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. Convert "struct sil24_ata_block" and "struct sil24_atapi_block" to use a flexible array member for their sge[] array. The previous static size of SIL24_MAX_SGE depends on PAGE_SIZE so doesn't work for boot-time page size. 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.roberts@xxxxxxx> --- ***NOTE*** Any confused maintainers may want to read the cover note here for context: https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@xxxxxxx/ drivers/ata/sata_sil24.c | 46 +++++++++++++++++++--------------------- 1 file changed, 22 insertions(+), 24 deletions(-) diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c index 72c03cbdaff43..85c6382976626 100644 --- a/drivers/ata/sata_sil24.c +++ b/drivers/ata/sata_sil24.c @@ -42,26 +42,25 @@ struct sil24_sge { __le32 flags; }; +/* + * sil24 fetches in chunks of 64bytes. The first block + * contains the PRB and two SGEs. From the second block, it's + * consisted of four SGEs and called SGT. Calculate the + * number of SGTs that fit into one page. + */ +#define SIL24_PRB_SZ (sizeof(struct sil24_prb) + 2 * sizeof(struct sil24_sge)) +#define SIL24_MAX_SGT ((PAGE_SIZE - SIL24_PRB_SZ) / (4 * sizeof(struct sil24_sge))) + +/* + * This will give us one unused SGEs for ATA. This extra SGE + * will be used to store CDB for ATAPI devices. + */ +#define SIL24_MAX_SGE (4 * SIL24_MAX_SGT + 1) enum { SIL24_HOST_BAR = 0, SIL24_PORT_BAR = 2, - /* sil24 fetches in chunks of 64bytes. The first block - * contains the PRB and two SGEs. From the second block, it's - * consisted of four SGEs and called SGT. Calculate the - * number of SGTs that fit into one page. - */ - SIL24_PRB_SZ = sizeof(struct sil24_prb) - + 2 * sizeof(struct sil24_sge), - SIL24_MAX_SGT = (PAGE_SIZE - SIL24_PRB_SZ) - / (4 * sizeof(struct sil24_sge)), - - /* This will give us one unused SGEs for ATA. This extra SGE - * will be used to store CDB for ATAPI devices. - */ - SIL24_MAX_SGE = 4 * SIL24_MAX_SGT + 1, - /* * Global controller registers (128 bytes @ BAR0) */ @@ -244,13 +243,13 @@ enum { struct sil24_ata_block { struct sil24_prb prb; - struct sil24_sge sge[SIL24_MAX_SGE]; + struct sil24_sge sge[]; }; struct sil24_atapi_block { struct sil24_prb prb; u8 cdb[16]; - struct sil24_sge sge[SIL24_MAX_SGE]; + struct sil24_sge sge[]; }; union sil24_cmd_block { @@ -373,7 +372,7 @@ static struct pci_driver sil24_pci_driver = { #endif }; -static const struct scsi_host_template sil24_sht = { +static DEFINE_GLOBAL_PAGE_SIZE_VAR_CONST(struct scsi_host_template, sil24_sht, { __ATA_BASE_SHT(DRV_NAME), .can_queue = SIL24_MAX_CMDS, .sg_tablesize = SIL24_MAX_SGE, @@ -382,7 +381,7 @@ static const struct scsi_host_template sil24_sht = { .sdev_groups = ata_ncq_sdev_groups, .change_queue_depth = ata_scsi_change_queue_depth, .device_configure = ata_scsi_device_configure -}; +}); static struct ata_port_operations sil24_ops = { .inherits = &sata_pmp_port_ops, @@ -1193,7 +1192,7 @@ static int sil24_port_start(struct ata_port *ap) struct device *dev = ap->host->dev; struct sil24_port_priv *pp; union sil24_cmd_block *cb; - size_t cb_size = sizeof(*cb) * SIL24_MAX_CMDS; + size_t cb_size = PAGE_SIZE * SIL24_MAX_CMDS; dma_addr_t cb_dma; pp = devm_kzalloc(dev, sizeof(*pp), GFP_KERNEL); @@ -1258,7 +1257,6 @@ static void sil24_init_controller(struct ata_host *host) static int sil24_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) { - extern int __MARKER__sil24_cmd_block_is_sized_wrongly; struct ata_port_info pi = sil24_port_info[ent->driver_data]; const struct ata_port_info *ppi[] = { &pi, NULL }; void __iomem * const *iomap; @@ -1266,9 +1264,9 @@ static int sil24_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) int rc; u32 tmp; - /* cause link error if sil24_cmd_block is sized wrongly */ - if (sizeof(union sil24_cmd_block) != PAGE_SIZE) - __MARKER__sil24_cmd_block_is_sized_wrongly = 1; + /* union sil24_cmd_block must be PAGE_SIZE */ + BUG_ON(struct_size_t(struct sil24_atapi_block, sge, SIL24_MAX_SGE) != PAGE_SIZE); + BUG_ON(struct_size_t(struct sil24_ata_block, sge, SIL24_MAX_SGE) > PAGE_SIZE); ata_print_version_once(&pdev->dev, DRV_VERSION); -- 2.43.0
