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authorTejun Heo <htejun@gmail.com>2007-11-22 18:46:57 +0900
committerJeff Garzik <jeff@garzik.org>2007-11-23 19:23:55 -0500
commit93e2618e0cee1f5b5a4cfc1b7521939318dbf5bb (patch)
treee535579b3e39c603f81e0144dbf744d0204c6975 /drivers/ata/sata_sil24.c
parent0706efd61edfcf958c2c19669aa65c2180ec3ba0 (diff)
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>
Diffstat (limited to 'drivers/ata/sata_sil24.c')
-rw-r--r--drivers/ata/sata_sil24.c26
1 files changed, 23 insertions, 3 deletions
diff --git a/drivers/ata/sata_sil24.c b/drivers/ata/sata_sil24.c
index 187dcb02c681..96fd5260446d 100644
--- a/drivers/ata/sata_sil24.c
+++ b/drivers/ata/sata_sil24.c
@@ -63,6 +63,21 @@ 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)
*/
@@ -247,13 +262,13 @@ enum {
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 @@ static struct scsi_host_template sil24_sht = {
.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 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;
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 @@ static int sil24_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
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");