From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Tue, 22 Aug 2017 19:04:45 +0000 (-0400)
Subject: Port fix: don't round mmap offset to next page
X-Git-Tag: v2.0.0-pre4~114
X-Git-Url: http://git.efficios.com/?p=babeltrace.git;a=commitdiff_plain;h=52eb1a72ea30c44e7ddd39d19566255e2d4c32bf

Port fix: don't round mmap offset to next page

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/plugins/ctf/fs-src/data-stream-file.c b/plugins/ctf/fs-src/data-stream-file.c
index bae0bd14..2fddc39d 100644
--- a/plugins/ctf/fs-src/data-stream-file.c
+++ b/plugins/ctf/fs-src/data-stream-file.c
@@ -50,7 +50,7 @@
 static inline
 size_t remaining_mmap_bytes(struct ctf_fs_ds_file *ds_file)
 {
-	return ds_file->mmap_valid_len - ds_file->request_offset;
+	return ds_file->mmap_len - ds_file->request_offset;
 }
 
 static
@@ -93,23 +93,20 @@ enum bt_ctf_notif_iter_medium_status ds_file_mmap_next(
 		}
 
 		/*
-		 * mmap_valid_len is guaranteed to be page-aligned except on the
+		 * mmap_len is guaranteed to be page-aligned except on the
 		 * last mapping where it may not be possible (since the file's
 		 * size itself may not be a page multiple).
 		 */
-		ds_file->mmap_offset += ds_file->mmap_valid_len;
+		ds_file->mmap_offset += ds_file->mmap_len;
 		ds_file->request_offset = 0;
 	}
 
-	ds_file->mmap_valid_len = MIN(ds_file->file->size - ds_file->mmap_offset,
+	ds_file->mmap_len = MIN(ds_file->file->size - ds_file->mmap_offset,
 			ds_file->mmap_max_len);
-	if (ds_file->mmap_valid_len == 0) {
+	if (ds_file->mmap_len == 0) {
 		ret = BT_CTF_NOTIF_ITER_MEDIUM_STATUS_EOF;
 		goto end;
 	}
-	/* Round up to next page, assuming page size being a power of 2. */
-	ds_file->mmap_len = (ds_file->mmap_valid_len + page_size - 1)
-			& ~(page_size - 1);
 	/* Map new region */
 	assert(ds_file->mmap_len);
 	ds_file->mmap_addr = bt_mmap((void *) 0, ds_file->mmap_len,
diff --git a/plugins/ctf/fs-src/data-stream-file.h b/plugins/ctf/fs-src/data-stream-file.h
index 56397dff..1d3e51e6 100644
--- a/plugins/ctf/fs-src/data-stream-file.h
+++ b/plugins/ctf/fs-src/data-stream-file.h
@@ -105,12 +105,9 @@ struct ctf_fs_ds_file {
 	 */
 	size_t mmap_max_len;
 
-	/* Length of the current mapping. */
+	/* Length of the current mapping. Never exceeds the file's length. */
 	size_t mmap_len;
 
-	/* Length of the current mapping which *exists* in the backing file. */
-	size_t mmap_valid_len;
-
 	/* Offset in the file where the current mapping starts. */
 	off_t mmap_offset;