[1/5] brd: convert to folios

Message ID	20230306120127.21375-2-hare@suse.de (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-block-owner@vger.kernel.org> From: Hannes Reinecke <hare@suse.de> To: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org, Matthew Wilcox <willy@infradead.org>, Luis Chamberlain <mcgrof@kernel.org>, Keith Busch <kbusch@kernel.org>, Hannes Reinecke <hare@suse.de> Subject: [PATCH 1/5] brd: convert to folios Date: Mon, 6 Mar 2023 13:01:23 +0100 Message-Id: <20230306120127.21375-2-hare@suse.de> In-Reply-To: <20230306120127.21375-1-hare@suse.de> References: <20230306120127.21375-1-hare@suse.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	brd: Allow to change block sizes \| expand [0/5] brd: Allow to change block sizes [1/5] brd: convert to folios [2/5] brd: abstract page_size conventions [3/5] brd: make sector size configurable [4/5] brd: limit maximal block size to 32M [5/5] brd: make logical sector size configurable

diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 34177f1bd97d..7efc276c4963 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -28,8 +28,8 @@ #include <linux/uaccess.h> /* - * Each block ramdisk device has a radix_tree brd_pages of pages that stores - * the pages containing the block device's contents. A brd page's ->index is + * Each block ramdisk device has a radix_tree brd_folios of folios that stores + * the folios containing the block device's contents. A brd folio's ->index is * its offset in PAGE_SIZE units. This is similar to, but in no way connected * with, the kernel's pagecache or buffer cache (which sit above our block * device). @@ -40,25 +40,25 @@ struct brd_device { struct list_head brd_list; /* - * Backing store of pages and lock to protect it. This is the contents - * of the block device. + * Backing store of folios and lock to protect it. + * This is the contents of the block device. */ spinlock_t brd_lock; - struct radix_tree_root brd_pages; - u64 brd_nr_pages; + struct radix_tree_root brd_folios; + u64 brd_nr_folios; }; /* - * Look up and return a brd's page for a given sector. + * Look up and return a brd's folio for a given sector. */ -static struct page *brd_lookup_page(struct brd_device *brd, sector_t sector) +static struct folio *brd_lookup_folio(struct brd_device *brd, sector_t sector) { pgoff_t idx; - struct page *page; + struct folio *folio; /* - * The page lifetime is protected by the fact that we have opened the - * device node -- brd pages will never be deleted under us, so we + * The folio lifetime is protected by the fact that we have opened the + * device node -- brd folios will never be deleted under us, so we * don't need any further locking or refcounting. * * This is strictly true for the radix-tree nodes as well (ie. we @@ -68,49 +68,49 @@ static struct page *brd_lookup_page(struct brd_device *brd, sector_t sector) * here, only deletes). */ rcu_read_lock(); - idx = sector >> PAGE_SECTORS_SHIFT; /* sector to page index */ - page = radix_tree_lookup(&brd->brd_pages, idx); + idx = sector >> PAGE_SECTORS_SHIFT; /* sector to folio index */ + folio = radix_tree_lookup(&brd->brd_folios, idx); rcu_read_unlock(); - BUG_ON(page && page->index != idx); + BUG_ON(folio && folio->index != idx); - return page; + return folio; } /* - * Insert a new page for a given sector, if one does not already exist. + * Insert a new folio for a given sector, if one does not already exist. */ -static int brd_insert_page(struct brd_device *brd, sector_t sector, gfp_t gfp) +static int brd_insert_folio(struct brd_device *brd, sector_t sector, gfp_t gfp) { pgoff_t idx; - struct page *page; + struct folio *folio; int ret = 0; - page = brd_lookup_page(brd, sector); - if (page) + folio = brd_lookup_folio(brd, sector); + if (folio) return 0; - page = alloc_page(gfp | __GFP_ZERO | __GFP_HIGHMEM); - if (!page) + folio = folio_alloc(gfp | __GFP_ZERO, 0); + if (!folio) return -ENOMEM; if (radix_tree_maybe_preload(gfp)) { - __free_page(page); + folio_put(folio); return -ENOMEM; } spin_lock(&brd->brd_lock); idx = sector >> PAGE_SECTORS_SHIFT; - page->index = idx; - if (radix_tree_insert(&brd->brd_pages, idx, page)) { - __free_page(page); - page = radix_tree_lookup(&brd->brd_pages, idx); - if (!page) + folio->index = idx; + if (radix_tree_insert(&brd->brd_folios, idx, folio)) { + folio_put(folio); + folio = radix_tree_lookup(&brd->brd_folios, idx); + if (!folio) ret = -ENOMEM; - else if (page->index != idx) + else if (folio->index != idx) ret = -EIO; } else { - brd->brd_nr_pages++; + brd->brd_nr_folios++; } spin_unlock(&brd->brd_lock); @@ -119,30 +119,30 @@ static int brd_insert_page(struct brd_device *brd, sector_t sector, gfp_t gfp) } /* - * Free all backing store pages and radix tree. This must only be called when + * Free all backing store folios and radix tree. This must only be called when * there are no other users of the device. */ #define FREE_BATCH 16 -static void brd_free_pages(struct brd_device *brd) +static void brd_free_folios(struct brd_device *brd) { unsigned long pos = 0; - struct page *pages[FREE_BATCH]; - int nr_pages; + struct folio *folios[FREE_BATCH]; + int nr_folios; do { int i; - nr_pages = radix_tree_gang_lookup(&brd->brd_pages, - (void **)pages, pos, FREE_BATCH); + nr_folios = radix_tree_gang_lookup(&brd->brd_folios, + (void **)folios, pos, FREE_BATCH); - for (i = 0; i < nr_pages; i++) { + for (i = 0; i < nr_folios; i++) { void *ret; - BUG_ON(pages[i]->index < pos); - pos = pages[i]->index; - ret = radix_tree_delete(&brd->brd_pages, pos); - BUG_ON(!ret || ret != pages[i]); - __free_page(pages[i]); + BUG_ON(folios[i]->index < pos); + pos = folios[i]->index; + ret = radix_tree_delete(&brd->brd_folios, pos); + BUG_ON(!ret || ret != folios[i]); + folio_put(folios[i]); } pos++; @@ -155,10 +155,10 @@ static void brd_free_pages(struct brd_device *brd) /* * This assumes radix_tree_gang_lookup always returns as - * many pages as possible. If the radix-tree code changes, + * many folios as possible. If the radix-tree code changes, * so will this have to. */ - } while (nr_pages == FREE_BATCH); + } while (nr_folios == FREE_BATCH); } /* @@ -172,12 +172,12 @@ static int copy_to_brd_setup(struct brd_device *brd, sector_t sector, size_t n, int ret; copy = min_t(size_t, n, PAGE_SIZE - offset); - ret = brd_insert_page(brd, sector, gfp); + ret = brd_insert_folio(brd, sector, gfp); if (ret) return ret; if (copy < n) { sector += copy >> SECTOR_SHIFT; - ret = brd_insert_page(brd, sector, gfp); + ret = brd_insert_folio(brd, sector, gfp); } return ret; } @@ -188,29 +188,29 @@ static int copy_to_brd_setup(struct brd_device *brd, sector_t sector, size_t n, static void copy_to_brd(struct brd_device *brd, const void *src, sector_t sector, size_t n) { - struct page *page; + struct folio *folio; void *dst; unsigned int offset = (sector & (PAGE_SECTORS-1)) << SECTOR_SHIFT; size_t copy; copy = min_t(size_t, n, PAGE_SIZE - offset); - page = brd_lookup_page(brd, sector); - BUG_ON(!page); + folio = brd_lookup_folio(brd, sector); + BUG_ON(!folio); - dst = kmap_atomic(page); - memcpy(dst + offset, src, copy); - kunmap_atomic(dst); + dst = kmap_local_folio(folio, offset); + memcpy(dst, src, copy); + kunmap_local(dst); if (copy < n) { src += copy; sector += copy >> SECTOR_SHIFT; copy = n - copy; - page = brd_lookup_page(brd, sector); - BUG_ON(!page); + folio = brd_lookup_folio(brd, sector); + BUG_ON(!folio); - dst = kmap_atomic(page); + dst = kmap_local_folio(folio, 0); memcpy(dst, src, copy); - kunmap_atomic(dst); + kunmap_local(dst); } } @@ -220,17 +220,17 @@ static void copy_to_brd(struct brd_device *brd, const void *src, static void copy_from_brd(void *dst, struct brd_device *brd, sector_t sector, size_t n) { - struct page *page; + struct folio *folio; void *src; unsigned int offset = (sector & (PAGE_SECTORS-1)) << SECTOR_SHIFT; size_t copy; copy = min_t(size_t, n, PAGE_SIZE - offset); - page = brd_lookup_page(brd, sector); - if (page) { - src = kmap_atomic(page); - memcpy(dst, src + offset, copy); - kunmap_atomic(src); + folio = brd_lookup_folio(brd, sector); + if (folio) { + src = kmap_local_folio(folio, offset); + memcpy(dst, src, copy); + kunmap_local(src); } else memset(dst, 0, copy); @@ -238,20 +238,20 @@ static void copy_from_brd(void *dst, struct brd_device *brd, dst += copy; sector += copy >> SECTOR_SHIFT; copy = n - copy; - page = brd_lookup_page(brd, sector); - if (page) { - src = kmap_atomic(page); + folio = brd_lookup_folio(brd, sector); + if (folio) { + src = kmap_local_folio(folio, 0); memcpy(dst, src, copy); - kunmap_atomic(src); + kunmap_local(src); } else memset(dst, 0, copy); } } /* - * Process a single bvec of a bio. + * Process a single folio of a bio. */ -static int brd_do_bvec(struct brd_device *brd, struct page *page, +static int brd_do_folio(struct brd_device *brd, struct folio *folio, unsigned int len, unsigned int off, blk_opf_t opf, sector_t sector) { @@ -261,7 +261,7 @@ static int brd_do_bvec(struct brd_device *brd, struct page *page, if (op_is_write(opf)) { /* * Must use NOIO because we don't want to recurse back into the - * block or filesystem layers from page reclaim. + * block or filesystem layers from folio reclaim. */ gfp_t gfp = opf & REQ_NOWAIT ? GFP_NOWAIT : GFP_NOIO; @@ -270,15 +270,15 @@ static int brd_do_bvec(struct brd_device *brd, struct page *page, goto out; } - mem = kmap_atomic(page); + mem = kmap_local_folio(folio, off); if (!op_is_write(opf)) { - copy_from_brd(mem + off, brd, sector, len); - flush_dcache_page(page); + copy_from_brd(mem, brd, sector, len); + flush_dcache_folio(folio); } else { - flush_dcache_page(page); - copy_to_brd(brd, mem + off, sector, len); + flush_dcache_folio(folio); + copy_to_brd(brd, mem, sector, len); } - kunmap_atomic(mem); + kunmap_local(mem); out: return err; @@ -288,19 +288,18 @@ static void brd_submit_bio(struct bio *bio) { struct brd_device *brd = bio->bi_bdev->bd_disk->private_data; sector_t sector = bio->bi_iter.bi_sector; - struct bio_vec bvec; - struct bvec_iter iter; + struct folio_iter iter; - bio_for_each_segment(bvec, bio, iter) { - unsigned int len = bvec.bv_len; + bio_for_each_folio_all(iter, bio) { + unsigned int len = iter.length; int err; /* Don't support un-aligned buffer */ - WARN_ON_ONCE((bvec.bv_offset & (SECTOR_SIZE - 1)) || + WARN_ON_ONCE((iter.offset & (SECTOR_SIZE - 1)) || (len & (SECTOR_SIZE - 1))); - err = brd_do_bvec(brd, bvec.bv_page, len, bvec.bv_offset, - bio->bi_opf, sector); + err = brd_do_folio(brd, iter.folio, len, iter.offset, + bio->bi_opf, sector); if (err) { if (err == -ENOMEM && bio->bi_opf & REQ_NOWAIT) { bio_wouldblock_error(bio); @@ -373,12 +372,12 @@ static int brd_alloc(int i) list_add_tail(&brd->brd_list, &brd_devices); spin_lock_init(&brd->brd_lock); - INIT_RADIX_TREE(&brd->brd_pages, GFP_ATOMIC); + INIT_RADIX_TREE(&brd->brd_folios, GFP_ATOMIC); snprintf(buf, DISK_NAME_LEN, "ram%d", i); if (!IS_ERR_OR_NULL(brd_debugfs_dir)) debugfs_create_u64(buf, 0444, brd_debugfs_dir, - &brd->brd_nr_pages); + &brd->brd_nr_folios); disk = brd->brd_disk = blk_alloc_disk(NUMA_NO_NODE); if (!disk) @@ -434,7 +433,7 @@ static void brd_cleanup(void) list_for_each_entry_safe(brd, next, &brd_devices, brd_list) { del_gendisk(brd->brd_disk); put_disk(brd->brd_disk); - brd_free_pages(brd); + brd_free_folios(brd); list_del(&brd->brd_list); kfree(brd); } @@ -465,7 +464,7 @@ static int __init brd_init(void) brd_check_and_reset_par(); - brd_debugfs_dir = debugfs_create_dir("ramdisk_pages", NULL); + brd_debugfs_dir = debugfs_create_dir("ramdisk_folios", NULL); for (i = 0; i < rd_nr; i++) { err = brd_alloc(i);

[1/5] brd: convert to folios

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