Messages in this thread Patch in this message | | | Date | Wed, 16 Apr 2008 13:48:05 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH -mm] relayfs: support larger relay buffer take 3 |
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On Wed, 16 Apr 2008 15:51:56 -0400 Masami Hiramatsu <mhiramat@redhat.com> wrote:
> +static struct page **relay_alloc_page_array(unsigned int n_pages) > +{ > + struct page **array; > + unsigned int pa_size = n_pages * sizeof(struct page *); > + > + if (pa_size > PAGE_SIZE) { > + array = vmalloc(pa_size); > + if (array) > + memset(array, 0, pa_size); > + } else { > + array = kcalloc(n_pages, sizeof(struct page *), GFP_KERNEL); > + } > + return array; > +}
It's a bit odd to multiply n_pages*sizeof() and to then call kcalloc(), which needs to do the same multiplication.
The compiler will presumably optimise that away, but still, how about this?
--- a/kernel/relay.c~relayfs-support-larger-relay-buffer-take-3-cleanup +++ a/kernel/relay.c @@ -71,14 +71,14 @@ static struct vm_operations_struct relay static struct page **relay_alloc_page_array(unsigned int n_pages) { struct page **array; - unsigned int pa_size = n_pages * sizeof(struct page *); + size_t pa_size = n_pages * sizeof(struct page *); if (pa_size > PAGE_SIZE) { array = vmalloc(pa_size); if (array) memset(array, 0, pa_size); } else { - array = kcalloc(n_pages, sizeof(struct page *), GFP_KERNEL); + array = kzalloc(pa_size, GFP_KERNEL); } return array; } _
size_t is strictly the correct type for pa_size here. Even though vmalloc() takes a ulong.
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