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authorAlex Elder <elder@dreamhost.com>2012-03-07 11:40:08 -0600
committerAlex Elder <elder@dreamhost.com>2012-03-22 10:47:52 -0500
commit8d63e318c4eb1bea6f7e3cb4b77849eaa167bfec (patch)
tree4783d4d0ab9a5d9c17e8eb0f93b0d279ad1b879a /net
parent9bd1966344bf975b5ce65e80fd6bacc41b4325a8 (diff)
downloadlinux-8d63e318c4eb1bea6f7e3cb4b77849eaa167bfec.tar.gz
libceph: isolate kmap() call in write_partial_msg_pages()
In write_partial_msg_pages(), every case now does an identical call
to kmap(page).  Instead, just call it once inside the CRC-computing
block where it's needed.  Move the definition of kaddr inside that
block, and make it a (char *) to ensure portable pointer arithmetic.

We still don't kunmap() it until after the sendpage() call, in case
that also ends up needing to use the mapping.

Signed-off-by: Alex Elder <elder@dreamhost.com>
Reviewed-by: Sage Weil <sage@newdream.net>
Diffstat (limited to 'net')
-rw-r--r--net/ceph/messenger.c13
1 files changed, 2 insertions, 11 deletions
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 2bf9ab4429e6..f0993af2ae4d 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -835,7 +835,6 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 
 	while (data_len > con->out_msg_pos.data_pos) {
 		struct page *page = NULL;
-		void *kaddr = NULL;
 		int max_write = PAGE_SIZE;
 		int bio_offset = 0;
 
@@ -856,18 +855,12 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 
 			page = list_first_entry(&msg->trail->head,
 						struct page, lru);
-			if (do_datacrc)
-				kaddr = kmap(page);
 			max_write = PAGE_SIZE;
 		} else if (msg->pages) {
 			page = msg->pages[con->out_msg_pos.page];
-			if (do_datacrc)
-				kaddr = kmap(page);
 		} else if (msg->pagelist) {
 			page = list_first_entry(&msg->pagelist->head,
 						struct page, lru);
-			if (do_datacrc)
-				kaddr = kmap(page);
 #ifdef CONFIG_BLOCK
 		} else if (msg->bio) {
 			struct bio_vec *bv;
@@ -875,14 +868,10 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 			bv = bio_iovec_idx(msg->bio_iter, msg->bio_seg);
 			page = bv->bv_page;
 			bio_offset = bv->bv_offset;
-			if (do_datacrc)
-				kaddr = kmap(page);
 			max_write = bv->bv_len;
 #endif
 		} else {
 			page = zero_page;
-			if (do_datacrc)
-				kaddr = kmap(page);
 		}
 		len = min_t(int, max_write - con->out_msg_pos.page_pos,
 			    total_max_write);
@@ -891,7 +880,9 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 			void *base;
 			u32 crc;
 			u32 tmpcrc = le32_to_cpu(con->out_msg->footer.data_crc);
+			char *kaddr;
 
+			kaddr = kmap(page);
 			BUG_ON(kaddr == NULL);
 			base = kaddr + con->out_msg_pos.page_pos + bio_offset;
 			crc = crc32c(tmpcrc, base, len);