linux-kernel - Re: [PATCH v3 26/30] mm: shmem: use SHMEM_F_* flags instead of VM

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Message-ID: <mafs0sehvwfy0.fsf@kernel.org>
Date: Wed, 13 Aug 2025 14:42:47 +0200
From: Pratyush Yadav <pratyush@...nel.org>
To: Vipin Sharma <vipinsh@...gle.com>
Cc: Pasha Tatashin <pasha.tatashin@...een.com>,  pratyush@...nel.org,
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Subject: Re: [PATCH v3 26/30] mm: shmem: use SHMEM_F_* flags instead of VM_*
 flags

On Mon, Aug 11 2025, Vipin Sharma wrote:

> On 2025-08-07 01:44:32, Pasha Tatashin wrote:
>> From: Pratyush Yadav <ptyadav@...zon.de>
>> @@ -3123,7 +3123,9 @@ static struct inode *__shmem_get_inode(struct mnt_idmap *idmap,
>>  	spin_lock_init(&info->lock);
>>  	atomic_set(&info->stop_eviction, 0);
>>  	info->seals = F_SEAL_SEAL;
>> -	info->flags = flags & VM_NORESERVE;
>> +	info->flags = 0;
>
> This is not needed as the 'info' is being set to 0 just above
> spin_lock_init.
>
>> +	if (flags & VM_NORESERVE)
>> +		info->flags |= SHMEM_F_NORESERVE;
>
> As info->flags will be 0, this can be just direct assignment '='.

I think it is a bit more readable this way.

Anyway, I don't have a strong opinion, so if you insist, I'll change
this.

>
>>  	info->i_crtime = inode_get_mtime(inode);
>>  	info->fsflags = (dir == NULL) ? 0 :
>>  		SHMEM_I(dir)->fsflags & SHMEM_FL_INHERITED;
>> @@ -5862,8 +5864,10 @@ static inline struct inode *shmem_get_inode(struct mnt_idmap *idmap,
>>  /* common code */
>>  
>>  static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name,
>> -			loff_t size, unsigned long flags, unsigned int i_flags)
>> +				       loff_t size, unsigned long vm_flags,
>> +				       unsigned int i_flags)
>
> Nit: Might be just my editor, but this alignment seems off.

Looks fine for me:
https://gist.github.com/prati0100/a06229ca99cac5aae795fb962bb24ac5

Checkpatch also doesn't complain. Can you double-check? And if it still
looks off, can you describe what's wrong?

>
>>  {
>> +	unsigned long flags = (vm_flags & VM_NORESERVE) ? SHMEM_F_NORESERVE : 0;
>>  	struct inode *inode;
>>  	struct file *res;
>>  
>> @@ -5880,7 +5884,7 @@ static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *name,
>>  		return ERR_PTR(-ENOMEM);
>>  
>>  	inode = shmem_get_inode(&nop_mnt_idmap, mnt->mnt_sb, NULL,
>> -				S_IFREG | S_IRWXUGO, 0, flags);
>> +				S_IFREG | S_IRWXUGO, 0, vm_flags);
>>  	if (IS_ERR(inode)) {
>>  		shmem_unacct_size(flags, size);
>>  		return ERR_CAST(inode);
>> -- 
>> 2.50.1.565.gc32cd1483b-goog
>> 

-- 
Regards,
Pratyush Yadav