scsi: core: don't preallocate small SGL in case of NO_SG_CHAIN

The preallocated small SGL depends on SG_CHAIN so if the ARCH doesn't
support SG_CHAIN, preallocation of small SGL can't work at all.

Fix this issue by not using small preallocation in case of NO_SG_CHAIN.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Ewan D. Milne <emilne@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: Ming Lei

drivers/scsi/scsi_lib.c

@@ -43,9 +43,13 @@
  * Size of integrity metadata is usually small, 1 inline sg should
  * cover normal cases.
  */
+#ifdef CONFIG_ARCH_NO_SG_CHAIN
+#define  SCSI_INLINE_PROT_SG_CNT  0
+#define  SCSI_INLINE_SG_CNT  0
+#else
 #define  SCSI_INLINE_PROT_SG_CNT  1
-
 #define  SCSI_INLINE_SG_CNT  2
+#endif
 
 static struct kmem_cache *scsi_sdb_cache;
 static struct kmem_cache *scsi_sense_cache;