Re: [PATCH net-next v2 11/17] ethernet: ucc_geth: don't statically allocate eight ucc_geth_info

[Christophe Leroy]

Le 19/01/2021 à 16:07, Rasmus Villemoes a écrit :

struct ucc_geth_info is somewhat large, and on systems with only one
or two UCC instances, that just wastes a few KB of memory. So
allocate and populate a chunk of memory at probe time instead of
initializing them all during driver init.

Note that the existing "ug_info == NULL" check was dead code, as the
address of some static array element can obviously never be NULL.

Signed-off-by: Rasmus Villemoes <rasmus.villem...@prevas.dk>
---
  drivers/net/ethernet/freescale/ucc_geth.c | 32 +++++++++--------------
  1 file changed, 12 insertions(+), 20 deletions(-)

diff --git a/drivers/net/ethernet/freescale/ucc_geth.c 
b/drivers/net/ethernet/freescale/ucc_geth.c
index 65ef7ae38912..67b93d60243e 100644
--- a/drivers/net/ethernet/freescale/ucc_geth.c
+++ b/drivers/net/ethernet/freescale/ucc_geth.c
@@ -157,8 +157,6 @@ static const struct ucc_geth_info ugeth_primary_info = {
        .riscRx = QE_RISC_ALLOCATION_RISC1_AND_RISC2,
  };

-static struct ucc_geth_info ugeth_info[8];

-
  #ifdef DEBUG
  static void mem_disp(u8 *addr, int size)
  {
@@ -3715,25 +3713,23 @@ static int ucc_geth_probe(struct platform_device* ofdev)
        if ((ucc_num < 0) || (ucc_num > 7))
                return -ENODEV;

- ug_info = &ugeth_info[ucc_num];

-       if (ug_info == NULL) {
-               if (netif_msg_probe(&debug))
-                       pr_err("[%d] Missing additional data!\n", ucc_num);
-               return -ENODEV;
-       }
+       ug_info = kmalloc(sizeof(*ug_info), GFP_KERNEL);

What about using devm_kmalloc() and avoid those kfree and associated goto ?

+       if (ug_info == NULL)
+               return -ENOMEM;
+       memcpy(ug_info, &ugeth_primary_info, sizeof(*ug_info));

ug_info->uf_info.ucc_num = ucc_num; err = ucc_geth_parse_clock(np, "rx", &ug_info->uf_info.rx_clock);

        if (err)
-               return err;
+               goto err_free_info;
        err = ucc_geth_parse_clock(np, "tx", &ug_info->uf_info.tx_clock);
        if (err)
-               return err;
+               goto err_free_info;

err = of_address_to_resource(np, 0, &res);

        if (err)
-               return -EINVAL;
+               goto err_free_info;

ug_info->uf_info.regs = res.start;

        ug_info->uf_info.irq = irq_of_parse_and_map(np, 0);