From f81face7256339c584ee9baba3240ddac74a0293 Mon Sep 17 00:00:00 2001 From: Uma Krishnan Date: Mon, 26 Mar 2018 11:35:00 -0500 Subject: [PATCH] scsi: cxlflash: Introduce OCXL context state machine In order to protect the OCXL hardware contexts from getting clobbered, a simple state machine is added to indicate when a context is in open, close or start state. The expected states are validated throughout the code to prevent illegal operations on a context. A mutex is added to protect writes to the context state field. Signed-off-by: Uma Krishnan Acked-by: Matthew R. Ochs Signed-off-by: Martin K. Petersen --- drivers/scsi/cxlflash/ocxl_hw.c | 59 +++++++++++++++++++++++++++++++-- drivers/scsi/cxlflash/ocxl_hw.h | 8 +++++ 2 files changed, 64 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/cxlflash/ocxl_hw.c b/drivers/scsi/cxlflash/ocxl_hw.c index f77f4d7f6a34..89d3d89f22ed 100644 --- a/drivers/scsi/cxlflash/ocxl_hw.c +++ b/drivers/scsi/cxlflash/ocxl_hw.c @@ -163,6 +163,16 @@ err1: static void __iomem *ocxlflash_psa_map(void *ctx_cookie) { struct ocxlflash_context *ctx = ctx_cookie; + struct device *dev = ctx->hw_afu->dev; + + mutex_lock(&ctx->state_mutex); + if (ctx->state != STARTED) { + dev_err(dev, "%s: Context not started, state=%d\n", __func__, + ctx->state); + mutex_unlock(&ctx->state_mutex); + return NULL; + } + mutex_unlock(&ctx->state_mutex); return ioremap(ctx->psn_phys, ctx->psn_size); } @@ -343,6 +353,14 @@ static int start_context(struct ocxlflash_context *ctx) int rc = 0; u32 pid; + mutex_lock(&ctx->state_mutex); + if (ctx->state != OPENED) { + dev_err(dev, "%s: Context state invalid, state=%d\n", + __func__, ctx->state); + rc = -EINVAL; + goto out; + } + if (master) { ctx->psn_size = acfg->global_mmio_size; ctx->psn_phys = afu->gmmio_phys; @@ -366,7 +384,10 @@ static int start_context(struct ocxlflash_context *ctx) __func__, rc); goto out; } + + ctx->state = STARTED; out: + mutex_unlock(&ctx->state_mutex); return rc; } @@ -396,7 +417,15 @@ static int ocxlflash_stop_context(void *ctx_cookie) struct ocxl_afu_config *acfg = &afu->acfg; struct pci_dev *pdev = afu->pdev; struct device *dev = afu->dev; - int rc; + enum ocxlflash_ctx_state state; + int rc = 0; + + mutex_lock(&ctx->state_mutex); + state = ctx->state; + ctx->state = CLOSED; + mutex_unlock(&ctx->state_mutex); + if (state != STARTED) + goto out; rc = ocxl_config_terminate_pasid(pdev, acfg->dvsec_afu_control_pos, ctx->pe); @@ -474,7 +503,9 @@ static void *ocxlflash_dev_context_init(struct pci_dev *pdev, void *afu_cookie) spin_lock_init(&ctx->slock); init_waitqueue_head(&ctx->wq); + mutex_init(&ctx->state_mutex); + ctx->state = OPENED; ctx->pe = rc; ctx->master = false; ctx->mapping = NULL; @@ -499,11 +530,23 @@ err1: static int ocxlflash_release_context(void *ctx_cookie) { struct ocxlflash_context *ctx = ctx_cookie; + struct device *dev; int rc = 0; if (!ctx) goto out; + dev = ctx->hw_afu->dev; + mutex_lock(&ctx->state_mutex); + if (ctx->state >= STARTED) { + dev_err(dev, "%s: Context in use, state=%d\n", __func__, + ctx->state); + mutex_unlock(&ctx->state_mutex); + rc = -EBUSY; + goto out; + } + mutex_unlock(&ctx->state_mutex); + idr_remove(&ctx->hw_afu->idr, ctx->pe); ocxlflash_release_mapping(ctx); kfree(ctx); @@ -947,7 +990,7 @@ static unsigned int afu_poll(struct file *file, struct poll_table_struct *poll) spin_lock_irqsave(&ctx->slock, lock_flags); if (ctx_event_pending(ctx)) mask |= POLLIN | POLLRDNORM; - else + else if (ctx->state == CLOSED) mask |= POLLERR; spin_unlock_irqrestore(&ctx->slock, lock_flags); @@ -990,7 +1033,7 @@ static ssize_t afu_read(struct file *file, char __user *buf, size_t count, for (;;) { prepare_to_wait(&ctx->wq, &event_wait, TASK_INTERRUPTIBLE); - if (ctx_event_pending(ctx)) + if (ctx_event_pending(ctx) || (ctx->state == CLOSED)) break; if (file->f_flags & O_NONBLOCK) { @@ -1076,12 +1119,22 @@ static int ocxlflash_mmap_fault(struct vm_fault *vmf) { struct vm_area_struct *vma = vmf->vma; struct ocxlflash_context *ctx = vma->vm_file->private_data; + struct device *dev = ctx->hw_afu->dev; u64 mmio_area, offset; offset = vmf->pgoff << PAGE_SHIFT; if (offset >= ctx->psn_size) return VM_FAULT_SIGBUS; + mutex_lock(&ctx->state_mutex); + if (ctx->state != STARTED) { + dev_err(dev, "%s: Context not started, state=%d\n", + __func__, ctx->state); + mutex_unlock(&ctx->state_mutex); + return VM_FAULT_SIGBUS; + } + mutex_unlock(&ctx->state_mutex); + mmio_area = ctx->psn_phys; mmio_area += offset; diff --git a/drivers/scsi/cxlflash/ocxl_hw.h b/drivers/scsi/cxlflash/ocxl_hw.h index acd280135989..1829e55c974a 100644 --- a/drivers/scsi/cxlflash/ocxl_hw.h +++ b/drivers/scsi/cxlflash/ocxl_hw.h @@ -46,6 +46,12 @@ struct ocxl_hw_afu { bool is_present; /* Function has AFUs defined */ }; +enum ocxlflash_ctx_state { + CLOSED, + OPENED, + STARTED +}; + struct ocxlflash_context { struct ocxl_hw_afu *hw_afu; /* HW AFU back pointer */ struct address_space *mapping; /* Mapping for pseudo filesystem */ @@ -57,6 +63,8 @@ struct ocxlflash_context { spinlock_t slock; /* Protects irq/fault/event updates */ wait_queue_head_t wq; /* Wait queue for poll and interrupts */ + struct mutex state_mutex; /* Mutex to update context state */ + enum ocxlflash_ctx_state state; /* Context state */ struct ocxlflash_irqs *irqs; /* Pointer to array of structures */ int num_irqs; /* Number of interrupts */