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

Chris Leech
2025-07-28T18:58:39Z

purex_item.iocb is defined as a 64-element u8 array, but 64 is the
minimum size and it can be allocated larger.
This makes it a standard empty flex array.

This was motivated by field-spanning write warnings during FPIN testing.
https://lore.kernel.org/linux-nvme/20250709211919.49100-1-bgurney@redhat.com/

> kernel: memcpy: detected field-spanning write (size 60) of single field
> "((uint8_t *)fpin_pkt + buffer_copy_offset)"
> at drivers/scsi/qla2xxx/qla_isr.c:1221 (size 44)

I removed the outer wrapper from the iocb flex array, so that it can be
linked to purex_item.size with __counted_by.

The non-flex-array portion of purex_item is now defined within the
struct_group_tagged macro to create a type definition for just the
header. This was then used for the scsi_qla_host.default_item
definition to deal with -Wflex-array-member-not-at-end warnings.

These changes remove the default minimum 64-byte allocation, requiring
further changes.

In struct scsi_qla_host the embedded default_item is now followed by
__default_item_iocb[QLA_DEFAULT_PAYLOAD_SIZE] to reserve space that
will be used as default_item.iocb

qla24xx_alloc_purex_item is adjusted to no longer expect the default
minimum size to be part of sizeof(struct purex_item), the entire
flexible array size is added to the structure size for allocation.

This also slightly changes the layout of the purex_item struct, as
2-bytes of padding are added to purex_item_hdr and therefor between size
and iocb. The resulting size is the same, but iocb is shifted 2-bytes
(the old purex_item was padded at the end, after the 64-byte defined
array size). I don't think this is a problem.

Tested-by: Bryan Gurney <bgurney@redhat.com>
Signed-off-by: Chris Leech <cleech@redhat.com>
---
drivers/scsi/qla2xxx/qla_def.h | 23 ++++++++++++-----------
drivers/scsi/qla2xxx/qla_isr.c | 19 +++++++++----------
drivers/scsi/qla2xxx/qla_nvme.c | 2 +-
drivers/scsi/qla2xxx/qla_os.c | 9 +++++----
4 files changed, 27 insertions(+), 26 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
index cb95b7b12051d..0e7d201b1feb0 100644
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -4883,16 +4883,16 @@ struct active_regions {
* is variable) starting at "iocb".
*/
struct purex_item {
- void *purls_context;
- struct list_head list;
- struct scsi_qla_host *vha;
- void (*process_item)(struct scsi_qla_host *vha,
- struct purex_item *pkt);
- atomic_t in_use;
- uint16_t size;
- struct {
- uint8_t iocb[64];
- } iocb;
+ struct_group_tagged(purex_item_hdr, __hdr,
+ void *purls_context;
+ struct list_head list;
+ struct scsi_qla_host *vha;
+ void (*process_item)(struct scsi_qla_host *vha,
+ struct purex_item *pkt);
+ atomic_t in_use;
+ uint16_t size;
+ );
+ uint8_t iocb[] __counted_by(size);
};

#include "qla_edif.h"
@@ -5101,7 +5101,8 @@ typedef struct scsi_qla_host {
struct list_head head;
spinlock_t lock;
} purex_list;
- struct purex_item default_item;
+ struct purex_item_hdr default_item;
+ uint8_t __default_item_iocb[QLA_DEFAULT_PAYLOAD_SIZE];

struct name_list_extended gnl;
/* Count of active session/fcport */
diff --git a/drivers/scsi/qla2xxx/qla_isr.c b/drivers/scsi/qla2xxx/qla_isr.c
index fe98c76e9be32..a00c06a9898ec 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;
+ item = (struct purex_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 8ee2e337c9e1b..92488890bc04e 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 d4b484c0fd9d7..ef8a4fce0e03c 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -3971,7 +3971,7 @@ qla2x00_remove_one(struct pci_dev *pdev)
static inline void
qla24xx_free_purex_list(struct purex_list *list)
{
- struct purex_item *item, *next;
+ struct purex_item_hdr *item, *next;
ulong flags;

spin_lock_irqsave(&list->lock, flags);
@@ -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)
- memset(&item->vha->default_item, 0, sizeof(struct purex_item));
- else
+ if (item == (struct purex_item *)&item->vha->default_item) {
+ memset(&item->vha->default_item, 0, sizeof(struct purex_item_hdr));
+ memset(&item->vha->__default_item_iocb, 0, QLA_DEFAULT_PAYLOAD_SIZE);
+ } else
kfree(item);
}

--
2.50.1