From: Al Viro <viro@zeniv.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
David Sterba <dsterba@suse.com>,
Miklos Szeredi <miklos@szeredi.hu>,
Anton Altaparmakov <anton@tuxera.com>,
David Howells <dhowells@redhat.com>,
Matthew Wilcox <willy@infradead.org>,
Pavel Begunkov <asml.silence@gmail.com>
Subject: [RFC PATCH 21/37] csum_and_copy_to_iter(): massage into form closer to csum_and_copy_from_iter()
Date: Sun, 6 Jun 2021 19:10:35 +0000 [thread overview]
Message-ID: <20210606191051.1216821-21-viro@zeniv.linux.org.uk> (raw)
In-Reply-To: <20210606191051.1216821-1-viro@zeniv.linux.org.uk>
Namely, have off counted starting from 0 rather than from csstate->off.
To compensate we need to shift the initial value (csstate->sum) (rotate
by 8 bits, as usual for csum) and do the same after we are finished adding
the pieces up.
What we get out of that is a bit more redundancy in our variables - from
is always equal to addr + off, which will be useful several commits down
the road.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
include/net/checksum.h | 14 ++++++++------
lib/iov_iter.c | 8 ++++----
2 files changed, 12 insertions(+), 10 deletions(-)
diff --git a/include/net/checksum.h b/include/net/checksum.h
index 0d05b9e8690b..5b96d5bd6e54 100644
--- a/include/net/checksum.h
+++ b/include/net/checksum.h
@@ -80,16 +80,18 @@ static inline __sum16 csum16_sub(__sum16 csum, __be16 addend)
return csum16_add(csum, ~addend);
}
-static inline __wsum
-csum_block_add(__wsum csum, __wsum csum2, int offset)
+static inline __wsum csum_shift(__wsum sum, int offset)
{
- u32 sum = (__force u32)csum2;
-
/* rotate sum to align it with a 16b boundary */
if (offset & 1)
- sum = ror32(sum, 8);
+ return (__force __wsum)ror32((__force u32)sum, 8);
+ return sum;
+}
- return csum_add(csum, (__force __wsum)sum);
+static inline __wsum
+csum_block_add(__wsum csum, __wsum csum2, int offset)
+{
+ return csum_add(csum, csum_shift(csum2, offset));
}
static inline __wsum
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index dbd6b92f6200..906e9d49c487 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1794,8 +1794,8 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate,
if (unlikely(iov_iter_is_pipe(i)))
return csum_and_copy_to_pipe_iter(addr, bytes, _csstate, i);
- sum = csstate->csum;
- off = csstate->off;
+ sum = csum_shift(csstate->csum, csstate->off);
+ off = 0;
if (unlikely(iov_iter_is_discard(i))) {
WARN_ON(1); /* for now */
return 0;
@@ -1830,8 +1830,8 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate,
off += v.bv_len;
})
)
- csstate->csum = sum;
- csstate->off = off;
+ csstate->csum = csum_shift(sum, csstate->off);
+ csstate->off += bytes;
return bytes;
}
EXPORT_SYMBOL(csum_and_copy_to_iter);
--
2.11.0
next prev parent reply other threads:[~2021-06-06 19:12 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-06 19:07 [RFC][PATCHSET] iov_iter work Al Viro
2021-06-06 19:10 ` [RFC PATCH 01/37] ntfs_copy_from_user_iter(): don't bother with copying iov_iter Al Viro
2021-06-06 19:10 ` [RFC PATCH 02/37] generic_perform_write()/iomap_write_actor(): saner logics for short copy Al Viro
2021-06-06 19:10 ` [RFC PATCH 03/37] fuse_fill_write_pages(): don't bother with iov_iter_single_seg_count() Al Viro
2021-06-06 19:10 ` [RFC PATCH 04/37] iov_iter: Remove iov_iter_for_each_range() Al Viro
2021-06-06 19:10 ` [RFC PATCH 05/37] teach copy_page_to_iter() to handle compound pages Al Viro
2021-06-06 19:10 ` [RFC PATCH 06/37] copy_page_to_iter(): fix ITER_DISCARD case Al Viro
2021-06-06 19:10 ` [RFC PATCH 07/37] [xarray] iov_iter_fault_in_readable() should do nothing in xarray case Al Viro
2021-06-06 19:10 ` [RFC PATCH 08/37] iov_iter_advance(): use consistent semantics for move past the end Al Viro
2021-06-06 19:10 ` [RFC PATCH 09/37] iov_iter: switch ..._full() variants of primitives to use of iov_iter_revert() Al Viro
2021-06-06 19:10 ` [RFC PATCH 10/37] iov_iter: reorder handling of flavours in primitives Al Viro
2021-06-06 19:10 ` [RFC PATCH 11/37] iov_iter_advance(): don't modify ->iov_offset for ITER_DISCARD Al Viro
2021-06-06 19:10 ` [RFC PATCH 12/37] iov_iter: separate direction from flavour Al Viro
2021-06-06 19:10 ` [RFC PATCH 13/37] iov_iter: optimize iov_iter_advance() for iovec and kvec Al Viro
2021-06-06 19:10 ` [RFC PATCH 14/37] sanitize iov_iter_fault_in_readable() Al Viro
2021-06-06 19:10 ` [RFC PATCH 15/37] iov_iter_alignment(): don't bother with iterate_all_kinds() Al Viro
2021-06-06 19:10 ` [RFC PATCH 16/37] iov_iter_gap_alignment(): get rid of iterate_all_kinds() Al Viro
2021-06-09 13:01 ` Qian Cai
2021-06-09 18:06 ` Al Viro
2021-06-06 19:10 ` [RFC PATCH 17/37] get rid of iterate_all_kinds() in iov_iter_get_pages()/iov_iter_get_pages_alloc() Al Viro
2021-06-06 19:10 ` [RFC PATCH 18/37] iov_iter_npages(): don't bother with iterate_all_kinds() Al Viro
2021-06-06 19:10 ` [RFC PATCH 19/37] [xarray] iov_iter_npages(): just use DIV_ROUND_UP() Al Viro
2021-06-06 19:10 ` [RFC PATCH 20/37] iov_iter: replace iov_iter_copy_from_user_atomic() with iterator-advancing variant Al Viro
2021-06-06 19:10 ` Al Viro [this message]
2021-06-06 19:10 ` [RFC PATCH 22/37] iterate_and_advance(): get rid of magic in case when n is 0 Al Viro
2021-06-06 19:10 ` [RFC PATCH 23/37] iov_iter: massage iterate_iovec and iterate_kvec to logics similar to iterate_bvec Al Viro
2021-06-06 19:10 ` [RFC PATCH 24/37] iov_iter: unify iterate_iovec and iterate_kvec Al Viro
2021-06-06 19:10 ` [RFC PATCH 25/37] iterate_bvec(): expand bvec.h macro forest, massage a bit Al Viro
2021-06-06 19:10 ` [RFC PATCH 26/37] iov_iter: teach iterate_{bvec,xarray}() about possible short copies Al Viro
2021-06-06 19:10 ` [RFC PATCH 27/37] iov_iter: get rid of separate bvec and xarray callbacks Al Viro
2021-06-06 19:10 ` [RFC PATCH 28/37] iov_iter: make the amount already copied available to iterator callbacks Al Viro
2021-06-06 19:10 ` [RFC PATCH 29/37] iov_iter: make iterator callbacks use base and len instead of iovec Al Viro
2021-06-06 19:10 ` [RFC PATCH 30/37] pull handling of ->iov_offset into iterate_{iovec,bvec,xarray} Al Viro
2021-06-06 19:10 ` [RFC PATCH 31/37] iterate_xarray(): only of the first iteration we might get offset != 0 Al Viro
2021-06-06 19:10 ` [RFC PATCH 32/37] copy_page_to_iter(): don't bother with kmap_atomic() for bvec/kvec cases Al Viro
2021-06-06 19:10 ` [RFC PATCH 33/37] copy_page_from_iter(): don't need kmap_atomic() for kvec/bvec cases Al Viro
2021-06-06 19:10 ` [RFC PATCH 34/37] iov_iter: clean csum_and_copy_...() primitives up a bit Al Viro
2021-06-06 19:10 ` [RFC PATCH 35/37] pipe_zero(): we don't need no stinkin' kmap_atomic() Al Viro
2021-06-06 19:10 ` [RFC PATCH 36/37] clean up copy_mc_pipe_to_iter() Al Viro
2021-06-06 19:10 ` [RFC PATCH 37/37] csum_and_copy_to_pipe_iter(): leave handling of csum_state to caller Al Viro
2021-06-06 22:05 ` [RFC][PATCHSET] iov_iter work Linus Torvalds
2021-06-06 22:46 ` Linus Torvalds
2021-06-07 9:28 ` Christoph Hellwig
2021-06-07 14:43 ` Al Viro
2021-06-07 15:59 ` Christoph Hellwig
2021-06-07 21:07 ` Al Viro
2021-06-07 22:01 ` Linus Torvalds
2021-06-07 23:35 ` Linus Torvalds
2021-06-08 5:25 ` Christoph Hellwig
2021-06-08 11:27 ` Al Viro
2021-06-06 23:29 ` Al Viro
2021-06-07 10:38 ` Pavel Begunkov
2021-06-08 14:43 ` David Laight
2021-06-10 14:29 ` Qian Cai
2021-06-10 15:35 ` Al Viro
2021-06-10 15:48 ` Al Viro
2021-06-10 19:08 ` Qian Cai
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