Re: [PATCH v2 1/1] scsi: qla2xxx: replace non-standard flexible array purex_item.iocb

["Gustavo A. R. Silva" <gustavo@embeddedor.com>]

Hi Bryan,

I wonder if you could run your tests on the patch below and let me
know if it passes. If it does, I'll go ahead and submit it as a
proper patch (including your Tested-by tag) to the SCSI list.

Thank you!
-Gustavo

> 
> The (untested) patch below avoids the use of `struct_group_tagged()`
> and the casts to `struct purex_item *`:
> 
> diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
> index cb95b7b12051..4bdf8adf04ed 100644
> --- a/drivers/scsi/qla2xxx/qla_def.h
> +++ b/drivers/scsi/qla2xxx/qla_def.h
> @@ -4890,9 +4890,7 @@ struct purex_item {
>                               struct purex_item *pkt);
>          atomic_t in_use;
>          uint16_t size;
> -       struct {
> -               uint8_t iocb[64];
> -       } iocb;
> +       uint8_t iocb[] __counted_by(size);
>   };
> 
>   #include "qla_edif.h"
> @@ -5101,7 +5099,6 @@ typedef struct scsi_qla_host {
>                  struct list_head head;
>                  spinlock_t lock;
>          } purex_list;
> -       struct purex_item default_item;
> 
>          struct name_list_extended gnl;
>          /* Count of active session/fcport */
> @@ -5130,6 +5127,10 @@ typedef struct scsi_qla_host {
>   #define DPORT_DIAG_IN_PROGRESS                 BIT_0
>   #define DPORT_DIAG_CHIP_RESET_IN_PROGRESS      BIT_1
>          uint16_t dport_status;
> +
> +       TRAILING_OVERLAP(struct purex_item, default_item, iocb,
> +               uint8_t __default_item_iocb[QLA_DEFAULT_PAYLOAD_SIZE];
> +       );
>   } scsi_qla_host_t;
> 
>   struct qla27xx_image_status {
> diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
> index c4c6b5c6658c..4559b490614d 100644
> --- a/drivers/scsi/qla2xxx/qla_isr.c
> +++ b/drivers/scsi/qla2xxx/qla_isr.c
> @@ -1077,17 +1077,17 @@ static struct purex_item *
>   qla24xx_alloc_purex_item(scsi_qla_host_t *vha, uint16_t size)
>   {
>          struct purex_item *item = NULL;
> -       uint8_t item_hdr_size = sizeof(*item);
> 
>          if (size > QLA_DEFAULT_PAYLOAD_SIZE) {
> -               item = kzalloc(item_hdr_size +
> -                   (size - QLA_DEFAULT_PAYLOAD_SIZE), GFP_ATOMIC);
> +               item = kzalloc(struct_size(item, iocb, size), GFP_ATOMIC);
>          } else {
>                  if (atomic_inc_return(&vha->default_item.in_use) == 1) {
>                          item = &vha->default_item;
>                          goto initialize_purex_header;
>                  } else {
> -                       item = kzalloc(item_hdr_size, GFP_ATOMIC);
> +                       item = kzalloc(
> +                               struct_size(item, iocb, QLA_DEFAULT_PAYLOAD_SIZE),
> +                               GFP_ATOMIC);
>                  }
>          }
>          if (!item) {
> @@ -1127,17 +1127,16 @@ qla24xx_queue_purex_item(scsi_qla_host_t *vha, struct purex_item *pkt,
>    * @vha: SCSI driver HA context
>    * @pkt: ELS packet
>    */
> -static struct purex_item
> -*qla24xx_copy_std_pkt(struct scsi_qla_host *vha, void *pkt)
> +static struct purex_item *
> +qla24xx_copy_std_pkt(struct scsi_qla_host *vha, void *pkt)
>   {
>          struct purex_item *item;
> 
> -       item = qla24xx_alloc_purex_item(vha,
> -                                       QLA_DEFAULT_PAYLOAD_SIZE);
> +       item = qla24xx_alloc_purex_item(vha, QLA_DEFAULT_PAYLOAD_SIZE);
>          if (!item)
>                  return item;
> 
> -       memcpy(&item->iocb, pkt, sizeof(item->iocb));
> +       memcpy(&item->iocb, pkt, QLA_DEFAULT_PAYLOAD_SIZE);
>          return item;
>   }
> 
> diff --git a/drivers/scsi/qla2xxx/qla_nvme.c b/drivers/scsi/qla2xxx/qla_nvme.c
> index 8ee2e337c9e1..92488890bc04 100644
> --- a/drivers/scsi/qla2xxx/qla_nvme.c
> +++ b/drivers/scsi/qla2xxx/qla_nvme.c
> @@ -1308,7 +1308,7 @@ void qla2xxx_process_purls_iocb(void **pkt, struct rsp_que **rsp)
> 
>          ql_dbg(ql_dbg_unsol, vha, 0x2121,
>                 "PURLS OP[%01x] size %d xchg addr 0x%x portid %06x\n",
> -              item->iocb.iocb[3], item->size, uctx->exchange_address,
> +              item->iocb[3], item->size, uctx->exchange_address,
>                 fcport->d_id.b24);
>          /* +48    0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F
>           * ----- -----------------------------------------------
> diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
> index d4b484c0fd9d..253f802605d6 100644
> --- a/drivers/scsi/qla2xxx/qla_os.c
> +++ b/drivers/scsi/qla2xxx/qla_os.c
> @@ -6459,9 +6459,10 @@ void qla24xx_process_purex_rdp(struct scsi_qla_host *vha,
>   void
>   qla24xx_free_purex_item(struct purex_item *item)
>   {
> -       if (item == &item->vha->default_item)
> +       if (item == &item->vha->default_item) {
>                  memset(&item->vha->default_item, 0, sizeof(struct purex_item));
> -       else
> +               memset(&item->vha->__default_item_iocb, 0, QLA_DEFAULT_PAYLOAD_SIZE);
> +       } else
>                  kfree(item);
> 
> Thanks
> -Gustavo