sector_t bi_sector; /* device address in 512 byte
- sectors */
- unsigned int bi_size; /* residual I/O count */
-
- unsigned int bi_idx; /* current index into bvl_vec */
-
- unsigned int bi_bvec_done; /* number of bytes completed in
- current bvec */
+ /*
+ * Current device address in 512 byte sectors. Only updated by the bio
+ * iter wrappers and not the bvec iterator helpers themselves.
+ */
+ sector_t bi_sector;
+
+ /*
+ * Remaining size in bytes.
+ */
+ unsigned int bi_size;
+
+ /*
+ * Current index into the bvec array. This indexes into `bi_io_vec` when
+ * iterating a bvec array that is part of a `bio`.
+ */
+ unsigned int bi_idx;
+
+ /*
+ * Current offset in the bvec entry pointed to by `bi_idx`.
+ */
+ unsigned int bi_bvec_done;
} __packed __aligned(4);
struct bvec_iter_all {