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SubjectRe: [PATCH] vhost-scsi: Depend on NET for memcpy_fromiovec
Date
Randy Dunlap <rdunlap@infradead.org> writes:
> On 05/16/13 16:42, Rusty Russell wrote:
>> Joe Perches <joe@perches.com> writes:
>>> On Thu, 2013-05-16 at 13:04 +0930, Rusty Russell wrote:
>>>> Asias He <asias@redhat.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@rustcorp.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@infradead.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

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.
*/


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