diff options
Diffstat (limited to 'drivers/dax/dax.c')
-rw-r--r-- | drivers/dax/dax.c | 67 |
1 files changed, 49 insertions, 18 deletions
diff --git a/drivers/dax/dax.c b/drivers/dax/dax.c index 286447a83dab..40be3747724d 100644 --- a/drivers/dax/dax.c +++ b/drivers/dax/dax.c @@ -24,6 +24,7 @@ #include "dax.h" static dev_t dax_devt; +DEFINE_STATIC_SRCU(dax_srcu); static struct class *dax_class; static DEFINE_IDA(dax_minor_ida); static int nr_dax = CONFIG_NR_DEV_DAX; @@ -59,7 +60,7 @@ struct dax_region { * @region - parent region * @dev - device backing the character device * @cdev - core chardev data - * @alive - !alive + rcu grace period == no new mappings can be established + * @alive - !alive + srcu grace period == no new mappings can be established * @id - child id in the region * @num_resources - number of physical address extents in this device * @res - array of physical address ranges @@ -334,6 +335,7 @@ static int __dax_dev_fault(struct dax_dev *dax_dev, struct vm_area_struct *vma, int rc = VM_FAULT_SIGBUS; phys_addr_t phys; pfn_t pfn; + unsigned int fault_size = PAGE_SIZE; if (check_vma(dax_dev, vma, __func__)) return VM_FAULT_SIGBUS; @@ -344,6 +346,9 @@ static int __dax_dev_fault(struct dax_dev *dax_dev, struct vm_area_struct *vma, return VM_FAULT_SIGBUS; } + if (fault_size != dax_region->align) + return VM_FAULT_SIGBUS; + phys = pgoff_to_phys(dax_dev, vmf->pgoff, PAGE_SIZE); if (phys == -1) { dev_dbg(dev, "%s: phys_to_pgoff(%#lx) failed\n", __func__, @@ -389,6 +394,7 @@ static int __dax_dev_pmd_fault(struct dax_dev *dax_dev, phys_addr_t phys; pgoff_t pgoff; pfn_t pfn; + unsigned int fault_size = PMD_SIZE; if (check_vma(dax_dev, vma, __func__)) return VM_FAULT_SIGBUS; @@ -405,6 +411,16 @@ static int __dax_dev_pmd_fault(struct dax_dev *dax_dev, return VM_FAULT_SIGBUS; } + if (fault_size < dax_region->align) + return VM_FAULT_SIGBUS; + else if (fault_size > dax_region->align) + return VM_FAULT_FALLBACK; + + /* if we are outside of the VMA */ + if (pmd_addr < vma->vm_start || + (pmd_addr + PMD_SIZE) > vma->vm_end) + return VM_FAULT_SIGBUS; + pgoff = linear_page_index(vma, pmd_addr); phys = pgoff_to_phys(dax_dev, pgoff, PMD_SIZE); if (phys == -1) { @@ -422,7 +438,7 @@ static int __dax_dev_pmd_fault(struct dax_dev *dax_dev, static int dax_dev_pmd_fault(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd, unsigned int flags) { - int rc; + int rc, id; struct file *filp = vma->vm_file; struct dax_dev *dax_dev = filp->private_data; @@ -430,9 +446,9 @@ static int dax_dev_pmd_fault(struct vm_area_struct *vma, unsigned long addr, current->comm, (flags & FAULT_FLAG_WRITE) ? "write" : "read", vma->vm_start, vma->vm_end); - rcu_read_lock(); + id = srcu_read_lock(&dax_srcu); rc = __dax_dev_pmd_fault(dax_dev, vma, addr, pmd, flags); - rcu_read_unlock(); + srcu_read_unlock(&dax_srcu, id); return rc; } @@ -530,36 +546,43 @@ static void dax_dev_release(struct device *dev) struct dax_dev *dax_dev = to_dax_dev(dev); struct dax_region *dax_region = dax_dev->region; - ida_simple_remove(&dax_region->ida, dax_dev->id); + if (dax_dev->id >= 0) + ida_simple_remove(&dax_region->ida, dax_dev->id); ida_simple_remove(&dax_minor_ida, MINOR(dev->devt)); dax_region_put(dax_region); iput(dax_dev->inode); kfree(dax_dev); } -static void unregister_dax_dev(void *dev) +static void kill_dax_dev(struct dax_dev *dax_dev) { - struct dax_dev *dax_dev = to_dax_dev(dev); struct cdev *cdev = &dax_dev->cdev; - dev_dbg(dev, "%s\n", __func__); - /* * Note, rcu is not protecting the liveness of dax_dev, rcu is * ensuring that any fault handlers that might have seen * dax_dev->alive == true, have completed. Any fault handlers - * that start after synchronize_rcu() has started will abort + * that start after synchronize_srcu() has started will abort * upon seeing dax_dev->alive == false. */ dax_dev->alive = false; - synchronize_rcu(); + synchronize_srcu(&dax_srcu); unmap_mapping_range(dax_dev->inode->i_mapping, 0, 0, 1); cdev_del(cdev); +} + +static void unregister_dax_dev(void *dev) +{ + struct dax_dev *dax_dev = to_dax_dev(dev); + + dev_dbg(dev, "%s\n", __func__); + + kill_dax_dev(dax_dev); device_unregister(dev); } struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region, - struct resource *res, int count) + int id, struct resource *res, int count) { struct device *parent = dax_region->dev; struct dax_dev *dax_dev; @@ -586,10 +609,16 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region, if (i < count) goto err_id; - dax_dev->id = ida_simple_get(&dax_region->ida, 0, 0, GFP_KERNEL); - if (dax_dev->id < 0) { - rc = dax_dev->id; - goto err_id; + if (id < 0) { + id = ida_simple_get(&dax_region->ida, 0, 0, GFP_KERNEL); + dax_dev->id = id; + if (id < 0) { + rc = id; + goto err_id; + } + } else { + /* region provider owns @id lifetime */ + dax_dev->id = -1; } minor = ida_simple_get(&dax_minor_ida, 0, 0, GFP_KERNEL); @@ -628,9 +657,10 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region, dev->parent = parent; dev->groups = dax_attribute_groups; dev->release = dax_dev_release; - dev_set_name(dev, "dax%d.%d", dax_region->id, dax_dev->id); + dev_set_name(dev, "dax%d.%d", dax_region->id, id); rc = device_add(dev); if (rc) { + kill_dax_dev(dax_dev); put_device(dev); return ERR_PTR(rc); } @@ -646,7 +676,8 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region, err_inode: ida_simple_remove(&dax_minor_ida, minor); err_minor: - ida_simple_remove(&dax_region->ida, dax_dev->id); + if (dax_dev->id >= 0) + ida_simple_remove(&dax_region->ida, dax_dev->id); err_id: kfree(dax_dev); |