提交 9b2e0016 编写于 作者: P Pavel Begunkov 提交者: Jens Axboe

bvec/iter: disallow zero-length segment bvecs

zero-length bvec segments are allowed in general, but not handled by bio
and down the block layer so filtered out. This inconsistency may be
confusing and prevent from optimisations. As zero-length segments are
useless and places that were generating them are patched, declare them
not allowed.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NPavel Begunkov <asml.silence@gmail.com>
Reviewed-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
上级 0f1d344f
......@@ -40,6 +40,8 @@ normal code doesn't have to deal with bi_bvec_done.
There is a lower level advance function - bvec_iter_advance() - which takes
a pointer to a biovec, not a bio; this is used by the bio integrity code.
As of 5.12 bvec segments with zero bv_len are not supported.
What's all this get us?
=======================
......
......@@ -865,3 +865,10 @@ no matter what. Everything is handled by the caller.
clone_private_mount() returns a longterm mount now, so the proper destructor of
its result is kern_unmount() or kern_unmount_array().
---
**mandatory**
zero-length bvec segments are disallowed, they must be filtered out before
passed on to an iterator.
......@@ -72,8 +72,6 @@
__start.bi_bvec_done = skip; \
__start.bi_idx = 0; \
for_each_bvec(__v, i->bvec, __bi, __start) { \
if (!__v.bv_len) \
continue; \
(void)(STEP); \
} \
}
......
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