PNP: reduce redundancy in pnp_check_port() and others

[linux-2.6-omap-h63xx.git] / fs / ecryptfs / read_write.c

diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
index 6b7474a4336a5844cd004d3b8af923f19d6fc536..0c4928623bbc414f7f0a4861e4dc727bfcdf132f 100644 (file)
--- a/fs/ecryptfs/read_write.c
+++ b/fs/ecryptfs/read_write.c
@@ -124,6 +124,10 @@ int ecryptfs_write(struct file *ecryptfs_file, char *data, loff_t offset,
        loff_t pos;
        int rc = 0;
 
+       /*
+        * if we are writing beyond current size, then start pos
+        * at the current size - we'll fill in zeros from there.
+        */
        if (offset > ecryptfs_file_size)
                pos = ecryptfs_file_size;
        else
@@ -137,6 +141,7 @@ int ecryptfs_write(struct file *ecryptfs_file, char *data, loff_t offset,
                if (num_bytes > total_remaining_bytes)
                        num_bytes = total_remaining_bytes;
                if (pos < offset) {
+                       /* remaining zeros to write, up to destination offset */
                        size_t total_remaining_zeros = (offset - pos);
 
                        if (num_bytes > total_remaining_zeros)
@@ -167,17 +172,27 @@ int ecryptfs_write(struct file *ecryptfs_file, char *data, loff_t offset,
                        }
                }
                ecryptfs_page_virt = kmap_atomic(ecryptfs_page, KM_USER0);
+
+               /*
+                * pos: where we're now writing, offset: where the request was
+                * If current pos is before request, we are filling zeros
+                * If we are at or beyond request, we are writing the *data*
+                * If we're in a fresh page beyond eof, zero it in either case
+                */
+               if (pos < offset || !start_offset_in_page) {
+                       /* We are extending past the previous end of the file.
+                        * Fill in zero values to the end of the page */
+                       memset(((char *)ecryptfs_page_virt
+                               + start_offset_in_page), 0,
+                               PAGE_CACHE_SIZE - start_offset_in_page);
+               }
+
+               /* pos >= offset, we are now writing the data request */
                if (pos >= offset) {
                        memcpy(((char *)ecryptfs_page_virt
                                + start_offset_in_page),
                               (data + data_offset), num_bytes);
                        data_offset += num_bytes;
-               } else {
-                       /* We are extending past the previous end of the file.
-                        * Fill in zero values up to the start of where we
-                        * will be writing data. */
-                       memset(((char *)ecryptfs_page_virt
-                               + start_offset_in_page), 0, num_bytes);
                }
                kunmap_atomic(ecryptfs_page_virt, KM_USER0);
                flush_dcache_page(ecryptfs_page);
@@ -278,6 +293,7 @@ int ecryptfs_read_lower_page_segment(struct page *page_for_ecryptfs,
        return rc;
 }
 
+#if 0
 /**
  * ecryptfs_read
  * @data: The virtual address into which to write the data read (and
@@ -356,3 +372,4 @@ int ecryptfs_read(char *data, loff_t offset, size_t size,
 out:
        return rc;
 }
+#endif  /*  0  */