BLK_RELEASE_QUEUE(9) Block Devices BLK_RELEASE_QUEUE(9)NAME
blk_release_queue - release a struct request_queue when it is no longer needed
void blk_release_queue(struct kobject * kobj);
the kobj belonging to the request queue to be released
blk_release_queue is the pair to blk_init_queue or blk_queue_make_request. It should be called when a request queue is being released;
typically when a block device is being de-registered. Currently, its primary task it to free all the struct request structures that were
allocated to the queue and the queue itself.
Hopefully the low level driver will have finished any outstanding requests first...
COPYRIGHT Kernel Hackers Manual 3.10 June 2014 BLK_RELEASE_QUEUE(9)
Check Out this Related Man Page
BLK_MAKE_REQUEST(9) Block Devices BLK_MAKE_REQUEST(9)NAME
blk_make_request - given a bio, allocate a corresponding struct request.
struct request * blk_make_request(struct request_queue * q, struct bio * bio, gfp_t gfp_mask);
target request queue
The bio describing the memory mappings that will be submitted for IO. It may be a chained-bio properly constructed by block/bio layer.
gfp flags to be used for memory allocation
blk_make_request is the parallel of generic_make_request for BLOCK_PC type commands. Where the struct request needs to be farther
initialized by the caller. It is passed a struct bio, which describes the memory info of the I/O transfer.
The caller of blk_make_request must make sure that bi_io_vec are set to describe the memory buffers. That bio_data_dir will return the
needed direction of the request. (And all bio's in the passed bio-chain are properly set accordingly)
If called under none-sleepable conditions, mapped bio buffers must not need bouncing, by calling the appropriate masked or flagged
allocator, suitable for the target device. Otherwise the call to blk_queue_bounce will BUG.
When allocating/cloning a bio-chain, careful consideration should be given to how you allocate bios. In particular, you cannot use
__GFP_WAIT for anything but the first bio in the chain. Otherwise you risk waiting for IO completion of a bio that hasn't been submitted
yet, thus resulting in a deadlock. Alternatively bios should be allocated using bio_kmalloc instead of bio_alloc, as that avoids the
mempool deadlock. If possible a big IO should be split into smaller parts when allocation fails. Partial allocation should not be an error,
or you risk a live-lock.
COPYRIGHT Kernel Hackers Manual 3.10 June 2014 BLK_MAKE_REQUEST(9)
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