Messages in this thread | | | Subject | Re: [PATCH net-next] svcrdma: Use struct_size() in kmalloc() | From | "Gustavo A. R. Silva" <> | Date | Tue, 15 Jan 2019 15:53:48 -0600 |
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On 1/15/19 3:49 PM, Chuck Lever wrote: > > > On Jan 15, 2019, at 4:11 PM, Gustavo A. R. Silva <gustavo@embeddedor.com> wrote: > >> One of the more common cases of allocation size calculations is finding >> the size of a structure that has a zero-sized array at the end, along >> with memory for some number of elements for that array. For example: >> >> struct foo { >> int stuff; >> struct boo entry[]; >> }; >> >> instance = kmalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL); >> >> Instead of leaving these open-coded and prone to type mistakes, we can >> now use the new struct_size() helper: >> >> instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL); >> >> This code was detected with the help of Coccinelle. >> >> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> > > Reviewed-by: Chuck Lever <chuck.lever@oracle.com> >
Thank you, Chuck. -- Gustavo
> >> --- >> net/sunrpc/xprtrdma/svc_rdma_rw.c | 3 +-- >> 1 file changed, 1 insertion(+), 2 deletions(-) >> >> diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c >> index dc1951759a8e..cad37c2122ab 100644 >> --- a/net/sunrpc/xprtrdma/svc_rdma_rw.c >> +++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c >> @@ -64,8 +64,7 @@ svc_rdma_get_rw_ctxt(struct svcxprt_rdma *rdma, unsigned int sges) >> spin_unlock(&rdma->sc_rw_ctxt_lock); >> } else { >> spin_unlock(&rdma->sc_rw_ctxt_lock); >> - ctxt = kmalloc(sizeof(*ctxt) + >> - SG_CHUNK_SIZE * sizeof(struct scatterlist), >> + ctxt = kmalloc(struct_size(ctxt, rw_first_sgl, SG_CHUNK_SIZE), >> GFP_KERNEL); >> if (!ctxt) >> goto out; >> -- >> 2.20.1 > > -- > Chuck Lever > > >
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