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Commit 5b99c2ff authored by Jens Axboe's avatar Jens Axboe
Browse files

block: make bi_phys_segments an unsigned int instead of short 



raid5 can overflow with more than 255 stripes, and we can increase it
to an int for free on both 32 and 64-bit archs due to the padding.

Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 960e739d

drivers/md/raid5.c

+6 −6
Original line number Diff line number Diff line
@@ -102,17 +102,17 @@ const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256))); 
#endif



/*

 * We maintain a biased count of active stripes in the bottom 8 bits of

 * bi_phys_segments, and a count of processed stripes in the upper 8 bits

 * We maintain a biased count of active stripes in the bottom 16 bits of

 * bi_phys_segments, and a count of processed stripes in the upper 16 bits

 */

static inline int raid5_bi_phys_segments(struct bio *bio)

{

	return bio->bi_phys_segments & 0xff;

	return bio->bi_phys_segments & 0xffff;

}



static inline int raid5_bi_hw_segments(struct bio *bio)

{

	return (bio->bi_phys_segments >> 8) & 0xff;

	return (bio->bi_phys_segments >> 16) & 0xffff;

}



static inline int raid5_dec_bi_phys_segments(struct bio *bio)
@@ -126,13 +126,13 @@ static inline int raid5_dec_bi_hw_segments(struct bio *bio) 
	unsigned short val = raid5_bi_hw_segments(bio);



	--val;

	bio->bi_phys_segments = (val << 8) | raid5_bi_phys_segments(bio);

	bio->bi_phys_segments = (val << 16) | raid5_bi_phys_segments(bio);

	return val;

}



static inline void raid5_set_bi_hw_segments(struct bio *bio, unsigned int cnt)

{

	bio->bi_phys_segments = raid5_bi_phys_segments(bio) || (cnt << 8);

	bio->bi_phys_segments = raid5_bi_phys_segments(bio) || (cnt << 16);

}



static inline int raid6_next_disk(int disk, int raid_disks)

include/linux/bio.h

+1 −1
Original line number Diff line number Diff line
@@ -75,7 +75,7 @@ struct bio { 
	/* Number of segments in this BIO after

	 * physical address coalescing is performed.

	 */

	unsigned short		bi_phys_segments;

	unsigned int		bi_phys_segments;



	unsigned int		bi_size;	/* residual I/O count */