vmcore: convert copy_oldmem_page() to take an iov_iter

Patch series "Convert vmcore to use an iov_iter", v5.

For some reason several people have been sending bad patches to fix
compiler warnings in vmcore recently.  Here's how it should be done.
Compile-tested only on x86.  As noted in the first patch, s390 should take
this conversion a bit further, but I'm not inclined to do that work
myself.

This patch (of 3):

Instead of passing in a 'buf' and 'userbuf' argument, pass in an iov_iter.
s390 needs more work to pass the iov_iter down further, or refactor, but
I'd be more comfortable if someone who can test on s390 did that work.

It's more convenient to convert the whole of read_from_oldmem() to take an
iov_iter at the same time, so rename it to read_from_oldmem_iter() and add
a temporary read_from_oldmem() wrapper that creates an iov_iter.

Link: https://lkml.kernel.org/r/20220408090636.560886-1-bhe@redhat.com
Link: https://lkml.kernel.org/r/20220408090636.560886-2-bhe@redhat.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/arm/kernel/crash_dump.c b/arch/arm/kernel/crash_dump.c
index 53cb924353920263617bba724ff6039d9fe483a5..938bd932df9a0bad9423632670807ee8f41701fc 100644 (file)
--- a/arch/arm/kernel/crash_dump.c
+++ b/arch/arm/kernel/crash_dump.c
@@ -14,22 +14,10 @@
 #include <linux/crash_dump.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
+#include <linux/uio.h>
 
-/**
- * copy_oldmem_page() - copy one page from old kernel memory
- * @pfn: page frame number to be copied
- * @buf: buffer where the copied page is placed
- * @csize: number of bytes to copy
- * @offset: offset in bytes into the page
- * @userbuf: if set, @buf is int he user address space
- *
- * This function copies one page from old kernel memory into buffer pointed by
- * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes
- * copied or negative error in case of failure.
- */
-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)
 {
        void *vaddr;
 
@@ -40,14 +28,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
        if (!vaddr)
                return -ENOMEM;
 
-       if (userbuf) {
-               if (copy_to_user(buf, vaddr + offset, csize)) {
-                       iounmap(vaddr);
-                       return -EFAULT;
-               }
-       } else {
-               memcpy(buf, vaddr + offset, csize);
-       }
+       csize = copy_to_iter(vaddr + offset, csize, iter);
 
        iounmap(vaddr);
        return csize;

diff --git a/arch/arm64/kernel/crash_dump.c b/arch/arm64/kernel/crash_dump.c
index 58303a9ec32c4f4a58ff6726fa9de90092d7bf30..670e4ce818223c2d2ba91ad76084fdd78369ac04 100644 (file)
--- a/arch/arm64/kernel/crash_dump.c
+++ b/arch/arm64/kernel/crash_dump.c
@@ -9,25 +9,11 @@
 #include <linux/crash_dump.h>
 #include <linux/errno.h>
 #include <linux/io.h>
-#include <linux/memblock.h>
-#include <linux/uaccess.h>
+#include <linux/uio.h>
 #include <asm/memory.h>
 
-/**
- * copy_oldmem_page() - copy one page from old kernel memory
- * @pfn: page frame number to be copied
- * @buf: buffer where the copied page is placed
- * @csize: number of bytes to copy
- * @offset: offset in bytes into the page
- * @userbuf: if set, @buf is in a user address space
- *
- * This function copies one page from old kernel memory into buffer pointed by
- * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes
- * copied or negative error in case of failure.
- */
-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)
 {
        void *vaddr;
 
@@ -38,14 +24,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
        if (!vaddr)
                return -ENOMEM;
 
-       if (userbuf) {
-               if (copy_to_user((char __user *)buf, vaddr + offset, csize)) {
-                       memunmap(vaddr);
-                       return -EFAULT;
-               }
-       } else {
-               memcpy(buf, vaddr + offset, csize);
-       }
+       csize = copy_to_iter(vaddr + offset, csize, iter);
 
        memunmap(vaddr);
 

diff --git a/arch/ia64/kernel/crash_dump.c b/arch/ia64/kernel/crash_dump.c
index 0ed3c3dee4cde90889c3e53b4df9b458a496d10c..4ef68e2aa7571793dff687a3091bbcbd4ac6f4d4 100644 (file)
--- a/arch/ia64/kernel/crash_dump.c
+++ b/arch/ia64/kernel/crash_dump.c
@@ -10,42 +10,18 @@
 #include <linux/errno.h>
 #include <linux/types.h>
 #include <linux/crash_dump.h>
-
+#include <linux/uio.h>
 #include <asm/page.h>
-#include <linux/uaccess.h>
 
-/**
- * copy_oldmem_page - copy one page from "oldmem"
- * @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 "oldmem". For this page, there is no pte mapped
- * in the current kernel. We stitch up a pte, similar to kmap_atomic.
- *
- * Calling copy_to_user() in atomic context is not desirable. Hence first
- * copying the data to a pre-allocated kernel page and then copying to user
- * space in non-atomic context.
- */
-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)
 {
        void  *vaddr;
 
        if (!csize)
                return 0;
        vaddr = __va(pfn<<PAGE_SHIFT);
-       if (userbuf) {
-               if (copy_to_user(buf, (vaddr + offset), csize)) {
-                       return -EFAULT;
-               }
-       } else
-               memcpy(buf, (vaddr + offset), csize);
+       csize = copy_to_iter(vaddr + offset, csize, iter);
        return csize;
 }
 

diff --git a/arch/mips/kernel/crash_dump.c b/arch/mips/kernel/crash_dump.c
index 2e50f55185a651f9f0d7d1aa74c96bce1e171084..6e50f49024094ac31342a2e8de48fc9b0f166fcf 100644 (file)
--- a/arch/mips/kernel/crash_dump.c
+++ b/arch/mips/kernel/crash_dump.c
@@ -1,22 +1,10 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/highmem.h>
 #include <linux/crash_dump.h>
+#include <linux/uio.h>
 
-/**
- * copy_oldmem_page - copy one page from "oldmem"
- * @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 "oldmem". For this page, there is no pte mapped
- * in the current kernel.
- */
-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)
 {
        void  *vaddr;
 
@@ -24,14 +12,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
                return 0;
 
        vaddr = kmap_local_pfn(pfn);
-
-       if (!userbuf) {
-               memcpy(buf, vaddr + offset, csize);
-       } else {
-               if (copy_to_user(buf, vaddr + offset, csize))
-                       csize = -EFAULT;
-       }
-
+       csize = copy_to_iter(vaddr + offset, csize, iter);
        kunmap_local(vaddr);
 
        return csize;

diff --git a/arch/powerpc/kernel/crash_dump.c b/arch/powerpc/kernel/crash_dump.c
index 5693e1c67c2b469af88344ccc50ff4079f4db1d7..32b4a97f1b79bb2aae51f0a9cee46ca6e6a65a39 100644 (file)
--- a/arch/powerpc/kernel/crash_dump.c
+++ b/arch/powerpc/kernel/crash_dump.c
@@ -16,7 +16,7 @@
 #include <asm/kdump.h>
 #include <asm/prom.h>
 #include <asm/firmware.h>
-#include <linux/uaccess.h>
+#include <linux/uio.h>
 #include <asm/rtas.h>
 #include <asm/inst.h>
 
@@ -68,33 +68,8 @@ void __init setup_kdump_trampoline(void)
 }
 #endif /* CONFIG_NONSTATIC_KERNEL */
 
-static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize,
-                               unsigned long offset, int userbuf)
-{
-       if (userbuf) {
-               if (copy_to_user((char __user *)buf, (vaddr + offset), csize))
-                       return -EFAULT;
-       } else
-               memcpy(buf, (vaddr + offset), csize);
-
-       return csize;
-}
-
-/**
- * copy_oldmem_page - copy one page from "oldmem"
- * @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 "oldmem". 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)
 {
        void  *vaddr;
        phys_addr_t paddr;
@@ -107,10 +82,10 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
 
        if (memblock_is_region_memory(paddr, csize)) {
                vaddr = __va(paddr);
-               csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
+               csize = copy_to_iter(vaddr + offset, csize, iter);
        } else {
                vaddr = ioremap_cache(paddr, PAGE_SIZE);
-               csize = copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf);
+               csize = copy_to_iter(vaddr + offset, csize, iter);
                iounmap(vaddr);
        }
 

diff --git a/arch/riscv/kernel/crash_dump.c b/arch/riscv/kernel/crash_dump.c
index 86cc0ada5752219c7f1d34380db3d7854bf5d1aa..ea2158cee97b344c5e5a2811493a0985d4d2e56a 100644 (file)
--- a/arch/riscv/kernel/crash_dump.c
+++ b/arch/riscv/kernel/crash_dump.c
@@ -7,22 +7,10 @@
 
 #include <linux/crash_dump.h>
 #include <linux/io.h>
+#include <linux/uio.h>
 
-/**
- * copy_oldmem_page() - copy one page from old kernel memory
- * @pfn: page frame number to be copied
- * @buf: buffer where the copied page is placed
- * @csize: number of bytes to copy
- * @offset: offset in bytes into the page
- * @userbuf: if set, @buf is in a user address space
- *
- * This function copies one page from old kernel memory into buffer pointed by
- * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes
- * copied or negative error in case of failure.
- */
-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)
 {
        void *vaddr;
 
@@ -33,13 +21,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
        if (!vaddr)
                return -ENOMEM;
 
-       if (userbuf) {
-               if (copy_to_user((char __user *)buf, vaddr + offset, csize)) {
-                       memunmap(vaddr);
-                       return -EFAULT;
-               }
-       } else
-               memcpy(buf, vaddr + offset, csize);
+       csize = copy_to_iter(vaddr + offset, csize, iter);
 
        memunmap(vaddr);
        return csize;

diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index 69819b76525047d3b8c163880179f6c740945afa..a2c1c55daec03c8faee196c7edf5ed6b865b3a96 100644 (file)
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -15,6 +15,7 @@
 #include <linux/slab.h>
 #include <linux/memblock.h>
 #include <linux/elf.h>
+#include <linux/uio.h>
 #include <asm/asm-offsets.h>
 #include <asm/os_info.h>
 #include <asm/elf.h>
@@ -212,8 +213,8 @@ static int copy_oldmem_user(void __user *dst, unsigned long src, size_t count)
 /*
  * Copy one page from "oldmem"
  */
-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)
 {
        unsigned long src;
        int rc;
@@ -221,10 +222,12 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
        if (!csize)
                return 0;
        src = pfn_to_phys(pfn) + offset;
-       if (userbuf)
-               rc = copy_oldmem_user((void __force __user *) buf, src, csize);
+
+       /* XXX: pass the iov_iter down to a common function */
+       if (iter_is_iovec(iter))
+               rc = copy_oldmem_user(iter->iov->iov_base, src, csize);
        else
-               rc = copy_oldmem_kernel((void *) buf, src, csize);
+               rc = copy_oldmem_kernel(iter->kvec->iov_base, src, csize);
        return rc;
 }
 

diff --git a/arch/sh/kernel/crash_dump.c b/arch/sh/kernel/crash_dump.c
index 5b41b59698c1e494f7c17346718ebbaea5f60fd6..19ce6a950aaca83b6b74d7ffbd46968b0cf71a79 100644 (file)
--- a/arch/sh/kernel/crash_dump.c
+++ b/arch/sh/kernel/crash_dump.c
@@ -8,23 +8,11 @@
 #include <linux/errno.h>
 #include <linux/crash_dump.h>
 #include <linux/io.h>
+#include <linux/uio.h>
 #include <linux/uaccess.h>
 
-/**
- * copy_oldmem_page - copy one page from "oldmem"
- * @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 "oldmem". 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)
 {
        void  __iomem *vaddr;
 
@@ -32,15 +20,8 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
                return 0;
 
        vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
-
-       if (userbuf) {
-               if (copy_to_user((void __user *)buf, (vaddr + offset), csize)) {
-                       iounmap(vaddr);
-                       return -EFAULT;
-               }
-       } else
-       memcpy(buf, (vaddr + offset), csize);
-
+       csize = copy_to_iter(vaddr + offset, csize, iter);
        iounmap(vaddr);
+
        return csize;
 }

diff --git a/arch/x86/kernel/crash_dump_32.c b/arch/x86/kernel/crash_dump_32.c
index 5fcac46aaf6b185ed109cdb36f50c18e079f108a..5f4ae5476e193014686d5835be35fc467af11583 100644 (file)
--- a/arch/x86/kernel/crash_dump_32.c
+++ b/arch/x86/kernel/crash_dump_32.c
@@ -10,8 +10,7 @@
 #include <linux/errno.h>
 #include <linux/highmem.h>
 #include <linux/crash_dump.h>
-
-#include <linux/uaccess.h>
+#include <linux/uio.h>
 
 static inline bool is_crashed_pfn_valid(unsigned long pfn)
 {
@@ -29,21 +28,8 @@ static inline bool is_crashed_pfn_valid(unsigned long pfn)
 #endif
 }
 
-/**
- * copy_oldmem_page - copy one page from "oldmem"
- * @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 "oldmem". For this page, there might be no pte mapped
- * in the current kernel.
- */
-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)
 {
        void  *vaddr;
 
@@ -54,14 +40,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
                return -EFAULT;
 
        vaddr = kmap_local_pfn(pfn);
-
-       if (!userbuf) {
-               memcpy(buf, vaddr + offset, csize);
-       } else {
-               if (copy_to_user(buf, vaddr + offset, csize))
-                       csize = -EFAULT;
-       }
-
+       csize = copy_to_iter(vaddr + offset, csize, iter);
        kunmap_local(vaddr);
 
        return csize;

diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_64.c
index 97529552dd2496421cd7f684c38e7a3629ad40c5..94fe4aff9694b84bba0e3380bb04171be4453114 100644 (file)
--- 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;
@@ -29,46 +29,27 @@ 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)

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 6f1b8ddc6f7a45c82d8cb3f6e34a11a1257b2977..54dda2e19ed1270a4529f2d84e2215afc8f29f07 100644 (file)
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -26,6 +26,7 @@
 #include <linux/vmalloc.h>
 #include <linux/pagemap.h>
 #include <linux/uaccess.h>
+#include <linux/uio.h>
 #include <linux/cc_platform.h>
 #include <asm/io.h>
 #include "internal.h"
@@ -128,9 +129,8 @@ static int open_vmcore(struct inode *inode, struct file *file)
 }
 
 /* Reads a page from the oldmem device from given offset. */
-ssize_t read_from_oldmem(char *buf, size_t count,
-                        u64 *ppos, int userbuf,
-                        bool encrypted)
+static ssize_t read_from_oldmem_iter(struct iov_iter *iter, size_t count,
+                        u64 *ppos, bool encrypted)
 {
        unsigned long pfn, offset;
        size_t nr_bytes;
@@ -152,29 +152,23 @@ ssize_t read_from_oldmem(char *buf, size_t count,
 
                /* If pfn is not ram, return zeros for sparse dump files */
                if (!pfn_is_ram(pfn)) {
-                       tmp = 0;
-                       if (!userbuf)
-                               memset(buf, 0, nr_bytes);
-                       else if (clear_user(buf, nr_bytes))
-                               tmp = -EFAULT;
+                       tmp = iov_iter_zero(nr_bytes, iter);
                } else {
                        if (encrypted)
-                               tmp = copy_oldmem_page_encrypted(pfn, buf,
+                               tmp = copy_oldmem_page_encrypted(iter, pfn,
                                                                 nr_bytes,
-                                                                offset,
-                                                                userbuf);
+                                                                offset);
                        else
-                               tmp = copy_oldmem_page(pfn, buf, nr_bytes,
-                                                      offset, userbuf);
+                               tmp = copy_oldmem_page(iter, pfn, nr_bytes,
+                                                      offset);
                }
-               if (tmp < 0) {
+               if (tmp < nr_bytes) {
                        srcu_read_unlock(&vmcore_cb_srcu, idx);
-                       return tmp;
+                       return -EFAULT;
                }
 
                *ppos += nr_bytes;
                count -= nr_bytes;
-               buf += nr_bytes;
                read += nr_bytes;
                ++pfn;
                offset = 0;
@@ -184,6 +178,27 @@ ssize_t read_from_oldmem(char *buf, size_t count,
        return read;
 }
 
+ssize_t read_from_oldmem(char *buf, size_t count,
+                        u64 *ppos, int userbuf,
+                        bool encrypted)
+{
+       struct iov_iter iter;
+       struct iovec iov;
+       struct kvec kvec;
+
+       if (userbuf) {
+               iov.iov_base = (__force void __user *)buf;
+               iov.iov_len = count;
+               iov_iter_init(&iter, READ, &iov, 1, count);
+       } else {
+               kvec.iov_base = buf;
+               kvec.iov_len = count;
+               iov_iter_kvec(&iter, READ, &kvec, 1, count);
+       }
+
+       return read_from_oldmem_iter(&iter, count, ppos, encrypted);
+}
+
 /*
  * Architectures may override this function to allocate ELF header in 2nd kernel
  */
@@ -228,11 +243,10 @@ int __weak remap_oldmem_pfn_range(struct vm_area_struct *vma,
 /*
  * Architectures which support memory encryption override this.
  */
-ssize_t __weak
-copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
-                          unsigned long offset, int userbuf)
+ssize_t __weak 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);
+       return copy_oldmem_page(iter, pfn, csize, offset);
 }
 
 /*

diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
index 620821549b23ab7938be5d34efc889c00feaa6a0..a1cf7d5c03c7c90ceeaf30eecf865a590e5f9612 100644 (file)
--- a/include/linux/crash_dump.h
+++ b/include/linux/crash_dump.h
@@ -24,11 +24,10 @@ extern int remap_oldmem_pfn_range(struct vm_area_struct *vma,
                                  unsigned long from, unsigned long pfn,
                                  unsigned long size, pgprot_t prot);
 
-extern ssize_t copy_oldmem_page(unsigned long, char *, size_t,
-                                               unsigned long, int);
-extern ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf,
-                                         size_t csize, unsigned long offset,
-                                         int userbuf);
+ssize_t copy_oldmem_page(struct iov_iter *i, unsigned long pfn, size_t csize,
+               unsigned long offset);
+ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn,
+                                  size_t csize, unsigned long offset);
 
 void vmcore_cleanup(void);