Re: [PATCH 3/5] xfs: remove kmem_zalloc() wrapper

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

On Thu, Nov 21, 2019 at 08:24:01AM +1100, Dave Chinner wrote:
> On Wed, Nov 20, 2019 at 11:44:23AM +0100, Carlos Maiolino wrote:
> > Use kzalloc() directly
> > 
> > Special attention goes to function xfs_buf_map_from_irec(). Giving the
> > fact we are not allowed to fail there, I removed the 'if (!map)'
> > conditional from there, I'd just like somebody to double check if it's
> > fine as I believe it is
> > 
> > Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
> 
> It looks good as a 1:1 translation, but I've noticed a few places we
> actually have the context wrong and have been saved by the fact tehy
> are called in transaction context (hence GFP_NOFS is enforced by
> task flags).
> 
> This can be fixed in a separate patch, I've noted the ones I think
> need changing below.
> 
> > diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
> > index 795b9b21b64d..67de68584224 100644
> > --- a/fs/xfs/libxfs/xfs_attr_leaf.c
> > +++ b/fs/xfs/libxfs/xfs_attr_leaf.c
> > @@ -2253,7 +2253,8 @@ xfs_attr3_leaf_unbalance(
> >  		struct xfs_attr_leafblock *tmp_leaf;
> >  		struct xfs_attr3_icleaf_hdr tmphdr;
> >  
> > -		tmp_leaf = kmem_zalloc(state->args->geo->blksize, 0);
> > +		tmp_leaf = kzalloc(state->args->geo->blksize,
> > +				   GFP_KERNEL | __GFP_NOFAIL);
> 
> In a transaction, GFP_NOFS.

As we're discussing on IRC, this is probably correct, but let's do a
straight KM_ -> GFP_ conversion here, warts and all; and then do a
separate series to sort out incorrect flag usage.

--D

> > diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
> > index dc39b2d1b351..4fea8e5e70fb 100644
> > --- a/fs/xfs/xfs_buf_item.c
> > +++ b/fs/xfs/xfs_buf_item.c
> > @@ -701,8 +701,8 @@ xfs_buf_item_get_format(
> >  		return 0;
> >  	}
> >  
> > -	bip->bli_formats = kmem_zalloc(count * sizeof(struct xfs_buf_log_format),
> > -				0);
> > +	bip->bli_formats = kzalloc(count * sizeof(struct xfs_buf_log_format),
> > +				   GFP_KERNEL | __GFP_NOFAIL);
> >  	if (!bip->bli_formats)
> >  		return -ENOMEM;
> >  	return 0;
> 
> In a transaction, GFP_NOFS.
> 
> > diff --git a/fs/xfs/xfs_dquot_item.c b/fs/xfs/xfs_dquot_item.c
> > index 1b5e68ccef60..91bd47e8b832 100644
> > --- a/fs/xfs/xfs_dquot_item.c
> > +++ b/fs/xfs/xfs_dquot_item.c
> > @@ -347,7 +347,8 @@ xfs_qm_qoff_logitem_init(
> >  {
> >  	struct xfs_qoff_logitem	*qf;
> >  
> > -	qf = kmem_zalloc(sizeof(struct xfs_qoff_logitem), 0);
> > +	qf = kzalloc(sizeof(struct xfs_qoff_logitem),
> > +		     GFP_KERNEL | __GFP_NOFAIL);
> 
> In a transaction, GFP_NOFS.
> 
> > diff --git a/fs/xfs/xfs_extent_busy.c b/fs/xfs/xfs_extent_busy.c
> > index 9f0b99c7b34a..0ce50b47fc28 100644
> > --- a/fs/xfs/xfs_extent_busy.c
> > +++ b/fs/xfs/xfs_extent_busy.c
> > @@ -33,7 +33,8 @@ xfs_extent_busy_insert(
> >  	struct rb_node		**rbp;
> >  	struct rb_node		*parent = NULL;
> >  
> > -	new = kmem_zalloc(sizeof(struct xfs_extent_busy), 0);
> > +	new = kzalloc(sizeof(struct xfs_extent_busy),
> > +		      GFP_KERNEL | __GFP_NOFAIL);
> 
> transaction, GFP_NOFS.
> 
> >  	new->agno = agno;
> >  	new->bno = bno;
> >  	new->length = len;
> > diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c
> > index c3b8804aa396..872312029957 100644
> > --- a/fs/xfs/xfs_extfree_item.c
> > +++ b/fs/xfs/xfs_extfree_item.c
> > @@ -163,7 +163,7 @@ xfs_efi_init(
> >  	if (nextents > XFS_EFI_MAX_FAST_EXTENTS) {
> >  		size = (uint)(sizeof(xfs_efi_log_item_t) +
> >  			((nextents - 1) * sizeof(xfs_extent_t)));
> > -		efip = kmem_zalloc(size, 0);
> > +		efip = kzalloc(size, GFP_KERNEL | __GFP_NOFAIL);
> >  	} else {
> >  		efip = kmem_cache_zalloc(xfs_efi_zone,
> >  					 GFP_KERNEL | __GFP_NOFAIL);
> 
> Both of these GFP_NOFS.
> 
> > @@ -333,9 +333,9 @@ xfs_trans_get_efd(
> >  	ASSERT(nextents > 0);
> >  
> >  	if (nextents > XFS_EFD_MAX_FAST_EXTENTS) {
> > -		efdp = kmem_zalloc(sizeof(struct xfs_efd_log_item) +
> > +		efdp = kzalloc(sizeof(struct xfs_efd_log_item) +
> >  				(nextents - 1) * sizeof(struct xfs_extent),
> > -				0);
> > +				GFP_KERNEL | __GFP_NOFAIL);
> >  	} else {
> >  		efdp = kmem_cache_zalloc(xfs_efd_zone,
> >  					 GFP_KERNEL | __GFP_NOFAIL);
> 
> Same here.
> 
> Hmmm. I guess I better go look at the kmem_cache_[z]alloc() patches,
> too.
> 
> > diff --git a/fs/xfs/xfs_refcount_item.c b/fs/xfs/xfs_refcount_item.c
> > index 76b39f2a0260..7ec70a5f1cb0 100644
> > --- a/fs/xfs/xfs_refcount_item.c
> > +++ b/fs/xfs/xfs_refcount_item.c
> > @@ -143,8 +143,8 @@ xfs_cui_init(
> >  
> >  	ASSERT(nextents > 0);
> >  	if (nextents > XFS_CUI_MAX_FAST_EXTENTS)
> > -		cuip = kmem_zalloc(xfs_cui_log_item_sizeof(nextents),
> > -				0);
> > +		cuip = kzalloc(xfs_cui_log_item_sizeof(nextents),
> > +			       GFP_KERNEL | __GFP_NOFAIL);
> >  	else
> >  		cuip = kmem_cache_zalloc(xfs_cui_zone,
> >  					 GFP_KERNEL | __GFP_NOFAIL);
> 
> Both GFP_NOFS.
> 
> > diff --git a/fs/xfs/xfs_rmap_item.c b/fs/xfs/xfs_rmap_item.c
> > index 6aeb6745d007..82d822885996 100644
> > --- a/fs/xfs/xfs_rmap_item.c
> > +++ b/fs/xfs/xfs_rmap_item.c
> > @@ -142,7 +142,8 @@ xfs_rui_init(
> >  
> >  	ASSERT(nextents > 0);
> >  	if (nextents > XFS_RUI_MAX_FAST_EXTENTS)
> > -		ruip = kmem_zalloc(xfs_rui_log_item_sizeof(nextents), 0);
> > +		ruip = kzalloc(xfs_rui_log_item_sizeof(nextents),
> > +			       GFP_KERNEL | __GFP_NOFAIL);
> >  	else
> >  		ruip = kmem_cache_zalloc(xfs_rui_zone,
> >  					 GFP_KERNEL | __GFP_NOFAIL);
> 
> Both GFP_NOFS.
> 
> Cheers,
> 
> Dave.
> -- 
> Dave Chinner
> david@fromorbit.com