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![Manoj Kumar](/assets/img/avatar_default.png)
If an async error interrupt is generated, and the error requires the FC link to be reset, it cannot be performed in the interrupt context. So a work element is scheduled to complete the link reset in a process context. If either an EEH event or an escalation occurs in between when the interrupt is generated and the scheduled work is started, the MMIO space may no longer be available. This will cause an oops in the worker thread. [ 606.806583] NIP kthread_data+0x28/0x40 [ 606.806633] LR wq_worker_sleeping+0x30/0x100 [ 606.806694] Call Trace: [ 606.806721] 0x50 (unreliable) [ 606.806796] wq_worker_sleeping+0x30/0x100 [ 606.806884] __schedule+0x69c/0x8a0 [ 606.806959] schedule+0x44/0xc0 [ 606.807034] do_exit+0x770/0xb90 [ 606.807109] die+0x300/0x460 [ 606.807185] bad_page_fault+0xd8/0x150 [ 606.807259] handle_page_fault+0x2c/0x30 [ 606.807338] wait_port_offline.constprop.12+0x60/0x130 [cxlflash] To prevent the problem space area from being unmapped, when there is pending work, a mapcount (using the kref mechanism) is held. The mapcount is released only when the work is completed. The last reference release is tied to the unmapping service. Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com> Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com> Reviewed-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
206 lines
5.4 KiB
C
206 lines
5.4 KiB
C
/*
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* CXL Flash Device Driver
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*
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* Written by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>, IBM Corporation
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* Matthew R. Ochs <mrochs@linux.vnet.ibm.com>, IBM Corporation
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*
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* Copyright (C) 2015 IBM Corporation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _CXLFLASH_COMMON_H
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#define _CXLFLASH_COMMON_H
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#include <linux/list.h>
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#include <linux/rwsem.h>
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#include <linux/types.h>
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#include <scsi/scsi.h>
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#include <scsi/scsi_device.h>
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extern const struct file_operations cxlflash_cxl_fops;
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#define MAX_CONTEXT CXLFLASH_MAX_CONTEXT /* num contexts per afu */
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#define CXLFLASH_BLOCK_SIZE 4096 /* 4K blocks */
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#define CXLFLASH_MAX_XFER_SIZE 16777216 /* 16MB transfer */
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#define CXLFLASH_MAX_SECTORS (CXLFLASH_MAX_XFER_SIZE/512) /* SCSI wants
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max_sectors
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in units of
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512 byte
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sectors
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*/
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#define NUM_RRQ_ENTRY 16 /* for master issued cmds */
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#define MAX_RHT_PER_CONTEXT (PAGE_SIZE / sizeof(struct sisl_rht_entry))
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/* AFU command retry limit */
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#define MC_RETRY_CNT 5 /* sufficient for SCSI check and
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certain AFU errors */
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/* Command management definitions */
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#define CXLFLASH_NUM_CMDS (2 * CXLFLASH_MAX_CMDS) /* Must be a pow2 for
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alignment and more
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efficient array
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index derivation
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*/
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#define CXLFLASH_MAX_CMDS 16
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#define CXLFLASH_MAX_CMDS_PER_LUN CXLFLASH_MAX_CMDS
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static inline void check_sizes(void)
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{
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BUILD_BUG_ON_NOT_POWER_OF_2(CXLFLASH_NUM_CMDS);
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}
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/* AFU defines a fixed size of 4K for command buffers (borrow 4K page define) */
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#define CMD_BUFSIZE SIZE_4K
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/* flags in IOA status area for host use */
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#define B_DONE 0x01
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#define B_ERROR 0x02 /* set with B_DONE */
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#define B_TIMEOUT 0x04 /* set with B_DONE & B_ERROR */
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enum cxlflash_lr_state {
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LINK_RESET_INVALID,
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LINK_RESET_REQUIRED,
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LINK_RESET_COMPLETE
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};
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enum cxlflash_init_state {
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INIT_STATE_NONE,
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INIT_STATE_PCI,
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INIT_STATE_AFU,
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INIT_STATE_SCSI
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};
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enum cxlflash_state {
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STATE_NORMAL, /* Normal running state, everything good */
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STATE_RESET, /* Reset state, trying to reset/recover */
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STATE_FAILTERM /* Failed/terminating state, error out users/threads */
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};
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/*
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* Each context has its own set of resource handles that is visible
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* only from that context.
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*/
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struct cxlflash_cfg {
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struct afu *afu;
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struct cxl_context *mcctx;
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struct pci_dev *dev;
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struct pci_device_id *dev_id;
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struct Scsi_Host *host;
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ulong cxlflash_regs_pci;
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struct work_struct work_q;
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enum cxlflash_init_state init_state;
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enum cxlflash_lr_state lr_state;
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int lr_port;
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atomic_t scan_host_needed;
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struct cxl_afu *cxl_afu;
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struct pci_dev *parent_dev;
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atomic_t recovery_threads;
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struct mutex ctx_recovery_mutex;
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struct mutex ctx_tbl_list_mutex;
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struct rw_semaphore ioctl_rwsem;
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struct ctx_info *ctx_tbl[MAX_CONTEXT];
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struct list_head ctx_err_recovery; /* contexts w/ recovery pending */
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struct file_operations cxl_fops;
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/* Parameters that are LUN table related */
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int last_lun_index[CXLFLASH_NUM_FC_PORTS];
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int promote_lun_index;
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struct list_head lluns; /* list of llun_info structs */
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wait_queue_head_t tmf_waitq;
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spinlock_t tmf_slock;
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bool tmf_active;
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wait_queue_head_t reset_waitq;
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enum cxlflash_state state;
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};
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struct afu_cmd {
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struct sisl_ioarcb rcb; /* IOARCB (cache line aligned) */
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struct sisl_ioasa sa; /* IOASA must follow IOARCB */
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spinlock_t slock;
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struct completion cevent;
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char *buf; /* per command buffer */
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struct afu *parent;
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int slot;
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atomic_t free;
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u8 cmd_tmf:1;
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/* As per the SISLITE spec the IOARCB EA has to be 16-byte aligned.
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* However for performance reasons the IOARCB/IOASA should be
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* cache line aligned.
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*/
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} __aligned(cache_line_size());
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struct afu {
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/* Stuff requiring alignment go first. */
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u64 rrq_entry[NUM_RRQ_ENTRY]; /* 128B RRQ */
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/*
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* Command & data for AFU commands.
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*/
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struct afu_cmd cmd[CXLFLASH_NUM_CMDS];
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/* Beware of alignment till here. Preferably introduce new
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* fields after this point
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*/
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/* AFU HW */
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struct cxl_ioctl_start_work work;
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struct cxlflash_afu_map __iomem *afu_map; /* entire MMIO map */
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struct sisl_host_map __iomem *host_map; /* MC host map */
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struct sisl_ctrl_map __iomem *ctrl_map; /* MC control map */
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struct kref mapcount;
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ctx_hndl_t ctx_hndl; /* master's context handle */
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u64 *hrrq_start;
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u64 *hrrq_end;
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u64 *hrrq_curr;
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bool toggle;
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bool read_room;
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atomic64_t room;
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u64 hb;
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u32 cmd_couts; /* Number of command checkouts */
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u32 internal_lun; /* User-desired LUN mode for this AFU */
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char version[16];
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u64 interface_version;
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struct cxlflash_cfg *parent; /* Pointer back to parent cxlflash_cfg */
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};
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static inline u64 lun_to_lunid(u64 lun)
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{
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__be64 lun_id;
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int_to_scsilun(lun, (struct scsi_lun *)&lun_id);
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return be64_to_cpu(lun_id);
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}
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int cxlflash_afu_sync(struct afu *, ctx_hndl_t, res_hndl_t, u8);
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void cxlflash_list_init(void);
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void cxlflash_term_global_luns(void);
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void cxlflash_free_errpage(void);
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int cxlflash_ioctl(struct scsi_device *, int, void __user *);
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void cxlflash_stop_term_user_contexts(struct cxlflash_cfg *);
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int cxlflash_mark_contexts_error(struct cxlflash_cfg *);
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void cxlflash_term_local_luns(struct cxlflash_cfg *);
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void cxlflash_restore_luntable(struct cxlflash_cfg *);
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#endif /* ifndef _CXLFLASH_COMMON_H */
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