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: Jens Axboe <jens.axboe@oracle.com>

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 05b22925cce4a015b9eaa4a8396d5eea4d294319..37e546528f9cf58621cfecb74e24cafcb1435edc 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -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)

diff --git a/include/linux/bio.h b/include/linux/bio.h
index dfc3556d311cba057298780b8f45a3efe7da6a53..2c0c09034fd244d7bb76b99d805936dcc6e8753e 100644 (file)
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -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 */