diff mbox series

[next] scsi: mpt3sas: Replace unnecessary dynamic allocation with a static one

Message ID 20210310235951.GA108661@embeddedor (mailing list archive)
State Accepted
Headers show
Series [next] scsi: mpt3sas: Replace unnecessary dynamic allocation with a static one | expand

Commit Message

Gustavo A. R. Silva March 10, 2021, 11:59 p.m. UTC
Dynamic memory allocation isn't actually needed and it can be
replaced by statically allocating memory for struct object
io_unit_pg3 with 36 hardcoded entries for its GPIOVal array.

Also, this helps the with ongoing efforts to enable -Warray-bounds
by fixing the following warning:

drivers/scsi/mpt3sas/mpt3sas_ctl.c: In function ‘BRM_status_show’:
drivers/scsi/mpt3sas/mpt3sas_ctl.c:3257:63: warning: array subscript 24 is above array bounds of ‘U16[1]’ {aka ‘short unsigned int[1]’} [-Warray-bounds]
 3257 |  backup_rail_monitor_status = le16_to_cpu(io_unit_pg3->GPIOVal[24]);
./include/uapi/linux/byteorder/little_endian.h:36:51: note: in definition of macro ‘__le16_to_cpu’
   36 | #define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
      |                                                   ^
drivers/scsi/mpt3sas/mpt3sas_ctl.c:3257:31: note: in expansion of macro ‘le16_to_cpu’
 3257 |  backup_rail_monitor_status = le16_to_cpu(io_unit_pg3->GPIOVal[24]);

Link: https://github.com/KSPP/linux/issues/109
Link: https://lore.kernel.org/lkml/202103101058.16ED27BE3@keescook/
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/scsi/mpt3sas/mpi/mpi2_cnfg.h |  2 +-
 drivers/scsi/mpt3sas/mpt3sas_ctl.c   | 24 ++++++++----------------
 2 files changed, 9 insertions(+), 17 deletions(-)

Comments

Gustavo A. R. Silva March 17, 2021, 2:41 a.m. UTC | #1
Hi Martin,

On 3/16/21 22:32, Martin K. Petersen wrote:
> 
> Gustavo,
> 
>> Dynamic memory allocation isn't actually needed and it can be replaced
>> by statically allocating memory for struct object io_unit_pg3 with 36
>> hardcoded entries for its GPIOVal array.
> 
> Applied to 5.13/scsi-staging, thanks!

Awesome. :)

I wonder if you can take a look at this one, too, please:

https://lore.kernel.org/lkml/20210304203822.GA102218@embeddedor/

Thanks!
--
Gustavo
Martin K. Petersen March 17, 2021, 3:32 a.m. UTC | #2
Gustavo,

> Dynamic memory allocation isn't actually needed and it can be replaced
> by statically allocating memory for struct object io_unit_pg3 with 36
> hardcoded entries for its GPIOVal array.

Applied to 5.13/scsi-staging, thanks!
Martin K. Petersen March 19, 2021, 3:46 a.m. UTC | #3
On Wed, 10 Mar 2021 17:59:51 -0600, Gustavo A. R. Silva wrote:

> Dynamic memory allocation isn't actually needed and it can be
> replaced by statically allocating memory for struct object
> io_unit_pg3 with 36 hardcoded entries for its GPIOVal array.
> 
> Also, this helps the with ongoing efforts to enable -Warray-bounds
> by fixing the following warning:
> 
> [...]

Applied to 5.13/scsi-queue, thanks!

[1/1] scsi: mpt3sas: Replace unnecessary dynamic allocation with a static one
      https://git.kernel.org/mkp/scsi/c/a1c4d7741323
diff mbox series

Patch

diff --git a/drivers/scsi/mpt3sas/mpi/mpi2_cnfg.h b/drivers/scsi/mpt3sas/mpi/mpi2_cnfg.h
index 43a3bf8ff428..d00431f553e1 100644
--- a/drivers/scsi/mpt3sas/mpi/mpi2_cnfg.h
+++ b/drivers/scsi/mpt3sas/mpi/mpi2_cnfg.h
@@ -992,7 +992,7 @@  typedef struct _MPI2_CONFIG_PAGE_IO_UNIT_1 {
  *one and check the value returned for GPIOCount at runtime.
  */
 #ifndef MPI2_IO_UNIT_PAGE_3_GPIO_VAL_MAX
-#define MPI2_IO_UNIT_PAGE_3_GPIO_VAL_MAX    (1)
+#define MPI2_IO_UNIT_PAGE_3_GPIO_VAL_MAX    (36)
 #endif
 
 typedef struct _MPI2_CONFIG_PAGE_IO_UNIT_3 {
diff --git a/drivers/scsi/mpt3sas/mpt3sas_ctl.c b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
index 44f9a05db94e..bc56e058a523 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_ctl.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
@@ -3203,7 +3203,7 @@  BRM_status_show(struct device *cdev, struct device_attribute *attr,
 {
 	struct Scsi_Host *shost = class_to_shost(cdev);
 	struct MPT3SAS_ADAPTER *ioc = shost_priv(shost);
-	Mpi2IOUnitPage3_t *io_unit_pg3 = NULL;
+	Mpi2IOUnitPage3_t io_unit_pg3;
 	Mpi2ConfigReply_t mpi_reply;
 	u16 backup_rail_monitor_status = 0;
 	u16 ioc_status;
@@ -3220,17 +3220,10 @@  BRM_status_show(struct device *cdev, struct device_attribute *attr,
 	if (ioc->pci_error_recovery || ioc->remove_host)
 		goto out;
 
-	/* allocate upto GPIOVal 36 entries */
-	sz = offsetof(Mpi2IOUnitPage3_t, GPIOVal) + (sizeof(u16) * 36);
-	io_unit_pg3 = kzalloc(sz, GFP_KERNEL);
-	if (!io_unit_pg3) {
-		rc = -ENOMEM;
-		ioc_err(ioc, "%s: failed allocating memory for iounit_pg3: (%d) bytes\n",
-			__func__, sz);
-		goto out;
-	}
+	sz = sizeof(io_unit_pg3);
+	memset(&io_unit_pg3, 0, sz);
 
-	if (mpt3sas_config_get_iounit_pg3(ioc, &mpi_reply, io_unit_pg3, sz) !=
+	if (mpt3sas_config_get_iounit_pg3(ioc, &mpi_reply, &io_unit_pg3, sz) !=
 	    0) {
 		ioc_err(ioc, "%s: failed reading iounit_pg3\n",
 			__func__);
@@ -3246,19 +3239,18 @@  BRM_status_show(struct device *cdev, struct device_attribute *attr,
 		goto out;
 	}
 
-	if (io_unit_pg3->GPIOCount < 25) {
-		ioc_err(ioc, "%s: iounit_pg3->GPIOCount less than 25 entries, detected (%d) entries\n",
-			__func__, io_unit_pg3->GPIOCount);
+	if (io_unit_pg3.GPIOCount < 25) {
+		ioc_err(ioc, "%s: iounit_pg3.GPIOCount less than 25 entries, detected (%d) entries\n",
+			__func__, io_unit_pg3.GPIOCount);
 		rc = -EINVAL;
 		goto out;
 	}
 
 	/* BRM status is in bit zero of GPIOVal[24] */
-	backup_rail_monitor_status = le16_to_cpu(io_unit_pg3->GPIOVal[24]);
+	backup_rail_monitor_status = le16_to_cpu(io_unit_pg3.GPIOVal[24]);
 	rc = snprintf(buf, PAGE_SIZE, "%d\n", (backup_rail_monitor_status & 1));
 
  out:
-	kfree(io_unit_pg3);
 	mutex_unlock(&ioc->pci_access_mutex);
 	return rc;
 }