aboutsummaryrefslogtreecommitdiff
path: root/Documentation/block/biodoc.txt
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/block/biodoc.txt')
-rw-r--r--Documentation/block/biodoc.txt19
1 files changed, 9 insertions, 10 deletions
diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index 5be8a7f4cc7f..9490f2845f06 100644
--- a/Documentation/block/biodoc.txt
+++ b/Documentation/block/biodoc.txt
@@ -115,7 +115,7 @@ i. Per-queue limits/values exported to the generic layer by the driver
Various parameters that the generic i/o scheduler logic uses are set at
a per-queue level (e.g maximum request size, maximum number of segments in
-a scatter-gather list, hardsect size)
+a scatter-gather list, logical block size)
Some parameters that were earlier available as global arrays indexed by
major/minor are now directly associated with the queue. Some of these may
@@ -156,7 +156,7 @@ Some new queue property settings:
blk_queue_max_segment_size(q, max_seg_size)
Maximum size of a clustered segment, 64kB default.
- blk_queue_hardsect_size(q, hardsect_size)
+ blk_queue_logical_block_size(q, logical_block_size)
Lowest possible sector size that the hardware can operate
on, 512 bytes default.
@@ -269,7 +269,7 @@ Arjan's proposed request priority scheme allows higher levels some broad
requests which haven't aged too much on the queue. Potentially this priority
could even be exposed to applications in some manner, providing higher level
tunability. Time based aging avoids starvation of lower priority
- requests. Some bits in the bi_rw flags field in the bio structure are
+ requests. Some bits in the bi_opf flags field in the bio structure are
intended to be used for this priority information.
@@ -348,7 +348,7 @@ Drivers can now specify a request prepare function (q->prep_rq_fn) that the
block layer would invoke to pre-build device commands for a given request,
or perform other preparatory processing for the request. This is routine is
called by elv_next_request(), i.e. typically just before servicing a request.
-(The prepare function would not be called for requests that have REQ_DONTPREP
+(The prepare function would not be called for requests that have RQF_DONTPREP
enabled)
Aside:
@@ -432,7 +432,7 @@ struct bio {
struct bio *bi_next; /* request queue link */
struct block_device *bi_bdev; /* target device */
unsigned long bi_flags; /* status, command, etc */
- unsigned long bi_rw; /* low bits: r/w, high: priority */
+ unsigned long bi_opf; /* low bits: r/w, high: priority */
unsigned int bi_vcnt; /* how may bio_vec's */
struct bvec_iter bi_iter; /* current index into bio_vec array */
@@ -553,8 +553,8 @@ struct request {
struct request_list *rl;
}
-See the rq_flag_bits definitions for an explanation of the various flags
-available. Some bits are used by the block layer or i/o scheduler.
+See the req_ops and req_flag_bits definitions for an explanation of the various
+flags available. Some bits are used by the block layer or i/o scheduler.
The behaviour of the various sector counts are almost the same as before,
except that since we have multi-segment bios, current_nr_sectors refers
@@ -632,7 +632,7 @@ to i/o submission, if the bio fields are likely to be accessed after the
i/o is issued (since the bio may otherwise get freed in case i/o completion
happens in the meantime).
-The bio_clone() routine may be used to duplicate a bio, where the clone
+The bio_clone_fast() routine may be used to duplicate a bio, where the clone
shares the bio_vec_list with the original bio (i.e. both point to the
same bio_vec_list). This would typically be used for splitting i/o requests
in lvm or md.
@@ -1024,8 +1024,7 @@ could be on demand. For example wait_on_buffer sets the unplugging going
through sync_buffer() running blk_run_address_space(mapping). Or the caller
can do it explicity through blk_unplug(bdev). So in the read case,
the queue gets explicitly unplugged as part of waiting for completion on that
-buffer. For page driven IO, the address space ->sync_page() takes care of
-doing the blk_run_address_space().
+buffer.
Aside:
This is kind of controversial territory, as it's not clear if plugging is