| Message ID | 20190115211140.GA16131@embeddedor |
|---|---|
| State | Not Applicable |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net-next] svcrdma: Use struct_size() in kmalloc() | expand |
On Tue, Jan 15, 2019 at 04:49:16PM -0500, 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> Thanks, applying for 5.1.--b. > > > > --- > > 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 > >
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;
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> --- net/sunrpc/xprtrdma/svc_rdma_rw.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)