From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3znTX73lcnzF1kn for ; Fri, 23 Feb 2018 09:28:23 +1100 (AEDT) Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w1MMO3Pg000967 for ; Thu, 22 Feb 2018 17:28:21 -0500 Received: from e38.co.us.ibm.com (e38.co.us.ibm.com [32.97.110.159]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ga268hvt5-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 22 Feb 2018 17:28:21 -0500 Received: from localhost by e38.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 22 Feb 2018 15:28:20 -0700 From: Uma Krishnan To: linux-scsi@vger.kernel.org, James Bottomley , "Martin K. Petersen" , "Matthew R. Ochs" , "Manoj N. Kumar" Cc: linuxppc-dev@lists.ozlabs.org, Andrew Donnellan , Frederic Barrat , Christophe Lombard Subject: [PATCH 35/38] cxlflash: Introduce OCXL context state machine Date: Thu, 22 Feb 2018 16:28:16 -0600 In-Reply-To: <1519338010-51782-1-git-send-email-ukrishn@linux.vnet.ibm.com> References: <1519338010-51782-1-git-send-email-ukrishn@linux.vnet.ibm.com> Message-Id: <1519338496-53048-1-git-send-email-ukrishn@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 --- 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 1044bee..535b21a 100644 --- a/drivers/scsi/cxlflash/ocxl_hw.c +++ b/drivers/scsi/cxlflash/ocxl_hw.c @@ -163,6 +163,16 @@ static struct file *ocxlflash_getfile(struct device *dev, const char *name, 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 @@ static void *ocxlflash_dev_context_init(struct pci_dev *pdev, void *afu_cookie) 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); @@ -939,7 +982,7 @@ 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); @@ -982,7 +1025,7 @@ 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) { @@ -1068,12 +1111,22 @@ 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 bdf9422..c23b681 100644 --- a/drivers/scsi/cxlflash/ocxl_hw.h +++ b/drivers/scsi/cxlflash/ocxl_hw.h @@ -45,6 +45,12 @@ struct ocxl_hw_afu { int max_pasid; /* Maximum number of contexts */ }; +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 */ @@ -56,6 +62,8 @@ 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 */ -- 2.1.0