Commit 35b4bfbd authored by Huacai Chen's avatar Huacai Chen Committed by Greg Kroah-Hartman

scsi: libsas: align sata_device's rps_resp on a cacheline

commit c2e8fbf9 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 84bda12a ("libata:
align ap->sector_buf") and Commit 4ee34ea3 ("libata: Align
ata_device's id on a cacheline").
Signed-off-by: default avatarHuacai Chen <>
Signed-off-by: default avatarChristoph Hellwig <>
Signed-off-by: default avatarMartin K. Petersen <>
Signed-off-by: default avatarGreg Kroah-Hartman <>
parent 326ebe77
......@@ -165,11 +165,11 @@ struct expander_device {
struct sata_device {
unsigned int class;
struct smp_resp rps_resp; /* report_phy_sata_resp */
u8 port_no; /* port number, if this is a PM (Port) */
struct ata_port *ap;
struct ata_host ata_host;
struct smp_resp rps_resp ____cacheline_aligned; /* report_phy_sata_resp */
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