2022-07-11 20:00:41

by Christophe JAILLET

Subject: [PATCH 1/2] cxl: Use the bitmap API to allocate bitmaps

Use bitmap_zalloc()/bitmap_free() instead of hand-writing them.

It is less verbose and it improves the semantic.

Signed-off-by: Christophe JAILLET <[email protected]>
---
drivers/misc/cxl/context.c | 2 +-
drivers/misc/cxl/guest.c | 2 +-
drivers/misc/cxl/irq.c | 3 +--
drivers/misc/cxl/of.c | 5 ++---
4 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c
index e627b4056623..acaa44809c58 100644
--- a/drivers/misc/cxl/context.c
+++ b/drivers/misc/cxl/context.c
@@ -331,7 +331,7 @@ static void reclaim_ctx(struct rcu_head *rcu)
__free_page(ctx->ff_page);
ctx->sstp = NULL;

- kfree(ctx->irq_bitmap);
+ bitmap_free(ctx->irq_bitmap);

/* Drop ref to the afu device taken during cxl_context_init */
cxl_afu_put(ctx->afu);
diff --git a/drivers/misc/cxl/guest.c b/drivers/misc/cxl/guest.c
index 3321c014913c..375f692ae9d6 100644
--- a/drivers/misc/cxl/guest.c
+++ b/drivers/misc/cxl/guest.c
@@ -1053,7 +1053,7 @@ static void free_adapter(struct cxl *adapter)
if (adapter->guest->irq_avail) {
for (i = 0; i < adapter->guest->irq_nranges; i++) {
cur = &adapter->guest->irq_avail[i];
- kfree(cur->bitmap);
+ bitmap_free(cur->bitmap);
}
kfree(adapter->guest->irq_avail);
}
diff --git a/drivers/misc/cxl/irq.c b/drivers/misc/cxl/irq.c
index 5f0e2dcebb34..0ce91d99aead 100644
--- a/drivers/misc/cxl/irq.c
+++ b/drivers/misc/cxl/irq.c
@@ -319,8 +319,7 @@ int afu_allocate_irqs(struct cxl_context *ctx, u32 count)
}

ctx->irq_count = count;
- ctx->irq_bitmap = kcalloc(BITS_TO_LONGS(count),
- sizeof(*ctx->irq_bitmap), GFP_KERNEL);
+ ctx->irq_bitmap = bitmap_zalloc(count, GFP_KERNEL);
if (!ctx->irq_bitmap)
goto out;

diff --git a/drivers/misc/cxl/of.c b/drivers/misc/cxl/of.c
index 1cfecba42d01..25ce725035e7 100644
--- a/drivers/misc/cxl/of.c
+++ b/drivers/misc/cxl/of.c
@@ -308,8 +308,7 @@ static int read_adapter_irq_config(struct cxl *adapter, struct device_node *np)
cur = &adapter->guest->irq_avail[i];
cur->offset = be32_to_cpu(ranges[i * 2]);
cur->range = be32_to_cpu(ranges[i * 2 + 1]);
- cur->bitmap = kcalloc(BITS_TO_LONGS(cur->range),
- sizeof(*cur->bitmap), GFP_KERNEL);
+ cur->bitmap = bitmap_zalloc(cur->range, GFP_KERNEL);
if (cur->bitmap == NULL)
goto err;
if (cur->offset < adapter->guest->irq_base_offset)
@@ -326,7 +325,7 @@ static int read_adapter_irq_config(struct cxl *adapter, struct device_node *np)
err:
for (i--; i >= 0; i--) {
cur = &adapter->guest->irq_avail[i];
- kfree(cur->bitmap);
+ bitmap_free(cur->bitmap);
}
kfree(adapter->guest->irq_avail);
adapter->guest->irq_avail = NULL;
--
2.34.1

2022-07-11 20:06:33

by Christophe JAILLET

Subject: [PATCH 2/2] cxl: Fix a memory leak in an error handling path

A bitmap_zalloc() must be balanced by a corresponding bitmap_free() in the
error handling path of afu_allocate_irqs().

Signed-off-by: Christophe JAILLET <[email protected]>
---
The error handling path should be done in the reversed order but it should
work as-is.
---
drivers/misc/cxl/irq.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/misc/cxl/irq.c b/drivers/misc/cxl/irq.c
index 0ce91d99aead..b730e022a48e 100644
--- a/drivers/misc/cxl/irq.c
+++ b/drivers/misc/cxl/irq.c
@@ -349,6 +349,7 @@ int afu_allocate_irqs(struct cxl_context *ctx, u32 count)

out:
cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
+ bitmap_free(ctx->irq_bitmap);
afu_irq_name_free(ctx);
return -ENOMEM;
}
--
2.34.1

2022-07-12 17:01:39

by Andrew Donnellan

Subject: Re: [PATCH 2/2] cxl: Fix a memory leak in an error handling path

On Mon, 2022-07-11 at 21:14 +0200, Christophe JAILLET wrote:
> A bitmap_zalloc() must be balanced by a corresponding bitmap_free()
> in the
> error handling path of afu_allocate_irqs().
>
> Signed-off-by: Christophe JAILLET <[email protected]>

Thanks for catching this.

Acked-by: Andrew Donnellan <[email protected]>

> ---
> The error handling path should be done in the reversed order but it
> should
> work as-is.
> ---
>  drivers/misc/cxl/irq.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/misc/cxl/irq.c b/drivers/misc/cxl/irq.c
> index 0ce91d99aead..b730e022a48e 100644
> --- a/drivers/misc/cxl/irq.c
> +++ b/drivers/misc/cxl/irq.c
> @@ -349,6 +349,7 @@ int afu_allocate_irqs(struct cxl_context *ctx,
> u32 count)
>  
>  out:
>         cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
> +       bitmap_free(ctx->irq_bitmap);
>         afu_irq_name_free(ctx);
>         return -ENOMEM;
>  }

2022-07-12 17:31:40

by Andrew Donnellan

Subject: Re: [PATCH 1/2] cxl: Use the bitmap API to allocate bitmaps

On Mon, 2022-07-11 at 21:14 +0200, Christophe JAILLET wrote:
> Use bitmap_zalloc()/bitmap_free() instead of hand-writing them.
>
> It is less verbose and it improves the semantic.
>
> Signed-off-by: Christophe JAILLET <[email protected]>

Thanks!

Acked-by: Andrew Donnellan <[email protected]>

> ---
>  drivers/misc/cxl/context.c | 2 +-
>  drivers/misc/cxl/guest.c   | 2 +-
>  drivers/misc/cxl/irq.c     | 3 +--
>  drivers/misc/cxl/of.c      | 5 ++---
>  4 files changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c
> index e627b4056623..acaa44809c58 100644
> --- a/drivers/misc/cxl/context.c
> +++ b/drivers/misc/cxl/context.c
> @@ -331,7 +331,7 @@ static void reclaim_ctx(struct rcu_head *rcu)
>                 __free_page(ctx->ff_page);
>         ctx->sstp = NULL;
>  
> -       kfree(ctx->irq_bitmap);
> +       bitmap_free(ctx->irq_bitmap);
>  
>         /* Drop ref to the afu device taken during cxl_context_init
> */
>         cxl_afu_put(ctx->afu);
> diff --git a/drivers/misc/cxl/guest.c b/drivers/misc/cxl/guest.c
> index 3321c014913c..375f692ae9d6 100644
> --- a/drivers/misc/cxl/guest.c
> +++ b/drivers/misc/cxl/guest.c
> @@ -1053,7 +1053,7 @@ static void free_adapter(struct cxl *adapter)
>                 if (adapter->guest->irq_avail) {
>                         for (i = 0; i < adapter->guest->irq_nranges;
> i++) {
>                                 cur = &adapter->guest->irq_avail[i];
> -                               kfree(cur->bitmap);
> +                               bitmap_free(cur->bitmap);
>                         }
>                         kfree(adapter->guest->irq_avail);
>                 }
> diff --git a/drivers/misc/cxl/irq.c b/drivers/misc/cxl/irq.c
> index 5f0e2dcebb34..0ce91d99aead 100644
> --- a/drivers/misc/cxl/irq.c
> +++ b/drivers/misc/cxl/irq.c
> @@ -319,8 +319,7 @@ int afu_allocate_irqs(struct cxl_context *ctx,
> u32 count)
>         }
>  
>         ctx->irq_count = count;
> -       ctx->irq_bitmap = kcalloc(BITS_TO_LONGS(count),
> -                                 sizeof(*ctx->irq_bitmap),
> GFP_KERNEL);
> +       ctx->irq_bitmap = bitmap_zalloc(count, GFP_KERNEL);
>         if (!ctx->irq_bitmap)
>                 goto out;
>  
> diff --git a/drivers/misc/cxl/of.c b/drivers/misc/cxl/of.c
> index 1cfecba42d01..25ce725035e7 100644
> --- a/drivers/misc/cxl/of.c
> +++ b/drivers/misc/cxl/of.c
> @@ -308,8 +308,7 @@ static int read_adapter_irq_config(struct cxl
> *adapter, struct device_node *np)
>                 cur = &adapter->guest->irq_avail[i];
>                 cur->offset = be32_to_cpu(ranges[i * 2]);
>                 cur->range  = be32_to_cpu(ranges[i * 2 + 1]);
> -               cur->bitmap = kcalloc(BITS_TO_LONGS(cur->range),
> -                               sizeof(*cur->bitmap), GFP_KERNEL);
> +               cur->bitmap = bitmap_zalloc(cur->range, GFP_KERNEL);
>                 if (cur->bitmap == NULL)
>                         goto err;
>                 if (cur->offset < adapter->guest->irq_base_offset)
> @@ -326,7 +325,7 @@ static int read_adapter_irq_config(struct cxl
> *adapter, struct device_node *np)
>  err:
>         for (i--; i >= 0; i--) {
>                 cur = &adapter->guest->irq_avail[i];
> -               kfree(cur->bitmap);
> +               bitmap_free(cur->bitmap);
>         }
>         kfree(adapter->guest->irq_avail);
>         adapter->guest->irq_avail = NULL;