Re: [PATCH] Coccinelle: Update and rename api/alloc/pci_free_consistent.cocci

From: Julia Lawall
Date: Sat Jun 26 2021 - 16:16:06 EST




On Wed, 16 Jun 2021, Christophe JAILLET wrote:

> 'pci_alloc_consistent()' is about to be removed from the kernel.
> It is now more useful to check for dma_alloc_coherent/dma_free_coherent.
>
> So change the script accordingly and rename it.

There also seem to be a lot of false positives, where the value is used in
unexpected ways, such as:

for (i = 0; i < nr_pages; ++i) {
cpu_addr = dma_alloc_coherent(dma_dev, PAGE_SIZE, &dma_addr,
CIO_DMA_GFP);
if (!cpu_addr)
return gp_dma;
gen_pool_add_virt(gp_dma, (unsigned long) cpu_addr,
dma_addr, PAGE_SIZE, -1);
}

Maybe the rule should be dropped?

julia

>
> Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> ---
> Not sure that the script works.
> There are 718 'dma_alloc_coherent' calls in 5.13-rc6. It is surprising
> to have no match at all, not even a single false positive.
> ---
> ..._consistent.cocci => dma_free_coherent.cocci} | 16 ++++++++--------
> 1 file changed, 8 insertions(+), 8 deletions(-)
> rename scripts/coccinelle/free/{pci_free_consistent.cocci => dma_free_coherent.cocci} (52%)
>
> diff --git a/scripts/coccinelle/free/pci_free_consistent.cocci b/scripts/coccinelle/free/dma_free_coherent.cocci
> similarity index 52%
> rename from scripts/coccinelle/free/pci_free_consistent.cocci
> rename to scripts/coccinelle/free/dma_free_coherent.cocci
> index d51e92556b42..75f159e7b6d7 100644
> --- a/scripts/coccinelle/free/pci_free_consistent.cocci
> +++ b/scripts/coccinelle/free/dma_free_coherent.cocci
> @@ -1,10 +1,10 @@
> // SPDX-License-Identifier: GPL-2.0-only
> -/// Find missing pci_free_consistent for every pci_alloc_consistent.
> +/// Find missing dma_free_coherent for every dma_alloc_coherent.
> ///
> // Confidence: Moderate
> // Copyright: (C) 2013 Petr Strnad.
> // URL: http://coccinelle.lip6.fr/
> -// Keywords: pci_free_consistent, pci_alloc_consistent
> +// Keywords: dma_free_coherent, dma_alloc_coherent
> // Options: --no-includes --include-headers
>
> virtual report
> @@ -17,12 +17,12 @@ position p1,p2;
> type T;
> @@
>
> -id = pci_alloc_consistent@p1(x,y,&z)
> +id = dma_alloc_coherent@p1(x,y,&z)
> ... when != e = id
> if (id == NULL || ...) { ... return ...; }
> -... when != pci_free_consistent(x,y,id,z)
> - when != if (id) { ... pci_free_consistent(x,y,id,z) ... }
> - when != if (y) { ... pci_free_consistent(x,y,id,z) ... }
> +... when != dma_free_coherent(x,y,id,z)
> + when != if (id) { ... dma_free_coherent(x,y,id,z) ... }
> + when != if (y) { ... dma_free_coherent(x,y,id,z) ... }
> when != e = (T)id
> when exists
> (
> @@ -40,7 +40,7 @@ p1 << search.p1;
> p2 << search.p2;
> @@
>
> -msg = "ERROR: missing pci_free_consistent; pci_alloc_consistent on line %s and return without freeing on line %s" % (p1[0].line,p2[0].line)
> +msg = "ERROR: missing dma_free_coherent; dma_alloc_coherent on line %s and return without freeing on line %s" % (p1[0].line,p2[0].line)
> coccilib.report.print_report(p2[0],msg)
>
> @script:python depends on org@
> @@ -48,6 +48,6 @@ p1 << search.p1;
> p2 << search.p2;
> @@
>
> -msg = "ERROR: missing pci_free_consistent; pci_alloc_consistent on line %s and return without freeing on line %s" % (p1[0].line,p2[0].line)
> +msg = "ERROR: missing dma_free_coherent; dma_alloc_coherent on line %s and return without freeing on line %s" % (p1[0].line,p2[0].line)
> cocci.print_main(msg,p1)
> cocci.print_secs("",p2)
> --
> 2.30.2
>
>