scsi: ibmvscsis: Silence -Warray-bounds warning

Instead of doing a cast to storage that is too small, add a union for the
high 64 bits. Silences the warnings under -Warray-bounds:

drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c: In function 'ibmvscsis_send_messages':
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:1934:44: error: array subscript 'struct viosrp_crq[0]' is partly outside array bounds of 'u64[1]' {aka 'long long unsigned int[1]'} [-Werror=array-bounds]
 1934 |                                         crq->valid = VALID_CMD_RESP_EL;
      |                                            ^~
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c:1875:13: note: while referencing 'msg_hi'
 1875 |         u64 msg_hi = 0;
      |             ^~~~~~

There is no change to the resulting binary instructions.

Link: https://lore.kernel.org/lkml/20220125142430.75c3160e@canb.auug.org.au
Link: https://lore.kernel.org/r/20220208061231.3429486-1-keescook@chromium.org
Cc: Michael Cyr <mikecyr@linux.ibm.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Tyrel Datwyler <tyreld@linux.ibm.com>
Cc: linux-scsi@vger.kernel.org
Cc: target-devel@vger.kernel.org
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
index 61f06f6885a5626920a34e115fd9935aefd85c74..80238e6a3c9839294b438e7f74e1fb4602c36ca5 100644 (file)
--- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
+++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
@@ -1872,11 +1872,8 @@ static void srp_snd_msg_failed(struct scsi_info *vscsi, long rc)
  */
 static void ibmvscsis_send_messages(struct scsi_info *vscsi)
 {
-       u64 msg_hi = 0;
-       /* note do not attempt to access the IU_data_ptr with this pointer
-        * it is not valid
-        */
-       struct viosrp_crq *crq = (struct viosrp_crq *)&msg_hi;
+       struct viosrp_crq empty_crq = { };
+       struct viosrp_crq *crq = &empty_crq;
        struct ibmvscsis_cmd *cmd, *nxt;
        long rc = ADAPT_SUCCESS;
        bool retry = false;
@@ -1940,7 +1937,7 @@ static void ibmvscsis_send_messages(struct scsi_info *vscsi)
                                        crq->IU_length = cpu_to_be16(cmd->rsp.len);
 
                                        rc = h_send_crq(vscsi->dma_dev->unit_address,
-                                                       be64_to_cpu(msg_hi),
+                                                       be64_to_cpu(crq->high),
                                                        be64_to_cpu(cmd->rsp.tag));
 
                                        dev_dbg(&vscsi->dev, "send_messages: cmd %p, tag 0x%llx, rc %ld\n",

diff --git a/include/scsi/viosrp.h b/include/scsi/viosrp.h
index c978133c83e37d8ee48e53c4596e21026b2e962b..6c5559d2b28542f66413a5aae4772975920484b4 100644 (file)
--- a/include/scsi/viosrp.h
+++ b/include/scsi/viosrp.h
@@ -70,12 +70,17 @@ enum viosrp_crq_status {
 };
 
 struct viosrp_crq {
-       u8 valid;               /* used by RPA */
-       u8 format;              /* SCSI vs out-of-band */
-       u8 reserved;
-       u8 status;              /* non-scsi failure? (e.g. DMA failure) */
-       __be16 timeout;         /* in seconds */
-       __be16 IU_length;               /* in bytes */
+       union {
+               __be64 high;                    /* High 64 bits */
+               struct {
+                       u8 valid;               /* used by RPA */
+                       u8 format;              /* SCSI vs out-of-band */
+                       u8 reserved;
+                       u8 status;              /* non-scsi failure? (e.g. DMA failure) */
+                       __be16 timeout;         /* in seconds */
+                       __be16 IU_length;       /* in bytes */
+               };
+       };
        __be64 IU_data_ptr;     /* the TCE for transferring data */
 };