To prepare for supporting boot-time page size selection, refactor code to remove assumptions about PAGE_SIZE being compile-time constant. Code intended to be equivalent when compile-time page size is active.
Updated multiple BUILD_BUG_ON() instances to test against page size limits. Wrap global variables that are initialized with PAGE_SIZE derived values using DEFINE_GLOBAL_PAGE_SIZE_VAR() so their initialization can be deferred for boot-time page size builds. Signed-off-by: Ryan Roberts <ryan.robe...@arm.com> --- ***NOTE*** Any confused maintainers may want to read the cover note here for context: https://lore.kernel.org/all/20241014105514.3206191-1-ryan.robe...@arm.com/ drivers/block/virtio_blk.c | 2 +- drivers/virtio/virtio_balloon.c | 10 ++++++---- net/9p/trans_virtio.c | 4 ++-- 3 files changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 194417abc1053..8a8960b609bc9 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -899,7 +899,7 @@ static ssize_t serial_show(struct device *dev, int err; /* sysfs gives us a PAGE_SIZE buffer */ - BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES); + BUILD_BUG_ON(PAGE_SIZE_MIN < VIRTIO_BLK_ID_BYTES); buf[VIRTIO_BLK_ID_BYTES] = '\0'; err = virtblk_get_id(disk, buf); diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 54469277ca303..3818d894bd212 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -25,6 +25,7 @@ * page units. */ #define VIRTIO_BALLOON_PAGES_PER_PAGE (unsigned int)(PAGE_SIZE >> VIRTIO_BALLOON_PFN_SHIFT) +#define VIRTIO_BALLOON_PAGES_PER_PAGE_MAX (unsigned int)(PAGE_SIZE_MAX >> VIRTIO_BALLOON_PFN_SHIFT) #define VIRTIO_BALLOON_ARRAY_PFNS_MAX 256 /* Maximum number of (4k) pages to deflate on OOM notifications. */ #define VIRTIO_BALLOON_OOM_NR_PAGES 256 @@ -138,7 +139,7 @@ static u32 page_to_balloon_pfn(struct page *page) { unsigned long pfn = page_to_pfn(page); - BUILD_BUG_ON(PAGE_SHIFT < VIRTIO_BALLOON_PFN_SHIFT); + BUILD_BUG_ON(PAGE_SHIFT_MIN < VIRTIO_BALLOON_PFN_SHIFT); /* Convert pfn from Linux page size to balloon page size. */ return pfn * VIRTIO_BALLOON_PAGES_PER_PAGE; } @@ -228,7 +229,7 @@ static void set_page_pfns(struct virtio_balloon *vb, { unsigned int i; - BUILD_BUG_ON(VIRTIO_BALLOON_PAGES_PER_PAGE > VIRTIO_BALLOON_ARRAY_PFNS_MAX); + BUILD_BUG_ON(VIRTIO_BALLOON_PAGES_PER_PAGE_MAX > VIRTIO_BALLOON_ARRAY_PFNS_MAX); /* * Set balloon pfns pointing at this page. @@ -1042,8 +1043,9 @@ static int virtballoon_probe(struct virtio_device *vdev) * host's base page size. However, it needs more work to report * that value. The hard-coded order would be fine currently. */ -#if defined(CONFIG_ARM64) && defined(CONFIG_ARM64_64K_PAGES) - vb->pr_dev_info.order = 5; +#if defined(CONFIG_ARM64) + if (PAGE_SIZE == SZ_64K) + vb->pr_dev_info.order = 5; #endif err = page_reporting_register(&vb->pr_dev_info); diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index 0b8086f58ad55..25b8253011cec 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -786,7 +786,7 @@ static struct virtio_driver p9_virtio_drv = { .remove = p9_virtio_remove, }; -static struct p9_trans_module p9_virtio_trans = { +static DEFINE_GLOBAL_PAGE_SIZE_VAR(struct p9_trans_module, p9_virtio_trans, { .name = "virtio", .create = p9_virtio_create, .close = p9_virtio_close, @@ -804,7 +804,7 @@ static struct p9_trans_module p9_virtio_trans = { .pooled_rbuffers = false, .def = 1, .owner = THIS_MODULE, -}; +}); /* The standard init function */ static int __init p9_virtio_init(void) -- 2.43.0
