2024-01-29 21:07:14

by Mathieu Desnoyers

Subject: [RFC PATCH 4/7] ext2: Use dax_is_supported()

Use dax_is_supported() to validate whether the architecture has
virtually aliased caches at mount time.

This is relevant for architectures which require a dynamic check
to validate whether they have virtually aliased data caches
(ARCH_HAS_CACHE_ALIASING_DYNAMIC=y).

Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches")
Signed-off-by: Mathieu Desnoyers <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: [email protected]
Cc: Andrew Morton <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Dan Williams <[email protected]>
Cc: Vishal Verma <[email protected]>
Cc: Dave Jiang <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: [email protected]
Cc: [email protected]
---
fs/ext2/super.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 01f9addc8b1f..0398e7a90eb6 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -585,13 +585,13 @@ static int parse_options(char *options, struct super_block *sb,
set_opt(opts->s_mount_opt, XIP);
fallthrough;
case Opt_dax:
-#ifdef CONFIG_FS_DAX
- ext2_msg(sb, KERN_WARNING,
- "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
- set_opt(opts->s_mount_opt, DAX);
-#else
- ext2_msg(sb, KERN_INFO, "dax option not supported");
-#endif
+ if (dax_is_supported()) {
+ ext2_msg(sb, KERN_WARNING,
+ "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
+ set_opt(opts->s_mount_opt, DAX);
+ } else {
+ ext2_msg(sb, KERN_INFO, "dax option not supported");
+ }
break;

#if defined(CONFIG_QUOTA)
--
2.39.2

2024-01-30 15:23:58

by Mathieu Desnoyers

Subject: Re: [RFC PATCH 4/7] ext2: Use dax_is_supported()

On 2024-01-30 06:33, Jan Kara wrote:
> On Mon 29-01-24 16:06:28, Mathieu Desnoyers wrote:
>> Use dax_is_supported() to validate whether the architecture has
>> virtually aliased caches at mount time.
>>
>> This is relevant for architectures which require a dynamic check
>> to validate whether they have virtually aliased data caches
>> (ARCH_HAS_CACHE_ALIASING_DYNAMIC=y).
>>
>> Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches")
>> Signed-off-by: Mathieu Desnoyers <[email protected]>
>> Cc: Jan Kara <[email protected]>
>> Cc: [email protected]
>> Cc: Andrew Morton <[email protected]>
>> Cc: Linus Torvalds <[email protected]>
>> Cc: [email protected]
>> Cc: [email protected]
>> Cc: Dan Williams <[email protected]>
>> Cc: Vishal Verma <[email protected]>
>> Cc: Dave Jiang <[email protected]>
>> Cc: Matthew Wilcox <[email protected]>
>> Cc: [email protected]
>> Cc: [email protected]
>
> Looks good to me (although I share Dave's opinion it would be nice to CC
> the whole series to fsdevel - luckily we have lore these days so it is not
> that tedious to find the whole series :)). Feel free to add:
>
> Acked-by: Jan Kara <[email protected]>

Hi Jan,

Thanks for looking at it! I will do significant changes for v2, so
I will hold on before integrating your acked-by if it's OK with you.

Thanks!

Mathieu

>
> Honza
>
>> ---
>> fs/ext2/super.c | 14 +++++++-------
>> 1 file changed, 7 insertions(+), 7 deletions(-)
>>
>> diff --git a/fs/ext2/super.c b/fs/ext2/super.c
>> index 01f9addc8b1f..0398e7a90eb6 100644
>> --- a/fs/ext2/super.c
>> +++ b/fs/ext2/super.c
>> @@ -585,13 +585,13 @@ static int parse_options(char *options, struct super_block *sb,
>> set_opt(opts->s_mount_opt, XIP);
>> fallthrough;
>> case Opt_dax:
>> -#ifdef CONFIG_FS_DAX
>> - ext2_msg(sb, KERN_WARNING,
>> - "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
>> - set_opt(opts->s_mount_opt, DAX);
>> -#else
>> - ext2_msg(sb, KERN_INFO, "dax option not supported");
>> -#endif
>> + if (dax_is_supported()) {
>> + ext2_msg(sb, KERN_WARNING,
>> + "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
>> + set_opt(opts->s_mount_opt, DAX);
>> + } else {
>> + ext2_msg(sb, KERN_INFO, "dax option not supported");
>> + }
>> break;
>>
>> #if defined(CONFIG_QUOTA)
>> --
>> 2.39.2
>>

--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com