From: Hou Tao <[email protected]>
__hash_remove() removes hash_cell with _hash_lock locked, so acquiring
_hash_lock can guarantee no-NULL hc returned from dm_get_mdptr() must
have not been removed and hc->md must still be md.
__hash_remove() also acquires dm_hash_cells_mutex before setting mdptr
as NULL, so in dm_copy_name_and_uuid() after acquiring
dm_hash_cells_mutex and ensuring returned hc is not NULL, the returned
hc must still be alive and hc->md must still be md.
So removing these unnecessary hc->md != md checks when using
dm_get_mdptr() with _hash_lock or dm_hash_cells_mutex acquired.
Signed-off-by: Hou Tao <[email protected]>
---
drivers/md/dm-ioctl.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 3bfc1583c20a..2a86524661d1 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -772,7 +772,7 @@ static struct dm_table *dm_get_inactive_table(struct mapped_device *md, int *src
down_read(&_hash_lock);
hc = dm_get_mdptr(md);
- if (!hc || hc->md != md) {
+ if (!hc) {
DMERR("device has been removed from the dev hash table.");
goto out;
}
@@ -1476,7 +1476,7 @@ static int table_load(struct file *filp, struct dm_ioctl *param, size_t param_si
/* stage inactive table */
down_write(&_hash_lock);
hc = dm_get_mdptr(md);
- if (!hc || hc->md != md) {
+ if (!hc) {
DMERR("device has been removed from the dev hash table.");
up_write(&_hash_lock);
r = -ENXIO;
@@ -2128,7 +2128,7 @@ int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
mutex_lock(&dm_hash_cells_mutex);
hc = dm_get_mdptr(md);
- if (!hc || hc->md != md) {
+ if (!hc) {
r = -ENXIO;
goto out;
}
--
2.29.2
ping ?
On 12/16/2022 12:23 PM, Hou Tao wrote:
> From: Hou Tao <[email protected]>
>
> __hash_remove() removes hash_cell with _hash_lock locked, so acquiring
> _hash_lock can guarantee no-NULL hc returned from dm_get_mdptr() must
> have not been removed and hc->md must still be md.
>
> __hash_remove() also acquires dm_hash_cells_mutex before setting mdptr
> as NULL, so in dm_copy_name_and_uuid() after acquiring
> dm_hash_cells_mutex and ensuring returned hc is not NULL, the returned
> hc must still be alive and hc->md must still be md.
>
> So removing these unnecessary hc->md != md checks when using
> dm_get_mdptr() with _hash_lock or dm_hash_cells_mutex acquired.
>
> Signed-off-by: Hou Tao <[email protected]>
> ---
> drivers/md/dm-ioctl.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
> index 3bfc1583c20a..2a86524661d1 100644
> --- a/drivers/md/dm-ioctl.c
> +++ b/drivers/md/dm-ioctl.c
> @@ -772,7 +772,7 @@ static struct dm_table *dm_get_inactive_table(struct mapped_device *md, int *src
>
> down_read(&_hash_lock);
> hc = dm_get_mdptr(md);
> - if (!hc || hc->md != md) {
> + if (!hc) {
> DMERR("device has been removed from the dev hash table.");
> goto out;
> }
> @@ -1476,7 +1476,7 @@ static int table_load(struct file *filp, struct dm_ioctl *param, size_t param_si
> /* stage inactive table */
> down_write(&_hash_lock);
> hc = dm_get_mdptr(md);
> - if (!hc || hc->md != md) {
> + if (!hc) {
> DMERR("device has been removed from the dev hash table.");
> up_write(&_hash_lock);
> r = -ENXIO;
> @@ -2128,7 +2128,7 @@ int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
>
> mutex_lock(&dm_hash_cells_mutex);
> hc = dm_get_mdptr(md);
> - if (!hc || hc->md != md) {
> + if (!hc) {
> r = -ENXIO;
> goto out;
> }
ping ? Any comments on this clean up patch ?
On 1/18/2023 9:16 PM, Hou Tao wrote:
> ping ?
>
> On 12/16/2022 12:23 PM, Hou Tao wrote:
>> From: Hou Tao <[email protected]>
>>
>> __hash_remove() removes hash_cell with _hash_lock locked, so acquiring
>> _hash_lock can guarantee no-NULL hc returned from dm_get_mdptr() must
>> have not been removed and hc->md must still be md.
>>
>> __hash_remove() also acquires dm_hash_cells_mutex before setting mdptr
>> as NULL, so in dm_copy_name_and_uuid() after acquiring
>> dm_hash_cells_mutex and ensuring returned hc is not NULL, the returned
>> hc must still be alive and hc->md must still be md.
>>
>> So removing these unnecessary hc->md != md checks when using
>> dm_get_mdptr() with _hash_lock or dm_hash_cells_mutex acquired.
>>
>> Signed-off-by: Hou Tao <[email protected]>
>> ---
>> drivers/md/dm-ioctl.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
>> index 3bfc1583c20a..2a86524661d1 100644
>> --- a/drivers/md/dm-ioctl.c
>> +++ b/drivers/md/dm-ioctl.c
>> @@ -772,7 +772,7 @@ static struct dm_table *dm_get_inactive_table(struct mapped_device *md, int *src
>>
>> down_read(&_hash_lock);
>> hc = dm_get_mdptr(md);
>> - if (!hc || hc->md != md) {
>> + if (!hc) {
>> DMERR("device has been removed from the dev hash table.");
>> goto out;
>> }
>> @@ -1476,7 +1476,7 @@ static int table_load(struct file *filp, struct dm_ioctl *param, size_t param_si
>> /* stage inactive table */
>> down_write(&_hash_lock);
>> hc = dm_get_mdptr(md);
>> - if (!hc || hc->md != md) {
>> + if (!hc) {
>> DMERR("device has been removed from the dev hash table.");
>> up_write(&_hash_lock);
>> r = -ENXIO;
>> @@ -2128,7 +2128,7 @@ int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
>>
>> mutex_lock(&dm_hash_cells_mutex);
>> hc = dm_get_mdptr(md);
>> - if (!hc || hc->md != md) {
>> + if (!hc) {
>> r = -ENXIO;
>> goto out;
>> }
ping ? Any comments on this clean up patch ?
On 1/31/2023 9:44 AM, Hou Tao wrote:
> ping ? Any comments on this clean up patch ?
>
> On 1/18/2023 9:16 PM, Hou Tao wrote:
>> ping ?
>>
>> On 12/16/2022 12:23 PM, Hou Tao wrote:
>>> From: Hou Tao <[email protected]>
>>>
>>> __hash_remove() removes hash_cell with _hash_lock locked, so acquiring
>>> _hash_lock can guarantee no-NULL hc returned from dm_get_mdptr() must
>>> have not been removed and hc->md must still be md.
>>>
>>> __hash_remove() also acquires dm_hash_cells_mutex before setting mdptr
>>> as NULL, so in dm_copy_name_and_uuid() after acquiring
>>> dm_hash_cells_mutex and ensuring returned hc is not NULL, the returned
>>> hc must still be alive and hc->md must still be md.
>>>
>>> So removing these unnecessary hc->md != md checks when using
>>> dm_get_mdptr() with _hash_lock or dm_hash_cells_mutex acquired.
>>>
>>> Signed-off-by: Hou Tao <[email protected]>
>>> ---
>>> drivers/md/dm-ioctl.c | 6 +++---
>>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
>>> index 3bfc1583c20a..2a86524661d1 100644
>>> --- a/drivers/md/dm-ioctl.c
>>> +++ b/drivers/md/dm-ioctl.c
>>> @@ -772,7 +772,7 @@ static struct dm_table *dm_get_inactive_table(struct mapped_device *md, int *src
>>>
>>> down_read(&_hash_lock);
>>> hc = dm_get_mdptr(md);
>>> - if (!hc || hc->md != md) {
>>> + if (!hc) {
>>> DMERR("device has been removed from the dev hash table.");
>>> goto out;
>>> }
>>> @@ -1476,7 +1476,7 @@ static int table_load(struct file *filp, struct dm_ioctl *param, size_t param_si
>>> /* stage inactive table */
>>> down_write(&_hash_lock);
>>> hc = dm_get_mdptr(md);
>>> - if (!hc || hc->md != md) {
>>> + if (!hc) {
>>> DMERR("device has been removed from the dev hash table.");
>>> up_write(&_hash_lock);
>>> r = -ENXIO;
>>> @@ -2128,7 +2128,7 @@ int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)
>>>
>>> mutex_lock(&dm_hash_cells_mutex);
>>> hc = dm_get_mdptr(md);
>>> - if (!hc || hc->md != md) {
>>> + if (!hc) {
>>> r = -ENXIO;
>>> goto out;
>>> }
> .