From: Jason Gunthorpe <jgg@nvidia.com>
To: Maor Gottlieb <maorg@nvidia.com>
Cc: dledford@redhat.com, hch@infradead.org, leonro@nvidia.com,
aelior@marvell.com, daniel@ffwll.ch, airlied@linux.ie,
dennis.dalessandro@cornelisnetworks.com,
dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org,
jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com,
linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
maarten.lankhorst@linux.intel.com, mripard@kernel.org,
mkalderon@marvell.com, mike.marciniszyn@cornelisnetworks.com,
mustafa.ismail@intel.com, rodrigo.vivi@intel.com,
sroland@vmware.com, shiraz.saleem@intel.com, tzimmermann@suse.de,
linux-graphics-maintainer@vmware.com, liweihang@huawei.com,
liangwenpeng@huawei.com, yishaih@nvidia.com, zackr@vmware.com,
zyjzyj2000@gmail.com
Subject: Re: [PATCH rdma-next v4 2/3] lib/scatterlist: Fix wrong update of orig_nents
Date: Wed, 25 Aug 2021 10:09:23 -0300 [thread overview]
Message-ID: <20210825130923.GF1721383@nvidia.com> (raw)
In-Reply-To: <4f4a712a-71d4-ebac-48f2-766bfda61f1e@nvidia.com>
On Wed, Aug 25, 2021 at 07:59:27AM +0300, Maor Gottlieb wrote:
>
> On 8/24/2021 10:12 PM, Jason Gunthorpe wrote:
> > On Tue, Aug 24, 2021 at 05:25:30PM +0300, Maor Gottlieb wrote:
> > > @@ -514,11 +531,13 @@ struct scatterlist *sg_alloc_append_table_from_pages(struct sg_table *sgt,
> > > offset = 0;
> > > cur_page = j;
> > > }
> > > - sgt->nents += added_nents;
> > > + sgt_append->sgt.nents += added_nents;
> > > + sgt_append->sgt.orig_nents = sgt_append->sgt.nents;
> > > + sgt_append->prv = s;
> > Why is nents being touched here?
> >
> > Shouldn't it just be
> >
> > sgt_append->sgt.orig_nents += added_nents;
> > sgt_append->prv = s;
> >
> > ?
>
> In general yes, but all the sg_alloc_* functions update both
> orig_nents and nents (to same value). May be drivers that pass nents
> instead of orig_nents to dma_map_sg* (like umem did before this
> patch set). So I prefer to set it here as well, also not to break
> sg_alloc_table_from_pages_segment which use the same path. This kind
> of change could be done very carefully next cycle for all
> sg_alloc_*.
Ok, interesting
Jason
WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgg@nvidia.com>
To: Maor Gottlieb <maorg@nvidia.com>
Cc: dledford@redhat.com, hch@infradead.org, leonro@nvidia.com,
aelior@marvell.com, daniel@ffwll.ch, airlied@linux.ie,
dennis.dalessandro@cornelisnetworks.com,
dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org,
jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com,
linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
maarten.lankhorst@linux.intel.com, mripard@kernel.org,
mkalderon@marvell.com, mike.marciniszyn@cornelisnetworks.com,
mustafa.ismail@intel.com, rodrigo.vivi@intel.com,
sroland@vmware.com, shiraz.saleem@intel.com, tzimmermann@suse.de,
linux-graphics-maintainer@vmware.com, liweihang@huawei.com,
liangwenpeng@huawei.com, yishaih@nvidia.com, zackr@vmware.com,
zyjzyj2000@gmail.com
Subject: Re: [Intel-gfx] [PATCH rdma-next v4 2/3] lib/scatterlist: Fix wrong update of orig_nents
Date: Wed, 25 Aug 2021 10:09:23 -0300 [thread overview]
Message-ID: <20210825130923.GF1721383@nvidia.com> (raw)
In-Reply-To: <4f4a712a-71d4-ebac-48f2-766bfda61f1e@nvidia.com>
On Wed, Aug 25, 2021 at 07:59:27AM +0300, Maor Gottlieb wrote:
>
> On 8/24/2021 10:12 PM, Jason Gunthorpe wrote:
> > On Tue, Aug 24, 2021 at 05:25:30PM +0300, Maor Gottlieb wrote:
> > > @@ -514,11 +531,13 @@ struct scatterlist *sg_alloc_append_table_from_pages(struct sg_table *sgt,
> > > offset = 0;
> > > cur_page = j;
> > > }
> > > - sgt->nents += added_nents;
> > > + sgt_append->sgt.nents += added_nents;
> > > + sgt_append->sgt.orig_nents = sgt_append->sgt.nents;
> > > + sgt_append->prv = s;
> > Why is nents being touched here?
> >
> > Shouldn't it just be
> >
> > sgt_append->sgt.orig_nents += added_nents;
> > sgt_append->prv = s;
> >
> > ?
>
> In general yes, but all the sg_alloc_* functions update both
> orig_nents and nents (to same value). May be drivers that pass nents
> instead of orig_nents to dma_map_sg* (like umem did before this
> patch set). So I prefer to set it here as well, also not to break
> sg_alloc_table_from_pages_segment which use the same path. This kind
> of change could be done very carefully next cycle for all
> sg_alloc_*.
Ok, interesting
Jason
next prev parent reply other threads:[~2021-08-25 13:09 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-24 14:25 [PATCH rdma-next v4 0/3] SG fix together with update to RDMA umem Maor Gottlieb
2021-08-24 14:25 ` [Intel-gfx] " Maor Gottlieb
2021-08-24 14:25 ` [PATCH rdma-next v4 1/3] lib/scatterlist: Provide a dedicated function to support table append Maor Gottlieb
2021-08-24 14:25 ` [Intel-gfx] " Maor Gottlieb
2021-08-24 14:25 ` [PATCH rdma-next v4 2/3] lib/scatterlist: Fix wrong update of orig_nents Maor Gottlieb
2021-08-24 14:25 ` [Intel-gfx] " Maor Gottlieb
2021-08-24 19:12 ` Jason Gunthorpe
2021-08-24 19:12 ` [Intel-gfx] " Jason Gunthorpe
2021-08-25 4:59 ` Maor Gottlieb
2021-08-25 4:59 ` [Intel-gfx] " Maor Gottlieb
2021-08-25 4:59 ` Maor Gottlieb
2021-08-25 13:09 ` Jason Gunthorpe [this message]
2021-08-25 13:09 ` [Intel-gfx] " Jason Gunthorpe
2021-08-24 14:25 ` [PATCH rdma-next v4 3/3] RDMA: Use the sg_table directly and remove the opencoded version from umem Maor Gottlieb
2021-08-24 14:25 ` [Intel-gfx] " Maor Gottlieb
2021-08-24 19:40 ` [Intel-gfx] ✗ Fi.CI.BUILD: failure for SG fix together with update to RDMA umem (rev4) Patchwork
2021-08-30 8:21 ` [PATCH rdma-next v4 0/3] SG fix together with update to RDMA umem Leon Romanovsky
2021-08-30 8:21 ` Leon Romanovsky
2021-08-30 8:21 ` [Intel-gfx] " Leon Romanovsky
2021-08-30 13:31 ` Jason Gunthorpe
2021-08-30 13:31 ` [Intel-gfx] " Jason Gunthorpe
2021-08-30 13:42 ` Leon Romanovsky
2021-08-30 13:42 ` [Intel-gfx] " Leon Romanovsky
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