Message-ID: <20130520020714.GA1386@hj.localdomain>
Date:	Mon, 20 May 2013 10:07:14 +0800
From:	Asias He <asias@...hat.com>
To:	Rusty Russell <rusty@...tcorp.com.au>
Cc:	Randy Dunlap <rdunlap@...radead.org>,
	Joe Perches <joe@...ches.com>,
	"Michael S. Tsirkin" <mst@...hat.com>,
	Nicholas Bellinger <nab@...ux-iscsi.org>,
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
	George Zhang <georgezhang@...are.com>,
	Dmitry Torokhov <dtor@...are.com>
Subject: Re: [PATCH] vhost-scsi: Depend on NET for memcpy_fromiovec

On Fri, May 17, 2013 at 04:25:49PM +0930, Rusty Russell wrote:
> Randy Dunlap <rdunlap@...radead.org> writes:
> > On 05/16/13 16:42, Rusty Russell wrote:
> >> Joe Perches <joe@...ches.com> writes:
> >>> On Thu, 2013-05-16 at 13:04 +0930, Rusty Russell wrote:
> >>>> Asias He <asias@...hat.com> writes:
> >>>>> On Wed, May 15, 2013 at 02:47:53PM +0930, Rusty Russell wrote:
> >>> []
> >>>>> 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.
> >>>
> >>> []
> >>>> 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 <rusty@...tcorp.com.au>
> 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@...radead.org>
> Acked-by: David S. Miller <davem@...emloft.net>
> Acked-by: Michael S. Tsirkin <mst@...hat.com>
> Signed-off-by: Rusty Russell <rusty@...tcorp.com.au>

Acked-by: Asias He <asias@...hat.com>

> diff --git a/drivers/dma/iovlock.c b/drivers/dma/iovlock.c
> index bb48a57..6943deb66 100644
> --- a/drivers/dma/iovlock.c
> +++ b/drivers/dma/iovlock.c
> @@ -28,7 +28,7 @@
>  #include <linux/dmaengine.h>
>  #include <linux/pagemap.h>
>  #include <linux/slab.h>
> -#include <net/tcp.h> /* for memcpy_toiovec */
> +#include <linux/uio.h> /* for memcpy_toiovec */
>  #include <asm/io.h>
>  #include <asm/uaccess.h>
>  
> diff --git a/drivers/misc/vmw_vmci/Kconfig b/drivers/misc/vmw_vmci/Kconfig
> index ea98f7e..39c2eca 100644
> --- a/drivers/misc/vmw_vmci/Kconfig
> +++ b/drivers/misc/vmw_vmci/Kconfig
> @@ -4,7 +4,7 @@
>  
>  config VMWARE_VMCI
>  	tristate "VMware VMCI Driver"
> -	depends on X86 && PCI && NET
> +	depends on X86 && PCI
>  	help
>  	  This is VMware's Virtual Machine Communication Interface.  It enables
>  	  high-speed communication between host and guest in a virtual
> diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c
> index d94245d..8ff2e5e 100644
> --- a/drivers/misc/vmw_vmci/vmci_queue_pair.c
> +++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c
> @@ -23,7 +23,7 @@
>  #include <linux/pagemap.h>
>  #include <linux/sched.h>
>  #include <linux/slab.h>
> -#include <linux/socket.h>
> +#include <linux/uio.h>
>  #include <linux/wait.h>
>  #include <linux/vmalloc.h>
>  
> diff --git a/include/linux/socket.h b/include/linux/socket.h
> index 428c37a..33bf2df 100644
> --- a/include/linux/socket.h
> +++ b/include/linux/socket.h
> @@ -305,7 +305,6 @@ struct ucred {
>  
>  extern void cred_to_ucred(struct pid *pid, const struct cred *cred, struct ucred *ucred);
>  
> -extern int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len);
>  extern int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
>  			       int offset, int len);
>  extern int csum_partial_copy_fromiovecend(unsigned char *kdata, 
> @@ -314,7 +313,6 @@ extern int csum_partial_copy_fromiovecend(unsigned char *kdata,
>  					  unsigned int len, __wsum *csump);
>  
>  extern int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr_storage *address, int mode);
> -extern int memcpy_toiovec(struct iovec *v, unsigned char *kdata, int len);
>  extern int memcpy_toiovecend(const struct iovec *v, unsigned char *kdata,
>  			     int offset, int len);
>  extern int move_addr_to_kernel(void __user *uaddr, int ulen, struct sockaddr_storage *kaddr);
> diff --git a/include/linux/uio.h b/include/linux/uio.h
> index 629aaf5..c55ce24 100644
> --- a/include/linux/uio.h
> +++ b/include/linux/uio.h
> @@ -35,4 +35,7 @@ static inline size_t iov_length(const struct iovec *iov, unsigned long nr_segs)
>  }
>  
>  unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to);
> +
> +int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len);
> +int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len);
>  #endif
> diff --git a/lib/Makefile b/lib/Makefile
> index e9c52e1..2377211 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -9,7 +9,7 @@ endif
>  
>  lib-y := ctype.o string.o vsprintf.o cmdline.o \
>  	 rbtree.o radix-tree.o dump_stack.o timerqueue.o\
> -	 idr.o int_sqrt.o extable.o \
> +	 idr.o int_sqrt.o extable.o iovec.o \
>  	 sha1.o md5.o irq_regs.o reciprocal_div.o argv_split.o \
>  	 proportions.o flex_proportions.o prio_heap.o ratelimit.o show_mem.o \
>  	 is_single_threaded.o plist.o decompress.o kobject_uevent.o \
> diff --git a/lib/iovec.c b/lib/iovec.c
> new file mode 100644
> index 0000000..454baa8
> --- /dev/null
> +++ b/lib/iovec.c
> @@ -0,0 +1,53 @@
> +#include <linux/uaccess.h>
> +#include <linux/export.h>
> +#include <linux/uio.h>
> +
> +/*
> + *	Copy iovec to kernel. Returns -EFAULT on error.
> + *
> + *	Note: this modifies the original iovec.
> + */
> +
> +int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len)
> +{
> +	while (len > 0) {
> +		if (iov->iov_len) {
> +			int copy = min_t(unsigned int, len, iov->iov_len);
> +			if (copy_from_user(kdata, iov->iov_base, copy))
> +				return -EFAULT;
> +			len -= copy;
> +			kdata += copy;
> +			iov->iov_base += copy;
> +			iov->iov_len -= copy;
> +		}
> +		iov++;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(memcpy_fromiovec);
> +
> +/*
> + *	Copy kernel to iovec. Returns -EFAULT on error.
> + *
> + *	Note: this modifies the original iovec.
> + */
> +
> +int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len)
> +{
> +	while (len > 0) {
> +		if (iov->iov_len) {
> +			int copy = min_t(unsigned int, iov->iov_len, len);
> +			if (copy_to_user(iov->iov_base, kdata, copy))
> +				return -EFAULT;
> +			kdata += copy;
> +			len -= copy;
> +			iov->iov_len -= copy;
> +			iov->iov_base += copy;
> +		}
> +		iov++;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(memcpy_toiovec);
> diff --git a/net/core/iovec.c b/net/core/iovec.c
> index 7e7aeb0..de178e4 100644
> --- a/net/core/iovec.c
> +++ b/net/core/iovec.c
> @@ -75,31 +75,6 @@ int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr_storage *a
>  
>  /*
>   *	Copy kernel to iovec. Returns -EFAULT on error.
> - *
> - *	Note: this modifies the original iovec.
> - */
> -
> -int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len)
> -{
> -	while (len > 0) {
> -		if (iov->iov_len) {
> -			int copy = min_t(unsigned int, iov->iov_len, len);
> -			if (copy_to_user(iov->iov_base, kdata, copy))
> -				return -EFAULT;
> -			kdata += copy;
> -			len -= copy;
> -			iov->iov_len -= copy;
> -			iov->iov_base += copy;
> -		}
> -		iov++;
> -	}
> -
> -	return 0;
> -}
> -EXPORT_SYMBOL(memcpy_toiovec);
> -
> -/*
> - *	Copy kernel to iovec. Returns -EFAULT on error.
>   */
>  
>  int memcpy_toiovecend(const struct iovec *iov, unsigned char *kdata,
> @@ -125,31 +100,6 @@ int memcpy_toiovecend(const struct iovec *iov, unsigned char *kdata,
>  EXPORT_SYMBOL(memcpy_toiovecend);
>  
>  /*
> - *	Copy iovec to kernel. Returns -EFAULT on error.
> - *
> - *	Note: this modifies the original iovec.
> - */
> -
> -int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len)
> -{
> -	while (len > 0) {
> -		if (iov->iov_len) {
> -			int copy = min_t(unsigned int, len, iov->iov_len);
> -			if (copy_from_user(kdata, iov->iov_base, copy))
> -				return -EFAULT;
> -			len -= copy;
> -			kdata += copy;
> -			iov->iov_base += copy;
> -			iov->iov_len -= copy;
> -		}
> -		iov++;
> -	}
> -
> -	return 0;
> -}
> -EXPORT_SYMBOL(memcpy_fromiovec);
> -
> -/*
>   *	Copy iovec from kernel. Returns -EFAULT on error.
>   */
>  

-- 
Asias
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