On 05/16/13 16:42, Rusty Russell wrote:
> Joe Perches <joe@xxxxxxxxxxx> writes:
>> On Thu, 2013-05-16 at 13:04 +0930, Rusty Russell wrote:
>>> Asias He <asias@xxxxxxxxxx> 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.
> Subject: Hoist memcpy_fromiovec 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.
>
> socket.h already include uio.h, so no callers need updating.
>
> Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Acked-by: David S. Miller <davem@xxxxxxxxxxxxx>
> Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
>
> diff --git a/include/linux/socket.h b/include/linux/socket.h
> index 428c37a..7266775 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,
> diff --git a/include/linux/uio.h b/include/linux/uio.h
> index 629aaf5..21628d3 100644
> --- a/include/linux/uio.h
> +++ b/include/linux/uio.h
> @@ -35,4 +35,6 @@ 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);
> #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..632c5ea
> --- /dev/null
> +++ b/lib/iovec.c
> @@ -0,0 +1,29 @@
> +#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);
> +
> diff --git a/net/core/iovec.c b/net/core/iovec.c
> index 7e7aeb0..d81257f 100644
> --- a/net/core/iovec.c
> +++ b/net/core/iovec.c
> @@ -125,31 +125,6 @@ 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.
> */
>
>
--
~Randy
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