linux_dsm_epyc7002/include/uapi/scsi/cxlflash_ioctl.h
Matthew R. Ochs d5e26bb1d8 cxlflash: Fix to avoid virtual LUN failover failure
Applications which use virtual LUN's that are backed by a physical LUN
over both adapter ports may experience an I/O failure in the event of a
link loss (e.g. cable pull).

Virtual LUNs may be accessed through one or both ports of the adapter.
This access is encoded in the translation entries that comprise the
virtual LUN and used by the AFU for load-balancing I/O and handling
failover scenarios. In a link loss scenario, even though the AFU is able
to maintain connectivity to the LUN, it is up to the application to
retry the failed I/O. When applications are unaware of the virtual LUN's
underlying topology, they are unable to make a sound decision of when to
retry an I/O and therefore are forced to make their reaction to a failed
I/O absolute. The result is either a failure to retry I/O or increased
latency for scenarios where a retry is pointless.

To remedy this scenario, provide feedback back to the application on
virtual LUN creation as to which ports the LUN may be accessed. LUN's
spanning both ports are candidates for a retry in a presence of an I/O
failure.

Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Acked-by: Manoj Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2016-01-06 20:50:08 -05:00

185 lines
6.7 KiB
C

/*
* CXL Flash Device Driver
*
* Written by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>, IBM Corporation
* Matthew R. Ochs <mrochs@linux.vnet.ibm.com>, IBM Corporation
*
* Copyright (C) 2015 IBM Corporation
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _CXLFLASH_IOCTL_H
#define _CXLFLASH_IOCTL_H
#include <linux/types.h>
/*
* Structure and flag definitions CXL Flash superpipe ioctls
*/
#define DK_CXLFLASH_VERSION_0 0
struct dk_cxlflash_hdr {
__u16 version; /* Version data */
__u16 rsvd[3]; /* Reserved for future use */
__u64 flags; /* Input flags */
__u64 return_flags; /* Returned flags */
};
/*
* Return flag definitions available to all ioctls
*
* Similar to the input flags, these are grown from the bottom-up with the
* intention that ioctl-specific return flag definitions would grow from the
* top-down, allowing the two sets to co-exist. While not required/enforced
* at this time, this provides future flexibility.
*/
#define DK_CXLFLASH_ALL_PORTS_ACTIVE 0x0000000000000001ULL
/*
* Notes:
* -----
* The 'context_id' field of all ioctl structures contains the context
* identifier for a context in the lower 32-bits (upper 32-bits are not
* to be used when identifying a context to the AFU). That said, the value
* in its entirety (all 64-bits) is to be treated as an opaque cookie and
* should be presented as such when issuing ioctls.
*
* For DK_CXLFLASH_ATTACH ioctl, user specifies read/write access
* permissions via the O_RDONLY, O_WRONLY, and O_RDWR flags defined in
* the fcntl.h header file.
*/
#define DK_CXLFLASH_ATTACH_REUSE_CONTEXT 0x8000000000000000ULL
struct dk_cxlflash_attach {
struct dk_cxlflash_hdr hdr; /* Common fields */
__u64 num_interrupts; /* Requested number of interrupts */
__u64 context_id; /* Returned context */
__u64 mmio_size; /* Returned size of MMIO area */
__u64 block_size; /* Returned block size, in bytes */
__u64 adap_fd; /* Returned adapter file descriptor */
__u64 last_lba; /* Returned last LBA on the device */
__u64 max_xfer; /* Returned max transfer size, blocks */
__u64 reserved[8]; /* Reserved for future use */
};
struct dk_cxlflash_detach {
struct dk_cxlflash_hdr hdr; /* Common fields */
__u64 context_id; /* Context to detach */
__u64 reserved[8]; /* Reserved for future use */
};
struct dk_cxlflash_udirect {
struct dk_cxlflash_hdr hdr; /* Common fields */
__u64 context_id; /* Context to own physical resources */
__u64 rsrc_handle; /* Returned resource handle */
__u64 last_lba; /* Returned last LBA on the device */
__u64 reserved[8]; /* Reserved for future use */
};
#define DK_CXLFLASH_UVIRTUAL_NEED_WRITE_SAME 0x8000000000000000ULL
struct dk_cxlflash_uvirtual {
struct dk_cxlflash_hdr hdr; /* Common fields */
__u64 context_id; /* Context to own virtual resources */
__u64 lun_size; /* Requested size, in 4K blocks */
__u64 rsrc_handle; /* Returned resource handle */
__u64 last_lba; /* Returned last LBA of LUN */
__u64 reserved[8]; /* Reserved for future use */
};
struct dk_cxlflash_release {
struct dk_cxlflash_hdr hdr; /* Common fields */
__u64 context_id; /* Context owning resources */
__u64 rsrc_handle; /* Resource handle to release */
__u64 reserved[8]; /* Reserved for future use */
};
struct dk_cxlflash_resize {
struct dk_cxlflash_hdr hdr; /* Common fields */
__u64 context_id; /* Context owning resources */
__u64 rsrc_handle; /* Resource handle of LUN to resize */
__u64 req_size; /* New requested size, in 4K blocks */
__u64 last_lba; /* Returned last LBA of LUN */
__u64 reserved[8]; /* Reserved for future use */
};
struct dk_cxlflash_clone {
struct dk_cxlflash_hdr hdr; /* Common fields */
__u64 context_id_src; /* Context to clone from */
__u64 context_id_dst; /* Context to clone to */
__u64 adap_fd_src; /* Source context adapter fd */
__u64 reserved[8]; /* Reserved for future use */
};
#define DK_CXLFLASH_VERIFY_SENSE_LEN 18
#define DK_CXLFLASH_VERIFY_HINT_SENSE 0x8000000000000000ULL
struct dk_cxlflash_verify {
struct dk_cxlflash_hdr hdr; /* Common fields */
__u64 context_id; /* Context owning resources to verify */
__u64 rsrc_handle; /* Resource handle of LUN */
__u64 hint; /* Reasons for verify */
__u64 last_lba; /* Returned last LBA of device */
__u8 sense_data[DK_CXLFLASH_VERIFY_SENSE_LEN]; /* SCSI sense data */
__u8 pad[6]; /* Pad to next 8-byte boundary */
__u64 reserved[8]; /* Reserved for future use */
};
#define DK_CXLFLASH_RECOVER_AFU_CONTEXT_RESET 0x8000000000000000ULL
struct dk_cxlflash_recover_afu {
struct dk_cxlflash_hdr hdr; /* Common fields */
__u64 reason; /* Reason for recovery request */
__u64 context_id; /* Context to recover / updated ID */
__u64 mmio_size; /* Returned size of MMIO area */
__u64 adap_fd; /* Returned adapter file descriptor */
__u64 reserved[8]; /* Reserved for future use */
};
#define DK_CXLFLASH_MANAGE_LUN_WWID_LEN 16
#define DK_CXLFLASH_MANAGE_LUN_ENABLE_SUPERPIPE 0x8000000000000000ULL
#define DK_CXLFLASH_MANAGE_LUN_DISABLE_SUPERPIPE 0x4000000000000000ULL
#define DK_CXLFLASH_MANAGE_LUN_ALL_PORTS_ACCESSIBLE 0x2000000000000000ULL
struct dk_cxlflash_manage_lun {
struct dk_cxlflash_hdr hdr; /* Common fields */
__u8 wwid[DK_CXLFLASH_MANAGE_LUN_WWID_LEN]; /* Page83 WWID, NAA-6 */
__u64 reserved[8]; /* Rsvd, future use */
};
union cxlflash_ioctls {
struct dk_cxlflash_attach attach;
struct dk_cxlflash_detach detach;
struct dk_cxlflash_udirect udirect;
struct dk_cxlflash_uvirtual uvirtual;
struct dk_cxlflash_release release;
struct dk_cxlflash_resize resize;
struct dk_cxlflash_clone clone;
struct dk_cxlflash_verify verify;
struct dk_cxlflash_recover_afu recover_afu;
struct dk_cxlflash_manage_lun manage_lun;
};
#define MAX_CXLFLASH_IOCTL_SZ (sizeof(union cxlflash_ioctls))
#define CXL_MAGIC 0xCA
#define CXL_IOWR(_n, _s) _IOWR(CXL_MAGIC, _n, struct _s)
#define DK_CXLFLASH_ATTACH CXL_IOWR(0x80, dk_cxlflash_attach)
#define DK_CXLFLASH_USER_DIRECT CXL_IOWR(0x81, dk_cxlflash_udirect)
#define DK_CXLFLASH_RELEASE CXL_IOWR(0x82, dk_cxlflash_release)
#define DK_CXLFLASH_DETACH CXL_IOWR(0x83, dk_cxlflash_detach)
#define DK_CXLFLASH_VERIFY CXL_IOWR(0x84, dk_cxlflash_verify)
#define DK_CXLFLASH_RECOVER_AFU CXL_IOWR(0x85, dk_cxlflash_recover_afu)
#define DK_CXLFLASH_MANAGE_LUN CXL_IOWR(0x86, dk_cxlflash_manage_lun)
#define DK_CXLFLASH_USER_VIRTUAL CXL_IOWR(0x87, dk_cxlflash_uvirtual)
#define DK_CXLFLASH_VLUN_RESIZE CXL_IOWR(0x88, dk_cxlflash_resize)
#define DK_CXLFLASH_VLUN_CLONE CXL_IOWR(0x89, dk_cxlflash_clone)
#endif /* ifndef _CXLFLASH_IOCTL_H */