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Commit d004a5e7 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
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block: remove __bio_kmap_atomic 



This helper doesn't buy us much over calling kmap_atomic directly.
In fact in the only caller it does a bit of useless work as the
caller already has the bvec at hand, and said caller would even
buggy for a multi-segment bio due to the use of this helper.

So just remove it.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 83f5f7ed

Documentation/block/biodoc.txt

+5 −6
Original line number Diff line number Diff line
@@ -216,10 +216,9 @@ may need to abort DMA operations and revert to PIO for the transfer, in 
which case a virtual mapping of the page is required. For SCSI it is also

done in some scenarios where the low level driver cannot be trusted to

handle a single sg entry correctly. The driver is expected to perform the

kmaps as needed on such occasions using the bio_kmap_irq and friends

routines as appropriate. A driver could also use the blk_queue_bounce()

routine on its own to bounce highmem i/o to low memory for specific requests

if so desired.

kmaps as needed on such occasions as appropriate. A driver could also use

the blk_queue_bounce() routine on its own to bounce highmem i/o to low

memory for specific requests if so desired.



iii. The i/o scheduler algorithm itself can be replaced/set as appropriate
@@ -1137,8 +1136,8 @@ use dma_map_sg for scatter gather) to be able to ship it to the driver. For 
PIO drivers (or drivers that need to revert to PIO transfer once in a

while (IDE for example)), where the CPU is doing the actual data

transfer a virtual mapping is needed. If the driver supports highmem I/O,

(Sec 1.1, (ii) ) it needs to use __bio_kmap_atomic or similar to

temporarily map a bio into the virtual address space.

(Sec 1.1, (ii) ) it needs to use kmap_atomic or similar to temporarily map

a bio into the virtual address space.





8. Prior/Related/Impacted patches

arch/xtensa/platforms/iss/simdisk.c

+2 −2
Original line number Diff line number Diff line
@@ -110,13 +110,13 @@ static blk_qc_t simdisk_make_request(struct request_queue *q, struct bio *bio) 
	sector_t sector = bio->bi_iter.bi_sector;



	bio_for_each_segment(bvec, bio, iter) {

		char *buffer = __bio_kmap_atomic(bio, iter);

		char *buffer = kmap_atomic(bvec.bv_page) + bvec.bv_offset;

		unsigned len = bvec.bv_len >> SECTOR_SHIFT;



		simdisk_transfer(dev, sector, len, buffer,

				bio_data_dir(bio) == WRITE);

		sector += len;

		__bio_kunmap_atomic(buffer);

		kunmap_atomic(buffer)

	}



	bio_endio(bio);

block/blk-settings.c

+1 −1
Original line number Diff line number Diff line
@@ -157,7 +157,7 @@ EXPORT_SYMBOL(blk_set_stacking_limits); 
 * 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

 *    kmap_atomic() to get a temporary kernel mapping, or by calling

 *    blk_queue_bounce() to create a buffer in normal memory.

 **/

void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn)

include/linux/bio.h

+0 −12
Original line number Diff line number Diff line
@@ -128,18 +128,6 @@ static inline void *bio_data(struct bio *bio) 
 */

#define bvec_to_phys(bv)	(page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)



/*

 * queues that have highmem support enabled may still need to revert to

 * PIO transfers occasionally and thus map high pages temporarily. For

 * permanent PIO fall back, user is probably better off disabling highmem

 * I/O completely on that queue (see ide-dma for example)

 */

#define __bio_kmap_atomic(bio, iter)				\

	(kmap_atomic(bio_iter_iovec((bio), (iter)).bv_page) +	\

		bio_iter_iovec((bio), (iter)).bv_offset)



#define __bio_kunmap_atomic(addr)	kunmap_atomic(addr)



/*

 * merge helpers etc

 */