Get rid of all the PFN arithmetics and just use an enum for the two
remaining options, and use PageHighMem for the actual bounce decision.
Add a fast path to entirely avoid the call for the common case of a queue
not using the legacy bouncing code.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
block/blk-core.c | 6 ++----
block/blk-settings.c | 42 ++++++++----------------------------------
block/blk.h | 16 ++++++++++++----
block/bounce.c | 35 +++++------------------------------
include/linux/blkdev.h | 29 +++++++++++------------------
5 files changed, 38 insertions(+), 90 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index fc60ff20849738..9bcdae93f6d4f7 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1161,10 +1161,8 @@ static blk_status_t blk_cloned_rq_check_limits(struct request_queue *q,
}
/*
- * queue's settings related to segment counting like q->bounce_pfn
- * may differ from that of other stacking queues.
- * Recalculate it to check the request correctly on this queue's
- * limitation.
+ * The queue settings related to segment counting may differ from the
+ * original queue.
*/
rq->nr_phys_segments = blk_recalc_rq_segments(rq);
if (rq->nr_phys_segments > queue_max_segments(q)) {
diff --git a/block/blk-settings.c b/block/blk-settings.c
index f9937dd2810e25..c7e26d16c59c0e 100644
--- a/block/blk-settings.c
+++ b/block/blk-settings.c
@@ -7,7 +7,6 @@
#include <linux/init.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
-#include <linux/memblock.h> /* for max_pfn/max_low_pfn */
#include <linux/gcd.h>
#include <linux/lcm.h>
#include <linux/jiffies.h>
@@ -17,11 +16,6 @@
#include "blk.h"
#include "blk-wbt.h"
-unsigned long blk_max_low_pfn;
-EXPORT_SYMBOL(blk_max_low_pfn);
-
-unsigned long blk_max_pfn;
-
void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
{
q->rq_timeout = timeout;
@@ -55,7 +49,7 @@ void blk_set_default_limits(struct queue_limits *lim)
lim->discard_alignment = 0;
lim->discard_misaligned = 0;
lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
- lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT);
+ lim->bounce = BLK_BOUNCE_NONE;
lim->alignment_offset = 0;
lim->io_opt = 0;
lim->misaligned = 0;
@@ -92,28 +86,16 @@ EXPORT_SYMBOL(blk_set_stacking_limits);
/**
* blk_queue_bounce_limit - set bounce buffer limit for queue
* @q: the request queue for the device
- * @max_addr: the maximum address the device can handle
+ * @bounce: bounce limit to enforce
*
* Description:
- * Different hardware can have different requirements as to what pages
- * it can do I/O directly to. A low level driver can call
- * blk_queue_bounce_limit to have lower memory pages allocated as bounce
- * buffers for doing I/O to pages residing above @max_addr.
+ * Force bouncing for ISA DMA ranges or highmem.
+ *
+ * DEPRECATED, don't use in new code.
**/
-void blk_queue_bounce_limit(struct request_queue *q, u64 max_addr)
+void blk_queue_bounce_limit(struct request_queue *q, enum blk_bounce bounce)
{
- unsigned long b_pfn = max_addr >> PAGE_SHIFT;
-
-#if BITS_PER_LONG == 64
- /*
- * Assume anything <= 4GB can be handled by IOMMU. Actually
- * some IOMMUs can handle everything, but I don't know of a
- * way to test this here.
- */
- q->limits.bounce_pfn = max(max_low_pfn, b_pfn);
-#else
- q->limits.bounce_pfn = b_pfn;
-#endif
+ q->limits.bounce = bounce;
}
EXPORT_SYMBOL(blk_queue_bounce_limit);
@@ -536,7 +518,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
b->max_write_zeroes_sectors);
t->max_zone_append_sectors = min(t->max_zone_append_sectors,
b->max_zone_append_sectors);
- t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn);
+ t->bounce = min_not_zero(t->bounce, b->bounce);
t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask,
b->seg_boundary_mask);
@@ -916,11 +898,3 @@ void blk_queue_set_zoned(struct gendisk *disk, enum blk_zoned_model model)
}
}
EXPORT_SYMBOL_GPL(blk_queue_set_zoned);
-
-static int __init blk_settings_init(void)
-{
- blk_max_low_pfn = max_low_pfn - 1;
- blk_max_pfn = max_pfn - 1;
- return 0;
-}
-subsys_initcall(blk_settings_init);
diff --git a/block/blk.h b/block/blk.h
index 895c9f4a5182a7..8f4337c5a9e66c 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -6,6 +6,7 @@
#include <linux/blk-mq.h>
#include <linux/part_stat.h>
#include <linux/blk-crypto.h>
+#include <linux/memblock.h> /* for max_pfn/max_low_pfn */
#include <xen/xen.h>
#include "blk-crypto-internal.h"
#include "blk-mq.h"
@@ -311,13 +312,20 @@ static inline void blk_throtl_bio_endio(struct bio *bio) { }
static inline void blk_throtl_stat_add(struct request *rq, u64 time) { }
#endif
-#ifdef CONFIG_BOUNCE
-extern void blk_queue_bounce(struct request_queue *q, struct bio **bio);
-#else
+void __blk_queue_bounce(struct request_queue *q, struct bio **bio);
+
+static inline bool blk_queue_may_bounce(struct request_queue *q)
+{
+ return IS_ENABLED(CONFIG_BOUNCE) &&
+ q->limits.bounce == BLK_BOUNCE_HIGH &&
+ max_low_pfn >= max_pfn;
+}
+
static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
{
+ if (unlikely(blk_queue_may_bounce(q) && bio_has_data(*bio)))
+ __blk_queue_bounce(q, bio);
}
-#endif /* CONFIG_BOUNCE */
#ifdef CONFIG_BLK_CGROUP_IOLATENCY
extern int blk_iolatency_init(struct request_queue *q);
diff --git a/block/bounce.c b/block/bounce.c
index debd5b0bd31890..6bafc0d1f867a1 100644
--- a/block/bounce.c
+++ b/block/bounce.c
@@ -18,7 +18,6 @@
#include <linux/init.h>
#include <linux/hash.h>
#include <linux/highmem.h>
-#include <linux/memblock.h>
#include <linux/printk.h>
#include <asm/tlbflush.h>
@@ -49,11 +48,11 @@ static void init_bounce_bioset(void)
bounce_bs_setup = true;
}
-#if defined(CONFIG_HIGHMEM)
static __init int init_emergency_pool(void)
{
int ret;
-#if defined(CONFIG_HIGHMEM) && !defined(CONFIG_MEMORY_HOTPLUG)
+
+#ifndef CONFIG_MEMORY_HOTPLUG
if (max_pfn <= max_low_pfn)
return 0;
#endif
@@ -67,9 +66,7 @@ static __init int init_emergency_pool(void)
}
__initcall(init_emergency_pool);
-#endif
-#ifdef CONFIG_HIGHMEM
/*
* highmem version, map in to vec
*/
@@ -82,13 +79,6 @@ static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom)
kunmap_atomic(vto);
}
-#else /* CONFIG_HIGHMEM */
-
-#define bounce_copy_vec(to, vfrom) \
- memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)
-
-#endif /* CONFIG_HIGHMEM */
-
/*
* Simple bounce buffer support for highmem pages. Depending on the
* queue gfp mask set, *to may or may not be a highmem page. kmap it
@@ -236,8 +226,7 @@ static struct bio *bounce_clone_bio(struct bio *bio_src)
return NULL;
}
-
-void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
+void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
{
struct bio *bio;
int rw = bio_data_dir(*bio_orig);
@@ -247,24 +236,10 @@ void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
bool bounce = false;
int sectors = 0;
- /*
- * Data-less bio, nothing to bounce
- */
- if (!bio_has_data(*bio_orig))
- return;
-
- /*
- * Just check if the bounce pfn is equal to or bigger than the highest
- * pfn in the system -- in that case, don't waste time iterating over
- * bio segments
- */
- if (q->limits.bounce_pfn >= blk_max_pfn)
- return;
-
bio_for_each_segment(from, *bio_orig, iter) {
if (i++ < BIO_MAX_VECS)
sectors += from.bv_len >> 9;
- if (page_to_pfn(from.bv_page) > q->limits.bounce_pfn)
+ if (PageHighMem(from.bv_page))
bounce = true;
}
if (!bounce)
@@ -287,7 +262,7 @@ void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
for (i = 0, to = bio->bi_io_vec; i < bio->bi_vcnt; to++, i++) {
struct page *page = to->bv_page;
- if (page_to_pfn(page) <= q->limits.bounce_pfn)
+ if (!PageHighMem(page))
continue;
to->bv_page = mempool_alloc(&page_pool, GFP_NOIO);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 0dbb72ea373529..55cc8b96c84427 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -313,8 +313,17 @@ enum blk_zoned_model {
BLK_ZONED_HM, /* Host-managed zoned block device */
};
+/*
+ * BLK_BOUNCE_NONE: never bounce (default)
+ * BLK_BOUNCE_HIGH: bounce all highmem pages
+ */
+enum blk_bounce {
+ BLK_BOUNCE_NONE,
+ BLK_BOUNCE_HIGH,
+};
+
struct queue_limits {
- unsigned long bounce_pfn;
+ enum blk_bounce bounce;
unsigned long seg_boundary_mask;
unsigned long virt_boundary_mask;
@@ -835,22 +844,6 @@ static inline unsigned int blk_queue_depth(struct request_queue *q)
return q->nr_requests;
}
-extern unsigned long blk_max_low_pfn, blk_max_pfn;
-
-/*
- * standard bounce addresses:
- *
- * BLK_BOUNCE_HIGH : bounce all highmem pages
- * BLK_BOUNCE_ANY : don't bounce anything
- */
-
-#if BITS_PER_LONG == 32
-#define BLK_BOUNCE_HIGH ((u64)blk_max_low_pfn << PAGE_SHIFT)
-#else
-#define BLK_BOUNCE_HIGH -1ULL
-#endif
-#define BLK_BOUNCE_ANY (-1ULL)
-
/*
* default timeout for SG_IO if none specified
*/
@@ -1134,7 +1127,7 @@ extern void blk_abort_request(struct request *);
* Access functions for manipulating queue properties
*/
extern void blk_cleanup_queue(struct request_queue *);
-extern void blk_queue_bounce_limit(struct request_queue *, u64);
+void blk_queue_bounce_limit(struct request_queue *q, enum blk_bounce limit);
extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
extern void blk_queue_chunk_sectors(struct request_queue *, unsigned int);
extern void blk_queue_max_segments(struct request_queue *, unsigned short);
--
2.30.1
