[PATCH 4/5] libceph: rename "page_shift" variable to something sensible

[Alex Elder <elder@dreamhost.com>]

In write_partial_msg_pages() there is a local variable used to
track the starting offset within a bio segment to use.  Its name,
"page_shift" defies the Linux convention of using that name for
log-base-2(page size).

Since it's only used in the bio case rename it "bio_offset".  Use it
along with the page_pos field to compute the memory offset when
computing CRC's in that function.  This makes the bio case match the
others more closely.

Signed-off-by: Alex Elder <elder@dreamhost.com>
---
  net/ceph/messenger.c |   11 ++++++-----
  1 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 4f1714c..2bf9ab4 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -837,7 +837,7 @@ static int write_partial_msg_pages(struct 
ceph_connection *con)
  		struct page *page = NULL;
  		void *kaddr = NULL;
  		int max_write = PAGE_SIZE;
-		int page_shift = 0;
+		int bio_offset = 0;

  		total_max_write = data_len - trail_len -
  			con->out_msg_pos.data_pos;
@@ -874,9 +874,9 @@ static int write_partial_msg_pages(struct 
ceph_connection *con)

  			bv = bio_iovec_idx(msg->bio_iter, msg->bio_seg);
  			page = bv->bv_page;
-			page_shift = bv->bv_offset;
+			bio_offset = bv->bv_offset;
  			if (do_datacrc)
-				kaddr = kmap(page) + page_shift;
+				kaddr = kmap(page);
  			max_write = bv->bv_len;
  #endif
  		} else {
@@ -888,17 +888,18 @@ static int write_partial_msg_pages(struct 
ceph_connection *con)
  			    total_max_write);

  		if (do_datacrc && !con->out_msg_pos.did_page_crc) {
+			void *base;
  			u32 crc;
-			void *base = kaddr + con->out_msg_pos.page_pos;
  			u32 tmpcrc = le32_to_cpu(con->out_msg->footer.data_crc);

  			BUG_ON(kaddr == NULL);
+			base = kaddr + con->out_msg_pos.page_pos + bio_offset;
  			crc = crc32c(tmpcrc, base, len);
  			con->out_msg->footer.data_crc = cpu_to_le32(crc);
  			con->out_msg_pos.did_page_crc = true;
  		}
  		ret = ceph_tcp_sendpage(con->sock, page,
-				      con->out_msg_pos.page_pos + page_shift,
+				      con->out_msg_pos.page_pos + bio_offset,
  				      len, 1);

  		if (do_datacrc)
-- 
1.7.5.4