2 files changed, 69 insertions, 5 deletions

diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index 3c5434c83daf..ecad6ee75705 100644
--- a/Documentation/block/biodoc.txt
+++ b/Documentation/block/biodoc.txt
@@ -186,8 +186,9 @@ a virtual address mapping (unlike the earlier scheme of virtual address
 do not have a corresponding kernel virtual address space mapping) and
 low-memory pages.
 
-Note: Please refer to DMA-mapping.txt for a discussion on PCI high mem DMA
-aspects and mapping of scatter gather lists, and support for 64 bit PCI.
+Note: Please refer to Documentation/PCI/PCI-DMA-mapping.txt for a discussion
+on PCI high mem DMA aspects and mapping of scatter gather lists, and support
+for 64 bit PCI.
 
 Special handling is required only for cases where i/o needs to happen on
 pages at physical memory addresses beyond what the device can support. In these
@@ -953,14 +954,14 @@ elevator_allow_merge_fn		called whenever the block layer determines
                                 results in some sort of conflict internally,
                                 this hook allows it to do that.
 
-elevator_dispatch_fn            fills the dispatch queue with ready requests.
+elevator_dispatch_fn*           fills the dispatch queue with ready requests.
                                 I/O schedulers are free to postpone requests by
                                 not filling the dispatch queue unless @force
                                 is non-zero.  Once dispatched, I/O schedulers
                                 are not allowed to manipulate the requests -
                                 they belong to generic dispatch queue.
 
-elevator_add_req_fn             called to add a new request into the scheduler
+elevator_add_req_fn*            called to add a new request into the scheduler
 
 elevator_queue_empty_fn         returns true if the merge queue is empty.
                                 Drivers shouldn't use this, but rather check
@@ -990,7 +991,7 @@ elevator_activate_req_fn	Called when device driver first sees a request.
 elevator_deactivate_req_fn      Called when device driver decides to delay
                                 a request by requeueing it.
 
-elevator_init_fn
+elevator_init_fn*
 elevator_exit_fn                Allocate and free any elevator specific storage
                                 for a queue.
 
diff --git a/Documentation/block/queue-sysfs.txt b/Documentation/block/queue-sysfs.txt
new file mode 100644
index 000000000000..e164403f60e1
--- /dev/null
+++ b/Documentation/block/queue-sysfs.txt
@@ -0,0 +1,63 @@
+Queue sysfs files
+=================
+
+This text file will detail the queue files that are located in the sysfs tree
+for each block device. Note that stacked devices typically do not export
+any settings, since their queue merely functions are a remapping target.
+These files are the ones found in the /sys/block/xxx/queue/ directory.
+
+Files denoted with a RO postfix are readonly and the RW postfix means
+read-write.
+
+hw_sector_size (RO)
+-------------------
+This is the hardware sector size of the device, in bytes.
+
+max_hw_sectors_kb (RO)
+----------------------
+This is the maximum number of kilobytes supported in a single data transfer.
+
+max_sectors_kb (RW)
+-------------------
+This is the maximum number of kilobytes that the block layer will allow
+for a filesystem request. Must be smaller than or equal to the maximum
+size allowed by the hardware.
+
+nomerges (RW)
+-------------
+This enables the user to disable the lookup logic involved with IO merging
+requests in the block layer. Merging may still occur through a direct
+1-hit cache, since that comes for (almost) free. The IO scheduler will not
+waste cycles doing tree/hash lookups for merges if nomerges is 1. Defaults
+to 0, enabling all merges.
+
+nr_requests (RW)
+----------------
+This controls how many requests may be allocated in the block layer for
+read or write requests. Note that the total allocated number may be twice
+this amount, since it applies only to reads or writes (not the accumulated
+sum).
+
+read_ahead_kb (RW)
+------------------
+Maximum number of kilobytes to read-ahead for filesystems on this block
+device.
+
+rq_affinity (RW)
+----------------
+If this option is enabled, the block layer will migrate request completions
+to the CPU that originally submitted the request. For some workloads
+this provides a significant reduction in CPU cycles due to caching effects.
+
+scheduler (RW)
+--------------
+When read, this file will display the current and available IO schedulers
+for this block device. The currently active IO scheduler will be enclosed
+in [] brackets. Writing an IO scheduler name to this file will switch
+control of this block device to that new IO scheduler. Note that writing
+an IO scheduler name to this file will attempt to load that IO scheduler
+module, if it isn't already present in the system.
+
+
+
+Jens Axboe <jens.axboe@oracle.com>, February 2009