Re: [PATCH] vhost-scsi: Depend on NET for memcpy_fromiovec

On Monday, May 20, 2013 10:07:14 AM Asias He wrote:

On Fri, May 17, 2013 at 04:25:49PM +0930, Rusty Russell wrote:

quoted

Randy Dunlap [off-list ref] writes:

quoted

On 05/16/13 16:42, Rusty Russell wrote:

quoted

Joe Perches [off-list ref] writes:

quoted

On Thu, 2013-05-16 at 13:04 +0930, Rusty Russell wrote:

quoted

Asias He [off-list ref] writes:

quoted

On Wed, May 15, 2013 at 02:47:53PM +0930, Rusty Russell wrote:

[]

quoted

quoted

Other users are using memcpy_fromiovec and friends outside net. It
seems
a good idea to put it in a util library. e.g. 
crypto/algif_skcipher.c
which also depends on NET for it.

[]

quoted

Subject: Hoist memcpy_fromiovec into lib/

You'll need the "friends" memcpy_toiovec too.

$ git grep -E \bmemcpy\w+iovec\w*"
crypto/algif_hash.c:    err = memcpy_toiovec(msg->msg_iov,
ctx->result, len); crypto/algif_skcipher.c:                       
err = memcpy_fromiovec(page_address(sg_page(sg)) +
crypto/algif_skcipher.c:                        err =
memcpy_fromiovec(page_address(sg_page(sg + i)),
drivers/dma/iovlock.c:#include <net/tcp.h> /* for memcpy_toiovec */
drivers/dma/iovlock.c:          return memcpy_toiovec(iov, kdata,
len); drivers/dma/iovlock.c:          err = memcpy_toiovec(iov, vaddr
+ offset, len); drivers/isdn/mISDN/socket.c:    if
(memcpy_fromiovec(skb_put(skb, len), msg->msg_iov, len)) {
drivers/misc/vmw_vmci/vmci_queue_pair.c:                        err =
memcpy_fromiovec((u8 *)va + page_o
drivers/misc/vmw_vmci/vmci_queue_pair.c:                        err =
memcpy_toiovec(iov, (u8 *)va + pag> >> 

Fascinating.  These all indirectly depend on NET, so there's no problem
at the moment.  But it is a bit weird...

crypto/algif_hash.c: depends on CRYPTO_USER_API_HASH -> NET
crypto/algif_skcipher.c: depends on CRYPTO_USER_API_SKCIPHER -> NET
drivers/dma/iovlock.c: depends on NET_DMA -> NET
drivers/isdn/mISDN/socket.c: depends on MISDN -> ISDN -> NET
drivers/misc/vmw_vmci/vmci_queue_pair.c: depends on VMCI -> NET

Patch welcome.

Meanwhile, to avoid more bikeshedding I've put the patch I posted with
all acks in my fixes branch.  One cycle through linux-next, then
straight to Linus.

I agree with whoever suggested that more be moved into /lib.
E.g., drivers/misc/vmw_vmci/Kconfig uses "depends on NET" because the
code there uses both memcpy_toiovec() and memcpy_fromiovec().
See commit ID 6d4f0139d642c45411a47879325891ce2a7c164a.

(CC's trimmed).

You Acked that commit :(

At a glance, the only way to drive the vmw_vmci device is through
net/vmw_vsock/vmci_transport.c, so without NET it's useless?  But let's
keep it neat anyway.  This was compiletested with CONFIG_VMCI,
CONFIG_DMA_ENGINE and !CONFIG_NET.

Thanks,
Rusty.

From: Rusty Russell <redacted>
Subject: [PATCH] Hoist memcpy_fromiovec/memcpy_toiovec into lib/

ERROR: "memcpy_fromiovec" [drivers/vhost/vhost_scsi.ko] undefined!

That function is only present with CONFIG_NET.  Turns out that
crypto/algif_skcipher.c also uses that outside net, but it actually
needs sockets anyway.

In addition, commit 6d4f0139d642c45411a47879325891ce2a7c164a added
CONFIG_NET dependency to CONFIG_VMCI for memcpy_toiovec, so hoist
that function and revert that commit too.

socket.h already include uio.h, so no callers *need* updating,
though I update the obvious ones.

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <redacted>

Acked-by: Asias He <redacted>

Acked-by: Dmitry Torokhov <redacted>

Thanks,
Dmitry