sata_sil24: fix sg table sizing
sil24 unnecessarily used LIBATA_MAX_PRD and ATAPI sg table was short
by one entry which might cause very obscure problems. This patch
updates sg table sizing such that
* One full page is used for PRB + sg table. On 4k page,
this results in 253 sg's.
* Make ATAPI sg block properly sized.
* Make build fail if command block size doesn't equal PAGE_SIZE.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c
index 187dcb0..96fd526 100644
--- a/drivers/ata/sata_sil24.c
+++ b/drivers/ata/sata_sil24.c
@@ -63,6 +63,21 @@
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)
*/
@@ -247,13 +262,13 @@
struct sil24_ata_block {
struct sil24_prb prb;
- struct sil24_sge sge[LIBATA_MAX_PRD];
+ struct sil24_sge sge[SIL24_MAX_SGE];
};
struct sil24_atapi_block {
struct sil24_prb prb;
u8 cdb[16];
- struct sil24_sge sge[LIBATA_MAX_PRD - 1];
+ struct sil24_sge sge[SIL24_MAX_SGE];
};
union sil24_cmd_block {
@@ -378,7 +393,7 @@
.change_queue_depth = ata_scsi_change_queue_depth,
.can_queue = SIL24_MAX_CMDS,
.this_id = ATA_SHT_THIS_ID,
- .sg_tablesize = LIBATA_MAX_PRD,
+ .sg_tablesize = SIL24_MAX_SGE,
.cmd_per_lun = ATA_SHT_CMD_PER_LUN,
.emulated = ATA_SHT_EMULATED,
.use_clustering = ATA_SHT_USE_CLUSTERING,
@@ -1284,6 +1299,7 @@
static int sil24_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
{
+ extern int __MARKER__sil24_cmd_block_is_sized_wrongly;
static int printed_version;
struct ata_port_info pi = sil24_port_info[ent->driver_data];
const struct ata_port_info *ppi[] = { &pi, NULL };
@@ -1292,6 +1308,10 @@
int i, 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;
+
if (!printed_version++)
dev_printk(KERN_DEBUG, &pdev->dev, "version " DRV_VERSION "\n");