lkml.org 
[lkml]   [2016]   [Mar]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 68/71] uprobes: get rid of PAGE_CACHE_* and page_cache_{get,release} macros
Date
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago
with promise that one day it will be possible to implement page cache with
bigger chunks than PAGE_SIZE.

This promise never materialized. And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_*
or PAGE_* constant should be used in a particular case, especially on the
border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special. They are not.

The changes are pretty straight-forward:

- <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

- PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

- page_cache_get() -> get_page();

- page_cache_release() -> put_page();

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
---
kernel/events/uprobes.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 5f6ce931f1ea..9be1cba0eb11 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -321,7 +321,7 @@ retry:
copy_to_page(new_page, vaddr, &opcode, UPROBE_SWBP_INSN_SIZE);

ret = __replace_page(vma, vaddr, old_page, new_page);
- page_cache_release(new_page);
+ put_page(new_page);
put_old:
put_page(old_page);

@@ -539,14 +539,14 @@ static int __copy_insn(struct address_space *mapping, struct file *filp,
* see uprobe_register().
*/
if (mapping->a_ops->readpage)
- page = read_mapping_page(mapping, offset >> PAGE_CACHE_SHIFT, filp);
+ page = read_mapping_page(mapping, offset >> PAGE_SHIFT, filp);
else
- page = shmem_read_mapping_page(mapping, offset >> PAGE_CACHE_SHIFT);
+ page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT);
if (IS_ERR(page))
return PTR_ERR(page);

copy_from_page(page, offset, insn, nbytes);
- page_cache_release(page);
+ put_page(page);

return 0;
}
--
2.7.0
\
 
 \ /
  Last update: 2016-03-20 20:21    [W:0.302 / U:0.200 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site