From: David Hildenbrand <david@xxxxxxxxxx> Subject: mm/vmalloc: remove vwrite() The last user (/dev/kmem) is gone. Let's drop it. Link: https://lkml.kernel.org/r/20210324102351.6932-4-david@xxxxxxxxxx Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: Hillf Danton <hdanton@xxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@xxxxxxxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Minchan Kim <minchan@xxxxxxxxxx> Cc: huang ying <huang.ying.caritas@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/vmalloc.h | 1 mm/nommu.c | 10 --- mm/vmalloc.c | 116 -------------------------------------- 3 files changed, 1 insertion(+), 126 deletions(-) --- a/include/linux/vmalloc.h~mm-vmalloc-remove-vwrite +++ a/include/linux/vmalloc.h @@ -229,7 +229,6 @@ static inline void set_vm_flush_reset_pe /* 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.. --- a/mm/nommu.c~mm-vmalloc-remove-vwrite +++ a/mm/nommu.c @@ -210,16 +210,6 @@ long vread(char *buf, char *addr, unsign return count; } -long vwrite(char *buf, char *addr, unsigned long count) -{ - /* Don't allow overflow */ - if ((unsigned long) addr + count < count) - count = -(unsigned long) addr; - - memcpy(addr, buf, count); - return count; -} - /* * vmalloc - allocate virtually contiguous memory * --- a/mm/vmalloc.c~mm-vmalloc-remove-vwrite +++ a/mm/vmalloc.c @@ -3146,10 +3146,7 @@ static int aligned_vread(char *buf, char * kmap() and get small overhead in this access function. */ if (p) { - /* - * we can expect USER0 is not used (see vread/vwrite's - * function description) - */ + /* We can expect USER0 is not used -- see vread() */ void *map = kmap_atomic(p); memcpy(buf, map + offset, length); kunmap_atomic(map); @@ -3164,43 +3161,6 @@ static int aligned_vread(char *buf, char 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 @@ -3283,80 +3243,6 @@ finished: 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 _
