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[86.146.209.214]) by smtp.gmail.com with ESMTPSA id d12-20020a056000114c00b002c6d0462163sm5587695wrx.100.2023.03.15.14.43.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Mar 2023 14:43:51 -0700 (PDT) Date: Wed, 15 Mar 2023 21:43:50 +0000 From: Lorenzo Stoakes To: Vlastimil Babka Cc: Andrew Morton , "Liam R. Howlett" , Matthew Wilcox , linux-mm@kvack.org, linux-kernel@vger.kernel.org, patches@lists.linux.dev, maple-tree@lists.infradead.org Subject: Re: [PATCH 08/10] mm/mmap/vma_merge: convert mergeability checks to return bool Message-ID: <7c7f9045-feda-446c-826c-5061534afcc0@lucifer.local> References: <20230309111258.24079-1-vbabka@suse.cz> <20230309111258.24079-9-vbabka@suse.cz> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230309111258.24079-9-vbabka@suse.cz> On Thu, Mar 09, 2023 at 12:12:56PM +0100, Vlastimil Babka wrote: > The comments already mention returning 'true' so make the code match > them. > > Signed-off-by: Vlastimil Babka > --- > mm/mmap.c | 53 +++++++++++++++++++++++++---------------------------- > 1 file changed, 25 insertions(+), 28 deletions(-) > > diff --git a/mm/mmap.c b/mm/mmap.c > index c51d69592e4e..d20bbe9ec613 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -744,10 +744,10 @@ int vma_shrink(struct vma_iterator *vmi, struct vm_area_struct *vma, > * If the vma has a ->close operation then the driver probably needs to release > * per-vma resources, so we don't attempt to merge those. > */ > -static inline int is_mergeable_vma(struct vm_area_struct *vma, > - struct file *file, unsigned long vm_flags, > - struct vm_userfaultfd_ctx vm_userfaultfd_ctx, > - struct anon_vma_name *anon_name) > +static inline bool is_mergeable_vma(struct vm_area_struct *vma, > + struct file *file, unsigned long vm_flags, > + struct vm_userfaultfd_ctx vm_userfaultfd_ctx, > + struct anon_vma_name *anon_name) > { > /* > * VM_SOFTDIRTY should not prevent from VMA merging, if we > @@ -758,21 +758,20 @@ static inline int is_mergeable_vma(struct vm_area_struct *vma, > * extended instead. > */ > if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY) > - return 0; > + return false; > if (vma->vm_file != file) > - return 0; > + return false; > if (vma->vm_ops && vma->vm_ops->close) > - return 0; > + return false; > if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx)) > - return 0; > + return false; > if (!anon_vma_name_eq(anon_vma_name(vma), anon_name)) > - return 0; > - return 1; > + return false; > + return true; > } > > -static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, > - struct anon_vma *anon_vma2, > - struct vm_area_struct *vma) > +static inline bool is_mergeable_anon_vma(struct anon_vma *anon_vma1, > + struct anon_vma *anon_vma2, struct vm_area_struct *vma) > { > /* > * The list_is_singular() test is to avoid merging VMA cloned from > @@ -780,7 +779,7 @@ static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, > */ > if ((!anon_vma1 || !anon_vma2) && (!vma || > list_is_singular(&vma->anon_vma_chain))) > - return 1; > + return true; > return anon_vma1 == anon_vma2; > } > > @@ -795,19 +794,18 @@ static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, > * indices (16TB on ia32) because do_mmap() does not permit mmap's which > * wrap, nor mmaps which cover the final page at index -1UL. > */ > -static int > +static bool > can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, > - struct anon_vma *anon_vma, struct file *file, > - pgoff_t vm_pgoff, > - struct vm_userfaultfd_ctx vm_userfaultfd_ctx, > - struct anon_vma_name *anon_name) > + struct anon_vma *anon_vma, struct file *file, > + pgoff_t vm_pgoff, struct vm_userfaultfd_ctx vm_userfaultfd_ctx, > + struct anon_vma_name *anon_name) > { > if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) && > is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { > if (vma->vm_pgoff == vm_pgoff) > - return 1; > + return true; > } > - return 0; > + return false; > } > > /* > @@ -817,21 +815,20 @@ can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, > * We cannot merge two vmas if they have differently assigned (non-NULL) > * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. > */ > -static int > +static bool > can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, > - struct anon_vma *anon_vma, struct file *file, > - pgoff_t vm_pgoff, > - struct vm_userfaultfd_ctx vm_userfaultfd_ctx, > - struct anon_vma_name *anon_name) > + struct anon_vma *anon_vma, struct file *file, > + pgoff_t vm_pgoff, struct vm_userfaultfd_ctx vm_userfaultfd_ctx, > + struct anon_vma_name *anon_name) > { > if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) && > is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { > pgoff_t vm_pglen; > vm_pglen = vma_pages(vma); > if (vma->vm_pgoff + vm_pglen == vm_pgoff) > - return 1; > + return true; > } > - return 0; > + return false; > } > > /* > -- > 2.39.2 > Partying like it's C99 :) Good improvement, feels sensible to move on from using return types as if the 1st edition of The C Programming Language were still current! Therefore, Reviewed-By: Lorenzo Stoakes