path: root/lib/scatterlist.c
diff options
authorLinus Torvalds <torvalds@linux-foundation.org>2012-10-11 09:04:23 +0900
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-11 09:04:23 +0900
commitce40be7a820bb393ac4ac69865f018d2f4038cf0 (patch)
treeb1fe5a93346eb06f22b1c303d63ec5456d7212ab /lib/scatterlist.c
parentba0a5a36f60e4c1152af3a2ae2813251974405bf (diff)
parent02f3939e1a9357b7c370a4a69717cf9c02452737 (diff)
Merge branch 'for-3.7/core' of git://git.kernel.dk/linux-block
Pull block IO update from Jens Axboe: "Core block IO bits for 3.7. Not a huge round this time, it contains: - First series from Kent cleaning up and generalizing bio allocation and freeing. - WRITE_SAME support from Martin. - Mikulas patches to prevent O_DIRECT crashes when someone changes the block size of a device. - Make bio_split() work on data-less bio's (like trim/discards). - A few other minor fixups." Fixed up silent semantic mis-merge as per Mikulas Patocka and Andrew Morton. It is due to the VM no longer using a prio-tree (see commit 6b2dbba8b6ac: "mm: replace vma prio_tree with an interval tree"). So make set_blocksize() use mapping_mapped() instead of open-coding the internal VM knowledge that has changed. * 'for-3.7/core' of git://git.kernel.dk/linux-block: (26 commits) block: makes bio_split support bio without data scatterlist: refactor the sg_nents scatterlist: add sg_nents fs: fix include/percpu-rwsem.h export error percpu-rw-semaphore: fix documentation typos fs/block_dev.c:1644:5: sparse: symbol 'blkdev_mmap' was not declared blockdev: turn a rw semaphore into a percpu rw semaphore Fix a crash when block device is read and block size is changed at the same time block: fix request_queue->flags initialization block: lift the initial queue bypass mode on blk_register_queue() instead of blk_init_allocated_queue() block: ioctl to zero block ranges block: Make blkdev_issue_zeroout use WRITE SAME block: Implement support for WRITE SAME block: Consolidate command flag and queue limit checks for merges block: Clean up special command handling logic block/blk-tag.c: Remove useless kfree block: remove the duplicated setting for congestion_threshold block: reject invalid queue attribute values block: Add bio_clone_bioset(), bio_clone_kmalloc() block: Consolidate bio_alloc_bioset(), bio_kmalloc() ...
Diffstat (limited to 'lib/scatterlist.c')
1 files changed, 19 insertions, 0 deletions
diff --git a/lib/scatterlist.c b/lib/scatterlist.c
index e76d85cf3175..3675452b23ca 100644
--- a/lib/scatterlist.c
+++ b/lib/scatterlist.c
@@ -39,6 +39,25 @@ struct scatterlist *sg_next(struct scatterlist *sg)
+ * sg_nents - return total count of entries in scatterlist
+ * @sg: The scatterlist
+ *
+ * Description:
+ * Allows to know how many entries are in sg, taking into acount
+ * chaining as well
+ *
+ **/
+int sg_nents(struct scatterlist *sg)
+ int nents;
+ for (nents = 0; sg; sg = sg_next(sg))
+ nents++;
+ return nents;
* sg_last - return the last scatterlist entry in a list
* @sgl: First entry in the scatterlist
* @nents: Number of entries in the scatterlist