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Date: Fri, 19 Mar 2021 15:34:52 +0100
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: linux-mm@...ck.org, David Hildenbrand <david@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Hillf Danton <hdanton@...a.com>,
Michal Hocko <mhocko@...e.com>,
Matthew Wilcox <willy@...radead.org>,
Oleksiy Avramchenko <oleksiy.avramchenko@...ymobile.com>,
Steven Rostedt <rostedt@...dmis.org>,
Minchan Kim <minchan@...nel.org>,
huang ying <huang.ying.caritas@...il.com>
Subject: [PATCH RFC 3/3] mm/vmalloc: remove vwrite()
The last user (/dev/kmem) is gone. Let's drop it.
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Hillf Danton <hdanton@...a.com>
Cc: Michal Hocko <mhocko@...e.com>
Cc: Matthew Wilcox <willy@...radead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@...ymobile.com>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: Minchan Kim <minchan@...nel.org>
Cc: huang ying <huang.ying.caritas@...il.com>
Signed-off-by: David Hildenbrand <david@...hat.com>
---
include/linux/vmalloc.h | 1 -
mm/vmalloc.c | 111 ----------------------------------------
2 files changed, 112 deletions(-)
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 390af680e916..9c1b17c7dd95 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -200,7 +200,6 @@ static inline void set_vm_flush_reset_perms(void *addr)
/* for /proc/kcore */
extern long vread(char *buf, char *addr, unsigned long count);
-extern long vwrite(char *buf, char *addr, unsigned long count);
/*
* Internals. Dont't use..
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index ccb405b82581..07a39881f9d6 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2820,43 +2820,6 @@ static int aligned_vread(char *buf, char *addr, unsigned long count)
return copied;
}
-static int aligned_vwrite(char *buf, char *addr, unsigned long count)
-{
- struct page *p;
- int copied = 0;
-
- while (count) {
- unsigned long offset, length;
-
- offset = offset_in_page(addr);
- length = PAGE_SIZE - offset;
- if (length > count)
- length = count;
- p = vmalloc_to_page(addr);
- /*
- * To do safe access to this _mapped_ area, we need
- * lock. But adding lock here means that we need to add
- * overhead of vmalloc()/vfree() calles for this _debug_
- * interface, rarely used. Instead of that, we'll use
- * kmap() and get small overhead in this access function.
- */
- if (p) {
- /*
- * we can expect USER0 is not used (see vread/vwrite's
- * function description)
- */
- void *map = kmap_atomic(p);
- memcpy(map + offset, buf, length);
- kunmap_atomic(map);
- }
- addr += length;
- buf += length;
- copied += length;
- count -= length;
- }
- return copied;
-}
-
/**
* vread() - read vmalloc area in a safe way.
* @buf: buffer for reading data
@@ -2936,80 +2899,6 @@ long vread(char *buf, char *addr, unsigned long count)
return buflen;
}
-/**
- * vwrite() - write vmalloc area in a safe way.
- * @buf: buffer for source data
- * @addr: vm address.
- * @count: number of bytes to be read.
- *
- * This function checks that addr is a valid vmalloc'ed area, and
- * copy data from a buffer to the given addr. If specified range of
- * [addr...addr+count) includes some valid address, data is copied from
- * proper area of @buf. If there are memory holes, no copy to hole.
- * IOREMAP area is treated as memory hole and no copy is done.
- *
- * If [addr...addr+count) doesn't includes any intersects with alive
- * vm_struct area, returns 0. @buf should be kernel's buffer.
- *
- * Note: In usual ops, vwrite() is never necessary because the caller
- * should know vmalloc() area is valid and can use memcpy().
- * This is for routines which have to access vmalloc area without
- * any information, as /dev/kmem.
- *
- * Return: number of bytes for which addr and buf should be
- * increased (same number as @count) or %0 if [addr...addr+count)
- * doesn't include any intersection with valid vmalloc area
- */
-long vwrite(char *buf, char *addr, unsigned long count)
-{
- struct vmap_area *va;
- struct vm_struct *vm;
- char *vaddr;
- unsigned long n, buflen;
- int copied = 0;
-
- /* Don't allow overflow */
- if ((unsigned long) addr + count < count)
- count = -(unsigned long) addr;
- buflen = count;
-
- spin_lock(&vmap_area_lock);
- list_for_each_entry(va, &vmap_area_list, list) {
- if (!count)
- break;
-
- if (!va->vm)
- continue;
-
- vm = va->vm;
- vaddr = (char *) vm->addr;
- if (addr >= vaddr + get_vm_area_size(vm))
- continue;
- while (addr < vaddr) {
- if (count == 0)
- goto finished;
- buf++;
- addr++;
- count--;
- }
- n = vaddr + get_vm_area_size(vm) - addr;
- if (n > count)
- n = count;
- if (!(vm->flags & VM_IOREMAP)) {
- aligned_vwrite(buf, addr, n);
- copied++;
- }
- buf += n;
- addr += n;
- count -= n;
- }
-finished:
- spin_unlock(&vmap_area_lock);
- if (!copied)
- return 0;
- return buflen;
-}
-
/**
* remap_vmalloc_range_partial - map vmalloc pages to userspace
* @vma: vma to cover
--
2.29.2
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