From: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
This new function allows us to support hole-punch for XIP files by zeroing
a partial page, as opposed to the xip_truncate_page() function which can
only truncate to the end of the page. Reimplement xip_truncate_page() as
a caller of xip_zero_page_range().
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@xxxxxxxxx>
[ported to 3.13-rc2]
Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
---
include/linux/fs.h | 8 ++++++++
mm/filemap_xip.c | 31 +++++++++++++++----------------
2 files changed, 23 insertions(+), 16 deletions(-)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 121f11f..a063bff 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2509,11 +2509,19 @@ extern int xip_file_mmap(struct file * file, struct vm_area_struct * vma);
extern ssize_t xip_file_write(struct file *filp, const char __user *buf,
size_t len, loff_t *ppos);
extern int xip_truncate_page(struct address_space *mapping, loff_t from);
+extern int xip_zero_page_range(struct address_space *, loff_t from,
+ unsigned length);
#else
static inline int xip_truncate_page(struct address_space *mapping, loff_t from)
{
return 0;
}
+
+static inline int xip_zero_page_range(struct address_space *mapping,
+ loff_t from, unsigned length)
+{
+ return 0;
+}
#endif
#ifdef CONFIG_BLOCK
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index c8d23e9..d808b72 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -461,33 +461,19 @@ xip_file_write(struct file *filp, const char __user *buf, size_t len,
}
EXPORT_SYMBOL_GPL(xip_file_write);
-/*
- * truncate a page used for execute in place
- * functionality is analog to block_truncate_page but does use get_xip_mem
- * to get the page instead of page cache
- */
-int
-xip_truncate_page(struct address_space *mapping, loff_t from)
+int xip_zero_page_range(struct address_space *mapping, loff_t from,
+ unsigned length)
{
pgoff_t index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE-1);
- unsigned blocksize;
- unsigned length;
void *xip_mem;
unsigned long xip_pfn;
int err;
- BUG_ON(!mapping->a_ops->get_xip_mem);
-
- blocksize = 1 << mapping->host->i_blkbits;
- length = offset & (blocksize - 1);
-
/* Block boundary? Nothing to do */
if (!length)
return 0;
- length = blocksize - length;
-
err = mapping->a_ops->get_xip_mem(mapping, index, 0,
&xip_mem, &xip_pfn);
if (unlikely(err)) {
@@ -497,7 +483,20 @@ xip_truncate_page(struct address_space *mapping, loff_t from)
else
return err;
}
+
memset(xip_mem + offset, 0, length);
return 0;
}
+EXPORT_SYMBOL_GPL(xip_zero_page_range);
+
+/*
+ * truncate a page used for execute in place
+ * functionality is analog to block_truncate_page but does use get_xip_mem
+ * to get the page instead of page cache
+ */
+int xip_truncate_page(struct address_space *mapping, loff_t from)
+{
+ unsigned length = PAGE_CACHE_ALIGN(from) - from;
+ return xip_zero_page_range(mapping, from, length);
+}
EXPORT_SYMBOL_GPL(xip_truncate_page);
--
1.7.10.4
--
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