From: David Woodhouse <dwmw@amazon.co.uk>
Date: Tue, 29 Apr 2025 16:49:36 +0000 (-0700)
Subject: Update to v6 posting
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=ea96822335b4514d0383a181dfa2a9016bdb104c;p=users%2Fdwmw2%2Fvmclock.git

Update to v6 posting
---

diff --git a/ptp_vmclock.c b/ptp_vmclock.c
index 65536b2..267a49c 100644
--- a/ptp_vmclock.c
+++ b/ptp_vmclock.c
@@ -53,8 +53,8 @@ struct vmclock_state {
 #define VMCLOCK_MIN_SIZE offsetof(struct vmclock_abi, pad)
 
 #define VMCLOCK_FIELD_PRESENT(_c, _f)			  \
-	le32_to_cpu((_c)->size) >= (offsetof(struct vmclock_abi, _f) +	\
-				    sizeof((_c)->_f))
+	(le32_to_cpu((_c)->size) >= (offsetof(struct vmclock_abi, _f) +	\
+				     sizeof((_c)->_f)))
 
 /*
  * Multiply a 64-bit count by a 64-bit tick 'period' in units of seconds >> 64
@@ -157,6 +157,10 @@ static int vmclock_get_crosststamp(struct vmclock_state *st,
 		if (!tai_adjust(st->clk, &tspec->tv_sec))
 			return -EINVAL;
 
+		/*
+		 * This pairs with a write barrier in the hypervisor
+		 * which populates this structure.
+		 */
 		virt_rmb();
 		if (seq == le32_to_cpu(st->clk->seq_count))
 			break;
@@ -193,7 +197,7 @@ static int vmclock_get_crosststamp_kvmclock(struct vmclock_state *st,
 					    struct timespec64 *tspec)
 {
 	struct pvclock_vcpu_time_info *pvti = this_cpu_pvti();
-	unsigned pvti_ver;
+	unsigned int pvti_ver;
 	int ret;
 
 	preempt_disable_notrace();
@@ -263,6 +267,7 @@ static int ptp_vmclock_getcrosststamp(struct ptp_clock_info *ptp,
 	 */
 	if (ret == -ENODEV) {
 		struct system_time_snapshot systime_snapshot;
+
 		ktime_get_snapshot(&systime_snapshot);
 
 		if (systime_snapshot.cs_id == CSID_X86_TSC ||
@@ -349,7 +354,8 @@ static struct ptp_clock *vmclock_ptp_register(struct device *dev,
 		return NULL;
 	}
 
-	st->sys_cs_id = st->cs_id = cs_id;
+	st->sys_cs_id = cs_id;
+	st->cs_id = cs_id;
 	st->ptp_clock_info = ptp_vmclock_info;
 	strscpy(st->ptp_clock_info.name, st->name, sizeof(st->ptp_clock_info.name));
 
@@ -365,14 +371,14 @@ static int vmclock_miscdev_mmap(struct file *fp, struct vm_area_struct *vma)
 		return -EROFS;
 
 	if (vma->vm_end - vma->vm_start != PAGE_SIZE || vma->vm_pgoff)
-		return -EINVAL;
+ 		return -EINVAL;
 
-        if (io_remap_pfn_range(vma, vma->vm_start,
+	if (io_remap_pfn_range(vma, vma->vm_start,
 			       st->res.start >> PAGE_SHIFT, PAGE_SIZE,
-                               vma->vm_page_prot))
-                return -EAGAIN;
+			       vma->vm_page_prot))
+		return -EAGAIN;
 
-        return 0;
+	return 0;
 }
 
 static ssize_t vmclock_miscdev_read(struct file *fp, char __user *buf,
@@ -393,11 +399,13 @@ static ssize_t vmclock_miscdev_read(struct file *fp, char __user *buf,
 
 	while (1) {
 		seq = le32_to_cpu(st->clk->seq_count) & ~1U;
+		/* Pairs with hypervisor wmb */
 		virt_rmb();
 
 		if (copy_to_user(buf, ((char *)st->clk) + *ppos, count))
 			return -EFAULT;
 
+		/* Pairs with hypervisor wmb */
 		virt_rmb();
 		if (seq == le32_to_cpu(st->clk->seq_count))
 			break;
@@ -411,8 +419,8 @@ static ssize_t vmclock_miscdev_read(struct file *fp, char __user *buf,
 }
 
 static const struct file_operations vmclock_miscdev_fops = {
-        .mmap = vmclock_miscdev_mmap,
-        .read = vmclock_miscdev_read,
+	.mmap = vmclock_miscdev_mmap,
+	.read = vmclock_miscdev_read,
 };
 
 /* module operations */
@@ -435,7 +443,7 @@ static acpi_status vmclock_acpi_resources(struct acpi_resource *ares, void *data
 {
 	struct vmclock_state *st = data;
 	struct resource_win win;
-	struct resource *res = &(win.res);
+	struct resource *res = &win.res;
 
 	if (ares->type == ACPI_RESOURCE_TYPE_END_TAG)
 		return AE_OK;
@@ -444,7 +452,7 @@ static acpi_status vmclock_acpi_resources(struct acpi_resource *ares, void *data
 	if (resource_type(&st->res) == IORESOURCE_MEM)
 		return AE_ERROR;
 
-        if (acpi_dev_resource_memory(ares, res) ||
+	if (acpi_dev_resource_memory(ares, res) ||
 	    acpi_dev_resource_address_space(ares, &win)) {
 
 		if (resource_type(res) != IORESOURCE_MEM ||
@@ -494,7 +502,7 @@ static int vmclock_probe(struct platform_device *pdev)
 	struct vmclock_state *st;
 	int ret;
 
-	st = devm_kzalloc(dev, sizeof (*st), GFP_KERNEL);
+	st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
 	if (!st)
 		return -ENOMEM;
 
@@ -612,4 +620,4 @@ module_platform_driver(vmclock_platform_driver)
 
 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 MODULE_DESCRIPTION("PTP clock using VMCLOCK");
-MODULE_LICENSE("GPL v2");
+MODULE_LICENSE("GPL");