Re: [PATCH 1/5] xfs: Remove kmem_zone_alloc() usage

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Wed, Jul 22, 2020 at 11:05:14AM +0200, Carlos Maiolino wrote:
> Use kmem_cache_alloc() directly.
> 
> All kmem_zone_alloc() users pass 0 as flags, which are translated into:
> GFP_KERNEL | __GFP_NOWARN, and kmem_zone_alloc() loops forever until the
> allocation succeeds.
> 
> We can use __GFP_NOFAIL to tell the allocator to loop forever rather
> than doing it ourself, and because the allocation will never fail, we do
> not need to use __GFP_NOWARN anymore. Hence, all callers can be
> converted to use GFP_KERNEL | __GFP_NOFAIL
> 
> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>

Looks ok to me too (I put the comment back in),
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> ---
> 
> Changelog:
> 	V2:
> 		- Wire up xfs_inode_alloc to use __GFP_NOFAIL
> 		  if it's called inside a transaction
> 		- Rewrite changelog in a more decent way.
> 	V3:
> 		- Use __GFP_NOFAIL unconditionally in xfs_inode_alloc(),
> 		  use of PF_FSTRANS will be added when the patch re-adding
> 		  it is moved to mainline.
> 
>  fs/xfs/libxfs/xfs_alloc.c |  3 ++-
>  fs/xfs/libxfs/xfs_bmap.c  |  3 ++-
>  fs/xfs/xfs_icache.c       | 10 ++--------
>  3 files changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
> index 203e74fa64aa6..583242253c027 100644
> --- a/fs/xfs/libxfs/xfs_alloc.c
> +++ b/fs/xfs/libxfs/xfs_alloc.c
> @@ -2467,7 +2467,8 @@ xfs_defer_agfl_block(
>  	ASSERT(xfs_bmap_free_item_zone != NULL);
>  	ASSERT(oinfo != NULL);
>  
> -	new = kmem_zone_alloc(xfs_bmap_free_item_zone, 0);
> +	new = kmem_cache_alloc(xfs_bmap_free_item_zone,
> +			       GFP_KERNEL | __GFP_NOFAIL);
>  	new->xefi_startblock = XFS_AGB_TO_FSB(mp, agno, agbno);
>  	new->xefi_blockcount = 1;
>  	new->xefi_oinfo = *oinfo;
> diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> index 667cdd0dfdf4a..fd5c0d669d0d7 100644
> --- a/fs/xfs/libxfs/xfs_bmap.c
> +++ b/fs/xfs/libxfs/xfs_bmap.c
> @@ -553,7 +553,8 @@ __xfs_bmap_add_free(
>  #endif
>  	ASSERT(xfs_bmap_free_item_zone != NULL);
>  
> -	new = kmem_zone_alloc(xfs_bmap_free_item_zone, 0);
> +	new = kmem_cache_alloc(xfs_bmap_free_item_zone,
> +			       GFP_KERNEL | __GFP_NOFAIL);
>  	new->xefi_startblock = bno;
>  	new->xefi_blockcount = (xfs_extlen_t)len;
>  	if (oinfo)
> diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
> index 58a750ce689c0..c2d97e4f131fb 100644
> --- a/fs/xfs/xfs_icache.c
> +++ b/fs/xfs/xfs_icache.c
> @@ -36,14 +36,8 @@ xfs_inode_alloc(
>  {
>  	struct xfs_inode	*ip;
>  
> -	/*
> -	 * if this didn't occur in transactions, we could use
> -	 * KM_MAYFAIL and return NULL here on ENOMEM. Set the
> -	 * code up to do this anyway.
> -	 */
> -	ip = kmem_zone_alloc(xfs_inode_zone, 0);
> -	if (!ip)
> -		return NULL;
> +	ip = kmem_cache_alloc(xfs_inode_zone, GFP_KERNEL | __GFP_NOFAIL);
> +
>  	if (inode_init_always(mp->m_super, VFS_I(ip))) {
>  		kmem_cache_free(xfs_inode_zone, ip);
>  		return NULL;
> -- 
> 2.26.2
>