scsi: hpsa: limit transfer length to 1MB
authorYadan Fan <ydfan@suse.com>
Fri, 23 Jun 2017 09:40:05 +0000 (17:40 +0800)
committerMartin K. Petersen <martin.petersen@oracle.com>
Tue, 18 Jul 2017 02:51:47 +0000 (22:51 -0400)
commite2c7b433f729cedb32514480af8cbdf2fe5cf264
treee34099c0d2c2f3cf9d672edeb6c6d9f5d457afe2
parent6f37e2102778d3437a416684680cc5ce295f2042
scsi: hpsa: limit transfer length to 1MB

The hpsa firmware will bypass the cache for any request larger than 1MB,
so we should cap the request size to avoid any performance degradation
in kernels later than v4.3

This degradation is caused from d2be537c3ba3568acd79cd178327b842e60d035e,
which changed max_sectors_kb to 1280k, but the hardware is able to work
fine with it, so the true fix should be from hpsa driver.

Signed-off-by: Yadan Fan <ydfan@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Acked-by: Don Brace <don.brace@microsemi.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
drivers/scsi/hpsa.c