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authorDavid S. Miller <davem@davemloft.net>2008-07-18 13:39:39 +0400
committerDavid S. Miller <davem@davemloft.net>2008-07-18 13:39:39 +0400
commit49997d75152b3d23c53b0fa730599f2f74c92c65 (patch)
tree46e93126170d02cfec9505172e545732c1b69656 /arch/x86/lib/usercopy_64.c
parenta0c80b80e0fb48129e4e9d6a9ede914f9ff1850d (diff)
parent5b664cb235e97afbf34db9c4d77f08ebd725335e (diff)
downloadlinux-49997d75152b3d23c53b0fa730599f2f74c92c65.tar.xz
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts: Documentation/powerpc/booting-without-of.txt drivers/atm/Makefile drivers/net/fs_enet/fs_enet-main.c drivers/pci/pci-acpi.c net/8021q/vlan.c net/iucv/iucv.c
Diffstat (limited to 'arch/x86/lib/usercopy_64.c')
-rw-r--r--arch/x86/lib/usercopy_64.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c
index 0c89d1bb0287..f4df6e7c718b 100644
--- a/arch/x86/lib/usercopy_64.c
+++ b/arch/x86/lib/usercopy_64.c
@@ -158,3 +158,26 @@ unsigned long copy_in_user(void __user *to, const void __user *from, unsigned le
}
EXPORT_SYMBOL(copy_in_user);
+/*
+ * Try to copy last bytes and clear the rest if needed.
+ * Since protection fault in copy_from/to_user is not a normal situation,
+ * it is not necessary to optimize tail handling.
+ */
+unsigned long
+copy_user_handle_tail(char *to, char *from, unsigned len, unsigned zerorest)
+{
+ char c;
+ unsigned zero_len;
+
+ for (; len; --len) {
+ if (__get_user_nocheck(c, from++, sizeof(char)))
+ break;
+ if (__put_user_nocheck(c, to++, sizeof(char)))
+ break;
+ }
+
+ for (c = 0, zero_len = len; zerorest && zero_len; --zero_len)
+ if (__put_user_nocheck(c, to++, sizeof(char)))
+ break;
+ return len;
+}