linux-kernel - [PATCH v3 1/3] s390/crash: move copy_to_user_real() to crash

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Date:   Mon, 18 Jul 2022 15:32:39 +0200
From:   Alexander Gordeev <agordeev@...ux.ibm.com>
To:     Matthew Wilcox <willy@...radead.org>,
        Alexander Egorenkov <egorenar@...ux.ibm.com>,
        Heiko Carstens <hca@...ux.ibm.com>
Cc:     Baoquan He <bhe@...hat.com>, Christoph Hellwig <hch@....de>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Al Viro <viro@...iv.linux.org.uk>,
        linux-kernel@...r.kernel.org, linux-s390@...r.kernel.org
Subject: [PATCH v3 1/3] s390/crash: move copy_to_user_real() to crash_dump.c

Function copy_to_user_real() does not really belong to maccess.c.
It is only used for copying oldmem to user space, so let's move
it to the friends.

Signed-off-by: Alexander Gordeev <agordeev@...ux.ibm.com>
---
 arch/s390/include/asm/uaccess.h |  1 -
 arch/s390/kernel/crash_dump.c   | 26 ++++++++++++++++++++++++++
 arch/s390/mm/maccess.c          | 26 --------------------------
 3 files changed, 26 insertions(+), 27 deletions(-)

diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
index f4511e21d646..2a067315fe59 100644
--- a/arch/s390/include/asm/uaccess.h
+++ b/arch/s390/include/asm/uaccess.h
@@ -285,7 +285,6 @@ static inline unsigned long __must_check clear_user(void __user *to, unsigned lo
 	return __clear_user(to, n);
 }
 
-int copy_to_user_real(void __user *dest, unsigned long src, unsigned long count);
 void *s390_kernel_write(void *dst, const void *src, size_t size);
 
 int __noreturn __put_kernel_bad(void);
diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index 0efee5c49b1e..8d7332d4444c 100644
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -173,6 +173,32 @@ int copy_oldmem_kernel(void *dst, unsigned long src, size_t count)
 	return 0;
 }
 
+/*
+ * Copy memory from kernel (real) to user (virtual)
+ */
+static int copy_to_user_real(void __user *dest, unsigned long src, unsigned long count)
+{
+	int offs = 0, size, rc;
+	char *buf;
+
+	buf = (char *)__get_free_page(GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	rc = -EFAULT;
+	while (offs < count) {
+		size = min(PAGE_SIZE, count - offs);
+		if (memcpy_real(buf, src + offs, size))
+			goto out;
+		if (copy_to_user(dest + offs, buf, size))
+			goto out;
+		offs += size;
+	}
+	rc = 0;
+out:
+	free_page((unsigned long)buf);
+	return rc;
+}
+
 /*
  * Copy memory of the old, dumped system to a user space virtual address
  */
diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c
index 421efa46946b..d6d84e02f35a 100644
--- a/arch/s390/mm/maccess.c
+++ b/arch/s390/mm/maccess.c
@@ -171,32 +171,6 @@ void memcpy_absolute(void *dest, void *src, size_t count)
 	arch_local_irq_restore(flags);
 }
 
-/*
- * Copy memory from kernel (real) to user (virtual)
- */
-int copy_to_user_real(void __user *dest, unsigned long src, unsigned long count)
-{
-	int offs = 0, size, rc;
-	char *buf;
-
-	buf = (char *) __get_free_page(GFP_KERNEL);
-	if (!buf)
-		return -ENOMEM;
-	rc = -EFAULT;
-	while (offs < count) {
-		size = min(PAGE_SIZE, count - offs);
-		if (memcpy_real(buf, src + offs, size))
-			goto out;
-		if (copy_to_user(dest + offs, buf, size))
-			goto out;
-		offs += size;
-	}
-	rc = 0;
-out:
-	free_page((unsigned long) buf);
-	return rc;
-}
-
 /*
  * Check if physical address is within prefix or zero page
  */
-- 
2.34.1