[PATCH v9 16/19] scsi: scsi_debug: Allocate the MODE SENSE response from the heap

[Bart Van Assche <bvanassche@acm.org>]

Make the MODE SENSE response buffer larger and allocate it from the heap.
This patch prepares for adding support for the IO Advice Hints Grouping
mode page.

Suggested-by: Douglas Gilbert <dgilbert@interlog.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Tested-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/scsi_debug.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 67a8e6243e5e..b544498324f6 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -43,6 +43,7 @@
 #include <linux/prefetch.h>
 #include <linux/debugfs.h>
 #include <linux/async.h>
+#include <linux/cleanup.h>
 
 #include <net/checksum.h>
 
@@ -2631,7 +2632,8 @@ static int resp_sas_sha_m_spg(unsigned char *p, int pcontrol)
 	return sizeof(sas_sha_m_pg);
 }
 
-#define SDEBUG_MAX_MSENSE_SZ 256
+/* PAGE_SIZE is more than necessary but provides room for future expansion. */
+#define SDEBUG_MAX_MSENSE_SZ PAGE_SIZE
 
 static int resp_mode_sense(struct scsi_cmnd *scp,
 			   struct sdebug_dev_info *devip)
@@ -2642,10 +2644,13 @@ static int resp_mode_sense(struct scsi_cmnd *scp,
 	int target_dev_id;
 	int target = scp->device->id;
 	unsigned char *ap;
-	unsigned char arr[SDEBUG_MAX_MSENSE_SZ];
+	unsigned char *arr __free(kfree);
 	unsigned char *cmd = scp->cmnd;
 	bool dbd, llbaa, msense_6, is_disk, is_zbc;
 
+	arr = kzalloc(SDEBUG_MAX_MSENSE_SZ, GFP_ATOMIC);
+	if (!arr)
+		return -ENOMEM;
 	dbd = !!(cmd[1] & 0x8);		/* disable block descriptors */
 	pcontrol = (cmd[2] & 0xc0) >> 6;
 	pcode = cmd[2] & 0x3f;