This addresses kernel panic observed when sending SCSI UNMAP
commands to SATA disks attached to isci(4).
1) Flesh out callback routines to allocate/free buffers needed for
translating SCSI UNMAP data to ATA DSM data.
2) Add controller-level pool for storing buffers previously allocated
for UNMAP translation, to lessen chance of no buffer available
under memory pressure.
3) Ensure driver properly handles case where buffer pool is empty
and contigmalloc returns NULL.
Sponsored by: Intel
Reported by: Maksim Yevmenkin <max at netflix dot com>
Discussed with: scottl
MFC after: 3 days
The isci driver is for the integrated SAS controller in the Intel C600
(Patsburg) chipset. Source files in sys/dev/isci directory are
FreeBSD-specific, and sys/dev/isci/scil subdirectory contains
an OS-agnostic library (SCIL) published by Intel to control the SAS
controller. This library is used primarily as-is in this driver, with
some post-processing to better integrate into the kernel build
environment.
isci.4 and a README in the sys/dev/isci directory contain a few
additional details.
This driver is only built for amd64 and i386 targets.
Sponsored by: Intel
Reviewed by: scottl
Approved by: scottl