linux/drivers/scsi/cxlflash/superpipe.h
Matthew R. Ochs 1a47401bb3 cxlflash: Fix to avoid corrupting port selection mask
The port selection mask of a LUN can be corrupted when the manage LUN
ioctl (DK_CXLFLASH_MANAGE_LUN) is issued more than once for any device.

This mask indicates to the AFU which port[s] can be used for a data
transfer to/from a particular LUN. The mask is critical to ensuring the
correct behavior when using the virtual LUN function of this adapter.
When the mask is configured for both ports, an I/O may be sent to either
port as the AFU assumes that each port has access to the same physical
device (specified by LUN ID in the port LUN table).

In a situation where the mask becomes incorrectly configured to reflect
access to both ports when in fact there is only access through a single
port, an I/O can be targeted to the wrong physical device. This can lead
to data corruption among other ill effects (e.g. security leaks).

The cause for this corruption is the assumption that the ioctl will only
be called a second time for a LUN when it is being configured for access
via a second port. A boolean 'newly_created' variable is used to
differentiate between a LUN that was created (and subsequently configured
for single port access) and one that is destined for access across both
ports. While initially set to 'true', this sticky boolean is toggled to
the 'false' state during a lookup on any next ioctl performed on a device
with a matching WWN/WWID. The code fails to realize that the match could
in fact be the same device calling in again. From here, an assumption is
made that any LUN with 'newly_created' set to 'false' is configured for
access over both ports and the port selection mask is set to reflect this.
Any future attempts to use this LUN for hosting a virtual LUN will result
in the port LUN table being incorrectly programmed.

As a remedy, the 'newly_created' concept was removed entirely and replaced
with code that always constructs the port selection mask based upon the
SCSI channel of the LUN being accessed. The bits remain sticky, therefore
allowing for a device to be accessed over both ports when that is in fact
the correct physical configuration.

Also included in this commit are a few minor related changes to enhance
the fix and provide better debug information for port selection mask and
port LUN table bugs in the future. These include renaming refresh_local()
to lookup_local(), tracing the WWN/WWID as a big-endian entity, and
tracing the port selection mask, SCSI channel, and LUN ID each time the
port LUN table is programmed.

Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Acked-by: Manoj Kumar <manoj@linux.vnet.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-10-30 17:23:55 +09:00

152 lines
4.6 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_SUPERPIPE_H
#define _CXLFLASH_SUPERPIPE_H
extern struct cxlflash_global global;
/*
* Terminology: use afu (and not adapter) to refer to the HW.
* Adapter is the entire slot and includes PSL out of which
* only the AFU is visible to user space.
*/
/* Chunk size parms: note sislite minimum chunk size is
0x10000 LBAs corresponding to a NMASK or 16.
*/
#define MC_CHUNK_SIZE (1 << MC_RHT_NMASK) /* in LBAs */
#define CMD_TIMEOUT 30 /* 30 secs */
#define CMD_RETRIES 5 /* 5 retries for scsi_execute */
#define MAX_SECTOR_UNIT 512 /* max_sector is in 512 byte multiples */
#define CHAN2PORT(_x) ((_x) + 1)
#define PORT2CHAN(_x) ((_x) - 1)
enum lun_mode {
MODE_NONE = 0,
MODE_VIRTUAL,
MODE_PHYSICAL
};
/* Global (entire driver, spans adapters) lun_info structure */
struct glun_info {
u64 max_lba; /* from read cap(16) */
u32 blk_len; /* from read cap(16) */
enum lun_mode mode; /* NONE, VIRTUAL, PHYSICAL */
int users; /* Number of users w/ references to LUN */
u8 wwid[16];
struct mutex mutex;
struct blka blka;
struct list_head list;
};
/* Local (per-adapter) lun_info structure */
struct llun_info {
u64 lun_id[CXLFLASH_NUM_FC_PORTS]; /* from REPORT_LUNS */
u32 lun_index; /* Index in the LUN table */
u32 host_no; /* host_no from Scsi_host */
u32 port_sel; /* What port to use for this LUN */
bool in_table; /* Whether a LUN table entry was created */
u8 wwid[16]; /* Keep a duplicate copy here? */
struct glun_info *parent; /* Pointer to entry in global LUN structure */
struct scsi_device *sdev;
struct list_head list;
};
struct lun_access {
struct llun_info *lli;
struct scsi_device *sdev;
struct list_head list;
};
enum ctx_ctrl {
CTX_CTRL_CLONE = (1 << 1),
CTX_CTRL_ERR = (1 << 2),
CTX_CTRL_ERR_FALLBACK = (1 << 3),
CTX_CTRL_NOPID = (1 << 4),
CTX_CTRL_FILE = (1 << 5)
};
#define ENCODE_CTXID(_ctx, _id) (((((u64)_ctx) & 0xFFFFFFFF0ULL) << 28) | _id)
#define DECODE_CTXID(_val) (_val & 0xFFFFFFFF)
struct ctx_info {
struct sisl_ctrl_map __iomem *ctrl_map; /* initialized at startup */
struct sisl_rht_entry *rht_start; /* 1 page (req'd for alignment),
alloc/free on attach/detach */
u32 rht_out; /* Number of checked out RHT entries */
u32 rht_perms; /* User-defined permissions for RHT entries */
struct llun_info **rht_lun; /* Mapping of RHT entries to LUNs */
u8 *rht_needs_ws; /* User-desired write-same function per RHTE */
struct cxl_ioctl_start_work work;
u64 ctxid;
int lfd;
pid_t pid;
bool unavail;
bool err_recovery_active;
struct mutex mutex; /* Context protection */
struct cxl_context *ctx;
struct list_head luns; /* LUNs attached to this context */
const struct vm_operations_struct *cxl_mmap_vmops;
struct file *file;
struct list_head list; /* Link contexts in error recovery */
};
struct cxlflash_global {
struct mutex mutex;
struct list_head gluns;/* list of glun_info structs */
struct page *err_page; /* One page of all 0xF for error notification */
};
int cxlflash_vlun_resize(struct scsi_device *, struct dk_cxlflash_resize *);
int _cxlflash_vlun_resize(struct scsi_device *, struct ctx_info *,
struct dk_cxlflash_resize *);
int cxlflash_disk_release(struct scsi_device *, struct dk_cxlflash_release *);
int _cxlflash_disk_release(struct scsi_device *, struct ctx_info *,
struct dk_cxlflash_release *);
int cxlflash_disk_clone(struct scsi_device *, struct dk_cxlflash_clone *);
int cxlflash_disk_virtual_open(struct scsi_device *, void *);
int cxlflash_lun_attach(struct glun_info *, enum lun_mode, bool);
void cxlflash_lun_detach(struct glun_info *);
struct ctx_info *get_context(struct cxlflash_cfg *, u64, void *, enum ctx_ctrl);
void put_context(struct ctx_info *);
struct sisl_rht_entry *get_rhte(struct ctx_info *, res_hndl_t,
struct llun_info *);
struct sisl_rht_entry *rhte_checkout(struct ctx_info *, struct llun_info *);
void rhte_checkin(struct ctx_info *, struct sisl_rht_entry *);
void cxlflash_ba_terminate(struct ba_lun *);
int cxlflash_manage_lun(struct scsi_device *, struct dk_cxlflash_manage_lun *);
int check_state(struct cxlflash_cfg *);
#endif /* ifndef _CXLFLASH_SUPERPIPE_H */