block: Don't save/copy bvec array anymore

Now that drivers have been converted to the bvec_iter primitives, they
shouldn't be modifying the biovec anymore and thus saving it is
unnecessary - code that was previously making a backup of the bvec array
can now just save bio->bi_iter.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>

1 files changed, 13 insertions, 41 deletions

diff --git a/fs/bio.c b/fs/bio.c
index 6e42b68ab0ac..9cff939b1bc6 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -967,60 +967,33 @@ void bio_copy_data(struct bio *dst, struct bio *src)
 EXPORT_SYMBOL(bio_copy_data);
 
 struct bio_map_data {
-        struct bio_vec *iovecs;
-        struct sg_iovec *sgvecs;
         int nr_sgvecs;
         int is_our_pages;
+        struct sg_iovec sgvecs[];
 };
 
 static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio,
                              struct sg_iovec *iov, int iov_count,
                              int is_our_pages)
 {
-        memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt);
         memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count);
         bmd->nr_sgvecs = iov_count;
         bmd->is_our_pages = is_our_pages;
         bio->bi_private = bmd;
 }
 
-static void bio_free_map_data(struct bio_map_data *bmd)
-{
-        kfree(bmd->iovecs);
-        kfree(bmd->sgvecs);
-        kfree(bmd);
-}
-
 static struct bio_map_data *bio_alloc_map_data(int nr_segs,
                                                unsigned int iov_count,
                                                gfp_t gfp_mask)
 {
-        struct bio_map_data *bmd;
-
         if (iov_count > UIO_MAXIOV)
                 return NULL;
 
-        bmd = kmalloc(sizeof(*bmd), gfp_mask);
-        if (!bmd)
-                return NULL;
-
-        bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask);
-        if (!bmd->iovecs) {
-                kfree(bmd);
-                return NULL;
-        }
-
-        bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask);
-        if (bmd->sgvecs)
-                return bmd;
-
-        kfree(bmd->iovecs);
-        kfree(bmd);
-        return NULL;
+        return kmalloc(sizeof(struct bio_map_data) +
+                       sizeof(struct sg_iovec) * iov_count, gfp_mask);
 }
 
-static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
-                          struct sg_iovec *iov, int iov_count,
+static int __bio_copy_iov(struct bio *bio, struct sg_iovec *iov, int iov_count,
                           int to_user, int from_user, int do_free_page)
 {
         int ret = 0, i;
@@ -1030,7 +1003,7 @@ static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs,
 
         bio_for_each_segment_all(bvec, bio, i) {
                 char *bv_addr = page_address(bvec->bv_page);
-                unsigned int bv_len = iovecs[i].bv_len;
+                unsigned int bv_len = bvec->bv_len;
 
                 while (bv_len && iov_idx < iov_count) {
                         unsigned int bytes;
@@ -1090,14 +1063,14 @@ int bio_uncopy_user(struct bio *bio)
                  * don't copy into a random user address space, just free.
                  */
                 if (current->mm)
-                        ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs,
-                                             bmd->nr_sgvecs, bio_data_dir(bio) == READ,
+                        ret = __bio_copy_iov(bio, bmd->sgvecs, bmd->nr_sgvecs,
+                                             bio_data_dir(bio) == READ,
                                              0, bmd->is_our_pages);
                 else if (bmd->is_our_pages)
                         bio_for_each_segment_all(bvec, bio, i)
                                 __free_page(bvec->bv_page);
         }
-        bio_free_map_data(bmd);
+        kfree(bmd);
         bio_put(bio);
         return ret;
 }
@@ -1211,7 +1184,7 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
          */
         if ((!write_to_vm && (!map_data || !map_data->null_mapped)) ||
             (map_data && map_data->from_user)) {
-                ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 1, 0);
+                ret = __bio_copy_iov(bio, iov, iov_count, 0, 1, 0);
                 if (ret)
                         goto cleanup;
         }
@@ -1225,7 +1198,7 @@ cleanup:
 
         bio_put(bio);
 out_bmd:
-        bio_free_map_data(bmd);
+        kfree(bmd);
         return ERR_PTR(ret);
 }
 
@@ -1542,16 +1515,15 @@ static void bio_copy_kern_endio(struct bio *bio, int err)
 
         bio_for_each_segment_all(bvec, bio, i) {
                 char *addr = page_address(bvec->bv_page);
-                int len = bmd->iovecs[i].bv_len;
 
                 if (read)
-                        memcpy(p, addr, len);
+                        memcpy(p, addr, bvec->bv_len);
 
                 __free_page(bvec->bv_page);
-                p += len;
+                p += bvec->bv_len;
         }
 
-        bio_free_map_data(bmd);
+        kfree(bmd);
         bio_put(bio);
 }