For making multipage bvec working well.
Signed-off-by: Ming Lei <tom.leiming@xxxxxxxxx>
---
fs/buffer.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index 63d2f40c21fd..014892593f57 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3063,8 +3063,7 @@ void guard_bio_eod(int op, struct bio *bio)
unsigned truncated_bytes;
/*
* It is safe to truncate the last bvec in the following way
- * even though multipage bvec is supported, but we need to
- * fix the parameters passed to zero_user().
+ * even though multipage bvec is supported.
*/
struct bio_vec *bvec = &bio->bi_io_vec[bio->bi_vcnt - 1];
@@ -3087,15 +3086,21 @@ void guard_bio_eod(int op, struct bio *bio)
/* Uhhuh. We've got a bio that straddles the device size! */
truncated_bytes = bio->bi_iter.bi_size - (maxsector << 9);
- /* Truncate the bio.. */
- bio->bi_iter.bi_size -= truncated_bytes;
- bvec->bv_len -= truncated_bytes;
-
/* ..and clear the end of the buffer for reads */
if (op == REQ_OP_READ) {
- zero_user(bvec->bv_page, bvec->bv_offset + bvec->bv_len,
- truncated_bytes);
+ struct bvec_iter start = BVEC_ITER_ALL_INIT;
+ struct bvec_iter iter;
+ struct bio_vec bv;
+
+ start.bi_bvec_done = bvec->bv_len - truncated_bytes;
+
+ __bvec_for_each_sp_bvec(bv, bvec, iter, start)
+ zero_user(bv.bv_page, bv.bv_offset, bv.bv_len);
}
+
+ /* Truncate the bio.. */
+ bio->bi_iter.bi_size -= truncated_bytes;
+ bvec->bv_len -= truncated_bytes;
}
static int submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
--
2.7.4
--
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