mbox series

[net-next,v3,00/10] crypto, splice, net: Make AF_ALG handle sendmsg(MSG_SPLICE_PAGES)

Message ID 20230606130856.1970660-1-dhowells@redhat.com
Headers show
Series crypto, splice, net: Make AF_ALG handle sendmsg(MSG_SPLICE_PAGES) | expand

Message

David Howells June 6, 2023, 1:08 p.m. UTC
Here are patches to make AF_ALG handle the MSG_SPLICE_PAGES internal
sendmsg flag.  MSG_SPLICE_PAGES is an internal hint that tells the protocol
that it should splice the pages supplied if it can.  The sendpage functions
are then turned into wrappers around that.

This set consists of the following parts:

 (1) Move netfs_extract_iter_to_sg() to somewhere more general and rename
     it to drop the "netfs" prefix.  We use this to extract directly from
     an iterator into a scatterlist.

 (2) Make AF_ALG use iov_iter_extract_pages().  This has the additional
     effect of pinning pages obtained from userspace rather than taking
     refs on them.  Pages from kernel-backed iterators would not be pinned,
     but AF_ALG isn't really meant for use by kernel services.

 (3) Change AF_ALG still further to use extract_iter_to_sg().

 (4) Make af_alg_sendmsg() support MSG_SPLICE_PAGES support and make
     af_alg_sendpage() just a wrapper around sendmsg().  This has to take
     refs on the pages pinned for the moment.

 (5) Make hash_sendmsg() support MSG_SPLICE_PAGES by simply ignoring it.
     hash_sendpage() is left untouched to be removed later, after the
     splice core has been changed to call sendmsg().

I've pushed the patches here also:

	https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/log/?h=sendpage-2-alg

David

ver #3)
 - Rebase and deal with fs/cifs/ moving.
 - Reimpose the ALG_MAX_PAGES limit in hash_sendmsg() for kernel iters.
 - Remove BVEC iter restriction when using MSG_SPLICE_PAGES.

ver #2)
 - Put the "netfs_" prefix removal first to shorten lines and avoid
   checkpatch 80-char warnings.
 - Fix a couple of spelling mistakes.
 - Wrap some lines at 80 chars.

Link: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=51c78a4d532efe9543a4df019ff405f05c6157f6 # part 1
Link: https://lore.kernel.org/r/20230526143104.882842-1-dhowells@redhat.com/ # v1
Link: https://lore.kernel.org/r/20230530141635.136968-1-dhowells@redhat.com/ # v2

David Howells (10):
  Drop the netfs_ prefix from netfs_extract_iter_to_sg()
  Fix a couple of spelling mistakes
  Wrap lines at 80
  Move netfs_extract_iter_to_sg() to lib/scatterlist.c
  crypto: af_alg: Pin pages rather than ref'ing if appropriate
  crypto: af_alg: Use extract_iter_to_sg() to create scatterlists
  crypto: af_alg: Indent the loop in af_alg_sendmsg()
  crypto: af_alg: Support MSG_SPLICE_PAGES
  crypto: af_alg: Convert af_alg_sendpage() to use MSG_SPLICE_PAGES
  crypto: af_alg/hash: Support MSG_SPLICE_PAGES

 crypto/af_alg.c           | 181 +++++++++++--------------
 crypto/algif_aead.c       |  38 +++---
 crypto/algif_hash.c       | 110 ++++++++++------
 crypto/algif_skcipher.c   |  10 +-
 fs/netfs/iterator.c       | 266 -------------------------------------
 fs/smb/client/smb2ops.c   |   4 +-
 fs/smb/client/smbdirect.c |   2 +-
 include/crypto/if_alg.h   |   7 +-
 include/linux/netfs.h     |   4 -
 include/linux/uio.h       |   5 +
 lib/scatterlist.c         | 269 ++++++++++++++++++++++++++++++++++++++
 11 files changed, 451 insertions(+), 445 deletions(-)

Comments

Herbert Xu June 7, 2023, 8:40 a.m. UTC | #1
On Tue, Jun 06, 2023 at 02:08:51PM +0100, David Howells wrote:
> Convert AF_ALG to use iov_iter_extract_pages() instead of
> iov_iter_get_pages().  This will pin pages or leave them unaltered rather
> than getting a ref on them as appropriate to the iterator.
> 
> The pages need to be pinned for DIO-read rather than having refs taken on
> them to prevent VM copy-on-write from malfunctioning during a concurrent
> fork() (the result of the I/O would otherwise end up only visible to the
> child process and not the parent).
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: Herbert Xu <herbert@gondor.apana.org.au>
> cc: "David S. Miller" <davem@davemloft.net>
> cc: Eric Dumazet <edumazet@google.com>
> cc: Jakub Kicinski <kuba@kernel.org>
> cc: Paolo Abeni <pabeni@redhat.com>
> cc: Jens Axboe <axboe@kernel.dk>
> cc: Matthew Wilcox <willy@infradead.org>
> cc: linux-crypto@vger.kernel.org
> cc: netdev@vger.kernel.org
> ---
>  crypto/af_alg.c         | 10 +++++++---
>  include/crypto/if_alg.h |  1 +
>  2 files changed, 8 insertions(+), 3 deletions(-)

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Herbert Xu June 7, 2023, 8:41 a.m. UTC | #2
On Tue, Jun 06, 2023 at 02:08:53PM +0100, David Howells wrote:
> Put the loop in af_alg_sendmsg() into an if-statement to indent it to make
> the next patch easier to review as that will add another branch to handle
> MSG_SPLICE_PAGES to the if-statement.
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: Herbert Xu <herbert@gondor.apana.org.au>
> cc: "David S. Miller" <davem@davemloft.net>
> cc: Eric Dumazet <edumazet@google.com>
> cc: Jakub Kicinski <kuba@kernel.org>
> cc: Paolo Abeni <pabeni@redhat.com>
> cc: Jens Axboe <axboe@kernel.dk>
> cc: Matthew Wilcox <willy@infradead.org>
> cc: linux-crypto@vger.kernel.org
> cc: netdev@vger.kernel.org
> ---
> 
> Notes:
>     ver #2)
>      - Fix a checkpatch warning.

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Herbert Xu June 7, 2023, 8:41 a.m. UTC | #3
On Tue, Jun 06, 2023 at 02:08:54PM +0100, David Howells wrote:
> Make AF_ALG sendmsg() support MSG_SPLICE_PAGES.  This causes pages to be
> spliced from the source iterator.
> 
> This allows ->sendpage() to be replaced by something that can handle
> multiple multipage folios in a single transaction.
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: Herbert Xu <herbert@gondor.apana.org.au>
> cc: "David S. Miller" <davem@davemloft.net>
> cc: Eric Dumazet <edumazet@google.com>
> cc: Jakub Kicinski <kuba@kernel.org>
> cc: Paolo Abeni <pabeni@redhat.com>
> cc: Jens Axboe <axboe@kernel.dk>
> cc: Matthew Wilcox <willy@infradead.org>
> cc: linux-crypto@vger.kernel.org
> cc: netdev@vger.kernel.org
> ---
> 
> Notes:
>     ver #3)
>      - Remove BVEC iter restriction when using MSG_SPLICE_PAGES.
> 
>  crypto/af_alg.c         | 24 ++++++++++++++++++++++--
>  crypto/algif_aead.c     | 22 +++++++++++-----------
>  crypto/algif_skcipher.c |  8 ++++----
>  3 files changed, 37 insertions(+), 17 deletions(-)

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Herbert Xu June 7, 2023, 8:48 a.m. UTC | #4
On Tue, Jun 06, 2023 at 02:08:56PM +0100, David Howells wrote:
> Make AF_ALG sendmsg() support MSG_SPLICE_PAGES in the hashing code.  This
> causes pages to be spliced from the source iterator if possible.
> 
> This allows ->sendpage() to be replaced by something that can handle
> multiple multipage folios in a single transaction.
> 
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: Herbert Xu <herbert@gondor.apana.org.au>
> cc: "David S. Miller" <davem@davemloft.net>
> cc: Eric Dumazet <edumazet@google.com>
> cc: Jakub Kicinski <kuba@kernel.org>
> cc: Paolo Abeni <pabeni@redhat.com>
> cc: Jens Axboe <axboe@kernel.dk>
> cc: Matthew Wilcox <willy@infradead.org>
> cc: linux-crypto@vger.kernel.org
> cc: netdev@vger.kernel.org
> ---
> 
> Notes:
>     ver #2)
>      - Fixed some checkpatch warnings.
> 
>  crypto/af_alg.c     |  11 +++--
>  crypto/algif_hash.c | 100 +++++++++++++++++++++++++++-----------------
>  2 files changed, 70 insertions(+), 41 deletions(-)

Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
patchwork-bot+netdevbpf@kernel.org June 8, 2023, 1:40 p.m. UTC | #5
Hello:

This series was applied to netdev/net-next.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Tue,  6 Jun 2023 14:08:46 +0100 you wrote:
> Here are patches to make AF_ALG handle the MSG_SPLICE_PAGES internal
> sendmsg flag.  MSG_SPLICE_PAGES is an internal hint that tells the protocol
> that it should splice the pages supplied if it can.  The sendpage functions
> are then turned into wrappers around that.
> 
> This set consists of the following parts:
> 
> [...]

Here is the summary with links:
  - [net-next,v3,01/10] Drop the netfs_ prefix from netfs_extract_iter_to_sg()
    https://git.kernel.org/netdev/net-next/c/0d7aeb68700f
  - [net-next,v3,02/10] Fix a couple of spelling mistakes
    https://git.kernel.org/netdev/net-next/c/3b9e9f72badf
  - [net-next,v3,03/10] Wrap lines at 80
    https://git.kernel.org/netdev/net-next/c/936dc763c52e
  - [net-next,v3,04/10] Move netfs_extract_iter_to_sg() to lib/scatterlist.c
    https://git.kernel.org/netdev/net-next/c/f5f82cd18732
  - [net-next,v3,05/10] crypto: af_alg: Pin pages rather than ref'ing if appropriate
    https://git.kernel.org/netdev/net-next/c/f9e7a5fa51fb
  - [net-next,v3,06/10] crypto: af_alg: Use extract_iter_to_sg() to create scatterlists
    https://git.kernel.org/netdev/net-next/c/c1abe6f570af
  - [net-next,v3,07/10] crypto: af_alg: Indent the loop in af_alg_sendmsg()
    https://git.kernel.org/netdev/net-next/c/73d7409cfdad
  - [net-next,v3,08/10] crypto: af_alg: Support MSG_SPLICE_PAGES
    https://git.kernel.org/netdev/net-next/c/bf63e250c4b1
  - [net-next,v3,09/10] crypto: af_alg: Convert af_alg_sendpage() to use MSG_SPLICE_PAGES
    https://git.kernel.org/netdev/net-next/c/fb800fa4c1f5
  - [net-next,v3,10/10] crypto: af_alg/hash: Support MSG_SPLICE_PAGES
    https://git.kernel.org/netdev/net-next/c/c662b043cdca

You are awesome, thank you!