suse man page for blk_queue_make_request

Query: blk_queue_make_request

OS: suse

Section: 9

Format: Original Unix Latex Style Formatted with HTML and a Horizontal Scroll Bar

BLK_QUEUE_MAKE_REQUE(9) 					   Block Devices					   BLK_QUEUE_MAKE_REQUE(9)

NAME
blk_queue_make_request - define an alternate make_request function for a device
SYNOPSIS
void blk_queue_make_request(struct request_queue * q, make_request_fn * mfn);
ARGUMENTS
q the request queue for the device to be affected mfn the alternate make_request function
DESCRIPTION
The normal way for struct bios to be passed to a device driver is for them to be collected into requests on a request queue, and then to allow the device driver to select requests off that queue when it is ready. This works well for many block devices. However some block devices (typically virtual devices such as md or lvm) do not benefit from the processing on the request queue, and are served best by having the requests passed directly to them. This can be achieved by providing a function to blk_queue_make_request.
CAVEAT
The driver that does this *must* be able to deal appropriately with buffers in "highmemory". This can be accomplished by either calling __bio_kmap_atomic to get a temporary kernel mapping, or by calling blk_queue_bounce to create a buffer in normal memory.
COPYRIGHT
Kernel Hackers Manual 2.6. July 2010 BLK_QUEUE_MAKE_REQUE(9)
Related Man Pages
tevent_queue(3) - centos
blk_init_queue(9) - centos
config_intrhook(9) - freebsd
struct_spi_master(9) - suse
config_intrhook_establish(9) - freebsd
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