Merge tag 'ata-6.11-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/libata/linux

Pull ata fixes from Damien Le Moal:

 - Fix the max segment size and max number of segments supported by the
   pata_macio driver to fix issues with BIO splitting leading to an
   overflow of the adapter DMA table (from Michael)

 - Related to the previous fix, change BUG_ON() calls for incorrect
   command buffer segmentation into WARN_ON() and an error return (from
   Michael)

* tag 'ata-6.11-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/libata/linux:
  ata: pata_macio: Use WARN instead of BUG
  ata: pata_macio: Fix DMA table overflow

Author: torvalds

drivers/ata/pata_macio.c

@@ -208,6 +208,19 @@ static const char* macio_ata_names[] = {
 /* Don't let a DMA segment go all the way to 64K */
 #define MAX_DBDMA_SEG		0xff00
 
+#ifdef CONFIG_PAGE_SIZE_64KB
+/*
+ * The SCSI core requires the segment size to cover at least a page, so
+ * for 64K page size kernels it must be at least 64K. However the
+ * hardware can't handle 64K, so pata_macio_qc_prep() will split large
+ * requests. To handle the split requests the tablesize must be halved.
+ */
+#define PATA_MACIO_MAX_SEGMENT_SIZE	SZ_64K
+#define PATA_MACIO_SG_TABLESIZE		(MAX_DCMDS / 2)
+#else
+#define PATA_MACIO_MAX_SEGMENT_SIZE	MAX_DBDMA_SEG
+#define PATA_MACIO_SG_TABLESIZE		MAX_DCMDS
+#endif
 
 /*
  * Wait 1s for disk to answer on IDE bus after a hard reset
@@ -541,7 +554,8 @@ static enum ata_completion_errors pata_macio_qc_prep(struct ata_queued_cmd *qc)
 
 		while (sg_len) {
 			/* table overflow should never happen */
-			BUG_ON (pi++ >= MAX_DCMDS);
+			if (WARN_ON_ONCE(pi >= MAX_DCMDS))
+				return AC_ERR_SYSTEM;
 
 			len = (sg_len < MAX_DBDMA_SEG) ? sg_len : MAX_DBDMA_SEG;
 			table->command = cpu_to_le16(write ? OUTPUT_MORE: INPUT_MORE);
@@ -553,11 +567,13 @@ static enum ata_completion_errors pata_macio_qc_prep(struct ata_queued_cmd *qc)
 			addr += len;
 			sg_len -= len;
 			++table;
+			++pi;
 		}
 	}
 
 	/* Should never happen according to Tejun */
-	BUG_ON(!pi);
+	if (WARN_ON_ONCE(!pi))
+		return AC_ERR_SYSTEM;
 
 	/* Convert the last command to an input/output */
 	table--;
@@ -912,16 +928,10 @@ static int pata_macio_do_resume(struct pata_macio_priv *priv)
 
 static const struct scsi_host_template pata_macio_sht = {
 	__ATA_BASE_SHT(DRV_NAME),
-	.sg_tablesize		= MAX_DCMDS,
+	.sg_tablesize		= PATA_MACIO_SG_TABLESIZE,
 	/* We may not need that strict one */
 	.dma_boundary		= ATA_DMA_BOUNDARY,
-	/*
-	 * The SCSI core requires the segment size to cover at least a page, so
-	 * for 64K page size kernels this must be at least 64K. However the
-	 * hardware can't handle 64K, so pata_macio_qc_prep() will split large
-	 * requests.
-	 */
-	.max_segment_size	= SZ_64K,
+	.max_segment_size	= PATA_MACIO_MAX_SEGMENT_SIZE,
 	.device_configure	= pata_macio_device_configure,
 	.sdev_groups		= ata_common_sdev_groups,
 	.can_queue		= ATA_DEF_QUEUE,