From ad40571b7aae5418d843ddb668d5d93fc0343300 Mon Sep 17 00:00:00 2001 From: Huacai Chen Date: Tue, 21 Nov 2017 14:23:39 +0100 Subject: [PATCH] scsi: libsas: align sata_device's rps_resp on a cacheline commit c2e8fbf908afd81ad502b567a6639598f92c9b9d upstream. The rps_resp buffer in ata_device is a DMA target, but it isn't explicitly cacheline aligned. Due to this, adjacent fields can be overwritten with stale data from memory on non-coherent architectures. As a result, the kernel is sometimes unable to communicate with an SATA device behind a SAS expander. Fix this by ensuring that the rps_resp buffer is cacheline aligned. This issue is similar to that fixed by Commit 84bda12af31f93 ("libata: align ap->sector_buf") and Commit 4ee34ea3a12396f35b26 ("libata: Align ata_device's id on a cacheline"). Signed-off-by: Huacai Chen Signed-off-by: Christoph Hellwig Signed-off-by: Martin K. Petersen [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- include/scsi/libsas.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/scsi/libsas.h b/include/scsi/libsas.h index e2c1e66d58ae..6f547906a49b 100644 --- a/include/scsi/libsas.h +++ b/include/scsi/libsas.h @@ -170,12 +170,12 @@ enum ata_command_set { struct sata_device { enum ata_command_set command_set; - struct smp_resp rps_resp; /* report_phy_sata_resp */ u8 port_no; /* port number, if this is a PM (Port) */ int pm_result; struct ata_port *ap; struct ata_host ata_host; + struct smp_resp rps_resp ____cacheline_aligned; /* report_phy_sata_resp */ u8 fis[ATA_RESP_FIS_SIZE]; };