ceph: Convert to immutable biovecs

Now that we've got a mechanism for immutable biovecs -
bi_iter.bi_bvec_done - we need to convert drivers to use primitives that
respect it instead of using the bvec array directly.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sage Weil <sage@inktank.com>
Cc: ceph-devel@vger.kernel.org

2 files changed, 19 insertions, 28 deletions

diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h
index 7c1420bb1dce..091fdb600d55 100644
--- a/include/linux/ceph/messenger.h
+++ b/include/linux/ceph/messenger.h
@@ -1,6 +1,7 @@
 #ifndef __FS_CEPH_MESSENGER_H
 #define __FS_CEPH_MESSENGER_H
 
+#include <linux/blk_types.h>
 #include <linux/kref.h>
 #include <linux/mutex.h>
 #include <linux/net.h>
@@ -119,8 +120,7 @@ struct ceph_msg_data_cursor {
 #ifdef CONFIG_BLOCK
                 struct {                                /* bio */
                         struct bio      *bio;           /* bio from list */
-                        unsigned int    vector_index;   /* vector from bio */
-                        unsigned int    vector_offset;  /* bytes from vector */
+                        struct bvec_iter bvec_iter;
                 };
 #endif /* CONFIG_BLOCK */
                 struct {                                /* pages */
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 4a5df7b1cc9f..18c039b95c22 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -777,13 +777,12 @@ static void ceph_msg_data_bio_cursor_init(struct ceph_msg_data_cursor *cursor,
 
         bio = data->bio;
         BUG_ON(!bio);
-        BUG_ON(!bio->bi_vcnt);
 
         cursor->resid = min(length, data->bio_length);
         cursor->bio = bio;
-        cursor->vector_index = 0;
-        cursor->vector_offset = 0;
-        cursor->last_piece = length <= bio->bi_io_vec[0].bv_len;
+        cursor->bvec_iter = bio->bi_iter;
+        cursor->last_piece =
+                cursor->resid <= bio_iter_len(bio, cursor->bvec_iter);
 }
 
 static struct page *ceph_msg_data_bio_next(struct ceph_msg_data_cursor *cursor,
@@ -792,71 +791,63 @@ static struct page *ceph_msg_data_bio_next(struct ceph_msg_data_cursor *cursor,
 {
         struct ceph_msg_data *data = cursor->data;
         struct bio *bio;
-        struct bio_vec *bio_vec;
-        unsigned int index;
+        struct bio_vec bio_vec;
 
         BUG_ON(data->type != CEPH_MSG_DATA_BIO);
 
         bio = cursor->bio;
         BUG_ON(!bio);
 
-        index = cursor->vector_index;
-        BUG_ON(index >= (unsigned int) bio->bi_vcnt);
+        bio_vec = bio_iter_iovec(bio, cursor->bvec_iter);
 
-        bio_vec = &bio->bi_io_vec[index];
-        BUG_ON(cursor->vector_offset >= bio_vec->bv_len);
-        *page_offset = (size_t) (bio_vec->bv_offset + cursor->vector_offset);
+        *page_offset = (size_t) bio_vec.bv_offset;
         BUG_ON(*page_offset >= PAGE_SIZE);
         if (cursor->last_piece) /* pagelist offset is always 0 */
                 *length = cursor->resid;
         else
-                *length = (size_t) (bio_vec->bv_len - cursor->vector_offset);
+                *length = (size_t) bio_vec.bv_len;
         BUG_ON(*length > cursor->resid);
         BUG_ON(*page_offset + *length > PAGE_SIZE);
 
-        return bio_vec->bv_page;
+        return bio_vec.bv_page;
 }
 
 static bool ceph_msg_data_bio_advance(struct ceph_msg_data_cursor *cursor,
                                         size_t bytes)
 {
         struct bio *bio;
-        struct bio_vec *bio_vec;
-        unsigned int index;
+        struct bio_vec bio_vec;
 
         BUG_ON(cursor->data->type != CEPH_MSG_DATA_BIO);
 
         bio = cursor->bio;
         BUG_ON(!bio);
 
-        index = cursor->vector_index;
-        BUG_ON(index >= (unsigned int) bio->bi_vcnt);
-        bio_vec = &bio->bi_io_vec[index];
+        bio_vec = bio_iter_iovec(bio, cursor->bvec_iter);
 
         /* Advance the cursor offset */
 
         BUG_ON(cursor->resid < bytes);
         cursor->resid -= bytes;
-        cursor->vector_offset += bytes;
-        if (cursor->vector_offset < bio_vec->bv_len)
+
+        bio_advance_iter(bio, &cursor->bvec_iter, bytes);
+
+        if (bytes < bio_vec.bv_len)
                 return false;   /* more bytes to process in this segment */
-        BUG_ON(cursor->vector_offset != bio_vec->bv_len);
 
         /* Move on to the next segment, and possibly the next bio */
 
-        if (++index == (unsigned int) bio->bi_vcnt) {
+        if (!cursor->bvec_iter.bi_size) {
                 bio = bio->bi_next;
-                index = 0;
+                cursor->bvec_iter = bio->bi_iter;
         }
         cursor->bio = bio;
-        cursor->vector_index = index;
-        cursor->vector_offset = 0;
 
         if (!cursor->last_piece) {
                 BUG_ON(!cursor->resid);
                 BUG_ON(!bio);
                 /* A short read is OK, so use <= rather than == */
-                if (cursor->resid <= bio->bi_io_vec[index].bv_len)
+                if (cursor->resid <= bio_iter_len(bio, cursor->bvec_iter))
                         cursor->last_piece = true;
         }