[PATCH] btrfs: use list_for_each_entry_safe() when delete items

2013-09-01 Thread Azat Khuzhin 
Replace list_for_each_entry() by list_for_each_entry_safe() in
__btrfs_close_devices()

list_for_each_entry() {
list_replace_rcu();
call_rcu(); --We may free the device, if we get next
   device by the current one, the page fault
   may happen.
}

Signed-off-by: Azat Khuzhin a3at.m...@gmail.com
Reviewed-by: Miao Xie mi...@cn.fujitsu.com
---
V2: Add some comments from Miao into commit message

 fs/btrfs/volumes.c |4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 78b8717..1d1b595 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -616,13 +616,13 @@ static void free_device(struct rcu_head *head)
 
 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 {
-   struct btrfs_device *device;
+   struct btrfs_device *device, *next;
 
if (--fs_devices-opened  0)
return 0;
 
mutex_lock(fs_devices-device_list_mutex);
-   list_for_each_entry(device, fs_devices-devices, dev_list) {
+   list_for_each_entry_safe(device, next, fs_devices-devices, dev_list) {
struct btrfs_device *new_device;
struct rcu_string *name;
 
-- 
1.7.10.4

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Re: [PATCH] btrfs: use list_for_each_entry_safe() when delete items

2013-08-31 Thread Azat Khuzhin 
On Tue, Jul 30, 2013 at 7:40 AM, Miao Xie mi...@cn.fujitsu.com wrote:
 On mon, 29 Jul 2013 11:48:32 +0400, Azat Khuzhin wrote:
 On Sat, Jul 27, 2013 at 2:12 PM, Azat Khuzhin a3at.m...@gmail.com wrote:
 Replace list_for_each_entry() by list_for_each_entry_safe() in
 __btrfs_close_devices()

 There is another place that delete items lock_stripe_add(), but there we
 don't need safe version, because after deleting we exit from loop.

 Signed-off-by: Azat Khuzhin a3at.m...@gmail.com
 ---
  fs/btrfs/volumes.c |4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

 diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
 index 78b8717..1d1b595 100644
 --- a/fs/btrfs/volumes.c
 +++ b/fs/btrfs/volumes.c
 @@ -616,13 +616,13 @@ static void free_device(struct rcu_head *head)

  static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
  {
 -   struct btrfs_device *device;
 +   struct btrfs_device *device, *next;

 if (--fs_devices-opened  0)
 return 0;

 mutex_lock(fs_devices-device_list_mutex);
 -   list_for_each_entry(device, fs_devices-devices, dev_list) {
 +   list_for_each_entry_safe(device, next, fs_devices-devices, 
 dev_list) {
 struct btrfs_device *new_device;
 struct rcu_string *name;

 There is kfree(device); at the end of loop, maybe there must goto
 again; after it?
 (instead of this patch)

Ugh. I was looking into another function!


 Your fix is right, we needn't search from the head once again.

 The other fix way is:
 call_rcu(device-rcu, free_device);
 +   device = new_device;
  }
 but from the viewpoint of the readability, this way is not so good.

 Reviewed-by: Miao Xie mi...@cn.fujitsu.com

Thanks!
Miao, should I resend patch with you reviewed-by?




 --
 1.7.10.4








-- 
Respectfully
Azat Khuzhin
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Re: [PATCH] btrfs: use list_for_each_entry_safe() when delete items

2013-07-29 Thread Azat Khuzhin 
On Sat, Jul 27, 2013 at 2:12 PM, Azat Khuzhin a3at.m...@gmail.com wrote:
 Replace list_for_each_entry() by list_for_each_entry_safe() in
 __btrfs_close_devices()

 There is another place that delete items lock_stripe_add(), but there we
 don't need safe version, because after deleting we exit from loop.

 Signed-off-by: Azat Khuzhin a3at.m...@gmail.com
 ---
  fs/btrfs/volumes.c |4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

 diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
 index 78b8717..1d1b595 100644
 --- a/fs/btrfs/volumes.c
 +++ b/fs/btrfs/volumes.c
 @@ -616,13 +616,13 @@ static void free_device(struct rcu_head *head)

  static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
  {
 -   struct btrfs_device *device;
 +   struct btrfs_device *device, *next;

 if (--fs_devices-opened  0)
 return 0;

 mutex_lock(fs_devices-device_list_mutex);
 -   list_for_each_entry(device, fs_devices-devices, dev_list) {
 +   list_for_each_entry_safe(device, next, fs_devices-devices, 
 dev_list) {
 struct btrfs_device *new_device;
 struct rcu_string *name;

There is kfree(device); at the end of loop, maybe there must goto
again; after it?
(instead of this patch)


 --
 1.7.10.4




-- 
Respectfully
Azat Khuzhin
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Re: [PATCH] btrfs: use list_for_each_entry_safe() when delete items

2013-07-29 Thread Miao Xie 
On mon, 29 Jul 2013 11:48:32 +0400, Azat Khuzhin wrote:
 On Sat, Jul 27, 2013 at 2:12 PM, Azat Khuzhin a3at.m...@gmail.com wrote:
 Replace list_for_each_entry() by list_for_each_entry_safe() in
 __btrfs_close_devices()

 There is another place that delete items lock_stripe_add(), but there we
 don't need safe version, because after deleting we exit from loop.

 Signed-off-by: Azat Khuzhin a3at.m...@gmail.com
 ---
  fs/btrfs/volumes.c |4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

 diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
 index 78b8717..1d1b595 100644
 --- a/fs/btrfs/volumes.c
 +++ b/fs/btrfs/volumes.c
 @@ -616,13 +616,13 @@ static void free_device(struct rcu_head *head)

  static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
  {
 -   struct btrfs_device *device;
 +   struct btrfs_device *device, *next;

 if (--fs_devices-opened  0)
 return 0;

 mutex_lock(fs_devices-device_list_mutex);
 -   list_for_each_entry(device, fs_devices-devices, dev_list) {
 +   list_for_each_entry_safe(device, next, fs_devices-devices, 
 dev_list) {
 struct btrfs_device *new_device;
 struct rcu_string *name;
 
 There is kfree(device); at the end of loop, maybe there must goto
 again; after it?
 (instead of this patch)

Your fix is right, we needn't search from the head once again.

The other fix way is:
call_rcu(device-rcu, free_device);
+   device = new_device;
 }
but from the viewpoint of the readability, this way is not so good.

Reviewed-by: Miao Xie mi...@cn.fujitsu.com

 

 --
 1.7.10.4

 
 
 

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[PATCH] btrfs: use list_for_each_entry_safe() when delete items

2013-07-27 Thread Azat Khuzhin 
Replace list_for_each_entry() by list_for_each_entry_safe() in
__btrfs_close_devices()

There is another place that delete items lock_stripe_add(), but there we
don't need safe version, because after deleting we exit from loop.

Signed-off-by: Azat Khuzhin a3at.m...@gmail.com
---
 fs/btrfs/volumes.c |4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 78b8717..1d1b595 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -616,13 +616,13 @@ static void free_device(struct rcu_head *head)
 
 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 {
-   struct btrfs_device *device;
+   struct btrfs_device *device, *next;
 
if (--fs_devices-opened  0)
return 0;
 
mutex_lock(fs_devices-device_list_mutex);
-   list_for_each_entry(device, fs_devices-devices, dev_list) {
+   list_for_each_entry_safe(device, next, fs_devices-devices, dev_list) {
struct btrfs_device *new_device;
struct rcu_string *name;
 
-- 
1.7.10.4

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[PATCH] btrfs: use list_for_each_entry_safe() when delete items

2013-07-26 Thread Azat Khuzhin 
Replace list_for_each_entry() by list_for_each_entry_safe() in next
functions:
- lock_stripe_add()
- __btrfs_close_devices()

Signed-off-by: Azat Khuzhin a3at.m...@gmail.com
---
 fs/btrfs/raid56.c  |4 ++--
 fs/btrfs/volumes.c |4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
index 0525e13..37e6dc9 100644
--- a/fs/btrfs/raid56.c
+++ b/fs/btrfs/raid56.c
@@ -636,7 +636,7 @@ static noinline int lock_stripe_add(struct btrfs_raid_bio 
*rbio)
 {
int bucket = rbio_bucket(rbio);
struct btrfs_stripe_hash *h = rbio-fs_info-stripe_hash_table-table + 
bucket;
-   struct btrfs_raid_bio *cur;
+   struct btrfs_raid_bio *cur, *next;
struct btrfs_raid_bio *pending;
unsigned long flags;
DEFINE_WAIT(wait);
@@ -646,7 +646,7 @@ static noinline int lock_stripe_add(struct btrfs_raid_bio 
*rbio)
int walk = 0;
 
spin_lock_irqsave(h-lock, flags);
-   list_for_each_entry(cur, h-hash_list, hash_list) {
+   list_for_each_entry_safe(cur, next, h-hash_list, hash_list) {
walk++;
if (cur-raid_map[0] == rbio-raid_map[0]) {
spin_lock(cur-bio_list_lock);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 78b8717..1d1b595 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -616,13 +616,13 @@ static void free_device(struct rcu_head *head)
 
 static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
 {
-   struct btrfs_device *device;
+   struct btrfs_device *device, *next;
 
if (--fs_devices-opened  0)
return 0;
 
mutex_lock(fs_devices-device_list_mutex);
-   list_for_each_entry(device, fs_devices-devices, dev_list) {
+   list_for_each_entry_safe(device, next, fs_devices-devices, dev_list) {
struct btrfs_device *new_device;
struct rcu_string *name;
 
-- 
1.7.10.4

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