linux.git/fs/ecryptfs/read_write.c, branch v6.12.80

fs/ecryptfs: Use kmap_local_page() in ecryptfs_write()

2023-07-10T12:36:10+00:00

kmap_atomic() is deprecated in favor of kmap_local_page().

Therefore, replace kmap_atomic() with kmap_local_page() in
ecryptfs_write().

kmap_atomic() is implemented like kmap_local_page() which also disables
page-faults and preemption (the latter only for !PREEMPT_RT kernels).

The code within the mapping/un-mapping in ecryptfs_write() does not
depend on the above-mentioned side effects so that a mere replacement of
the old API with the new one is all that is required (i.e., there is no
need to explicitly call pagefault_disable() and/or preempt_disable()).

Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.

Suggested-by: Ira Weiny 
Signed-off-by: "Fabio M. De Francesco" 
Message-Id: <20230426172223.8896-3-fmdefrancesco@gmail.com>
Signed-off-by: Christian Brauner

fs/ecryptfs: Replace kmap() with kmap_local_page()

2023-07-10T12:36:10+00:00

kmap() has been deprecated in favor of kmap_local_page().

Therefore, replace kmap() with kmap_local_page() in fs/ecryptfs.

There are two main problems with kmap(): (1) It comes with an overhead as
the mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap’s pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.

With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts).
It is faster than kmap() in kernels with HIGHMEM enabled. The tasks can
be preempted and, when they are scheduled to run again, the kernel
virtual addresses are restored and still valid.

Obviously, thread locality implies that the kernel virtual addresses
returned by kmap_local_page() are only valid in the context of the
callers (i.e., they cannot be handed to other threads).

The use of kmap_local_page() in fs/ecryptfs does not break the
above-mentioned assumption, so it is allowed and preferred.

Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.

Suggested-by: Ira Weiny 
Reviewed-by: Ira Weiny 
Signed-off-by: "Fabio M. De Francesco" 
Message-Id: <20230426172223.8896-2-fmdefrancesco@gmail.com>
Signed-off-by: Christian Brauner

ecryptfs: read_write: File headers do not make good candidates for kernel-doc

2021-04-19T04:42:13+00:00

Provide missing param description for 'page_index' too.

Fixes the following W=1 kernel build warning(s):

 fs/ecryptfs/read_write.c:16: warning: Incorrect use of kernel-doc format:  * ecryptfs_write_lower
 fs/ecryptfs/read_write.c:29: warning: Function parameter or member 'ecryptfs_inode' not described in 'ecryptfs_write_lower'
 fs/ecryptfs/read_write.c:29: warning: Function parameter or member 'data' not described in 'ecryptfs_write_lower'
 fs/ecryptfs/read_write.c:29: warning: Function parameter or member 'offset' not described in 'ecryptfs_write_lower'
 fs/ecryptfs/read_write.c:29: warning: Function parameter or member 'size' not described in 'ecryptfs_write_lower'
 fs/ecryptfs/read_write.c:29: warning: expecting prototype for eCryptfs(). Prototype was for ecryptfs_write_lower() instead
 fs/ecryptfs/read_write.c:248: warning: Function parameter or member 'page_index' not described in 'ecryptfs_read_lower_page_segment'

Cc: Tyler Hicks 
Cc: "Michael A. Halcrow" 
Cc: ecryptfs@vger.kernel.org
Signed-off-by: Lee Jones 
Signed-off-by: Tyler Hicks

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156

2019-05-30T18:26:35+00:00

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version this program is distributed in the
  hope that it will be useful but without any warranty without even
  the implied warranty of merchantability or fitness for a particular
  purpose see the gnu general public license for more details you
  should have received a copy of the gnu general public license along
  with this program if not write to the free software foundation inc
  59 temple place suite 330 boston ma 02111 1307 usa

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Reviewed-by: Richard Fontana 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman

fs: fix kernel_write prototype

2017-09-04T23:05:15+00:00

Make the position an in/out argument like all the other read/write
helpers and and make the buf argument a void pointer.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro

fs: fix kernel_read prototype

2017-09-04T23:05:15+00:00

Use proper ssize_t and size_t types for the return value and count
argument, move the offset last and make it an in/out argument like
all other read/write helpers, and make the buf argument a void pointer
to get rid of lots of casts in the callers.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro

sched/headers: Prepare to move signal wakeup & sigpending methods from into

2017-03-02T07:42:32+00:00

Fix up affected files that include this signal functionality via sched.h.

Acked-by: Linus Torvalds 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

2016-04-04T17:41:08+00:00

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:

 -  << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ;

 -  >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ;

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

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov 
Acked-by: Michal Hocko 
Signed-off-by: Linus Torvalds

ecryptfs: don't open-code kernel_read()

2013-05-09T17:39:58+00:00

Signed-off-by: Al Viro

export kernel_write(), convert open-coded instances

2013-02-26T07:46:11+00:00

Signed-off-by: Al Viro