On 7/6/2024 12:52 AM, Christoph Hellwig wrote:
Work on a single address to simplify the logic, and prepare the callers
from using better helpers.
Signed-off-by: Christoph Hellwig<hch@xxxxxx>
---
block/blk-merge.c | 25 +++++++++++--------------
1 file changed, 11 insertions(+), 14 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index cff20bcc0252a7..e41ea331809936 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -209,23 +209,22 @@ static inline unsigned get_max_io_size(struct bio *bio,
/**
* get_max_segment_size() - maximum number of bytes to add as a single segment
* @lim: Request queue limits.
- * @start_page: See below.
- * @offset: Offset from @start_page where to add a segment.
+ * @paddr: address of the range to add
+ * @max_len: maximum length available to add at @paddr
*
- * Returns the maximum number of bytes that can be added as a single segment.
+ * Returns the maximum number of bytes of the range starting at @paddr that can
+ * be added to a single segment.
*/
static inline unsigned get_max_segment_size(const struct queue_limits *lim,
- struct page *start_page, unsigned long offset)
+ phys_addr_t paddr, unsigned int len)
{
- unsigned long mask = lim->seg_boundary_mask;
-
- offset = mask & (page_to_phys(start_page) + offset);
-
/*
* Prevent an overflow if mask = ULONG_MAX and offset = 0 by adding 1
* after having calculated the minimum.
*/
- return min(mask - offset, (unsigned long)lim->max_segment_size - 1) + 1;
+ return min_t(unsigned long, len,
+ min(lim->seg_boundary_mask - (lim->seg_boundary_mask & paddr),
+ (unsigned long)lim->max_segment_size - 1) + 1);
}
Looks good, is it possible to re-write last
return min_t(..., ..., min(..., ...)) statement something like totally
untested in [1] ?
Irrespective of that, looks good.
Reviewed-by: Chaitanya Kulkarni <kch@xxxxxxxxxx>
-ck
[1]
static inline unsigned get_max_segment_size(const struct queue_limits *lim,
phys_addr_t paddr, unsigned int paddr_len)
{
unsigned long paddr_max_seg_allowed_len;
unsigned long paddr_seg_boundry;
paddr_seg_boundry =
lim->seg_boundary_mask - (lim->seg_boundary_mask & paddr);
/*
* Prevent an overflow if mask = ULONG_MAX and offset = 0 by
adding 1
* after having calculated the minimum.
*/
paddr_max_seg_allowed_len = min(paddr_seg_boundry,
(unsigned long)lim->max_segment_size -
1) + 1;
return min_t(unsigned long, paddr_len, paddr_max_seg_allowed_len);
}
