On Thu, Apr 23, 2020 at 10:46:20PM +0200, Christophe JAILLET wrote:
> 'struct fc_trace_flag_type' is just a few bytes long. There is no need
> to allocate such a structure with vmalloc. Using kmalloc instead.
>
> While at it, axe a useless test when freeing the memory.
>
> Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> ---
> drivers/scsi/fnic/fnic_debugfs.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/scsi/fnic/fnic_debugfs.c b/drivers/scsi/fnic/fnic_debugfs.c
> index 13f7d88d6e57..8d6ce3470594 100644
> --- a/drivers/scsi/fnic/fnic_debugfs.c
> +++ b/drivers/scsi/fnic/fnic_debugfs.c
> @@ -58,8 +58,7 @@ int fnic_debugfs_init(void)
> fnic_trace_debugfs_root);
>
> /* Allocate memory to structure */
> - fc_trc_flag = (struct fc_trace_flag_type *)
> - vmalloc(sizeof(struct fc_trace_flag_type));
> + fc_trc_flag = kmalloc(sizeof(*fc_trc_flag), GFP_KERNEL);
>
> if (fc_trc_flag) {
I hate success handling... This test should be reversed so that we do
error handling. It should return -ENOMEM instead of 0 on allocation
failure, otherwise it leads to a NULL dereference down the road.
Although, of course in current kernel small size allocations like this
never fail in real life.
The other thing I wonder is if we should just replace the vmalloc()
implementation with kvmalloc(). IOW rename vmalloc() to __vmalloc() and
"#define vmalloc kvmalloc" (not literally). That was allocations of
less than a page would always be done with kmalloc().
regards,
dan carpenter
