Merge tag 'mm-nonmm-stable-2022-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc updates from Andrew Morton:
 "The non-MM patch queue for this merge window.

  Not a lot of material this cycle. Many singleton patches against
  various subsystems. Most notably some maintenance work in ocfs2
  and initramfs"

* tag 'mm-nonmm-stable-2022-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (65 commits)
  kcov: update pos before writing pc in trace function
  ocfs2: dlmfs: fix error handling of user_dlm_destroy_lock
  ocfs2: dlmfs: don't clear USER_LOCK_ATTACHED when destroying lock
  fs/ntfs: remove redundant variable idx
  fat: remove time truncations in vfat_create/vfat_mkdir
  fat: report creation time in statx
  fat: ignore ctime updates, and keep ctime identical to mtime in memory
  fat: split fat_truncate_time() into separate functions
  MAINTAINERS: add Muchun as a memcg reviewer
  proc/sysctl: make protected_* world readable
  ia64: mca: drop redundant spinlock initialization
  tty: fix deadlock caused by calling printk() under tty_port->lock
  relay: remove redundant assignment to pointer buf
  fs/ntfs3: validate BOOT sectors_per_clusters
  lib/string_helpers: fix not adding strarray to device's resource list
  kernel/crash_core.c: remove redundant check of ck_cmdline
  ELF, uapi: fixup ELF_ST_TYPE definition
  ipc/mqueue: use get_tree_nodev() in mqueue_get_tree()
  ipc: update semtimedop() to use hrtimer
  ipc/sem: remove redundant assignments
  ...

1 files changed, 17 insertions, 31 deletions

diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c
index 97529552dd24..e75bc2f217ff 100644
--- a/arch/x86/kernel/crash_dump_64.c
+++ b/arch/x86/kernel/crash_dump_64.c
@@ -8,12 +8,12 @@
 
 #include <linux/errno.h>
 #include <linux/crash_dump.h>
-#include <linux/uaccess.h>
+#include <linux/uio.h>
 #include <linux/io.h>
 #include <linux/cc_platform.h>
 
-static ssize_t __copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
-				  unsigned long offset, int userbuf,
+static ssize_t __copy_oldmem_page(struct iov_iter *iter, unsigned long pfn,
+				  size_t csize, unsigned long offset,
 				  bool encrypted)
 {
 	void  *vaddr;
@@ -29,50 +29,36 @@ static ssize_t __copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
 	if (!vaddr)
 		return -ENOMEM;
 
-	if (userbuf) {
-		if (copy_to_user((void __user *)buf, vaddr + offset, csize)) {
-			iounmap((void __iomem *)vaddr);
-			return -EFAULT;
-		}
-	} else
-		memcpy(buf, vaddr + offset, csize);
+	csize = copy_to_iter(vaddr + offset, csize, iter);
 
 	iounmap((void __iomem *)vaddr);
 	return csize;
 }
 
-/**
- * copy_oldmem_page - copy one page of memory
- * @pfn: page frame number to be copied
- * @buf: target memory address for the copy; this can be in kernel address
- *	space or user address space (see @userbuf)
- * @csize: number of bytes to copy
- * @offset: offset in bytes into the page (based on pfn) to begin the copy
- * @userbuf: if set, @buf is in user address space, use copy_to_user(),
- *	otherwise @buf is in kernel address space, use memcpy().
- *
- * Copy a page from the old kernel's memory. For this page, there is no pte
- * mapped in the current kernel. We stitch up a pte, similar to kmap_atomic.
- */
-ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
-			 unsigned long offset, int userbuf)
+ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, size_t csize,
+			 unsigned long offset)
 {
-	return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, false);
+	return __copy_oldmem_page(iter, pfn, csize, offset, false);
 }
 
-/**
+/*
  * copy_oldmem_page_encrypted - same as copy_oldmem_page() above but ioremap the
  * memory with the encryption mask set to accommodate kdump on SME-enabled
  * machines.
  */
-ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
-				   unsigned long offset, int userbuf)
+ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn,
+				   size_t csize, unsigned long offset)
 {
-	return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, true);
+	return __copy_oldmem_page(iter, pfn, csize, offset, true);
 }
 
 ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
 {
-	return read_from_oldmem(buf, count, ppos, 0,
+	struct kvec kvec = { .iov_base = buf, .iov_len = count };
+	struct iov_iter iter;
+
+	iov_iter_kvec(&iter, READ, &kvec, 1, count);
+
+	return read_from_oldmem(&iter, count, ppos,
 				cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT));
 }