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Tue, 2 May 2023 22:09:11 +0200 (CEST) Authentication-Results: mail.tesarici.cz; dmarc=fail (p=none dis=none) header.from=tesarici.cz DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=tesarici.cz; s=mail; t=1683058152; bh=OQQDbaT1g8f2dPLm5XSkHxMIreXJIprIWNp5xqPtyjs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=ACEe9aMV7KAl5vtSygiD0xbm7GHaT9Eqyv4H5MpZy91H692eziATAh+Lllc4/9nF3 9e+F1G490J0hwPn2UyqIwUJB1EH4TqQrl+IsVypjDznWCqQ5uXNN5ITXEdhlYC04z/ xrT7brhbQqzJVnJhe0lj2PAIkzmIpYLQO5D13JOi/pXsgd3wv8CWwPcpd8CN8wKdXP X1wLEGxjC6cJJSdqG/m4XGAZK8W7DskDc/fFABNpCko/6HHqnxg3JJO8vtiG4/XE9H Q6YBS5/HHT1gl8+fWrS81CUQeFjzzEkOOTPV62RwgA77/pe3jfDZ4V6bi4OMBzKBTo 1Ci/3VokWKu1A== Date: Tue, 2 May 2023 22:09:09 +0200 From: Petr =?UTF-8?B?VGVzYcWZw61r?= To: Suren Baghdasaryan Cc: akpm@linux-foundation.org, kent.overstreet@linux.dev, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, roman.gushchin@linux.dev, mgorman@suse.de, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, corbet@lwn.net, void@manifault.com, peterz@infradead.org, juri.lelli@redhat.com, ldufour@linux.ibm.com, catalin.marinas@arm.com, will@kernel.org, arnd@arndb.de, tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com, x86@kernel.org, peterx@redhat.com, david@redhat.com, axboe@kernel.dk, mcgrof@kernel.org, masahiroy@kernel.org, nathan@kernel.org, dennis@kernel.org, tj@kernel.org, muchun.song@linux.dev, rppt@kernel.org, paulmck@kernel.org, pasha.tatashin@soleen.com, yosryahmed@google.com, yuzhao@google.com, dhowells@redhat.com, hughd@google.com, andreyknvl@gmail.com, keescook@chromium.org, ndesaulniers@google.com, gregkh@linuxfoundation.org, ebiggers@google.com, ytcoode@gmail.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, bristot@redhat.com, vschneid@redhat.com, cl@linux.com, penberg@kernel.org, iamjoonsoo.kim@lge.com, 42.hyeyoo@gmail.com, glider@google.com, elver@google.com, dvyukov@google.com, shakeelb@google.com, songmuchun@bytedance.com, jbaron@akamai.com, rientjes@google.com, minchan@google.com, kaleshsingh@google.com, kernel-team@android.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux.dev, linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-modules@vger.kernel.org, kasan-dev@googlegroups.com, cgroups@vger.kernel.org Subject: Re: [PATCH 19/40] change alloc_pages name in dma_map_ops to avoid name conflicts Message-ID: <20230502220909.3f55ae41@meshulam.tesarici.cz> In-Reply-To: References: <20230501165450.15352-1-surenb@google.com> <20230501165450.15352-20-surenb@google.com> <20230502175052.43814202@meshulam.tesarici.cz> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.37; x86_64-suse-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, 2 May 2023 11:38:49 -0700 Suren Baghdasaryan wrote: > On Tue, May 2, 2023 at 8:50=E2=80=AFAM Petr Tesa=C5=99=C3=ADk wrote: > > > > On Mon, 1 May 2023 09:54:29 -0700 > > Suren Baghdasaryan wrote: > > =20 > > > After redefining alloc_pages, all uses of that name are being replace= d. > > > Change the conflicting names to prevent preprocessor from replacing t= hem > > > when it's not intended. > > > > > > Signed-off-by: Suren Baghdasaryan > > > --- > > > arch/x86/kernel/amd_gart_64.c | 2 +- > > > drivers/iommu/dma-iommu.c | 2 +- > > > drivers/xen/grant-dma-ops.c | 2 +- > > > drivers/xen/swiotlb-xen.c | 2 +- > > > include/linux/dma-map-ops.h | 2 +- > > > kernel/dma/mapping.c | 4 ++-- > > > 6 files changed, 7 insertions(+), 7 deletions(-) > > > > > > diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart= _64.c > > > index 56a917df410d..842a0ec5eaa9 100644 > > > --- a/arch/x86/kernel/amd_gart_64.c > > > +++ b/arch/x86/kernel/amd_gart_64.c > > > @@ -676,7 +676,7 @@ static const struct dma_map_ops gart_dma_ops =3D { > > > .get_sgtable =3D dma_common_get_sgtable, > > > .dma_supported =3D dma_direct_supported, > > > .get_required_mask =3D dma_direct_get_required_mas= k, > > > - .alloc_pages =3D dma_direct_alloc_pages, > > > + .alloc_pages_op =3D dma_direct_alloc_pages, > > > .free_pages =3D dma_direct_free_pages, > > > }; > > > > > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > > > index 7a9f0b0bddbd..76a9d5ca4eee 100644 > > > --- a/drivers/iommu/dma-iommu.c > > > +++ b/drivers/iommu/dma-iommu.c > > > @@ -1556,7 +1556,7 @@ static const struct dma_map_ops iommu_dma_ops = =3D { > > > .flags =3D DMA_F_PCI_P2PDMA_SUPPORTED, > > > .alloc =3D iommu_dma_alloc, > > > .free =3D iommu_dma_free, > > > - .alloc_pages =3D dma_common_alloc_pages, > > > + .alloc_pages_op =3D dma_common_alloc_pages, > > > .free_pages =3D dma_common_free_pages, > > > .alloc_noncontiguous =3D iommu_dma_alloc_noncontiguous, > > > .free_noncontiguous =3D iommu_dma_free_noncontiguous, > > > diff --git a/drivers/xen/grant-dma-ops.c b/drivers/xen/grant-dma-ops.c > > > index 9784a77fa3c9..6c7d984f164d 100644 > > > --- a/drivers/xen/grant-dma-ops.c > > > +++ b/drivers/xen/grant-dma-ops.c > > > @@ -282,7 +282,7 @@ static int xen_grant_dma_supported(struct device = *dev, u64 mask) > > > static const struct dma_map_ops xen_grant_dma_ops =3D { > > > .alloc =3D xen_grant_dma_alloc, > > > .free =3D xen_grant_dma_free, > > > - .alloc_pages =3D xen_grant_dma_alloc_pages, > > > + .alloc_pages_op =3D xen_grant_dma_alloc_pages, > > > .free_pages =3D xen_grant_dma_free_pages, > > > .mmap =3D dma_common_mmap, > > > .get_sgtable =3D dma_common_get_sgtable, > > > diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c > > > index 67aa74d20162..5ab2616153f0 100644 > > > --- a/drivers/xen/swiotlb-xen.c > > > +++ b/drivers/xen/swiotlb-xen.c > > > @@ -403,6 +403,6 @@ const struct dma_map_ops xen_swiotlb_dma_ops =3D { > > > .dma_supported =3D xen_swiotlb_dma_supported, > > > .mmap =3D dma_common_mmap, > > > .get_sgtable =3D dma_common_get_sgtable, > > > - .alloc_pages =3D dma_common_alloc_pages, > > > + .alloc_pages_op =3D dma_common_alloc_pages, > > > .free_pages =3D dma_common_free_pages, > > > }; > > > diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h > > > index 31f114f486c4..d741940dcb3b 100644 > > > --- a/include/linux/dma-map-ops.h > > > +++ b/include/linux/dma-map-ops.h > > > @@ -27,7 +27,7 @@ struct dma_map_ops { > > > unsigned long attrs); > > > void (*free)(struct device *dev, size_t size, void *vaddr, > > > dma_addr_t dma_handle, unsigned long attrs); > > > - struct page *(*alloc_pages)(struct device *dev, size_t size, > > > + struct page *(*alloc_pages_op)(struct device *dev, size_t size, > > > dma_addr_t *dma_handle, enum dma_data_direction= dir, > > > gfp_t gfp); > > > void (*free_pages)(struct device *dev, size_t size, struct page= *vaddr, > > > diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c > > > index 9a4db5cce600..fc42930af14b 100644 > > > --- a/kernel/dma/mapping.c > > > +++ b/kernel/dma/mapping.c > > > @@ -570,9 +570,9 @@ static struct page *__dma_alloc_pages(struct devi= ce *dev, size_t size, > > > size =3D PAGE_ALIGN(size); > > > if (dma_alloc_direct(dev, ops)) > > > return dma_direct_alloc_pages(dev, size, dma_handle, di= r, gfp); > > > - if (!ops->alloc_pages) > > > + if (!ops->alloc_pages_op) > > > return NULL; > > > - return ops->alloc_pages(dev, size, dma_handle, dir, gfp); > > > + return ops->alloc_pages_op(dev, size, dma_handle, dir, gfp); > > > } > > > > > > struct page *dma_alloc_pages(struct device *dev, size_t size, =20 > > > > I'm not impressed. This patch increases churn for code which does not > > (directly) benefit from the change, and that for limitations in your > > tooling? > > > > Why not just rename the conflicting uses in your local tree, but then > > remove the rename from the final patch series? =20 >=20 > With alloc_pages function becoming a macro, the preprocessor ends up > replacing all instances of that name, even when it's not used as a > function. That what necessitates this change. If there is a way to > work around this issue without changing all alloc_pages() calls in the > source base I would love to learn it but I'm not quite clear about > your suggestion and if it solves the issue. Could you please provide > more details? Ah, right, I admit I did not quite understand why this change is needed. However, this is exactly what I don't like about preprocessor macros. Each macro effectively adds a new keyword to the language. I believe everything can be solved with inline functions. What exactly does not work if you rename alloc_pages() to e.g. alloc_pages_caller() and then add an alloc_pages() inline function which calls alloc_pages_caller() with _RET_IP_ as a parameter? Petr T