firmware: Kconfig: ROCKCHIP_SIP depends on HAVE_ARM_SMCCC and ARCH_ROCKCHIP

[firefly-linux-kernel-4.4.55.git] / fs / dax.c

diff --git a/fs/dax.c b/fs/dax.c
index a86d3cc2b38941b0e39f23be84e4986d8852ae42..43671b68220ed968386f5c1ad9067f236fbab67e 100644 (file)
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -29,6 +29,11 @@
 #include <linux/uio.h>
 #include <linux/vmstat.h>
 
+/*
+ * dax_clear_blocks() is called from within transaction context from XFS,
+ * and hence this means the stack from this point must follow GFP_NOFS
+ * semantics for all operations.
+ */
 int dax_clear_blocks(struct inode *inode, sector_t block, long size)
 {
        struct block_device *bdev = inode->i_sb->s_bdev;
@@ -169,8 +174,10 @@ static ssize_t dax_io(struct inode *inode, struct iov_iter *iter,
                else
                        len = iov_iter_zero(max - pos, iter);
 
-               if (!len)
+               if (!len) {
+                       retval = -EFAULT;
                        break;
+               }
 
                pos += len;
                addr += len;
@@ -534,6 +541,10 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
        unsigned long pfn;
        int result = 0;
 
+       /* dax pmd mappings are broken wrt gup and fork */
+       if (!IS_ENABLED(CONFIG_FS_DAX_PMD))
+               return VM_FAULT_FALLBACK;
+
        /* Fall back to PTEs if we're going to COW */
        if (write && !(vma->vm_flags & VM_SHARED))
                return VM_FAULT_FALLBACK;
@@ -622,6 +633,13 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
                if ((length < PMD_SIZE) || (pfn & PG_PMD_COLOUR))
                        goto fallback;
 
+               /*
+                * TODO: teach vmf_insert_pfn_pmd() to support
+                * 'pte_special' for pmds
+                */
+               if (pfn_valid(pfn))
+                       goto fallback;
+
                if (buffer_unwritten(&bh) || buffer_new(&bh)) {
                        int i;
                        for (i = 0; i < PTRS_PER_PMD; i++)