diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/Kconfig | 13 | ||||
| -rw-r--r-- | mm/bounce.c | 48 | ||||
| -rw-r--r-- | mm/page-writeback.c | 4 |
3 files changed, 61 insertions, 4 deletions
diff --git a/mm/Kconfig b/mm/Kconfig index 278e3ab1f16..7901d839aab 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -258,6 +258,19 @@ config BOUNCE def_bool y depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM) +# On the 'tile' arch, USB OHCI needs the bounce pool since tilegx will often +# have more than 4GB of memory, but we don't currently use the IOTLB to present +# a 32-bit address to OHCI. So we need to use a bounce pool instead. +# +# We also use the bounce pool to provide stable page writes for jbd. jbd +# initiates buffer writeback without locking the page or setting PG_writeback, +# and fixing that behavior (a second time; jbd2 doesn't have this problem) is +# a major rework effort. Instead, use the bounce buffer to snapshot pages +# (until jbd goes away). The only jbd user is ext3. +config NEED_BOUNCE_POOL + bool + default y if (TILE && USB_OHCI_HCD) || (BLK_DEV_INTEGRITY && JBD) + config NR_QUICK int depends on QUICKLIST diff --git a/mm/bounce.c b/mm/bounce.c index 04208677556..5f890176860 100644 --- a/mm/bounce.c +++ b/mm/bounce.c @@ -178,8 +178,45 @@ static void bounce_end_io_read_isa(struct bio *bio, int err) __bounce_end_io_read(bio, isa_page_pool, err); } +#ifdef CONFIG_NEED_BOUNCE_POOL +static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio) +{ + struct page *page; + struct backing_dev_info *bdi; + struct address_space *mapping; + struct bio_vec *from; + int i; + + if (bio_data_dir(bio) != WRITE) + return 0; + + if (!bdi_cap_stable_pages_required(&q->backing_dev_info)) + return 0; + + /* + * Based on the first page that has a valid mapping, decide whether or + * not we have to employ bounce buffering to guarantee stable pages. + */ + bio_for_each_segment(from, bio, i) { + page = from->bv_page; + mapping = page_mapping(page); + if (!mapping) + continue; + bdi = mapping->backing_dev_info; + return mapping->host->i_sb->s_flags & MS_SNAP_STABLE; + } + + return 0; +} +#else +static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio) +{ + return 0; +} +#endif /* CONFIG_NEED_BOUNCE_POOL */ + static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig, - mempool_t *pool) + mempool_t *pool, int force) { struct page *page; struct bio *bio = NULL; @@ -192,7 +229,7 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig, /* * is destination page below bounce pfn? */ - if (page_to_pfn(page) <= queue_bounce_pfn(q)) + if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force) continue; /* @@ -270,6 +307,7 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig, void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig) { + int must_bounce; mempool_t *pool; /* @@ -278,13 +316,15 @@ void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig) if (!bio_has_data(*bio_orig)) return; + must_bounce = must_snapshot_stable_pages(q, *bio_orig); + /* * for non-isa bounce case, 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->bounce_gfp & GFP_DMA)) { - if (queue_bounce_pfn(q) >= blk_max_pfn) + if (queue_bounce_pfn(q) >= blk_max_pfn && !must_bounce) return; pool = page_pool; } else { @@ -295,7 +335,7 @@ void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig) /* * slow path */ - __blk_queue_bounce(q, bio_orig, pool); + __blk_queue_bounce(q, bio_orig, pool, must_bounce); } EXPORT_SYMBOL(blk_queue_bounce); diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 355d5ee6905..7300c9d5e1d 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -2306,6 +2306,10 @@ void wait_for_stable_page(struct page *page) if (!bdi_cap_stable_pages_required(bdi)) return; +#ifdef CONFIG_NEED_BOUNCE_POOL + if (mapping->host->i_sb->s_flags & MS_SNAP_STABLE) + return; +#endif /* CONFIG_NEED_BOUNCE_POOL */ wait_on_page_writeback(page); } |