2020-01-06 15:29:45

by Qian Cai

Subject: [PATCH] iommu/dma: fix variable 'cookie' set but not used

The commit c18647900ec8 ("iommu/dma: Relax locking in
iommu_dma_prepare_msi()") introduced a compliation warning,

drivers/iommu/dma-iommu.c: In function 'iommu_dma_prepare_msi':
drivers/iommu/dma-iommu.c:1206:27: warning: variable 'cookie' set but
not used [-Wunused-but-set-variable]
struct iommu_dma_cookie *cookie;
^~~~~~

Fixes: c18647900ec8 ("iommu/dma: Relax locking in iommu_dma_prepare_msi()")
Signed-off-by: Qian Cai <[email protected]>
---
drivers/iommu/dma-iommu.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index c363294b3bb9..a2e96a5fd9a7 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1203,7 +1203,6 @@ int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr)
{
struct device *dev = msi_desc_to_dev(desc);
struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
- struct iommu_dma_cookie *cookie;
struct iommu_dma_msi_page *msi_page;
static DEFINE_MUTEX(msi_prepare_lock); /* see below */

@@ -1212,8 +1211,6 @@ int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr)
return 0;
}

- cookie = domain->iova_cookie;
-
/*
* In fact the whole prepare operation should already be serialised by
* irq_domain_mutex further up the callchain, but that's pretty subtle
--
2.21.0 (Apple Git-122.2)

2020-01-06 18:20:33

by Robin Murphy

Subject: Re: [PATCH] iommu/dma: fix variable 'cookie' set but not used

On 06/01/2020 3:27 pm, Qian Cai wrote:
> The commit c18647900ec8 ("iommu/dma: Relax locking in
> iommu_dma_prepare_msi()") introduced a compliation warning,
>
> drivers/iommu/dma-iommu.c: In function 'iommu_dma_prepare_msi':
> drivers/iommu/dma-iommu.c:1206:27: warning: variable 'cookie' set but
> not used [-Wunused-but-set-variable]
> struct iommu_dma_cookie *cookie;
> ^~~~~~

Fair enough... I guess this is a W=1 thing? Either way there's certainly
no harm in cleaning up.

Acked-by: Robin Murphy <[email protected]>

> Fixes: c18647900ec8 ("iommu/dma: Relax locking in iommu_dma_prepare_msi()")
> Signed-off-by: Qian Cai <[email protected]>
> ---
> drivers/iommu/dma-iommu.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index c363294b3bb9..a2e96a5fd9a7 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -1203,7 +1203,6 @@ int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr)
> {
> struct device *dev = msi_desc_to_dev(desc);
> struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
> - struct iommu_dma_cookie *cookie;
> struct iommu_dma_msi_page *msi_page;
> static DEFINE_MUTEX(msi_prepare_lock); /* see below */
>
> @@ -1212,8 +1211,6 @@ int iommu_dma_prepare_msi(struct msi_desc *desc, phys_addr_t msi_addr)
> return 0;
> }
>
> - cookie = domain->iova_cookie;
> -
> /*
> * In fact the whole prepare operation should already be serialised by
> * irq_domain_mutex further up the callchain, but that's pretty subtle
>

2020-01-06 18:45:19

by Qian Cai

Subject: Re: [PATCH] iommu/dma: fix variable 'cookie' set but not used

> On Jan 6, 2020, at 1:19 PM, Robin Murphy <[email protected]> wrote:
>
> Fair enough... I guess this is a W=1 thing?

Yes.

2020-01-07 16:06:26

by Jörg Rödel

Subject: Re: [PATCH] iommu/dma: fix variable 'cookie' set but not used

On Mon, Jan 06, 2020 at 10:27:27AM -0500, Qian Cai wrote:
> The commit c18647900ec8 ("iommu/dma: Relax locking in
> iommu_dma_prepare_msi()") introduced a compliation warning,
>
> drivers/iommu/dma-iommu.c: In function 'iommu_dma_prepare_msi':
> drivers/iommu/dma-iommu.c:1206:27: warning: variable 'cookie' set but
> not used [-Wunused-but-set-variable]
> struct iommu_dma_cookie *cookie;
> ^~~~~~
>
> Fixes: c18647900ec8 ("iommu/dma: Relax locking in iommu_dma_prepare_msi()")
> Signed-off-by: Qian Cai <[email protected]>
> ---
> drivers/iommu/dma-iommu.c | 3 ---
> 1 file changed, 3 deletions(-)

Applied for v5.5, thanks.