libata incorrectly passes NULL arguments to sg_set_buf, which
crashes on powerpc64 when looking for the corresponding mem_section.
This introduces a new ata_exec_nodma() wrapper that takes no buffer
arguments and does not call sg_set_buf either. In order to make it
easier to detect this sort of problem, it also adds a WARN_ON(!buf)
to sg_set_buf() so we get a log message even platforms without
sparsemem.
Signed-off-by: Arnd Bergmann <arnd.bergmann@xxxxxxxxxx>
Index: linux-2.6/drivers/ata/libata-core.c
===================================================================
--- linux-2.6.orig/drivers/ata/libata-core.c
+++ linux-2.6/drivers/ata/libata-core.c
@@ -1332,7 +1332,7 @@ unsigned ata_exec_internal_sg(struct ata
}
/**
- * ata_exec_internal_sg - execute libata internal command
+ * ata_exec_internal - execute libata internal command
* @dev: Device to which the command is sent
* @tf: Taskfile registers for the command and the result
* @cdb: CDB for packet command
@@ -1361,6 +1361,25 @@ unsigned ata_exec_internal(struct ata_de
}
/**
+ * ata_exec_nodma - execute libata internal command
+ * @dev: Device to which the command is sent
+ * @tf: Taskfile registers for the command and the result
+ *
+ * Wrapper around ata_exec_internal_sg() which takes no
+ * data buffer.
+ *
+ * LOCKING:
+ * None. Should be called with kernel context, might sleep.
+ *
+ * RETURNS:
+ * Zero on success, AC_ERR_* mask on failure
+ */
+static unsigned ata_exec_nodma(struct ata_device *dev, struct ata_taskfile *tf)
+{
+ return ata_exec_internal_sg(dev, tf, NULL, DMA_NONE, NULL, 0);
+}
+
+/**
* ata_do_simple_cmd - execute simple internal command
* @dev: Device to which the command is sent
* @cmd: Opcode to execute
@@ -1384,7 +1403,7 @@ unsigned int ata_do_simple_cmd(struct at
tf.flags |= ATA_TFLAG_DEVICE;
tf.protocol = ATA_PROT_NODATA;
- return ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0);
+ return ata_exec_nodma(dev, &tf);
}
/**
@@ -3475,7 +3494,7 @@ static unsigned int ata_dev_set_xfermode
tf.protocol = ATA_PROT_NODATA;
tf.nsect = dev->xfer_mode;
- err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0);
+ err_mask = ata_exec_nodma(dev, &tf);
DPRINTK("EXIT, err_mask=%x\n", err_mask);
return err_mask;
@@ -3513,7 +3532,7 @@ static unsigned int ata_dev_init_params(
tf.nsect = sectors;
tf.device |= (heads - 1) & 0x0f; /* max head = num. of heads - 1 */
- err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0);
+ err_mask = ata_exec_nodma(dev, &tf);
DPRINTK("EXIT, err_mask=%x\n", err_mask);
return err_mask;
Index: linux-2.6/include/linux/scatterlist.h
===================================================================
--- linux-2.6.orig/include/linux/scatterlist.h
+++ linux-2.6/include/linux/scatterlist.h
@@ -8,6 +8,8 @@
static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
unsigned int buflen)
{
+ WARN_ON(!buf); /* virt_to_page(NULL) crashes with sparsemem */
+
sg->page = virt_to_page(buf);
sg->offset = offset_in_page(buf);
sg->length = buflen;
-
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