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Groups > linux.kernel > #1500020
| From | Lorenzo Stoakes <lstoakes@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 09/10] mm: replace access_remote_vm() write parameter with gup_flags |
| Date | 2016-10-13 06:10 +0200 |
| Message-ID | <srFvb-6Bm-5@gated-at.bofh.it> (permalink) |
| References | <srC4h-3JZ-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
This patch removes the write parameter from access_remote_vm() and replaces it
with a gup_flags parameter as use of this function previously _implied_
FOLL_FORCE, whereas after this patch callers explicitly pass this flag.
We make this explicit as use of FOLL_FORCE can result in surprising behaviour
(and hence bugs) within the mm subsystem.
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
---
fs/proc/base.c | 19 +++++++++++++------
include/linux/mm.h | 2 +-
mm/memory.c | 11 +++--------
mm/nommu.c | 7 +++----
4 files changed, 20 insertions(+), 19 deletions(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index c2964d8..8e65446 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -252,7 +252,7 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
* Inherently racy -- command line shares address space
* with code and data.
*/
- rv = access_remote_vm(mm, arg_end - 1, &c, 1, 0);
+ rv = access_remote_vm(mm, arg_end - 1, &c, 1, FOLL_FORCE);
if (rv <= 0)
goto out_free_page;
@@ -270,7 +270,8 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
int nr_read;
_count = min3(count, len, PAGE_SIZE);
- nr_read = access_remote_vm(mm, p, page, _count, 0);
+ nr_read = access_remote_vm(mm, p, page, _count,
+ FOLL_FORCE);
if (nr_read < 0)
rv = nr_read;
if (nr_read <= 0)
@@ -305,7 +306,8 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
bool final;
_count = min3(count, len, PAGE_SIZE);
- nr_read = access_remote_vm(mm, p, page, _count, 0);
+ nr_read = access_remote_vm(mm, p, page, _count,
+ FOLL_FORCE);
if (nr_read < 0)
rv = nr_read;
if (nr_read <= 0)
@@ -354,7 +356,8 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf,
bool final;
_count = min3(count, len, PAGE_SIZE);
- nr_read = access_remote_vm(mm, p, page, _count, 0);
+ nr_read = access_remote_vm(mm, p, page, _count,
+ FOLL_FORCE);
if (nr_read < 0)
rv = nr_read;
if (nr_read <= 0)
@@ -832,6 +835,7 @@ static ssize_t mem_rw(struct file *file, char __user *buf,
unsigned long addr = *ppos;
ssize_t copied;
char *page;
+ unsigned int flags = FOLL_FORCE;
if (!mm)
return 0;
@@ -844,6 +848,9 @@ static ssize_t mem_rw(struct file *file, char __user *buf,
if (!atomic_inc_not_zero(&mm->mm_users))
goto free;
+ if (write)
+ flags |= FOLL_WRITE;
+
while (count > 0) {
int this_len = min_t(int, count, PAGE_SIZE);
@@ -852,7 +859,7 @@ static ssize_t mem_rw(struct file *file, char __user *buf,
break;
}
- this_len = access_remote_vm(mm, addr, page, this_len, write);
+ this_len = access_remote_vm(mm, addr, page, this_len, flags);
if (!this_len) {
if (!copied)
copied = -EIO;
@@ -965,7 +972,7 @@ static ssize_t environ_read(struct file *file, char __user *buf,
this_len = min(max_len, this_len);
retval = access_remote_vm(mm, (env_start + src),
- page, this_len, 0);
+ page, this_len, FOLL_FORCE);
if (retval <= 0) {
ret = retval;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 2a481d3..3e5234e 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1268,7 +1268,7 @@ static inline int fixup_user_fault(struct task_struct *tsk,
extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
- void *buf, int len, int write);
+ void *buf, int len, unsigned int gup_flags);
long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
diff --git a/mm/memory.c b/mm/memory.c
index 79ebed3..bac2d99 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3935,19 +3935,14 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
* @addr: start address to access
* @buf: source or destination buffer
* @len: number of bytes to transfer
- * @write: whether the access is a write
+ * @gup_flags: flags modifying lookup behaviour
*
* The caller must hold a reference on @mm.
*/
int access_remote_vm(struct mm_struct *mm, unsigned long addr,
- void *buf, int len, int write)
+ void *buf, int len, unsigned int gup_flags)
{
- unsigned int flags = FOLL_FORCE;
-
- if (write)
- flags |= FOLL_WRITE;
-
- return __access_remote_vm(NULL, mm, addr, buf, len, flags);
+ return __access_remote_vm(NULL, mm, addr, buf, len, gup_flags);
}
/*
diff --git a/mm/nommu.c b/mm/nommu.c
index bde7df3..93d5bb5 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1847,15 +1847,14 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
* @addr: start address to access
* @buf: source or destination buffer
* @len: number of bytes to transfer
- * @write: whether the access is a write
+ * @gup_flags: flags modifying lookup behaviour
*
* The caller must hold a reference on @mm.
*/
int access_remote_vm(struct mm_struct *mm, unsigned long addr,
- void *buf, int len, int write)
+ void *buf, int len, unsigned int gup_flags)
{
- return __access_remote_vm(NULL, mm, addr, buf, len,
- write ? FOLL_WRITE : 0);
+ return __access_remote_vm(NULL, mm, addr, buf, len, gup_flags);
}
/*
--
2.10.0
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
[PATCH 00/10] mm: adjust get_user_pages* functions to explicitly pass FOLL_* flags Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-13 02:30 +0200
[PATCH 02/10] mm: remove write/force parameters from __get_user_pages_unlocked() Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-13 02:30 +0200
Re: [PATCH 02/10] mm: remove write/force parameters from __get_user_pages_unlocked() Paolo Bonzini <pbonzini@redhat.com> - 2016-10-13 09:00 +0200
Re: [PATCH 02/10] mm: remove write/force parameters from __get_user_pages_unlocked() Jan Kara <jack@suse.cz> - 2016-10-18 14:50 +0200
[PATCH 03/10] mm: replace get_user_pages_unlocked() write/force parameters with gup_flags Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-13 02:30 +0200
Re: [PATCH 03/10] mm: replace get_user_pages_unlocked() write/force parameters with gup_flags Jan Kara <jack@suse.cz> - 2016-10-18 15:00 +0200
[PATCH 07/10] mm: replace get_user_pages_remote() write/force parameters with gup_flags Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-13 05:00 +0200
Re: [PATCH 07/10] mm: replace get_user_pages_remote() write/force parameters with gup_flags Jan Kara <jack@suse.cz> - 2016-10-19 11:10 +0200
[PATCH 09/10] mm: replace access_remote_vm() write parameter with gup_flags Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-13 06:10 +0200
[PATCH 08/10] mm: replace __access_remote_vm() write parameter with gup_flags Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-13 06:20 +0200
Re: [PATCH 08/10] mm: replace __access_remote_vm() write parameter with gup_flags Michal Hocko <mhocko@kernel.org> - 2016-10-19 11:10 +0200
Re: [PATCH 08/10] mm: replace __access_remote_vm() write parameter with gup_flags Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-19 16:50 +0200
Re: [PATCH 08/10] mm: replace __access_remote_vm() write parameter with gup_flags Michal Hocko <mhocko@kernel.org> - 2016-10-19 18:10 +0200
Re: [PATCH 08/10] mm: replace __access_remote_vm() write parameter with gup_flags Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-19 16:30 +0200
Re: [PATCH 08/10] mm: replace __access_remote_vm() write parameter with gup_flags Jan Kara <jack@suse.cz> - 2016-10-19 16:50 +0200
Re: [PATCH 08/10] mm: replace __access_remote_vm() write parameter with gup_flags Michal Hocko <mhocko@kernel.org> - 2016-10-19 18:30 +0200
[PATCH 05/10] mm: replace get_vaddr_frames() write/force parameters with gup_flags Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-13 06:20 +0200
Re: [PATCH 05/10] mm: replace get_vaddr_frames() write/force parameters with gup_flags Jan Kara <jack@suse.cz> - 2016-10-19 18:30 +0200
[PATCH 10/10] mm: replace access_process_vm() write parameter with gup_flags Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-13 06:40 +0200
Re: [PATCH 10/10] mm: replace access_process_vm() write parameter with gup_flags Jesper Nilsson <jesper.nilsson@axis.com> - 2016-10-17 11:30 +0200
[PATCH 06/10] mm: replace get_user_pages() write/force parameters with gup_flags Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-13 06:40 +0200
Re: [PATCH 06/10] mm: replace get_user_pages() write/force parameters with gup_flags Jesper Nilsson <jesper.nilsson@axis.com> - 2016-10-17 11:30 +0200
Re: [PATCH 06/10] mm: replace get_user_pages() write/force parameters with gup_flags Jan Kara <jack@suse.cz> - 2016-10-19 11:10 +0200
[PATCH 04/10] mm: replace get_user_pages_locked() write/force parameters with gup_flags Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-13 08:10 +0200
Re: [PATCH 04/10] mm: replace get_user_pages_locked() write/force parameters with gup_flags Jan Kara <jack@suse.cz> - 2016-10-18 15:00 +0200
Re: [PATCH 04/10] mm: replace get_user_pages_locked() write/force parameters with gup_flags Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-18 16:00 +0200
Re: [PATCH 04/10] mm: replace get_user_pages_locked() write/force parameters with gup_flags Jan Kara <jack@suse.cz> - 2016-10-19 09:40 +0200
Re: [PATCH 04/10] mm: replace get_user_pages_locked() write/force parameters with gup_flags Jan Kara <jack@suse.cz> - 2016-10-19 17:30 +0200
Re: [PATCH 00/10] mm: adjust get_user_pages* functions to explicitly pass FOLL_* flags Michal Hocko <mhocko@kernel.org> - 2016-10-18 17:40 +0200
Re: [PATCH 00/10] mm: adjust get_user_pages* functions to explicitly pass FOLL_* flags Michal Hocko <mhocko@kernel.org> - 2016-10-19 16:20 +0200
Re: [PATCH 00/10] mm: adjust get_user_pages* functions to explicitly pass FOLL_* flags Dave Hansen <dave.hansen@linux.intel.com> - 2016-10-19 19:00 +0200
Re: [PATCH 00/10] mm: adjust get_user_pages* functions to explicitly pass FOLL_* flags Michal Hocko <mhocko@kernel.org> - 2016-10-19 19:10 +0200
Re: [PATCH 00/10] mm: adjust get_user_pages* functions to explicitly pass FOLL_* flags Dave Hansen <dave.hansen@linux.intel.com> - 2016-10-19 19:30 +0200
Re: [PATCH 00/10] mm: adjust get_user_pages* functions to explicitly pass FOLL_* flags Michal Hocko <mhocko@kernel.org> - 2016-10-20 21:30 +0200
Re: [PATCH 00/10] mm: adjust get_user_pages* functions to explicitly pass FOLL_* flags Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-19 18:20 +0200
Re: [PATCH 00/10] mm: adjust get_user_pages* functions to explicitly pass FOLL_* flags Lorenzo Stoakes <lstoakes@gmail.com> - 2016-10-26 11:00 +0200
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