The quilt patch titled
Subject: vmcore: convert __read_vmcore to use an iov_iter
has been removed from the -mm tree. Its filename was
vmcore-convert-__read_vmcore-to-use-an-iov_iter.patch
This patch was dropped because it was merged into the mm-nonmm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: vmcore: convert __read_vmcore to use an iov_iter
This gets rid of copy_to() and let us use proc_read_iter() instead of
proc_read().
Link: https://lkml.kernel.org/r/20220408090636.560886-3-bhe@xxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/vmcore.c | 82 ++++++++++++++++-----------------------------
1 file changed, 30 insertions(+), 52 deletions(-)
--- a/fs/proc/vmcore.c~vmcore-convert-__read_vmcore-to-use-an-iov_iter
+++ a/fs/proc/vmcore.c
@@ -249,22 +249,8 @@ ssize_t __weak copy_oldmem_page_encrypte
return copy_oldmem_page(iter, pfn, csize, offset);
}
-/*
- * Copy to either kernel or user space
- */
-static int copy_to(void *target, void *src, size_t size, int userbuf)
-{
- if (userbuf) {
- if (copy_to_user((char __user *) target, src, size))
- return -EFAULT;
- } else {
- memcpy(target, src, size);
- }
- return 0;
-}
-
#ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP
-static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf)
+static int vmcoredd_copy_dumps(struct iov_iter *iter, u64 start, size_t size)
{
struct vmcoredd_node *dump;
u64 offset = 0;
@@ -277,14 +263,13 @@ static int vmcoredd_copy_dumps(void *dst
if (start < offset + dump->size) {
tsz = min(offset + (u64)dump->size - start, (u64)size);
buf = dump->buf + start - offset;
- if (copy_to(dst, buf, tsz, userbuf)) {
+ if (copy_to_iter(buf, tsz, iter) < tsz) {
ret = -EFAULT;
goto out_unlock;
}
size -= tsz;
start += tsz;
- dst += tsz;
/* Leave now if buffer filled already */
if (!size)
@@ -340,33 +325,28 @@ out_unlock:
/* Read from the ELF header and then the crash dump. On error, negative value is
* returned otherwise number of bytes read are returned.
*/
-static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos,
- int userbuf)
+static ssize_t __read_vmcore(struct iov_iter *iter, loff_t *fpos)
{
ssize_t acc = 0, tmp;
size_t tsz;
u64 start;
struct vmcore *m = NULL;
- if (buflen == 0 || *fpos >= vmcore_size)
+ if (!iov_iter_count(iter) || *fpos >= vmcore_size)
return 0;
- /* trim buflen to not go beyond EOF */
- if (buflen > vmcore_size - *fpos)
- buflen = vmcore_size - *fpos;
+ iov_iter_truncate(iter, vmcore_size - *fpos);
/* Read ELF core header */
if (*fpos < elfcorebuf_sz) {
- tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen);
- if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf))
+ tsz = min(elfcorebuf_sz - (size_t)*fpos, iov_iter_count(iter));
+ if (copy_to_iter(elfcorebuf + *fpos, tsz, iter) < tsz)
return -EFAULT;
- buflen -= tsz;
*fpos += tsz;
- buffer += tsz;
acc += tsz;
/* leave now if filled buffer already */
- if (buflen == 0)
+ if (!iov_iter_count(iter))
return acc;
}
@@ -387,35 +367,32 @@ static ssize_t __read_vmcore(char *buffe
/* Read device dumps */
if (*fpos < elfcorebuf_sz + vmcoredd_orig_sz) {
tsz = min(elfcorebuf_sz + vmcoredd_orig_sz -
- (size_t)*fpos, buflen);
+ (size_t)*fpos, iov_iter_count(iter));
start = *fpos - elfcorebuf_sz;
- if (vmcoredd_copy_dumps(buffer, start, tsz, userbuf))
+ if (vmcoredd_copy_dumps(iter, start, tsz))
return -EFAULT;
- buflen -= tsz;
*fpos += tsz;
- buffer += tsz;
acc += tsz;
/* leave now if filled buffer already */
- if (!buflen)
+ if (!iov_iter_count(iter))
return acc;
}
#endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */
/* Read remaining elf notes */
- tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen);
+ tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos,
+ iov_iter_count(iter));
kaddr = elfnotes_buf + *fpos - elfcorebuf_sz - vmcoredd_orig_sz;
- if (copy_to(buffer, kaddr, tsz, userbuf))
+ if (copy_to_iter(kaddr, tsz, iter) < tsz)
return -EFAULT;
- buflen -= tsz;
*fpos += tsz;
- buffer += tsz;
acc += tsz;
/* leave now if filled buffer already */
- if (buflen == 0)
+ if (!iov_iter_count(iter))
return acc;
}
@@ -423,19 +400,17 @@ static ssize_t __read_vmcore(char *buffe
if (*fpos < m->offset + m->size) {
tsz = (size_t)min_t(unsigned long long,
m->offset + m->size - *fpos,
- buflen);
+ iov_iter_count(iter));
start = m->paddr + *fpos - m->offset;
- tmp = read_from_oldmem(buffer, tsz, &start,
- userbuf, cc_platform_has(CC_ATTR_MEM_ENCRYPT));
+ tmp = read_from_oldmem_iter(iter, tsz, &start,
+ cc_platform_has(CC_ATTR_MEM_ENCRYPT));
if (tmp < 0)
return tmp;
- buflen -= tsz;
*fpos += tsz;
- buffer += tsz;
acc += tsz;
/* leave now if filled buffer already */
- if (buflen == 0)
+ if (!iov_iter_count(iter))
return acc;
}
}
@@ -443,15 +418,14 @@ static ssize_t __read_vmcore(char *buffe
return acc;
}
-static ssize_t read_vmcore(struct file *file, char __user *buffer,
- size_t buflen, loff_t *fpos)
+static ssize_t read_vmcore(struct kiocb *iocb, struct iov_iter *iter)
{
- return __read_vmcore((__force char *) buffer, buflen, fpos, 1);
+ return __read_vmcore(iter, &iocb->ki_pos);
}
/*
* The vmcore fault handler uses the page cache and fills data using the
- * standard __vmcore_read() function.
+ * standard __read_vmcore() function.
*
* On s390 the fault handler is used for memory regions that can't be mapped
* directly with remap_pfn_range().
@@ -461,9 +435,10 @@ static vm_fault_t mmap_vmcore_fault(stru
#ifdef CONFIG_S390
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
pgoff_t index = vmf->pgoff;
+ struct iov_iter iter;
+ struct kvec kvec;
struct page *page;
loff_t offset;
- char *buf;
int rc;
page = find_or_create_page(mapping, index, GFP_KERNEL);
@@ -471,8 +446,11 @@ static vm_fault_t mmap_vmcore_fault(stru
return VM_FAULT_OOM;
if (!PageUptodate(page)) {
offset = (loff_t) index << PAGE_SHIFT;
- buf = __va((page_to_pfn(page) << PAGE_SHIFT));
- rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0);
+ kvec.iov_base = page_address(page);
+ kvec.iov_len = PAGE_SIZE;
+ iov_iter_kvec(&iter, READ, &kvec, 1, PAGE_SIZE);
+
+ rc = __read_vmcore(&iter, &offset);
if (rc < 0) {
unlock_page(page);
put_page(page);
@@ -722,7 +700,7 @@ static int mmap_vmcore(struct file *file
static const struct proc_ops vmcore_proc_ops = {
.proc_open = open_vmcore,
- .proc_read = read_vmcore,
+ .proc_read_iter = read_vmcore,
.proc_lseek = default_llseek,
.proc_mmap = mmap_vmcore,
};
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
shmem-convert-shmem_alloc_hugepage-to-use-vma_alloc_folio.patch
mm-huge_memory-convert-do_huge_pmd_anonymous_page-to-use-vma_alloc_folio.patch
alpha-fix-alloc_zeroed_user_highpage_movable.patch
mm-remove-alloc_pages_vma.patch
vmscan-use-folio_mapped-in-shrink_page_list.patch
vmscan-convert-the-writeback-handling-in-shrink_page_list-to-folios.patch
swap-turn-get_swap_page-into-folio_alloc_swap.patch
swap-convert-add_to_swap-to-take-a-folio.patch
vmscan-convert-dirty-page-handling-to-folios.patch
vmscan-convert-page-buffer-handling-to-use-folios.patch
vmscan-convert-lazy-freeing-to-folios.patch
vmscan-move-initialisation-of-mapping-down.patch
vmscan-convert-the-activate_locked-portion-of-shrink_page_list-to-folios.patch
mm-allow-can_split_folio-to-be-called-when-thp-are-disabled.patch
vmscan-remove-remaining-uses-of-page-in-shrink_page_list.patch
mm-shmem-use-a-folio-in-shmem_unused_huge_shrink.patch
mm-swap-add-folio_throttle_swaprate.patch
mm-shmem-convert-shmem_add_to_page_cache-to-take-a-folio.patch
mm-shmem-turn-shmem_should_replace_page-into-shmem_should_replace_folio.patch
mm-shmem-add-shmem_alloc_folio.patch
mm-shmem-convert-shmem_alloc_and_acct_page-to-use-a-folio.patch
mm-shmem-convert-shmem_getpage_gfp-to-use-a-folio.patch
mm-shmem-convert-shmem_swapin_page-to-shmem_swapin_folio.patch
mm-add-folio_mapping_flags.patch
mm-add-folio_test_movable.patch
mm-migrate-convert-move_to_new_page-into-move_to_new_folio.patch
mm-add-vma-iterator.patch
mmap-use-the-vma-iterator-in-count_vma_pages_range.patch
proc-remove-vma-rbtree-use-from-nommu.patch
arm64-remove-mmap-linked-list-from-vdso.patch
parisc-remove-mmap-linked-list-from-cache-handling.patch
powerpc-remove-mmap-linked-list-walks.patch
s390-remove-vma-linked-list-walks.patch
x86-remove-vma-linked-list-walks.patch
xtensa-remove-vma-linked-list-walks.patch
cxl-remove-vma-linked-list-walk.patch
optee-remove-vma-linked-list-walk.patch
um-remove-vma-linked-list-walk.patch
coredump-remove-vma-linked-list-walk.patch
exec-use-vma-iterator-instead-of-linked-list.patch
fs-proc-task_mmu-stop-using-linked-list-and-highest_vm_end.patch
acct-use-vma-iterator-instead-of-linked-list.patch
perf-use-vma-iterator.patch
sched-use-maple-tree-iterator-to-walk-vmas.patch
fork-use-vma-iterator.patch
mm-khugepaged-stop-using-vma-linked-list.patch
mm-ksm-use-vma-iterators-instead-of-vma-linked-list.patch
mm-mlock-use-vma-iterator-and-maple-state-instead-of-vma-linked-list.patch
mm-pagewalk-use-vma_find-instead-of-vma-linked-list.patch
i915-use-the-vma-iterator.patch
nommu-remove-uses-of-vma-linked-list.patch
